WO2022255130A1 - Heat conductive sheet, and device equipped with heat conductive sheet - Google Patents

Heat conductive sheet, and device equipped with heat conductive sheet Download PDF

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Publication number
WO2022255130A1
WO2022255130A1 PCT/JP2022/020969 JP2022020969W WO2022255130A1 WO 2022255130 A1 WO2022255130 A1 WO 2022255130A1 JP 2022020969 W JP2022020969 W JP 2022020969W WO 2022255130 A1 WO2022255130 A1 WO 2022255130A1
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thermally conductive
conductive layer
inorganic particles
heat conductive
conductive inorganic
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PCT/JP2022/020969
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French (fr)
Japanese (ja)
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秀樹 冨澤
優介 畠中
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富士フイルム株式会社
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Priority to JP2023525729A priority Critical patent/JPWO2022255130A1/ja
Publication of WO2022255130A1 publication Critical patent/WO2022255130A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/38—Layered products comprising a layer of synthetic resin comprising epoxy resins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/10—Metal compounds
    • C08K3/105—Compounds containing metals of Groups 1 to 3 or of Groups 11 to 13 of the Periodic Table
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/13—Phenols; Phenolates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3412—Heterocyclic compounds having nitrogen in the ring having one nitrogen atom in the ring
    • C08K5/3415—Five-membered rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L35/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C08L61/04—Condensation polymers of aldehydes or ketones with phenols only
    • C08L61/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon

Definitions

  • the present invention relates to a thermally conductive sheet and a device with a thermally conductive sheet.
  • Patent Literature 1 discloses a thermally conductive sheet having multiple layers.
  • the present inventors have studied the heat conductive sheet as described in Patent Document 1 and the like, and found that when the heat conductive sheet is bonded to an object to be bonded at a low pressure (for example, 5 MPa or less), heat It has been found that there is room for improvement in the adhesion of the conductive sheet to the object to be bonded. Moreover, the thermally conductive sheet is also required to exhibit excellent thermal conductivity after the lamination.
  • an object of the present invention is to provide a thermally conductive sheet that exhibits excellent adhesion to an object to be bonded when bonded to the object to be bonded at a low pressure, and exhibits excellent thermal conductivity after bonding.
  • Another object of the present invention is to provide a device with a thermally conductive sheet.
  • a first thermally conductive layer having two main surfaces; a second heat conductive layer disposed only on one of the two main surfaces of the first heat conductive layer; The average film thickness of the first thermally conductive layer is greater than the average film thickness of the second thermally conductive layer,
  • the first thermally conductive layer contains first thermally conductive inorganic particles,
  • the second thermally conductive layer contains second thermally conductive inorganic particles and a curable compound,
  • the content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer,
  • the second thermally conductive inorganic particles in the second thermally conductive layer are aggregated boron nitride and have an average aspect ratio of 1.0 to 1.6, and a thermally conductive inorganic material different from the aggregated boron nitride a particle X, and
  • the heat conductive sheet wherein
  • At least one of the first thermally conductive layer and the second thermally conductive layer further comprises a surface modifier; According to any one of [1] to [9], wherein the aggregated boron nitride constitutes surface-modified aggregated boron nitride together with the surface modifier adsorbed on the surface of the aggregated boron nitride.
  • thermal conductive sheet [11] A device with a thermally conductive sheet, comprising a device and the thermally conductive sheet according to any one of [1] to [10] disposed on the device.
  • the heat conductive sheet which is excellent in the adhesiveness with respect to a to-be-bonded material when it is bonded to a to-be-bonded material at a low pressure, and shows the excellent thermal conductivity after bonding can be provided.
  • a device with a thermally conductive sheet can be provided.
  • FIG. 1 is a schematic diagram showing an example of a semiconductor module
  • FIG. 1 is a schematic diagram showing an example of a semiconductor module
  • FIG. 1 is a schematic diagram showing an example of a semiconductor module
  • FIG. 1 is a schematic diagram showing an example of a semiconductor module
  • FIG. 1 is a schematic diagram showing an example of a semiconductor module
  • a numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
  • (meth)acryloyl group means “either one or both of an acryloyl group and a methacryloyl group”.
  • the acid anhydride group may be either a monovalent group or a divalent group.
  • the acid anhydride group represents a monovalent group, it includes a substituent obtained by removing any hydrogen atom from acid anhydrides such as maleic anhydride, phthalic anhydride, pyromellitic anhydride and trimellitic anhydride.
  • the acid anhydride group represents a divalent group, it means a group represented by *--CO--O--CO--*. * represents a binding position.
  • the bonding direction of the divalent groups (eg, --COO--, etc.) indicated is not particularly limited unless otherwise specified.
  • the above compounds are "X-O-CO-Z" and "X-CO-O-Z" It may be any of
  • substituents and the like for which substitution or non-substitution is not specified may have further substituents, if possible, to the extent that the intended effect is not impaired.
  • alkyl group means a substituted or unsubstituted alkyl group (an alkyl group that may have a substituent) within a range that does not impair the intended effect.
  • the type of substituent, the position of the substituent, and the number of substituents in the case of "optionally having a substituent” are not particularly limited. Examples of the number of substituents include one and two or more.
  • the types of substituents are not particularly limited, and examples thereof include halogen atoms and alkyl groups. As used herein, halogen atoms include, for example, chlorine, fluorine, bromine and iodine atoms.
  • the heat conductive sheet of the present invention is a first thermally conductive layer having two main surfaces; a second thermally conductive layer disposed only on one of the two major surfaces of the first thermally conductive layer;
  • the average film thickness of the first thermally conductive layer is greater than the average film thickness of the second thermally conductive layer
  • the first thermally conductive layer comprises first thermally conductive inorganic particles
  • the second thermally conductive layer comprises second thermally conductive inorganic particles and a curable compound
  • the content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer
  • the second thermally conductive inorganic particles in the second thermally conductive layer are aggregated boron nitride, and thermally conductive inorganic particles X having an average aspect ratio of 1.0 to 1.6 and different from aggregated boron nitride. , including The content of
  • a feature of the thermally conductive sheet of the present invention is that it has a first thermally conductive layer and a second thermally conductive layer.
  • the second thermally conductive layer which is in contact with the object to be laminated, contains not only aggregated boron nitride exhibiting high thermal conductivity, but also thermal conductivity. Since it contains the inorganic particles X, it is also excellent in adhesion to the object to be bonded. Since the first thermally conductive layer contains the first thermally conductive inorganic particles, it exhibits high thermal conductivity. It is presumed that having such two layers provides excellent thermal conductivity and excellent adhesion.
  • the effect of at least one of thermal conductivity and adhesion is more excellent, the effect of the present invention is also said to be more excellent.
  • the heat conductive sheet 10 shown in FIG. 1 has a first heat conductive layer 12 having two main surfaces and a second heat conductive layer 14 arranged on one main surface of the first heat conductive layer 12 . It is arranged only on one main surface of the two main surfaces of the first thermally conductive layer. In other words, the second heat conductive layer is not arranged on the other main surface of the first heat conductive layer 12 .
  • the first thermally conductive layer 12 includes first thermally conductive inorganic particles 16, and the second thermally conductive layer 14 includes second thermally conductive inorganic particles 18 including aggregated boron nitride 20 and thermally conductive inorganic particles X22.
  • the thermally conductive sheet may have other members in addition to the first thermally conductive layer 12 and the second thermally conductive layer 14 .
  • Other members include, for example, a base material to be described later.
  • at least one of the first thermally conductive layer and the second thermally conductive layer further contains a surface modifier,
  • the aggregated boron nitride, together with the surface modifier adsorbed onto the surface of the aggregated boron nitride constitutes a surface-modified aggregated boron nitride. Details will be described later.
  • the members included in the heat conductive sheet are detailed below.
  • the thermally conductive sheet has a first thermally conductive layer with two main surfaces.
  • the first thermally conductive layer is not particularly limited as long as it contains the first thermally conductive inorganic particles.
  • the first thermally conductive layer preferably contains first thermally conductive inorganic particles and a curable compound.
  • the first thermally conductive layer contains first thermally conductive inorganic particles.
  • Examples of the shape of the first thermally conductive inorganic particles include rice grain-like, spherical, cubic, spindle-like, scale-like, aggregated and irregular shapes.
  • Examples of the first thermally conductive inorganic particles include inorganic nitrides and inorganic oxides.
  • inorganic nitrides include boron nitride (BN), carbon nitride ( C3N4 ), silicon nitride ( Si3N4 ), gallium nitride ( GaN ), indium nitride (InN), aluminum nitride ( AlN ), Chromium nitride ( Cr2N ), copper nitride (Cu3N), iron nitride ( Fe4N ), iron nitride ( Fe3N ) , lanthanum nitride (LaN), lithium nitride ( Li3N ), magnesium nitride (Mg 3N 2 ), molybdenum nitride (Mo 2 N), niobium nitride (NbN), tantalum nitride (TaN), titanium nitride (TiN
  • the inorganic nitride preferably contains aluminum atoms, boron atoms or silicon atoms, more preferably aluminum nitride, boron nitride or silicon nitride, still more preferably aluminum nitride or boron nitride, and boron nitride. is particularly preferred.
  • Boron nitride includes, for example, cubic boron nitride and hexagonal boron nitride.
  • the shape of boron nitride may be spherical, tabular, scaly, or aggregated, and aggregated boron nitride is preferred.
  • Aggregated boron nitride is secondary aggregated particles formed by aggregating primary particles of boron nitride (for example, scaly boron nitride).
  • inorganic oxides examples include zirconium oxide (ZrO 2 ), titanium oxide (TiO 2 ), silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), iron oxide (e.g., Fe 2 O 3 , FeO and Fe3O4 , etc. ), copper oxides (e.g., CuO and Cu2O , etc.), zinc oxide (ZnO), yttrium oxide (Y2O3), niobium oxide (Nb2O5 ) , molybdenum oxide ( MoO3 ) , indium oxide ( In2O3 , In2O ), tin oxide ( SnO2 ), tantalum oxide ( Ta2O5 ), tungsten oxide ( e.g.
  • the inorganic oxide may be an inorganic oxide that is produced by oxidizing an inorganic non-oxide over time.
  • the inorganic oxide is preferably titanium oxide, aluminum oxide or zinc oxide, more preferably aluminum oxide.
  • the first thermally conductive inorganic particles may be surface-treated.
  • the above surface treatment is different from surface modification using a surface modifier, which will be described later.
  • a functional group is introduced to the particle surface of the first thermally conductive inorganic particles, making it easier to interact with the first thermally conductive inorganic particles and the curable compound, etc., and improving the thermal conductivity of the thermally conductive sheet. It is presumed that the properties, peel strength, etc. are further improved.
  • Examples of surface treatment include plasma treatment (e.g., vacuum plasma treatment, atmospheric pressure plasma treatment, aqua plasma treatment, etc.), ultraviolet irradiation treatment, corona treatment, electron beam irradiation treatment, ozone treatment, baking treatment, flame treatment, and oxidizing agents. processing.
  • the oxidizing agent treatment may be carried out under either acidic conditions (eg, pH 6 or lower) or basic conditions (eg, pH 12 or higher).
  • the first thermally conductive layer includes a surface modifier, and the first thermally conductive inorganic particles are surface-modified first thermally conductive inorganic particles together with the surface modifier adsorbed on the surface of the first thermally conductive inorganic particles. preferably configured.
  • surface modification using a surface treatment agent means a state in which the surface treatment agent is adsorbed on at least part of the surface of the first thermally conductive inorganic particles. The form of adsorption is not particularly limited as long as it is in a bound state.
  • the surface modification includes a state in which an organic group obtained by partly desorbing the surface treatment agent is bonded to the surface of the first thermally conductive inorganic particles.
  • the bond may be any bond such as covalent bond, coordinate bond, ionic bond, hydrogen bond, van der Waals bond, and metallic bond.
  • the surface modification may be such as to form a monomolecular film on at least part of the surface.
  • a monolayer is a monolayer film formed by chemisorption of a surface treatment agent and is known as a Self-Assembled MonoLayer (SAM).
  • SAM Self-Assembled MonoLayer
  • the surface modification using the surface treatment agent may be applied to only a part of the surface of the first thermally conductive inorganic particles or to the entire surface.
  • surface-modified first thermally conductive inorganic particles are first thermally conductive inorganic particles that have been surface-modified with a surface modifier. That is, the surface-modified first thermally conductive inorganic particles are a material containing the first thermally conductive inorganic particles and the surface modifier adsorbed on the surfaces of the first thermally conductive inorganic particles.
  • the first thermally conductive inorganic particles together with the surface modifier adsorbed on the surfaces of the first thermally conductive inorganic particles can constitute the surface-modified first thermally conductive inorganic particles. preferable.
  • the first thermally conductive layer may include the first thermally conductive inorganic particles and the surface modifier by including the surface-modified first thermally conductive inorganic particles in the first thermally conductive layer.
  • Some or all of the first thermally conductive inorganic particles in the first thermally conductive layer may constitute surface-modified first thermally conductive inorganic particles together with a surface modifier.
  • some of the first thermally conductive inorganic particles are surface-modified first thermally conductive inorganic particles, and at the same time, they are not involved in the formation of the surface-modified first thermally conductive inorganic particles.
  • First thermally conductive inorganic particles may be present.
  • Part or all of the surface modifier in the first thermally conductive layer may constitute the surface-modified first thermally conductive inorganic particles together with the first thermally conductive inorganic particles.
  • part of the surface modifier in the first thermally conductive layer constitutes the surface-modified first thermally conductive inorganic particles, and at the same time, there is a surface modifier that does not participate in the formation of the surface-modified first thermally conductive inorganic particles. May be present.
  • the first thermally conductive layer is a surface-modified inorganic material in which the first thermally conductive inorganic particles constituting the surface-modified first thermally conductive inorganic particles are inorganic nitrides (preferably boron nitride or aggregated boron nitride). It preferably contains a nitride (preferably surface-modified boron nitride). Part or all of the inorganic nitride (preferably boron nitride) in the first thermally conductive layer may constitute a surface-modified inorganic nitride (preferably surface-modified boron nitride) together with a surface modifier.
  • inorganic nitride preferably boron nitride or aggregated boron nitride
  • Part or all of the inorganic nitride (preferably boron nitride) in the first thermally conductive layer may constitute a surface-modified inorganic nitride
  • the first thermally conductive layer is a surface-modified inorganic oxide (preferably a surface-modified aluminum).
  • the inorganic oxide (preferably aluminum oxide) in the first thermally conductive layer may constitute a surface-modified inorganic oxide (preferably surface-modified aluminum oxide) together with the surface modifier.
  • the surface-modified first thermally conductive inorganic particles can be formed, for example, by contacting the first thermally conductive inorganic particles with a surface modifier.
  • a surface modifier for example, in the process of forming the first thermally conductive layer described later, the first thermally conductive inorganic particles, the surface modifier, and other components constituting the composition are mixed to produce the first thermally conductive layer.
  • Surface-modified first thermally conductive inorganic particles may be formed.
  • the first thermally conductive inorganic particles and a surface modifier are mixed in advance in a solvent to prepare a mixed liquid containing the surface-modified first thermally conductive inorganic particles, and from the mixed liquid,
  • the surface-modified first thermally conductive inorganic particles may be separated by means such as filtering to obtain the separated surface-modified first thermally conductive inorganic particles.
  • the separated surface-modified first thermally conductive inorganic particles may be used to prepare a composition for forming a first thermally conductive layer, which will be described later, and the composition may be used to form the first thermally conductive layer.
  • surface modifier for example, conventionally known surface modifiers such as carboxylic acids such as long-chain alkyl fatty acids, organic phosphonic acids, organic phosphoric acid esters, and organic silane molecules (eg, silane coupling agents, etc.) can be used. Further, for example, surface modifiers described in JP-A-2009-502529, JP-A-2001-192500 and JP-A-4694929 may be used.
  • the silane coupling agent is, for example, a compound having a hydrolyzable group directly bonded to the Si atom.
  • the hydrolyzable group include alkoxy groups (preferably having 1 to 10 carbon atoms) and halogen atoms such as chlorine atoms.
  • the number of hydrolyzable groups directly bonded to Si atoms in the silane coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, and it is, for example, 10,000 or less.
  • the silane coupling agent also preferably has a reactive group.
  • the reactive groups include epoxy groups, oxetanyl groups, vinyl groups, (meth)acryl groups, styryl groups, amino groups, isocyanate groups, mercapto groups, and acid anhydride groups.
  • the number of reactive groups possessed by the silane coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, and it is, for example, 10,000 or less.
  • Silane coupling agents include, for example, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, Methoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptotriethoxysilane, and 3-ureidopropyltriethoxysilane.
  • the silane coupling agent may be a polyfunctional silane coupling agent. Examples thereof include the X-12 series of silane coupling agents (eg, X-12-1048, X-12-1050, X-12-981S and X-12-984S, manufactured by Shin-Etsu Chemical Co., Ltd.).
  • the surface modifiers may be used singly or in combination of two or more.
  • the content of the surface modifier is preferably 0.005 to 5% by mass, more preferably 0.05 to 3% by mass, based on the total mass of the first thermally conductive layer. more preferred.
  • the content of the surface modifier is preferably 0.01 to 10% by mass, more preferably 0.10 to 5% by mass, with respect to all the first thermally conductive inorganic particles. is more preferred.
  • the mass ratio of the surface modifier to the first thermally conductive inorganic particles in the surface-modified first thermally conductive inorganic particles is preferably 0.00001 to 0.5, more preferably 0.0001 to 0.1.
  • the content of the surface-modified first thermally conductive inorganic particles is 50.0 to 80.0 with respect to the total area of the first thermally conductive layer. 0% by volume is preferred, 55.0 to 75.0% by volume is more preferred, and 60.0 to 70.0% by volume is even more preferred.
  • the first thermally conductive layer contains a surface-modified nitride (preferably surface-modified boron nitride)
  • the content of the surface-modified nitride is on the other hand, 10 to 100% by mass is preferable, 40 to 100% by mass is more preferable, and 60 to 100% by mass is even more preferable.
  • the average particle size of the first thermally conductive inorganic particles is 1.0. ⁇ 300.0 ⁇ m is preferable, 5.0 to 100.0 ⁇ m is more preferable, and 10.0 to 80.0 ⁇ m is even more preferable.
  • the average particle size of the first thermally conductive inorganic particles is preferably 0.1 to 30.0 ⁇ m, more preferably 1.0 to 15.0 ⁇ m. 0 to 10.0 ⁇ m is more preferable, and 2.0 to 7.0 ⁇ m is particularly preferable.
  • the average particle size of the first thermally conductive inorganic particles can be measured using, for example, a scanning electron microscope (SEM) or a laser diffraction particle size distribution analyzer.
  • SEM scanning electron microscope
  • a transmission microscope HT7700 manufactured by Hitachi High-Technologies Corporation
  • the maximum length of the particle image obtained using a scanning electron microscope (Dmax: the maximum length at two points on the contour of the particle image) and the maximum vertical length (DV-max: two straight lines parallel to the maximum length
  • Dmax the maximum length at two points on the contour of the particle image
  • DV-max two straight lines parallel to the maximum length
  • the shortest length vertically connecting two straight lines when the image was sandwiched was measured, and the geometric mean value (Dmax ⁇ DV-max) 1/2 was taken as the grain size.
  • the particle size of 100 particles was measured by this method, and the arithmetic average value was taken as the average particle size of the particles.
  • the first thermally conductive inorganic particles preferably contain an inorganic nitride, more preferably contain boron nitride, contain boron nitride, and have an average aspect ratio of 1.0 to 1.6. It is more preferable not to contain organic particles X), and it is particularly preferable to consist only of boron nitride.
  • the first thermally conductive inorganic particles may be used singly or in combination of two or more.
  • the content of the first thermally conductive inorganic particles is preferably 50.0 to 80.0% by volume, more preferably 55.0 to 75.0% by volume, with respect to the total volume of the first thermally conductive layer. 0 to 70.0% by volume is more preferable.
  • the first thermally conductive layer may contain a curable compound.
  • a curable compound is a compound having a crosslinkable group.
  • crosslinkable groups include groups having ethylenically unsaturated bonds such as vinyl groups, (meth)allyl groups and (meth)acryloyl groups; cyclic ether groups such as epoxy groups and oxetane groups; phenolic hydroxy groups and methylol. hydroxy groups such as groups; carboxylic anhydride groups;
  • the curable compound may be, for example, a known compound that can be crosslinked by radicals, acids, bases and/or heat, and specific examples thereof include epoxy compounds, maleimide compounds, phenolic compounds and acid anhydrides.
  • the curable compound preferably contains one or more selected from the group consisting of epoxy compounds, maleimide compounds, phenol compounds and acid anhydrides, and one selected from the group consisting of epoxy compounds, maleimide compounds and phenol compounds. More preferably, it contains at least one selected from the group consisting of epoxy compounds and maleimide compounds.
  • An epoxy compound is a compound having one or more epoxy groups in one molecule.
  • An epoxy group is a group having one or more hydrogen atoms (preferably one hydrogen atom) removed from an oxirane ring. If possible, the epoxy group may further have a substituent (eg, a straight-chain or branched-chain alkyl group having 1 to 5 carbon atoms, etc.).
  • the number of epoxy groups possessed by the epoxy compound is preferably 2 or more, more preferably 2 to 1000, and even more preferably 2 to 40, in one molecule.
  • the molecular weight of the epoxy compound is preferably 150 or more, more preferably 300 or more.
  • the upper limit is preferably 100,000 or less, more preferably 10,000 or less.
  • the said molecular weight is a weight average molecular weight.
  • the weight average molecular weight is the weight average molecular weight obtained by gel permeation chromatography (GPC) in terms of polystyrene.
  • the epoxy group content of the epoxy compound is preferably 2.0 to 20.0 mmol/g, more preferably 5.0 to 15.0 mmol/g.
  • the said epoxy group content means the number of epoxy groups which 1g of epoxy compounds have.
  • the epoxy compound also preferably has an aromatic ring group (preferably an aromatic hydrocarbon ring group).
  • the epoxy compound may or may not exhibit liquid crystallinity. That is, the epoxy compound may be a liquid crystal compound. In other words, it may be a liquid crystal compound having an epoxy group.
  • epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, and bisphenol AD type epoxy compounds, which are glycidyl ethers of bisphenol A, F, S and AD; hydrogenated bisphenol A; type epoxy compound and hydrogenated bisphenol AD type epoxy compound; phenol novolac type glycidyl ether (phenol novolac type epoxy compound), cresol novolac type glycidyl ether (cresol novolac type epoxy compound) and bisphenol A novolac type glycidyl ether; Cyclopentadiene type glycidyl ether (dicyclopentadiene type epoxy compound); dihydroxypentadiene type glycidyl ether (dihydroxypentadiene type epoxy compound); polyhydroxybenzene type glycidyl ether such as glycidyl ether of dihydroxybenzene such as resorcinol (polyhydroxy benzene-type epoxy compounds); benzenepolycar
  • Each compound described above may have a substituent.
  • an aromatic ring group, a cycloalkane ring group and/or an alkylene group contained in each of the above compounds may be substituted with a substituent other than a glycidyl ether group, a glycidyl ester group, a diglycidylamino group and/or a diglycidylaminoalkylene group. may have.
  • the content of the epoxy compound is preferably 1.0 to 90.0% by mass, more preferably 2.0 to 50.0% by mass, and 4.0 to 20.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred.
  • the first heat conductive layer may contain a maleimide compound.
  • the first heat conductive layer has an interpenetrating network structure with respect to the polymer structure formed by the addition reaction of the maleimide compound with the phenol compound and/or the polymer structure formed by the above addition reaction with the other components in the composition. It is believed that forming a higher density polymer structure of the first thermally conductive layer can further enhance the thermal conductivity and heat resistance (Tg) of the thermally conductive sheet. In addition, since a denser polymer structure is formed in the first heat conductive layer, it is difficult for water to enter the heat conductive sheet, and hygroscopicity is suppressed.
  • a maleimide compound means a compound having one or more maleimide groups.
  • the maleimide compound is preferably a compound having one or two maleimide groups, and more preferably a compound having two maleimide groups (bismaleimide compound).
  • the number of maleimide groups possessed by the maleimide compound is 1 or more, preferably 1 to 100, more preferably 2 to 10, and still more preferably 2.
  • the maleimide compound may be either a high molecular weight compound or a low molecular weight compound.
  • the molecular weight of the maleimide compound is preferably from 100 to 3,000, more preferably from 200 to 2,000, even more preferably from 300 to 1,000.
  • the maleimide group possessed by the maleimide compound is preferably a group represented by formula (M).
  • X and Y each independently represent a hydrogen atom or a substituent.
  • substituents include known substituents (eg, alkyl group, etc.).
  • X and Y are preferably hydrogen atoms.
  • the maleimide compound is also preferably a compound having one or more (preferably 1 to 10) aromatic ring groups (eg, benzene ring group, etc.).
  • the maleimide compound is preferably a compound represented by Formula (1).
  • R 1 and R 2 each independently represent a hydrogen atom or a substituent.
  • an alkyl group is preferable.
  • the alkyl group may be linear or branched, and preferably has 1 to 10 carbon atoms.
  • R 1 and/or R 2 represent a substituent, it is also preferred that R 1 and/or R 2 are present at a position adjacent to the maleimide group on the benzene ring group.
  • R 1 and R 2 preferably represent different substituents, more preferably R 1 represents a methyl group and R 2 represents an ethyl group.
  • L 1 represents a divalent linking group.
  • the divalent linking group include an ether group (--O--), a carbonyl group (--CO--), an ester group (--COO--), and a thioether group (--S--).
  • R is a hydrogen atom or an alkyl group
  • divalent aliphatic hydrocarbon group e.g., alkylene group, cycloalkylene group, alkenylene group (—CH ⁇ CH— etc.), alkynylene groups (—C ⁇ C—, etc.
  • divalent aromatic ring groups arylene groups and heteroarylene groups
  • the number of carbon atoms in the divalent linking group represented by L 1 is preferably 1 or more, more preferably 1-100, even more preferably 3-15.
  • L 1 is preferably a group represented by “* p —(L 2 —Ar) k —* q ”.
  • * q represents the bonding position on the side directly bonded to the maleimide group
  • * p represents the bonding position on the opposite side.
  • k represents an integer of 1 or more, preferably an integer of 1 to 10, more preferably 1.
  • L 2 represents a single bond, -C(R 3 )(R 4 )-, -O- or -CO-, preferably -C(R 3 )(R 4 )-.
  • R 3 and R 4 each independently represent a hydrogen atom or a substituent, preferably an alkyl group (which may be linear or branched and has 1 to 10 carbon atoms).
  • Ar represents an arylene group.
  • the number of ring member atoms in the arylene group is preferably 6 to 15, more preferably 6.
  • the number of substituents is preferably 1-4, more preferably 1-2.
  • an alkyl group (which may be linear or branched and has 1 to 10 carbon atoms) is preferable.
  • Structures that Ar can have include, for example, structures that can have a benzene ring group bonded to R 1 and R 2 , which are clearly shown in formula (1).
  • the plurality of L 2 and the plurality of Ar may be the same or different.
  • n 1, two groups, a maleimido group and a group represented by "-(L 1 ) m -maleimido group", on the benzene ring group bonded to R 1 and R 2 are mutually ortho It may be placed at the meta-position, it may be placed at the para-position. Among others, the above two groups are preferably arranged at the meta-position or the para-position.
  • n 1
  • the divalent linking group represented by L1 has 3 to 15 carbon atoms. preferable.
  • the content of the maleimide compound is preferably 0.1 to 40.0% by mass, more preferably 1.0 to 15.0% by mass, and 5.0 to 20.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred.
  • a phenolic compound is a compound with one or more phenolic hydroxy groups.
  • the number of phenolic hydroxy groups possessed by the phenol compound is preferably 2 or more, more preferably 2-10.
  • the phenol compound preferably has a triazine skeleton. Having a triazine skeleton means that the phenol compound has one or more (preferably 1 to 5) triazine ring groups in the molecule.
  • the phenol compound is also preferably a compound represented by Formula (Z1).
  • the phenol compound preferably contains a compound represented by formula (Z1), and the phenol compound may be the compound represented by formula (Z1) itself.
  • the content of the compound represented by formula (Z1) is preferably 10 to 100% by mass, more preferably 25 to 100% by mass, and even more preferably 50 to 100% by mass, based on the total mass of the phenol compound.
  • r represents an integer of 0 or more. r is preferably an integer of 0 to 20, more preferably an integer of 0 to 10.
  • L represents a divalent organic group. Examples of the divalent organic group include a divalent aromatic ring group optionally having a substituent, a divalent aliphatic hydrocarbon group optionally having a substituent, and a substituent divalent aliphatic cyclic groups, -O-, -S-, -N(R N )- or -CO-, and groups combining these.
  • RN represents a hydrogen atom or a substituent. Examples of substituents represented by RN include straight-chain alkyl groups and branched-chain alkyl groups having 1 to 5 carbon atoms.
  • substituents which the aromatic ring group, the aliphatic hydrocarbon group and the aliphatic ring group represented by L may have include, for example, a linear alkyl group having 1 to 5 carbon atoms and a branched A chain alkyl group is mentioned.
  • R Z represents a hydrogen atom or a substituent.
  • the substituent represented by R Z is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and a linear or branched alkyl having 1 to 6 carbon atoms. groups are more preferred.
  • the ratio of R Z representing a substituent among (3+r) R Zs present is preferably 30% or more, more preferably 50% or more, and even more preferably 65% or more.
  • the upper limit is preferably 90% or less, more preferably 80% or less.
  • At least one of (3+r) R 2 Zs present in the formula (Z1) (eg, 1 to 2) may represent a hydrogen atom.
  • R z preferably R z which is a substituent
  • OH in formula (Z1) the R z (preferably R z which is a substituent) is bonded to the benzene ring group It is also preferred to be in the para position to NH.
  • phenol compound other phenol compounds may be included in addition to the above.
  • Other phenolic compounds include, for example, bisphenol A, F, S, AD, benzenepolyols such as benzenediol and benzenetriol, biphenylaralkyl-type phenolic resins, phenolic novolak resins, cresol novolak resins, aromatic hydrocarbon formaldehyde resins, modified phenolic resins.
  • dicyclopentadiene phenol addition type resin dicyclopentadiene phenol addition type resin, phenol aralkyl resin, polyhydric phenol novolac resin synthesized from polyhydric hydroxy compound and formaldehyde, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin, naphthol novolak resin, naphthol Phenol co-condensed novolac resins, naphthol cresol co-condensed novolac resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and alkoxy group-containing aromatic ring-modified novolac resins can be mentioned.
  • the molecular weight of the phenol compound is preferably 225-2000, more preferably 225-1000.
  • the said molecular weight is a weight average molecular weight.
  • the hydroxy group content of the phenol compound is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more.
  • the upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.
  • the hydroxy group content means the number of hydroxy groups (preferably phenolic hydroxy groups) possessed by 1 g of the phenol compound.
  • the phenol compound may or may not have an active hydrogen-containing group (for example, a carboxyl group) capable of polymerizing with the epoxy compound.
  • the content of active hydrogen in the phenol compound (the total content of hydrogen atoms in hydroxy groups, carboxy groups, etc.) is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more.
  • the upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.
  • composition of the present invention may contain, in addition to the phenol compound, a compound having a group capable of reacting with an epoxy compound (hereinafter also referred to as "other active hydrogen-containing compounds").
  • a compound having a group capable of reacting with an epoxy compound hereinafter also referred to as "other active hydrogen-containing compounds”
  • the mass ratio of the content of other active hydrogen-containing compounds to the content of phenolic compounds is preferably 0 to 1, more preferably 0 to 0.1. , 0 to 0.05 are more preferred.
  • the content of the phenol compound is preferably 1.0 to 90.0% by mass, more preferably 1.0 to 50.0% by mass, and 2.0 to 30.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred, and 3.0 to 10.0% by mass is particularly preferred.
  • the content of the maleimide compound is preferably 1 to 200% by mass, more preferably 5 to 100% by mass, more preferably 10 to 80% by mass, more preferably 20 to 80% by mass, based on the total content of the epoxy compound and the phenol compound. % by mass is more preferred.
  • the content of the maleimide compound is preferably 1 to 500% by mass, more preferably 20 to 300% by mass, still more preferably 50 to 200% by mass, and particularly preferably 70 to 180% by mass, relative to the content of the phenol compound. .
  • the total content of the epoxy compound and the phenol compound is preferably 3-90% by mass, more preferably 5-50% by mass, and even more preferably 7-40% by mass, relative to the total mass of the first heat conductive layer.
  • the ratio of the total number of epoxy groups contained in the epoxy compound to the number of hydroxy groups (preferably phenolic hydroxy groups) contained in the phenol compound is 3/97 to 97/3 is preferred, 30/70 to 70/30 is more preferred, 40/60 to 60/40 is even more preferred, and 45/55 to 55/45 is particularly preferred. That is, the content ratio of the phenolic compound and the epoxy compound is preferably such that the "number of epoxy groups/number of phenolic hydroxy groups" is within the above range.
  • Equivalent ratio (number of epoxy groups/activity
  • the number of hydrogen atoms) is preferably 3/97 to 97/3, more preferably 30/70 to 70/30, still more preferably 40/60 to 60/40, and particularly preferably 45/55 to 55/45.
  • the first thermally conductive layer may contain an acid anhydride.
  • An acid anhydride is a compound having one or more acid anhydride groups (groups represented by --CO--O--CO--).
  • the number of acid anhydride groups possessed by the acid anhydride is 1 or more, preferably 2 or more, and more preferably 3 or more.
  • the upper limit of the above number is, for example, 1000 or less.
  • the molecular weight of the acid anhydride (the weight average molecular weight if there is a molecular weight distribution) is preferably 100 or more, more preferably 2000 or more, and even more preferably 6000 or more.
  • the upper limit of the molecular weight is preferably 100,000 or less, more preferably 30,000 or less, and even more preferably 17,000 or less.
  • the acid anhydride may be a low-molecular-weight compound or a high-molecular-weight compound.
  • Acid anhydrides that are low-molecular-weight compounds include, for example, maleic anhydride, phthalic anhydride, pyromellitic anhydride, and trimellitic anhydride.
  • the acid anhydride which is a polymer compound
  • the acid anhydride group may be incorporated in the main chain or may be present in the side chain.
  • the acid anhydride groups contained in the repeating units are assumed to be incorporated in the main chain.
  • a commercially available product may be used as the acid anhydride.
  • Commercially available acid anhydrides include, for example, the SMA series manufactured by Tomoe Industries (XIRAN series manufactured by Polyscope Polymers BV), the OREVAC T series manufactured by Arkema, and the Alastor series manufactured by Arakawa Chemical Industries.
  • the content of the acid anhydride is preferably 0.01-40.0% by mass, more preferably 0.1-10.0% by mass, and 0.6-5. 0% by mass is more preferred.
  • the first thermally conductive layer preferably contains a curing accelerator.
  • curing accelerators include trisorthotolylphosphine, triphenylphosphine, boron trifluoride amine complex, compounds described in paragraph [0052] of JP-A-2012-067225, tetraphenylphosphonium tetraphenylborate (TPP- K), tetraphenylphosphonium tetra-p-tolylborate (TPP-MK), tetra-n-butylphosphonium laurate (TBP-LA), bis(tetra-n-butylphosphonium) pyromellitate and bis(naphthalene- Onium salt curing accelerators such as quaternary phosphonium compounds (phosphonium salts) such as 2,3-dioxy)phenyl silicate adducts.
  • the curing accelerator preferably contains a phosphorus atom-containing compound or a phosphonium salt, more preferably a phosphorus atom-containing compound.
  • the curing accelerator may be a compound having a phosphorus atom or the phosphonium salt itself.
  • the curing accelerator contains a phosphonium salt, the storage stability of the first heat conductive layer is excellent.
  • the content of the curing accelerator is preferably 0.002% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.07% by mass or more, relative to the total mass of the first heat conductive layer.
  • the upper limit is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less with respect to the total mass of the first heat conductive layer.
  • the first heat conductive layer may contain resin.
  • resins include cured products of the above-described curable compounds. Specifically, one or more selected from the group consisting of an epoxy compound and a maleimide compound and a cured product of a phenol compound can be mentioned.
  • the cured product preferably has one or more selected from the group consisting of epoxy groups and maleimide groups, and phenolic hydroxy groups.
  • the total content of the curable compound and its cured product is preferably 20-50% by volume, more preferably 25-45% by volume, and even more preferably 30-40% by volume, relative to the total volume of the first heat conductive layer.
  • the first thermally conductive layer may be a layer subjected to pressure treatment.
  • the pressure treatment removes voids and the like in the first heat conductive layer, and as a result, the thermal conductivity of the heat conductive sheet after lamination is excellent.
  • the thermally conductive sheet has a second thermally conductive layer disposed on only one of the two major surfaces of the first thermally conductive layer.
  • the second thermally conductive layer includes second thermally conductive inorganic particles and a curable compound.
  • the second thermally conductive layer contains a surface modifier, and the second thermally conductive inorganic particles are surface-modified second thermally conductive inorganic particles together with the surface modifier adsorbed on the surface of the second thermally conductive inorganic particles. preferably configured. Agglomerated boron nitride is preferable as the second thermally conductive inorganic particles constituting the surface-modified second thermally conductive inorganic particles.
  • the aggregated boron nitride, the surface modifier, and the surface-modified second thermally conductive inorganic particles are aggregated boron nitride, the surface modifier, and the surface-modified first thermally conductive inorganic particles, respectively, which the first thermally conductive inorganic particles may contain.
  • the inorganic particles it is synonymous with surface-modified inorganic particles composed of second thermally conductive inorganic particles, and the preferred embodiments are also the same.
  • the second thermally conductive inorganic particles include agglomerated boron nitride and thermally conductive inorganic particles X.
  • the thermally conductive inorganic particles X have an average aspect ratio of 1.0 to 1.6 and are thermally conductive inorganic particles different from the aggregated boron nitride.
  • Thermally conductive inorganic particles that can form the thermally conductive inorganic particles X include the inorganic particles exemplified above for the first thermally conductive inorganic particles (specifically, inorganic nitrides, inorganic oxides, etc.).
  • thermally conductive inorganic particles X for example, among the first thermally conductive inorganic particles, inorganic nitrides and inorganic oxides other than aggregated boron nitride and having an average aspect ratio of 1.0 to 1.6. Certain thermally conductive inorganic particles are included. As the thermally conductive inorganic particles X, inorganic oxides having an average aspect ratio of 1.0 to 1.6 are preferable, and aluminum oxide having an average aspect ratio of 1.0 to 1.6 is more preferable.
  • the second thermally conductive inorganic particles may contain other thermally conductive inorganic particles.
  • the other thermally conductive inorganic particles are not particularly limited as long as they are other than the aggregated boron nitride and the thermally conductive inorganic particles X.
  • the average particle size of the thermally conductive inorganic particles X is often 0.1 to 300.0 ⁇ m, preferably 1.0 to 100.0 ⁇ m, more preferably 1.0 to 15.0 ⁇ m, and 2.0 to 10 ⁇ m. 0 ⁇ m is more preferred, and 2.0 to 7.0 ⁇ m is particularly preferred.
  • the average aspect ratio of the thermally conductive inorganic particles X is 1.0 to 1.6, preferably 1.0 to 1.55, more preferably 1.0 to 1.50.
  • the average aspect ratio is obtained by measuring the major axis and minor axis of any 100 inorganic particles observed with a TEM (transmission electron microscope) or SEM (scanning electron microscope), The aspect ratio (major axis/minor axis) of each inorganic particle is calculated, and the arithmetic mean of 100 aspect ratios is obtained.
  • the major diameter of the particles means the length in the major axis direction of the particles
  • the minor diameter of the particles means the length of the particles orthogonal to the major axis direction of the particles.
  • the content of the second thermally conductive inorganic particles is 40.0 to 60.0% by volume, preferably 45.0 to 55.0% by volume, and 50.0% by volume with respect to the total volume of the second thermally conductive layer. ⁇ 55.0% by volume is more preferred.
  • the content of the second thermally conductive inorganic particles is, for example, when the second thermally conductive inorganic particles consist of aggregated boron nitride and thermally conductive inorganic particles X, the aggregated boron nitride and thermally conductive inorganic particles X means the total content of
  • the content of aggregated boron nitride is preferably 25.0 to 55.0% by volume, more preferably 30.0 to 55.0% by volume, more preferably 35.0 to 50%, relative to the total volume of the second heat conductive layer. 0 vol % is more preferred.
  • the content of the thermally conductive inorganic particles X is preferably 5.0 to 30.0% by volume, more preferably 7.5 to 27.5% by volume, and 10.0% by volume with respect to the total volume of the second thermally conductive layer. ⁇ 25.0% by volume is more preferred.
  • the volume ratio of aggregated boron nitride to thermally conductive inorganic particles X is preferably 2.5 to 10.5. 2.8 to 5.0 is more preferred.
  • the curable compound is synonymous with the curable compound that the first heat conductive layer may contain, and the preferred embodiments are also the same.
  • the second heat conductive layer may contain a cured product of a curable compound. Specifically, one or more selected from the group consisting of an epoxy compound and a maleimide compound and a cured product of a phenol compound can be mentioned.
  • the cured product preferably has one or more selected from the group consisting of epoxy groups and maleimide groups, and phenolic hydroxy groups.
  • the second heat conductive layer may contain components that the first heat conductive layer may contain (for example, a curing accelerator, etc.).
  • first thermally conductive layer and second thermally conductive layer [Relationship between first thermally conductive layer and second thermally conductive layer]
  • the first thermally conductive layer and the second thermally conductive layer satisfy requirement A and requirement B.
  • the average thickness of the first thermally conductive layer is greater than the average thickness of the second thermally conductive layer.
  • the value obtained by subtracting the average thickness of the second heat conductive layer from the average thickness of the first heat conductive layer is preferably 55 to 190 ⁇ m, more preferably 65 to 170 ⁇ m, and even more preferably 75 to 150 ⁇ m.
  • the average film thickness of the first heat conductive layer is preferably 70-250 ⁇ m, more preferably 85-225 ⁇ m, even more preferably 100-200 ⁇ m, and particularly preferably 100-150 ⁇ m.
  • the average film thickness of the second heat conductive layer is preferably 5 to 100 ⁇ m, more preferably 10 to 80 ⁇ m, even more preferably 10 to 70 ⁇ m.
  • a method for measuring the average film thickness of the first thermally conductive layer and the second thermally conductive layer for example, a method of cutting out a section of the thermally conductive sheet and observing the section with an SEM for measurement can be mentioned.
  • Examples of the method for adjusting the average film thickness of the first thermally conductive layer and the second thermally conductive layer include a method of applying an arbitrary pressure after forming the amount of each layer-forming composition and forming each layer.
  • Requirement B The content of the first thermally conductive inorganic particles in the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles in the total area of the second thermally conductive layer. There is no particular limitation as long as the content of the first thermally conductive inorganic particles relative to the total volume of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total volume of the second thermally conductive layer.
  • the value obtained by subtracting the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer from the content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is 5.0 to 65.0% by volume is preferred, 8.0 to 45.0% by volume is more preferred, and 10.0 to 25.0% by volume is even more preferred.
  • the content of each thermally conductive inorganic particle in each thermally conductive layer is as described above.
  • the thermally conductive sheet may have a base material.
  • the base material is a member that supports the heat conductive sheet, and may be finally peeled off.
  • the substrate may have either a single layer structure or a multilayer structure.
  • the shape of the substrate is preferably sheet-like.
  • Substrates include, for example, plastic materials, metal materials, and glass. Examples of plastic materials include polyesters such as polyethylene terephthalate (PET), polycarbonates, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cellulose derivatives, and silicones.
  • Metal materials include, for example, copper and aluminum.
  • the substrate is preferably surface-treated. Surface treatments include, for example, release treatment and roughening treatment.
  • the film thickness of the substrate is preferably 50-300 ⁇ m, more preferably 75-250 ⁇ m.
  • the heat conductive sheet is preferably insulating (electrically insulating).
  • the volume resistivity of the heat conductive sheet at 23° C. and 65% relative humidity is preferably 10 10 ⁇ cm or more, more preferably 10 12 ⁇ cm or more, and still more preferably 10 14 ⁇ cm or more.
  • the upper limit is preferably 10 18 ⁇ cm or less.
  • the thermal conductivity of the thermally conductive sheet is preferably isotropic.
  • the method for producing a thermally conductive sheet includes a first thermally conductive layer forming step of applying a composition for forming a first thermally conductive layer on a first substrate to form a first thermally conductive layer; a second thermally conductive layer forming step of applying a composition for forming a second thermally conductive layer on a second substrate to form a second thermally conductive layer; A manufacturing method including a bonding step of bonding together the surface of the first thermally conductive layer opposite to the first substrate and the surface of the second thermally conductive layer opposite to the second substrate is preferred.
  • the method for producing a thermally conductive sheet further includes a step of modifying the surface of the first thermally conductive inorganic particles or the second thermally conductive inorganic particles using a surface modifier (surface modification step). It is also preferable that the method for producing a thermally conductive sheet further includes a step of surface-treating the first thermally conductive inorganic particles or the second thermally conductive inorganic particles to obtain modified inorganic particles (modification step).
  • the modification step is preferably performed before the surface modification step. That is, it is preferable to perform the surface modification step on the surface of the modified inorganic particles. Each step will be described in detail below.
  • the modification step is a step of surface-treating the first thermally conductive inorganic particles or the second thermally conductive inorganic particles to obtain modified inorganic particles.
  • the modification step is preferably a step of bringing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles into contact with an oxidizing agent in an aqueous solution to obtain modified inorganic particles.
  • the first thermally conductive inorganic particles or the second thermally conductive inorganic particles to be subjected to the modification step are as described above.
  • the above aqueous solution is preferably an alkaline aqueous solution.
  • the pH of the alkaline aqueous solution is often 8 or more, preferably 12 or more, more preferably more than 12, even more preferably 13 or more, and particularly preferably more than 13.
  • the upper limit is preferably 14 or less.
  • the pH of the aqueous solution means the pH of the aqueous solution containing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent. That is, the aqueous solution contains an alkali compound, water, the first thermally conductive inorganic particles or the second thermally conductive inorganic particles, and an oxidizing agent, if necessary.
  • the time for contacting the first thermally conductive inorganic particles or the second thermally conductive inorganic particles with the oxidizing agent in the aqueous solution is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours. .5 to 6 hours is more preferred.
  • the temperature of the aqueous solution when the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent are brought into contact is preferably 1 to 95°C, more preferably 25 to 80°C, and 45 to 65°C. °C is more preferred.
  • Organic solvents include, for example, methanol, ethanol, 2-propanol, acetonitrile, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane and tetrahydrofuran. You may use an organic solvent individually by 1 type or in 2 or more types.
  • a method of contacting the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent for example, a method of contacting while stirring using a mechanical stirrer such as a three-one motor, a magnetic stirrer, or the like; For example, a solution containing an oxidizing agent is brought into contact with a cartridge filled with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles while being circulated by a pump or the like.
  • the method for extracting the modified inorganic particles from the aqueous solution include a method of filtering the aqueous solution and fractionating the modified inorganic particles as filtered matter. It is also preferable to wash the removed modified inorganic particles with water and/or an organic solvent. After washing, the inorganic particles are preferably dried in an oven or the like.
  • the content of water in the aqueous solution is preferably 20 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 65 to 90% by mass, relative to the total mass of the aqueous solution.
  • oxidizing agent used in the modification step examples include persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; nitrates such as cerium ammonium nitrate, sodium nitrate and ammonium nitrate; hydrogen peroxide and tert-butyl hydroperoxide.
  • transition metal compounds such as divalent copper compounds and manganese compounds; hypervalent iodine compounds such as potassium periodate and sodium periodate; quinone compounds such as benzoquinone, naphthoquinone, anthraquinone and chloranil; Salts of halogen oxoacids such as sodium hypochlorite and sodium chlorite are included.
  • the oxidizing agent preferably comprises a persulfate, more preferably a persulfate.
  • a catalyst may be used separately from the oxidant in order to assist the action of the oxidant. Examples of the catalyst include divalent iron compounds (such as FeSO4 ) and trivalent iron compounds. Note that the oxidizing agent and/or catalyst may be a hydrate.
  • the standard oxidation-reduction potential of the oxidizing agent is preferably 0.30 V or higher, more preferably 1.50 V or higher, and even more preferably 1.70 V or higher.
  • the upper limit is preferably 4.00 V or less, more preferably 2.50 V or less.
  • the above standard oxidation-reduction potential is a value based on a standard hydrogen electrode.
  • the oxidizing agents may be used singly or in combination of two or more.
  • the content of the oxidizing agent in the aqueous solution is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and further 1 to 20 parts by mass, relative to 100 parts by mass of water in the aqueous solution. preferable.
  • the catalyst may be used singly or in combination of two or more.
  • the content of the catalyst is preferably 0.005 to 2 parts by mass, more preferably 0.01 to 2 parts by mass, more preferably 0.1 with respect to 100 parts by mass of water in the aqueous solution. ⁇ 2 parts by mass is more preferred.
  • the aqueous solution preferably contains an alkaline compound in addition to the components described above.
  • the alkali compound include inorganic bases such as alkali metal hydroxides (eg, sodium hydroxide, etc.) and alkaline earth metal hydroxides; and organic bases.
  • the content of the alkaline compound in the aqueous solution may be an amount that appropriately adjusts the pH of the aqueous solution to a desired value. mentioned.
  • the surface modification step is a step of modifying the surface of the first thermally conductive inorganic particles or the second thermally conductive inorganic particles using a surface modifier.
  • the first thermally conductive inorganic particles or the second thermally conductive inorganic particles are preferably brought into contact with the surface modifier.
  • the method for bringing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles into contact with the surface modifying agent includes the same method as in the modification step.
  • the surface modifier to be brought into contact with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles is preferably a hydrolyzate or hydrolyzed condensate of the surface modifier. That is, the surface modifier is preferably hydrolyzed before being brought into contact with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles.
  • Hydrolysis treatment is treatment for hydrolyzing the surface modifier.
  • the surface modifier is a silane coupling agent
  • the hydrolysis treatment hydrolyzes the alkoxysilyl groups of the silane coupling agent to generate silanol groups, and the silanol groups form the first thermally conductive inorganic particles or the second thermally conductive particles. It can form a bond with the surface of the conductive inorganic particles.
  • the hydrolysis method is not particularly limited as long as the conditions are such that the surface modifier is hydrolyzed. Specifically, it is preferable to use an acidic solution (eg, aqueous hydrochloric acid and acetic acid solution).
  • the acidic solution may contain an organic solvent.
  • the first base material and the second base material are synonymous with the above base material, and the preferred embodiments are also the same.
  • the first substrate and the second substrate may be the same or different.
  • the composition for forming the first thermally conductive layer and the composition for forming the second thermally conductive layer will be described in detail later.
  • composition examples include known methods. Specific examples include a printing method, a spray method, a roll coating method, a bar coating method, a curtain coating method, a spin coating method and a die coating method (slit coating method).
  • the obtained coating film may be subjected to a drying treatment, if necessary.
  • Heat treatment is preferable as the drying treatment.
  • the temperature of the heat treatment is preferably a temperature at which the curing reaction of the curable compound hardly progresses, more preferably 50 to 130°C.
  • the obtained coating film may be semi-cured by subjecting it to a semi-cured state. That is, the first thermally conductive layer and the second thermally conductive layer may be semi-cured films.
  • the first thermally conductive layer is preferably a layer subjected to a semi-curing treatment in terms of excellent thermal conductivity of the thermally conductive sheet after lamination.
  • the semi-curing treatment includes heat treatment, and the heating condition is preferably a temperature at which curing of the curable compound proceeds or higher.
  • the first heat conductive layer is a layer subjected to pressure treatment (for example, pressing treatment). The pressure treatment reduces voids in the first thermally conductive layer, resulting in excellent thermal conductivity of the thermally conductive sheet after lamination.
  • Semi-curing treatment and pressure treatment may be performed separately or simultaneously.
  • the coating film on the substrate may be heated as it is without pressure to obtain a semi-cured product in a semi-cured state, or press processing may be performed.
  • a semi-cured product may be obtained by heating the coating film on the base material while using them together.
  • the press working may be performed before or after the semi-hardening treatment, or may be performed during the heating or the like. If pressing is performed in the semi-curing treatment, it may be easier to adjust the thickness of the resulting semi-cured product and/or reduce the amount of voids in the semi-cured product.
  • a press used for pressing for example, a flat plate press or a roll press may be used.
  • a roll press for example, a substrate with a coating film obtained by forming a coating film on the substrate is sandwiched between a pair of rolls facing each other, and the pair of rolls is rotated. It is preferable to apply pressure in the film thickness direction of the substrate with the coating film while allowing the substrate with the coating film to pass through.
  • the base material with the coating film may have the base material on only one side of the coating film, or may have the base material on both sides of the coating film.
  • the coated substrate may be passed through the roll press only once or may be passed multiple times. At the time of hardening treatment such as the semi-hardening treatment and/or the main hardening treatment, either one or both of flat press treatment and roll press treatment may be performed.
  • the lamination step for example, a method in which the surface of the first thermally conductive layer opposite to the first substrate and the surface of the second thermally conductive layer opposite to the second substrate are brought into contact with each other and pressed together.
  • the press-bonding method for example, a method of pressurizing and heating by lamination, rolls, or the like is preferable. Specifically, press working used in the above-described hardening treatment is exemplified.
  • the method for manufacturing the heat conductive sheet may further include a first heat conductive layer forming step, a second heat conductive layer forming step and/or a lamination step. That is, it may be a thermally conductive sheet having one or more first thermally conductive layers and one or more second thermally conductive layers.
  • Another method for producing a thermally conductive sheet includes a step of applying a composition for forming a first thermally conductive layer onto a first substrate to form a first thermally conductive layer; Also preferred is a manufacturing method comprising the step of further applying a composition for forming a second heat conductive layer on the first heat conductive layer to form a second heat conductive layer.
  • a manufacturing method comprising the step of further applying a composition for forming a second heat conductive layer on the first heat conductive layer to form a second heat conductive layer.
  • compositions (the composition for forming the first thermally conductive layer and the composition for forming the second thermally conductive layer) contain components contained in each thermally conductive layer and a solvent.
  • the composition for forming the first thermally conductive layer is a composition for forming the first thermally conductive layer, and contains at least the first thermally conductive inorganic particles described above.
  • the composition for forming the first thermally conductive layer may contain components other than the first thermally conductive inorganic particles (for example, a curable compound, etc.).
  • the composition for forming the second thermally conductive layer is a composition for forming the second thermally conductive layer, and contains at least the second thermally conductive inorganic particles and the curable compound described above.
  • the composition for forming the second thermally conductive layer may contain components other than the second thermally conductive inorganic particles and the curable compound.
  • the composition preferably contains a solvent.
  • Organic solvents are preferred as solvents.
  • Organic solvents include, for example, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane and tetrahydrofuran.
  • the content of the solvent is preferably an amount that makes the solid content concentration of the composition 20 to 90% by mass, more preferably 30 to 85% by mass, and 50 to 80% by mass. is more preferable.
  • the "solid content" of the composition means the components forming each thermally conductive layer formed using the composition, and when the composition contains a solvent, it means all components excluding the solvent.
  • a liquid component is also considered as a solid content.
  • the solvent content is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, even more preferably 20 to 50% by mass, relative to the total mass of the composition.
  • Methods for producing the composition include, for example, known methods.
  • Examples of the method for producing the composition include a method for mixing components contained in each heat conductive layer with a solvent. When mixing, each component may be mixed all at once or sequentially.
  • a method for mixing the components for example, a known method can be used.
  • the mixing device used for mixing is preferably a submerged disperser. A homogenizer is mentioned. You may use a mixing apparatus individually by 1 type or in 2 or more types. Degassing may be performed before, after and/or simultaneously with mixing.
  • the thermally conductive sheet of the present invention can be used, for example, as a heat dissipation material, and can be used for heat dissipation of various devices.
  • a device with a heat conductive sheet is produced by arranging a heat conductive sheet on the device, and heat generated from the device can be efficiently dissipated through the heat conductive layer of the heat conductive sheet.
  • the heat conductive sheet of the present invention has excellent adhesion to the device even when laminated at low pressure, so that the heat conductive sheet can be placed on the device at low pressure, and the risk of damage to the device can be reduced.
  • the thermally conductive layer may be a thermally conductive layer containing a thermally conductive multilayer sheet to be described later.
  • the heat conductive sheet of the present invention is suitable for heat dissipation of power semiconductor devices used in electrical equipment such as personal computers, general household appliances and automobiles.
  • a semiconductor module is one of the preferred uses of the heat conductive sheet of the present invention.
  • One preferred embodiment of a semiconductor module containing the heat conductive sheet of the present invention is the embodiment shown in FIG.
  • the semiconductor module 100A is a so-called case-type semiconductor module, and includes a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, two devices 34, and a region in which the devices 34 are mounted. and a sealing material 38 disposed within the case frame 36 .
  • a conductive paste layer may be disposed between the heat sink 30 and the metal layer 32 .
  • the second heat conductive layer 14 in the heat conductive sheet 10 is arranged on the device 34 side.
  • the configuration of the device 34 is not particularly limited, it preferably includes a semiconductor chip, and more preferably has a configuration in which a circuit section, a conductive paste layer, and a semiconductor chip are laminated from the heat conductive sheet 10 side.
  • two devices 34 are shown in the semiconductor module 100A, the number is not particularly limited, and an optimum number is selected according to various uses.
  • electrical connection to the device 34 may be made using metal electrodes or wire bonds (not shown).
  • Examples of the sealing material 38 include silicone gel.
  • the heat generated in the device 34 is transferred to the heat sink 30 through the heat conductive sheet 10 and radiated outside the semiconductor module 100A system.
  • the semiconductor module 100B is a so-called molded semiconductor module, and includes a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, two devices 34, and a sealing resin 40 that seals the devices 34. .
  • the semiconductor module 100B which is a mold-type semiconductor module, can fix and seal the device 34 more firmly than the semiconductor module 100A, which is a case-type semiconductor module.
  • the method of manufacturing the semiconductor module 100B is not particularly limited.
  • a method of manufacturing a semiconductor module by forming a sealing resin 40 in a mold, and placing a laminate having a configuration other than the sealing material 40 of the semiconductor module 100B in a mold, pouring the mold resin there, and applying heat.
  • a conductive paste layer may be disposed between the heat sink 30 and the metal layer 32 .
  • two devices 34 are shown in the semiconductor module 100B, the number is not particularly limited, and an optimum number is selected according to various uses. Also, electrical connection to the device 34 may be made using metal electrodes or wire bonds (not shown).
  • the sealing resin 40 for example, a resin obtained by thermosetting an epoxy resin can be used.
  • the heat generated in the device 34 is transferred to the heat sink 30 through the heat conductive sheet 10 and radiated outside the system of the semiconductor module 100B.
  • the metal layer 32 is arranged between the heat sink 30 and the heat conductive sheet 10, but the metal layer 32 is not arranged as in the semiconductor module 100C shown in FIG. It doesn't have to be.
  • a conductive paste layer may be arranged between the heat sink 30 and the thermally conductive sheet 10 in the semiconductor module 100C.
  • two semiconductor modules may be arranged so as to face each other.
  • laminates including a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, and a device 34 are arranged to face each other, and the device 34 in these two laminates is arranged to face each other.
  • a sealing resin 40 is arranged between the two laminates so as to seal the . In such a mode, heat is dissipated from both sides of the semiconductor module 100D.
  • the semiconductor module 100E includes a device 34, a heat-conducting sheet 10 arranged on one side of the device 34, a metal layer 32, a heat sink 30, and a heat-conducting sheet 100 arranged on the other side of the device 34. It includes a sheet 10 , a metal layer 32 , a heat sink 30 and an encapsulating resin 40 encapsulating the device 34 .
  • the heat generated in the device 34 is transferred to the two heat sinks 30 via the heat conductive sheets 10 arranged on both sides of the device 34, and is radiated outside the semiconductor module 100E system. ing.
  • the agglomerated boron nitride in the NaOH water was collected by filtration, and the filtered agglomerated boron nitride was washed with water (500 mL) and acetonitrile (250 mL) to form a denatured agglomerate. Boron nitride 1 was obtained.
  • the resulting modified aggregated boron nitride 1 was stirred in acetonitrile (100 mL), and a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: X12-984S) hydrolysis adjustment solution (1.25 g) was further added to the acetonitrile. added.
  • the acetonitrile was stirred at room temperature for 3 hours to carry out adsorption treatment (adsorption step). After filtering the modified aggregated boron nitride 1 in the acetonitrile, the filtered modified aggregated boron nitride 1 was washed with acetonitrile (100 mL) and dried in an oven at 40 ° C., thereby surface-modified aggregated boron nitride. Boron was obtained.
  • the silane coupling agent hydrolysis adjustment solution is prepared by mixing silane coupling agent (1 g), ethanol (500 ⁇ L), 2-propanol (500 ⁇ L), water (720 ⁇ L) and acetic acid (100 ⁇ L) and stirring for 1 hour.
  • X12-984S is a polymer-type silane coupling agent having an epoxy group and an ethoxysilyl group.
  • NaOH water NaOH: 40 g/water: 400 ml
  • aggregated boron nitride HP40MF100, 50 g
  • sodium persulfate water sodium persulfate: 9.6 g/water: 100 ml
  • the pH of the liquid was 14.
  • the content of the surface modifier in the surface-modified BN was more than 0% by mass and less than 1% by mass with respect to the total mass of the surface-modified BN.
  • TPP-MK Tetraphenylphosphonium tetra-p-tolylborate (manufactured by Hokko Chemical Industry Co., Ltd.)
  • composition for forming a first thermally conductive layer and a composition for forming a second thermally conductive layer were prepared in the following procedure. Specifically, first, an epoxy compound and a phenol compound were blended in equivalent amounts (an amount that equalizes the number of epoxy groups in the epoxy compound and the number of hydroxy groups in the phenol compound) to prepare a mixture. After mixing the above mixture and solvent, an acid anhydride, a curing accelerator and a maleimide compound were mixed. After that, each thermally conductive inorganic particle was further added.
  • compositions curable compositions
  • Tables 1 and 2 the content (% by mass) of each component with respect to the total mass of the composition for forming the first thermally conductive layer or the composition for forming the second thermally conductive layer is shown.
  • “remainder” means that the amount of solvent was adjusted so that the total amount with other components was 100% by mass.
  • each composition for forming the first heat conductive layer was uniformly applied onto the release surface of a release-treated PET film (PET756501, manufactured by Lintec, film thickness 75 ⁇ m) with a clearance of 450 ⁇ m. , and dried at 50° C. for 4 minutes to obtain a first laminate having a first thermally conductive layer with a film thickness of 220 ⁇ m.
  • the obtained first laminate was further dried at 120° C. for 5 minutes, and then cut into 5 cm ⁇ 5 cm.
  • the resulting cut material was vacuum-pressurized at a temperature of 188° C. and a pressure of 20 MPa.
  • each composition for forming the second heat conductive layer was uniformly applied with a clearance of 60 ⁇ m onto the release surface of a release-treated PET film (PET756501, Lintec, film thickness: 75 ⁇ m). It was applied and dried at 50° C. for 2 minutes to obtain a second laminate having a second heat conductive layer with a film thickness of 53 ⁇ m. The obtained second laminate was further dried at 120° C. for 2 minutes, and then cut into 5 cm ⁇ 5 cm.
  • the surface of the second heat conductive layer opposite to the PET film of the second laminate having the second heat conductive layer is replaced with the first heat conductive layer opposite to the PET film of the first heat conductive layer having the first heat conductive layer. It was attached to the surface of the thermally conductive layer and vacuum-pressurized at a temperature of 188° C. and a pressure of 5 MPa to obtain a resin sheet.
  • the PET films on both sides of the obtained resin sheet were peeled off to obtain the thermally conductive sheets of each example and each comparative example.
  • the thickness of the first thermally conductive layer of the obtained thermally conductive sheet was 120 ⁇ m
  • the thickness of the second thermally conductive layer of the obtained thermally conductive sheet was 36 ⁇ m.
  • the obtained thermal diffusivity was multiplied by the specific gravity and the specific heat to calculate the thermal conductivity in the film thickness direction of the sample for thermal conductivity measurement.
  • the thermal conductivity of the samples for thermal conductivity measurement was classified according to the following criteria, and the thermal conductivity was evaluated.
  • each composition for forming the first heat conductive layer was uniformly applied onto the release surface of a release-treated PET film (PET756501, manufactured by Lintec, film thickness 75 ⁇ m) with a clearance of 450 ⁇ m, After drying at 50° C. for 4 minutes, a laminate having a first heat conductive layer with a film thickness of 220 ⁇ m was obtained. The obtained laminate was further dried at 120° C. for 5 minutes, and then cut into 5 cm ⁇ 5 cm.
  • each composition for forming the second heat conductive layer was uniformly applied with a clearance of 48 ⁇ m and dried at 50° C. for 3 minutes to obtain a second laminate having a second heat conductive layer with a thickness of 37 ⁇ m.
  • the release-treated PET film of the first laminate was peeled off, and the exposed first thermally conductive layer and the exposed second thermally conductive layer of the second laminate were directly combined and subjected to vacuum heating at a temperature of 188 ° C. and a pressure of 5 MPa.
  • the thickness of the first heat conductive layer of the obtained laminate 3 was 120 ⁇ m, and the thickness of the second heat conductive layer of the obtained heat conductive sheet for adhesion evaluation was 36 ⁇ m. Furthermore, the laminate 3 was cut into a size of 2.0 cm width ⁇ 5.0 cm length and a size of 0.5 cm width ⁇ 5.0 cm length.
  • the copper foil peel strength of each laminate 3 obtained above was measured using a digital force gauge (ZTS-200N, manufactured by Imada) and a 90-degree peel test jig (P90-200N-BB, manufactured by Imada) according to JIS. It was measured according to the method for measuring peel strength in the state described in C 6481.
  • the peeling of the copper foil in the peel strength test was performed at an angle of 90° with respect to the laminate 3 at a peeling speed of 50 mm/min.
  • Insulation reliability measurement under high temperature and high humidity conditions and insulation reliability measurement under high temperature and high humidity conditions were carried out as insulation evaluation.
  • ⁇ Dielectric breakdown voltage measurement> A sample for dielectric breakdown voltage measurement was prepared in the same manner as the sample for insulation reliability measurement. Using "YST-243-100RHO" manufactured by Yamayo Test Instruments Co., Ltd., apply 1 kV to the dielectric breakdown voltage measurement sample in oil at 25 ° C. and 175 ° C. If it does not break for 20 seconds, the applied voltage is The measurement was repeated by increasing the voltage by 0.5 V and evaluating for 20 seconds. The maximum voltage at which no breakdown occurred was defined as the dielectric breakdown voltage, and the dielectric breakdown voltage property was evaluated by classifying the samples according to the following criteria. A: 5 kV or more B: 2 kV or more and less than 5 kV C: less than 2 kV
  • the thermally conductive sheet of the present invention has excellent thermal conductivity and adhesion. It was confirmed that the effect of the present invention is more excellent when the content of the second thermally conductive inorganic particles is 45.0 to 55.0% by volume with respect to the total volume of the second thermally conductive layer (implementation (comparison with Examples 1 to 5, etc.). It was confirmed that the effect of the present invention is more excellent when the volume ratio of the aggregated boron nitride to the thermally conductive inorganic particles X in the second thermally conductive layer is 2.8 to 5.0 (Example 1 , 6-10, etc.).
  • At least one of the first thermally conductive layer and the second thermally conductive layer further comprises a surface modifier, and the aggregated boron nitride is surface-modified aggregated nitriding with the surface modifier adsorbed on the surface of the aggregated boron nitride.
  • boron is composed (using the surface-modified first thermally conductive inorganic particles and/or the surface-modified first thermally conductive inorganic particles), the thermal conductivity, adhesion, insulation and void generation suppression are improved. It was confirmed to be excellent (comparison with Examples 3, 11, 15 and 16, etc.).
  • thermally conductive sheet 12 first thermally conductive layer 14 second thermally conductive layer 16 first thermally conductive inorganic particles 18 second thermally conductive inorganic particles 20 agglomerated boron nitride 22 thermally conductive inorganic particles X 30 heat sink 32 metal layer 34 device 36 case frame 38 sealing material 40 sealing resin 100A, 100B, 100C, 100D, 100E semiconductor module

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Abstract

The present invention addresses the problem of providing a heat conductive sheet and a device equipped with a heat conductive sheet, which demonstrate excellent adherence to an adherend when attached to the adherend with a low pressure and demonstrate excellent heat conductivity after bonding. This heat conductive sheet comprises a first heat conductive layer having two main surfaces and a second heat conductive layer disposed only on one of the two main surfaces of the first heat conductive layer. The average film thickness of the first heat conductive layer is greater than the average film thickness of the second heat conductive layer. The first heat conductive layer includes first heat conductive inorganic particles, and the second heat conductive layer includes second heat conductive inorganic particles and a curable compound. The content of the first heat conductive inorganic particles relative to the entire volume of the first heat conductive layer is greater than the content of the second heat conductive inorganic particles relative to the entire volume of the second heat conductive layer. The second heat conductive inorganic particles in the second heat conductive layer include aggregated boron nitride and heat conductive inorganic particles X that are different from the aggregated boron nitride and have an average aspect ratio of 1.0-1.6. The content of the second heat conductive inorganic particles relative to the entire volume of the second heat conductive layer is 40.0-60.0 vol%.

Description

熱伝導シート、熱伝導シート付きデバイスThermal conductive sheet, device with thermal conductive sheet
　本発明は、熱伝導シート及び熱伝導シート付きデバイスに関する。 The present invention relates to a thermally conductive sheet and a device with a thermally conductive sheet.
　パーソナルコンピュータ、一般家電及び自動車等の電気機器に用いられているパワー半導体デバイスは、近年、小型化が急速に進んでいる。小型化に伴って高密度化されたパワー半導体デバイスから発生する熱の制御が問題となっている。
　上記問題に対応するために、パワー半導体デバイスからの放熱を促進する熱伝導材料が用いられている。
　例えば、特許文献１には、複数の層を有する熱伝導シートが開示されている。 2. Description of the Related Art In recent years, power semiconductor devices used in electrical equipment such as personal computers, general household appliances, and automobiles are rapidly becoming smaller. Controlling the heat generated from power semiconductor devices, which have become denser with miniaturization, has become a problem.
In order to deal with the above problems, thermally conductive materials are used to promote heat dissipation from power semiconductor devices.
For example, Patent Literature 1 discloses a thermally conductive sheet having multiple layers.
特開２０１１－０４０５６５号公報JP 2011-040565 A
　本発明者らは、特許文献１等に記載されるような熱伝導シートについて検討したところ、低い圧力（例えば、５ＭＰａ以下等）で熱伝導シートを被貼合物に貼合した際に、熱伝導シートの被貼合物に対する密着性について改善の余地があることを知見した。
　また、熱伝導シートは、上記貼合後において優れた熱伝導性を示すことも求められる。 The present inventors have studied the heat conductive sheet as described in Patent Document 1 and the like, and found that when the heat conductive sheet is bonded to an object to be bonded at a low pressure (for example, 5 MPa or less), heat It has been found that there is room for improvement in the adhesion of the conductive sheet to the object to be bonded.
Moreover, the thermally conductive sheet is also required to exhibit excellent thermal conductivity after the lamination.
　そこで、本発明は、低い圧力で被貼合物に貼り合わせた際に被貼合物に対する密着性に優れ、貼合後に優れた熱伝導性を示す熱伝導シートを提供することを課題とする。
　また、本発明は、熱伝導シート付きデバイスを提供することも課題とする。 Accordingly, an object of the present invention is to provide a thermally conductive sheet that exhibits excellent adhesion to an object to be bonded when bonded to the object to be bonded at a low pressure, and exhibits excellent thermal conductivity after bonding. .
Another object of the present invention is to provide a device with a thermally conductive sheet.
　本発明者らは、上記課題を解決すべく鋭意検討した結果、以下の構成により上記課題が解決できることを見出した。 As a result of intensive studies aimed at solving the above problems, the inventors found that the above problems can be solved with the following configuration.
　〔１〕　２つの主面を有する第１熱伝導層と、
　上記第１熱伝導層の２つの主面のうち一方の主面上のみに配置された、第２熱伝導層とを有し、
　上記第１熱伝導層の平均膜厚が上記第２熱伝導層の平均膜厚よりも大きく、
　上記第１熱伝導層が、第１熱伝導性無機粒子を含み、
　上記第２熱伝導層が、第２熱伝導性無機粒子及び硬化性化合物を含み、
　上記第１熱伝導層全体積に対する上記第１熱伝導性無機粒子の含有量が、上記第２熱伝導層全体積に対する上記第２熱伝導性無機粒子の含有量よりも大きく、
　上記第２熱伝導層中の上記第２熱伝導性無機粒子が、凝集状窒化ホウ素と、平均アスペクト比が１．０～１．６であり、上記凝集状窒化ホウ素とは異なる熱伝導性無機粒子Ｘと、を含み、
　上記第２熱伝導性無機粒子の含有量が、上記第２熱伝導層全体積に対して、４０．０～６０．０体積％である、熱伝導シート。
　〔２〕　上記第２熱伝導層中、上記熱伝導性無機粒子Ｘに対する上記凝集状窒化ホウ素の体積比が、２．５～１０．５である、〔１〕に記載の熱伝導シート。
　〔３〕　上記熱伝導性無機粒子Ｘが、酸化アルミニウムである、〔１〕又は〔２〕に記載の熱伝導シート。
　〔４〕　上記熱伝導性無機粒子Ｘの平均粒径が、２．０～１０．０μｍである、〔１〕～〔３〕のいずれか１つに記載の熱伝導シート。
　〔５〕　上記硬化性化合物が、エポキシ化合物及びマレイミド化合物からなる群から選択される１種以上を含む、〔１〕～〔４〕のいずれか１つに記載の熱伝導シート。
　〔６〕　上記硬化性化合物が、フェノール化合物を含む、〔１〕～〔５〕のいずれか１つに記載の熱伝導シート。
　〔７〕　上記第２熱伝導層の平均膜厚が、１０～７０μｍである、〔１〕～〔６〕のいずれか１つに記載の熱伝導シート。
　〔８〕　上記第１熱伝導層の平均膜厚が、１００～１５０μｍである、〔１〕～〔７〕のいずれか１つに記載の熱伝導シート。
　〔９〕　上記凝集状窒化ホウ素の平均粒径が、１０．０～８０．０μｍである、〔１〕～〔８〕のいずれか１つに記載の熱伝導シート。
　〔１０〕
　上記第１熱伝導層及び上記第２熱伝導層の少なくとも一方が、更に、表面修飾剤を含み、
　上記凝集状窒化ホウ素が、上記凝集状窒化ホウ素の表面上に吸着した上記表面修飾剤とともに、表面修飾凝集状窒化ホウ素を構成している、〔１〕～〔９〕のいずれか１つに記載の熱伝導シート。
　〔１１〕　デバイスと、上記デバイス上に配置された〔１〕～〔１０〕のいずれか１つに記載の熱伝導シートとを有する、熱伝導シート付きデバイス。 [1] a first thermally conductive layer having two main surfaces;
a second heat conductive layer disposed only on one of the two main surfaces of the first heat conductive layer;
The average film thickness of the first thermally conductive layer is greater than the average film thickness of the second thermally conductive layer,
The first thermally conductive layer contains first thermally conductive inorganic particles,
The second thermally conductive layer contains second thermally conductive inorganic particles and a curable compound,
The content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer,
The second thermally conductive inorganic particles in the second thermally conductive layer are aggregated boron nitride and have an average aspect ratio of 1.0 to 1.6, and a thermally conductive inorganic material different from the aggregated boron nitride a particle X, and
The heat conductive sheet, wherein the content of the second heat conductive inorganic particles is 40.0 to 60.0% by volume with respect to the total volume of the second heat conductive layer.
[2] The thermally conductive sheet according to [1], wherein the volume ratio of the aggregated boron nitride to the thermally conductive inorganic particles X in the second thermally conductive layer is 2.5 to 10.5.
[3] The thermally conductive sheet according to [1] or [2], wherein the thermally conductive inorganic particles X are aluminum oxide.
[4] The thermally conductive sheet according to any one of [1] to [3], wherein the thermally conductive inorganic particles X have an average particle size of 2.0 to 10.0 μm.
[5] The heat conductive sheet according to any one of [1] to [4], wherein the curable compound contains one or more selected from the group consisting of epoxy compounds and maleimide compounds.
[6] The heat conductive sheet according to any one of [1] to [5], wherein the curable compound contains a phenol compound.
[7] The heat conductive sheet according to any one of [1] to [6], wherein the second heat conductive layer has an average thickness of 10 to 70 μm.
[8] The heat conductive sheet according to any one of [1] to [7], wherein the first heat conductive layer has an average film thickness of 100 to 150 μm.
[9] The heat conductive sheet according to any one of [1] to [8], wherein the aggregated boron nitride has an average particle size of 10.0 to 80.0 μm.
[10]
at least one of the first thermally conductive layer and the second thermally conductive layer further comprises a surface modifier;
According to any one of [1] to [9], wherein the aggregated boron nitride constitutes surface-modified aggregated boron nitride together with the surface modifier adsorbed on the surface of the aggregated boron nitride. thermal conductive sheet.
[11] A device with a thermally conductive sheet, comprising a device and the thermally conductive sheet according to any one of [1] to [10] disposed on the device.
　本発明によれば、低い圧力で被貼合物に貼り合わせた際に被貼合物に対する密着性に優れ、貼合後に優れた熱伝導性を示す熱伝導シートを提供できる。
　また、本発明によれば、熱伝導シート付きデバイスを提供できる。 ADVANTAGE OF THE INVENTION According to this invention, the heat conductive sheet which is excellent in the adhesiveness with respect to a to-be-bonded material when it is bonded to a to-be-bonded material at a low pressure, and shows the excellent thermal conductivity after bonding can be provided.
Moreover, according to the present invention, a device with a thermally conductive sheet can be provided.
熱伝導シートの一例を示す概略図である。It is a schematic diagram showing an example of a heat conduction sheet. 半導体モジュールの一例を示す概略図である。1 is a schematic diagram showing an example of a semiconductor module; FIG. 半導体モジュールの一例を示す概略図である。1 is a schematic diagram showing an example of a semiconductor module; FIG. 半導体モジュールの一例を示す概略図である。1 is a schematic diagram showing an example of a semiconductor module; FIG. 半導体モジュールの一例を示す概略図である。1 is a schematic diagram showing an example of a semiconductor module; FIG. 半導体モジュールの一例を示す概略図である。1 is a schematic diagram showing an example of a semiconductor module; FIG.
　以下、構成要件の説明は、本発明の代表的な実施態様に基づいてなされる場合があるが、本発明はそのような実施態様に制限されない。
　なお、本明細書において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限及び上限として含む範囲を意味する。 The following description of constituent elements may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
　また、本明細書において、「（メタ）アクリロイル基」との記載は、「アクリロイル基及びメタクリロイル基のいずれか一方又は双方」の意味を表す。 Also, in this specification, the description of "(meth)acryloyl group" means "either one or both of an acryloyl group and a methacryloyl group".
　本明細書において、酸無水物基は、１価の基及び２価の基のいずれであってもよい。酸無水物基が１価の基を表す場合、無水マレイン酸、無水フタル酸、無水ピロメリット酸及び無水トリメリット酸等の酸無水物から任意の水素原子を除いて得られる置換基が挙げられる。また、酸無水物基が２価の基を表す場合、＊－ＣＯ－Ｏ－ＣＯ－＊で表される基を意味する。＊は結合位置を表す。
　本明細書において、表記される２価の基（例えば、－ＣＯＯ－等）の結合方向は、特段の断りが限り、特に制限されない。例えば、「Ｘ－Ｙ－Ｚ」なる式で表される化合物中の、Ｙが－ＣＯＯ－である場合、上記化合物は「Ｘ－Ｏ－ＣＯ－Ｚ」及び「Ｘ－ＣＯ－Ｏ－Ｚ」のいずれであってもよい。 In this specification, the acid anhydride group may be either a monovalent group or a divalent group. When the acid anhydride group represents a monovalent group, it includes a substituent obtained by removing any hydrogen atom from acid anhydrides such as maleic anhydride, phthalic anhydride, pyromellitic anhydride and trimellitic anhydride. . Also, when the acid anhydride group represents a divalent group, it means a group represented by *--CO--O--CO--*. * represents a binding position.
In this specification, the bonding direction of the divalent groups (eg, --COO--, etc.) indicated is not particularly limited unless otherwise specified. For example, in the compound represented by the formula "XYZ", when Y is -COO-, the above compounds are "X-O-CO-Z" and "X-CO-O-Z" It may be any of
　本明細書において、置換又は無置換を明記していない置換基等については、可能な場合、目的とする効果を損なわない範囲で、その基に更に置換基を有していてもよい。例えば、「アルキル基」という表記は、目的とする効果を損なわない範囲で、置換又は無置換のアルキル基（置換基を有してもよいアルキル基）を意味する。
　本明細書において、「置換基を有していてもよい」という場合の置換基の種類、置換基の位置及び置換基の数は、特に制限されない。置換基の数としては、例えば、１つ及び２つ以上が挙げられる。置換基の種類は特に制限されず、例えば、ハロゲン原子及びアルキル基が挙げられる。
　本明細書において、ハロゲン原子としては、例えば、塩素原子、フッ素原子、臭素原子及びヨウ素原子が挙げられる。 In this specification, substituents and the like for which substitution or non-substitution is not specified may have further substituents, if possible, to the extent that the intended effect is not impaired. For example, the notation "alkyl group" means a substituted or unsubstituted alkyl group (an alkyl group that may have a substituent) within a range that does not impair the intended effect.
In the present specification, the type of substituent, the position of the substituent, and the number of substituents in the case of "optionally having a substituent" are not particularly limited. Examples of the number of substituents include one and two or more. The types of substituents are not particularly limited, and examples thereof include halogen atoms and alkyl groups.
As used herein, halogen atoms include, for example, chlorine, fluorine, bromine and iodine atoms.
［熱伝導シート］
　本発明の熱伝導シートは、
　２つの主面を有する第１熱伝導層と、
　第１熱伝導層の２つの主面のうち一方の主面上のみに配置された、第２熱伝導層とを有し、
　第１熱伝導層の平均膜厚が第２熱伝導層の平均膜厚よりも大きく、
　第１熱伝導層が、第１熱伝導性無機粒子を含み、
　第２熱伝導層が、第２熱伝導性無機粒子及び硬化性化合物を含み、
　第１熱伝導層全体積に対する第１熱伝導性無機粒子の含有量が、第２熱伝導層全体積に対する第２熱伝導性無機粒子の含有量よりも大きく、
　第２熱伝導層中の第２熱伝導性無機粒子が、凝集状窒化ホウ素と、平均アスペクト比が１．０～１．６であり、凝集状窒化ホウ素とは異なる熱伝導性無機粒子Ｘと、を含み、
　第２熱伝導性無機粒子の含有量が、第２熱伝導層全体積に対して、４０．０～６０．０体積％である。 [Heat conductive sheet]
The heat conductive sheet of the present invention is
a first thermally conductive layer having two main surfaces;
a second thermally conductive layer disposed only on one of the two major surfaces of the first thermally conductive layer;
The average film thickness of the first thermally conductive layer is greater than the average film thickness of the second thermally conductive layer,
the first thermally conductive layer comprises first thermally conductive inorganic particles;
the second thermally conductive layer comprises second thermally conductive inorganic particles and a curable compound;
The content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer,
The second thermally conductive inorganic particles in the second thermally conductive layer are aggregated boron nitride, and thermally conductive inorganic particles X having an average aspect ratio of 1.0 to 1.6 and different from aggregated boron nitride. , including
The content of the second thermally conductive inorganic particles is 40.0 to 60.0% by volume with respect to the total volume of the second thermally conductive layer.
　上記構成で本発明の課題が解決されるメカニズムは明らかではないが、本発明者らは以下のように推測している。
　本発明の熱伝導シートの特徴点としては、第１熱伝導層及び第２熱伝導層を有することが挙げられる。
　低い圧力で熱伝導シートを被貼合物に貼合した際に、被貼合物と接触する第２熱伝導層は、高い熱伝導性を示す凝集状窒化ホウ素に加えて、更に熱伝導性無機粒子Ｘとを含むため、被貼合物との密着性にも優れる。第１熱伝導層は、第１熱伝導性無機粒子を含むため、高い熱伝導性を示す。このような２層を有することで、熱伝導性に優れ、密着性にも優れると推測される。
　以下、熱伝導性及び密着性の少なくとも一方の効果が、より優れることを本発明の効果がより優れるともいう。 Although the mechanism by which the above configuration solves the problems of the present invention is not clear, the inventors presume as follows.
A feature of the thermally conductive sheet of the present invention is that it has a first thermally conductive layer and a second thermally conductive layer.
When the thermally conductive sheet is laminated to the object to be laminated at a low pressure, the second thermally conductive layer, which is in contact with the object to be laminated, contains not only aggregated boron nitride exhibiting high thermal conductivity, but also thermal conductivity. Since it contains the inorganic particles X, it is also excellent in adhesion to the object to be bonded. Since the first thermally conductive layer contains the first thermally conductive inorganic particles, it exhibits high thermal conductivity. It is presumed that having such two layers provides excellent thermal conductivity and excellent adhesion.
Hereinafter, when the effect of at least one of thermal conductivity and adhesion is more excellent, the effect of the present invention is also said to be more excellent.
　熱伝導シートの実施形態の例について説明する。
　図１に示す熱伝導シート１０は、２つの主面を有する第１熱伝導層１２と、第１熱伝導層１２の一方の主面上に配置された第２熱伝導層１４とを有する。第１熱伝導層の２つの主面のうち一方の主面上のみに配置される。換言すると、第１熱伝導層１２の他方の主面上には、第２熱伝導層は配置されない。
　第１熱伝導層１２は第１熱伝導性無機粒子１６を含み、第２熱伝導層１４は凝集状窒化ホウ素２０及び熱伝導性無機粒子Ｘ２２を含む第２熱伝導性無機粒子１８を含む。
　また、熱伝導シートは、第１熱伝導層１２及び第２熱伝導層１４以外に、他の部材を有していてもよい。他の部材としては、例えば、後述する基材が挙げられる。
　熱伝導シートにおいて、第１熱伝導層及び第２熱伝導層の少なくとも一方が、更に、表面修飾剤を含み、
　凝集状窒化ホウ素が、凝集状窒化ホウ素の表面上に吸着した表面修飾剤とともに、表面修飾凝集状窒化ホウ素を構成していることが好ましい。詳細は、後述する。 An example of an embodiment of a thermally conductive sheet will be described.
The heat conductive sheet 10 shown in FIG. 1 has a first heat conductive layer 12 having two main surfaces and a second heat conductive layer 14 arranged on one main surface of the first heat conductive layer 12 . It is arranged only on one main surface of the two main surfaces of the first thermally conductive layer. In other words, the second heat conductive layer is not arranged on the other main surface of the first heat conductive layer 12 .
The first thermally conductive layer 12 includes first thermally conductive inorganic particles 16, and the second thermally conductive layer 14 includes second thermally conductive inorganic particles 18 including aggregated boron nitride 20 and thermally conductive inorganic particles X22.
Moreover, the thermally conductive sheet may have other members in addition to the first thermally conductive layer 12 and the second thermally conductive layer 14 . Other members include, for example, a base material to be described later.
In the thermally conductive sheet, at least one of the first thermally conductive layer and the second thermally conductive layer further contains a surface modifier,
Preferably, the aggregated boron nitride, together with the surface modifier adsorbed onto the surface of the aggregated boron nitride, constitutes a surface-modified aggregated boron nitride. Details will be described later.
　以下、熱伝導シートに含まれる部材について詳述する。 The members included in the heat conductive sheet are detailed below.
〔第１熱伝導層〕
　熱伝導シートは、２つの主面を有する第１熱伝導層を有する。
　第１熱伝導層は、第１熱伝導性無機粒子を含めば、特に制限されない。第１熱伝導層は、第１熱伝導性無機粒子及び硬化性化合物を含むことが好ましい。 [First heat conductive layer]
The thermally conductive sheet has a first thermally conductive layer with two main surfaces.
The first thermally conductive layer is not particularly limited as long as it contains the first thermally conductive inorganic particles. The first thermally conductive layer preferably contains first thermally conductive inorganic particles and a curable compound.
＜第１熱伝導性無機粒子＞
　第１熱伝導層は、第１熱伝導性無機粒子を含む。 <First thermally conductive inorganic particles>
The first thermally conductive layer contains first thermally conductive inorganic particles.
　第１熱伝導性無機粒子の形状としては、例えば、米粒状、球形状、立方体状、紡錘形状、鱗片状、凝集状及び不定形状が挙げられる。 Examples of the shape of the first thermally conductive inorganic particles include rice grain-like, spherical, cubic, spindle-like, scale-like, aggregated and irregular shapes.
　第１熱伝導性無機粒子としては、例えば、無機窒化物及び無機酸化物が挙げられる。
　無機窒化物としては、例えば、窒化ホウ素（ＢＮ）、窒化炭素（Ｃ３Ｎ４）、窒化ケイ素（Ｓｉ３Ｎ４）、窒化ガリウム（ＧａＮ）、窒化インジウム（ＩｎＮ）、窒化アルミニウム（ＡｌＮ）、窒化クロム（Ｃｒ２Ｎ）、窒化銅（Ｃｕ３Ｎ）、窒化鉄（Ｆｅ４Ｎ）、窒化鉄（Ｆｅ３Ｎ）、窒化ランタン（ＬａＮ）、窒化リチウム（Ｌｉ３Ｎ）、窒化マグネシウム（Ｍｇ３Ｎ２）、窒化モリブデン（Ｍｏ２Ｎ）、窒化ニオブ（ＮｂＮ）、窒化タンタル（ＴａＮ）、窒化チタン（ＴｉＮ）、窒化タングステン（Ｗ２Ｎ）、窒化タングステン（ＷＮ２）、窒化イットリウム（ＹＮ）及び窒化ジルコニウム（ＺｒＮ）が挙げられる。
　無機窒化物は、アルミニウム原子、ホウ素原子又はケイ素原子を含むことが好ましく、窒化アルミニウム、窒化ホウ素又は窒化ケイ素を含むことがより好ましく、窒化アルミニウム又は窒化ホウ素を含むことが更に好ましく、窒化ホウ素を含むことが特に好ましい。 Examples of the first thermally conductive inorganic particles include inorganic nitrides and inorganic oxides.
Examples of inorganic nitrides include boron nitride (BN), carbon nitride ( C3N4 ), silicon nitride ( Si3N4 ), gallium nitride ( GaN ), indium nitride (InN), aluminum nitride ( AlN ), Chromium nitride ( Cr2N ), copper nitride (Cu3N), iron nitride ( Fe4N ), iron nitride ( Fe3N ) , lanthanum nitride (LaN), lithium nitride ( Li3N ), magnesium nitride (Mg 3N 2 ), molybdenum nitride (Mo 2 N), niobium nitride (NbN), tantalum nitride (TaN), titanium nitride (TiN), tungsten nitride (W 2 N), tungsten nitride (WN 2 ), yttrium nitride (YN ) and zirconium nitride (ZrN).
The inorganic nitride preferably contains aluminum atoms, boron atoms or silicon atoms, more preferably aluminum nitride, boron nitride or silicon nitride, still more preferably aluminum nitride or boron nitride, and boron nitride. is particularly preferred.
　窒化ホウ素としては、例えば、立方晶窒化ホウ素及び六方晶窒化ホウ素が挙げられる。
　窒化ホウ素の形状は、球状、平板状、鱗片状及び凝集状のいずれであってもよく、凝集状窒化ホウ素が好ましい。凝集状窒化ホウ素とは、窒化ホウ素（例えば、鱗片状窒化ホウ素等）の１次粒子を凝集させることにより形成される２次凝集粒子である。 Boron nitride includes, for example, cubic boron nitride and hexagonal boron nitride.
The shape of boron nitride may be spherical, tabular, scaly, or aggregated, and aggregated boron nitride is preferred. Aggregated boron nitride is secondary aggregated particles formed by aggregating primary particles of boron nitride (for example, scaly boron nitride).
　無機酸化物としては、例えば、酸化ジルコニウム（ＺｒＯ２）、酸化チタン（ＴｉＯ２）、酸化ケイ素（ＳｉＯ２）、酸化アルミニウム（Ａｌ２Ｏ３）、酸化鉄（例えば、Ｆｅ２Ｏ３、ＦｅＯ及びＦｅ３Ｏ４等）、酸化銅（例えば、ＣｕＯ及びＣｕ２Ｏ等）、酸化亜鉛（ＺｎＯ）、酸化イットリウム（Ｙ２Ｏ３）、酸化ニオブ（Ｎｂ２Ｏ５）、酸化モリブデン（ＭｏＯ３）、酸化インジウム（Ｉｎ２Ｏ３、Ｉｎ２Ｏ）、酸化スズ（ＳｎＯ２）、酸化タンタル（Ｔａ２Ｏ５）、酸化タングステン（例えば、ＷＯ３及びＷ２Ｏ５等）、酸化鉛（例えば、ＰｂＯ及びＰｂＯ２等）、酸化ビスマス（Ｂｉ２Ｏ３）、酸化セリウム（例えば、ＣｅＯ２及びＣｅ２Ｏ３等）、酸化アンチモン（例えば、Ｓｂ２Ｏ３及びＳｂ２Ｏ５等）、酸化ゲルマニウム（例えば、ＧｅＯ２及びＧｅＯ等）、酸化ランタン（Ｌａ２Ｏ３）及び酸化ルテニウム（ＲｕＯ２）が挙げられる。
　無機酸化物は、無機非酸化物が経時変化等して酸化されて生じる無機酸化物であってもよい。
　無機酸化物としては、酸化チタン、酸化アルミニウム又は酸化亜鉛が好ましく、酸化アルミニウムがより好ましい。 Examples of inorganic oxides include zirconium oxide (ZrO 2 ), titanium oxide (TiO 2 ), silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), iron oxide (e.g., Fe 2 O 3 , FeO and Fe3O4 , etc. ), copper oxides (e.g., CuO and Cu2O , etc.), zinc oxide (ZnO), yttrium oxide (Y2O3), niobium oxide (Nb2O5 ) , molybdenum oxide ( MoO3 ) , indium oxide ( In2O3 , In2O ), tin oxide ( SnO2 ), tantalum oxide ( Ta2O5 ), tungsten oxide ( e.g. , WO3 and W2O5 ), lead oxide (e.g., PbO and PbO2, etc.), bismuth oxide ( Bi2O3 ), cerium oxide ( e.g. , CeO2 and Ce2O3 , etc. ), antimony oxide ( e.g., Sb2O3 and Sb2O5 , etc.), germanium oxide (such as GeO 2 and GeO), lanthanum oxide (La 2 O 3 ) and ruthenium oxide (RuO 2 ).
The inorganic oxide may be an inorganic oxide that is produced by oxidizing an inorganic non-oxide over time.
The inorganic oxide is preferably titanium oxide, aluminum oxide or zinc oxide, more preferably aluminum oxide.
　第１熱伝導性無機粒子は、表面処理されていてもよい。
　上記表面処理は、後述する表面修飾剤を用いた表面修飾とは異なる処理である。
　表面処理を行うことで、第１熱伝導性無機粒子の粒子表面に官能基が導入され、第１熱伝導性無機粒子と、硬化性化合物等と相互作用しやすくなり、熱伝導シートの熱伝導性及びピール強度等がより改善すると推測される。
　表面処理としては、例えば、プラズマ処理（例えば、真空プラズマ処理、大気圧プラズマ処理及びアクアプラズマ処理等）、紫外線照射処理、コロナ処理、電子線照射処理、オゾン処理、焼成処理、火炎処理及び酸化剤処理が挙げられる。酸化剤処理は、酸性条件（例えば、ｐＨ６以下等）及び塩基性条件（例えば、ｐＨ１２以上等）のいずれで実施してもよい。 The first thermally conductive inorganic particles may be surface-treated.
The above surface treatment is different from surface modification using a surface modifier, which will be described later.
By performing the surface treatment, a functional group is introduced to the particle surface of the first thermally conductive inorganic particles, making it easier to interact with the first thermally conductive inorganic particles and the curable compound, etc., and improving the thermal conductivity of the thermally conductive sheet. It is presumed that the properties, peel strength, etc. are further improved.
Examples of surface treatment include plasma treatment (e.g., vacuum plasma treatment, atmospheric pressure plasma treatment, aqua plasma treatment, etc.), ultraviolet irradiation treatment, corona treatment, electron beam irradiation treatment, ozone treatment, baking treatment, flame treatment, and oxidizing agents. processing. The oxidizing agent treatment may be carried out under either acidic conditions (eg, pH 6 or lower) or basic conditions (eg, pH 12 or higher).
＜表面修飾剤、表面修飾第１熱伝導性無機粒子＞
　第１熱伝導層は、表面修飾剤を含み、第１熱伝導性無機粒子が、第１熱伝導性無機粒子の表面上に吸着した表面修飾剤とともに、表面修飾第１熱伝導性無機粒子を構成していることが好ましい。
　本明細書において、表面処理剤を用いた表面修飾とは、第１熱伝導性無機粒子の表面の少なくとも一部に表面処理剤が吸着している状態を意味する。吸着の形態は特に限定されず、結合している状態であればよい。すなわち、表面修飾は、表面処理剤の一部が脱離して得られる有機基が第１熱伝導性無機粒子表面に結合している状態も含む。結合は、共有結合、配位結合、イオン結合、水素結合、ファンデルワールス結合、及び、金属結合等のいずれの結合であってもよい。表面修飾は、表面の少なくとも一部に単分子膜を形成するようになされていてもよい。単分子膜は、表面処理剤の化学吸着によって形成される単層膜であり、Ｓｅｌｆ－ＡｓｓｅｍｂｌｅｄＭｏｎｏＬａｙｅｒ（ＳＡＭ）として知られている。なお、本明細書において、表面処理剤を用いた表面修飾は、第１熱伝導性無機粒子表面の一部のみであっても、全体であってもよい。 <Surface Modifier, Surface Modified First Thermally Conductive Inorganic Particles>
The first thermally conductive layer includes a surface modifier, and the first thermally conductive inorganic particles are surface-modified first thermally conductive inorganic particles together with the surface modifier adsorbed on the surface of the first thermally conductive inorganic particles. preferably configured.
As used herein, surface modification using a surface treatment agent means a state in which the surface treatment agent is adsorbed on at least part of the surface of the first thermally conductive inorganic particles. The form of adsorption is not particularly limited as long as it is in a bound state. That is, the surface modification includes a state in which an organic group obtained by partly desorbing the surface treatment agent is bonded to the surface of the first thermally conductive inorganic particles. The bond may be any bond such as covalent bond, coordinate bond, ionic bond, hydrogen bond, van der Waals bond, and metallic bond. The surface modification may be such as to form a monomolecular film on at least part of the surface. A monolayer is a monolayer film formed by chemisorption of a surface treatment agent and is known as a Self-Assembled MonoLayer (SAM). In this specification, the surface modification using the surface treatment agent may be applied to only a part of the surface of the first thermally conductive inorganic particles or to the entire surface.
　本明細書において、「表面修飾第１熱伝導性無機粒子」は、表面修飾剤により表面修飾されている第１熱伝導性無機粒子である。すなわち、表面修飾第１熱伝導性無機粒子は、第１熱伝導性無機粒子と上記第１熱伝導性無機粒子の表面上に吸着した表面修飾剤とを含む材料である。
　つまり、第１熱伝導層において、第１熱伝導性無機粒子は、第１熱伝導性無機粒子の表面上に吸着した表面修飾剤とともに、表面修飾第１熱伝導性無機粒子を構成することが好ましい。
　また、第１熱伝導層が表面修飾第１熱伝導性無機粒子を含むことによって、第１熱伝導層が第１熱伝導性無機粒子及び表面修飾剤を含むことになっていてもよい。
　第１熱伝導層中の第１熱伝導性無機粒子は、その一部又は全部が表面修飾剤とともに表面修飾第１熱伝導性無機粒子を構成していてもよい。例えば、第１熱伝導層中で、一部の第１熱伝導性無機粒子の表面修飾第１熱伝導性無機粒子を構成し、同時に、表面修飾第１熱伝導性無機粒子の構成に関与しない第１熱伝導性無機粒子が存在していてもよい。
　第１熱伝導層中の表面修飾剤は、その一部又は全部が第１熱伝導性無機粒子とともに表面修飾第１熱伝導性無機粒子を構成していてよい。例えば、第１熱伝導層中で、一部の表面修飾剤が表面修飾第１熱伝導性無機粒子を構成し、同時に、表面修飾第１熱伝導性無機粒子の構成に関与しない表面修飾剤が存在していてもよい。
　中でも、第１熱伝導層は、表面修飾第１熱伝導性無機粒子を構成する第１熱伝導性無機粒子が無機窒化物（好ましくは窒化ホウ素、又は凝集状窒化ホウ素）である、表面修飾無機窒化物（好ましくは表面修飾窒化ホウ素）を含むことが好ましい。第１熱伝導層中の無機窒化物（好ましくは窒化ホウ素）は、その一部又は全部が、表面修飾剤とともに表面修飾無機窒化物（好ましくは表面修飾窒化ホウ素）を構成していてよい。
　また、第１熱伝導層は表面修飾第１熱伝導性無機粒子を構成する第１熱伝導性無機粒子が無機酸化物（好ましくは酸化アルミニウム）である、表面修飾無機酸化物（好ましくは表面修飾アルミニウム）を含んでもよい。第１熱伝導層中の無機酸化物（好ましくは酸化アルミニウム）は、その一部又は全部が、表面修飾剤とともに表面修飾無機酸化物（好ましくは表面修飾酸化アルミニウム）を構成していてよい。 As used herein, "surface-modified first thermally conductive inorganic particles" are first thermally conductive inorganic particles that have been surface-modified with a surface modifier. That is, the surface-modified first thermally conductive inorganic particles are a material containing the first thermally conductive inorganic particles and the surface modifier adsorbed on the surfaces of the first thermally conductive inorganic particles.
In other words, in the first thermally conductive layer, the first thermally conductive inorganic particles together with the surface modifier adsorbed on the surfaces of the first thermally conductive inorganic particles can constitute the surface-modified first thermally conductive inorganic particles. preferable.
Further, the first thermally conductive layer may include the first thermally conductive inorganic particles and the surface modifier by including the surface-modified first thermally conductive inorganic particles in the first thermally conductive layer.
Some or all of the first thermally conductive inorganic particles in the first thermally conductive layer may constitute surface-modified first thermally conductive inorganic particles together with a surface modifier. For example, in the first thermally conductive layer, some of the first thermally conductive inorganic particles are surface-modified first thermally conductive inorganic particles, and at the same time, they are not involved in the formation of the surface-modified first thermally conductive inorganic particles. First thermally conductive inorganic particles may be present.
Part or all of the surface modifier in the first thermally conductive layer may constitute the surface-modified first thermally conductive inorganic particles together with the first thermally conductive inorganic particles. For example, in the first thermally conductive layer, part of the surface modifier constitutes the surface-modified first thermally conductive inorganic particles, and at the same time, there is a surface modifier that does not participate in the formation of the surface-modified first thermally conductive inorganic particles. May be present.
Among them, the first thermally conductive layer is a surface-modified inorganic material in which the first thermally conductive inorganic particles constituting the surface-modified first thermally conductive inorganic particles are inorganic nitrides (preferably boron nitride or aggregated boron nitride). It preferably contains a nitride (preferably surface-modified boron nitride). Part or all of the inorganic nitride (preferably boron nitride) in the first thermally conductive layer may constitute a surface-modified inorganic nitride (preferably surface-modified boron nitride) together with a surface modifier.
In addition, the first thermally conductive layer is a surface-modified inorganic oxide (preferably a surface-modified aluminum). Part or all of the inorganic oxide (preferably aluminum oxide) in the first thermally conductive layer may constitute a surface-modified inorganic oxide (preferably surface-modified aluminum oxide) together with the surface modifier.
　表面修飾第１熱伝導性無機粒子は、例えば、第１熱伝導性無機粒子と表面修飾剤とを接触させて形成できる。例えば、後述する第１熱伝導層形成用において、第１熱伝導性無機粒子と、表面修飾剤と、組成物を構成する他の成分とを混合し、第１熱伝導層を製造する過程で表面修飾第１熱伝導性無機粒子を形成してもよい。
　また、例えば、事前に、溶媒中で、第１熱伝導性無機粒子と表面修飾剤とを混合して、表面修飾第１熱伝導性無機粒子を含む混合液を調製し、上記混合液から、ろ別等の手段で、表面修飾第１熱伝導性無機粒子を分離し、分離された表面修飾第１熱伝導性無機粒子を得てもよい。分離された表面修飾第１熱伝導性無機粒子を用いて、後述する第１熱伝導層形成用組成物を調製し、更に上記組成物を用いて第１熱伝導層を形成してもよい。 The surface-modified first thermally conductive inorganic particles can be formed, for example, by contacting the first thermally conductive inorganic particles with a surface modifier. For example, in the process of forming the first thermally conductive layer described later, the first thermally conductive inorganic particles, the surface modifier, and other components constituting the composition are mixed to produce the first thermally conductive layer. Surface-modified first thermally conductive inorganic particles may be formed.
Alternatively, for example, the first thermally conductive inorganic particles and a surface modifier are mixed in advance in a solvent to prepare a mixed liquid containing the surface-modified first thermally conductive inorganic particles, and from the mixed liquid, The surface-modified first thermally conductive inorganic particles may be separated by means such as filtering to obtain the separated surface-modified first thermally conductive inorganic particles. The separated surface-modified first thermally conductive inorganic particles may be used to prepare a composition for forming a first thermally conductive layer, which will be described later, and the composition may be used to form the first thermally conductive layer.
　表面修飾剤としては、例えば、長鎖アルキル脂肪酸等のカルボン酸、有機ホスホン酸、有機リン酸エステル及び有機シラン分子（例えば、シランカップリング剤等）等の従来公知の表面修飾剤を使用できる。更に、例えば、特開２００９－５０２５２９号公報、特開２００１－１９２５００号公報及び特許４６９４９２９号に記載の表面修飾剤を用いてもよい。 As the surface modifier, for example, conventionally known surface modifiers such as carboxylic acids such as long-chain alkyl fatty acids, organic phosphonic acids, organic phosphoric acid esters, and organic silane molecules (eg, silane coupling agents, etc.) can be used. Further, for example, surface modifiers described in JP-A-2009-502529, JP-A-2001-192500 and JP-A-4694929 may be used.
　上記シランカップリング剤は、例えば、Ｓｉ原子に直接結合した加水分解性基を有する化合物である。
　上記加水分解性基としては、例えば、アルコキシ基（好ましくは炭素数１～１０）、及び、塩素原子等のハロゲン原子が挙げられる。
　シランカップリング剤が有する、Ｓｉ原子に直接結合した加水分解性基の数は、１以上が好ましく、２以上がより好ましく、３以上が更により好ましい。上記数に上限はなく、例えば、１００００以下である。
　シランカップリング剤は、反応性基を有することも好ましい。
　上記反応性基の具体例としては、エポキシ基、オキセタニル基、ビニル基、（メタ）クリル基、スチリル基、アミノ基、イソシアネート基、メルカプト基、及び、酸無水物基が挙げられる。
　シランカップリング剤が有する、反応性基の数は、１以上が好ましく、２以上がより好ましく、３以上が更により好ましい。上記数に上限はなく、例えば、１００００以下である。
　シランカップリング剤としては、例えば、３－アミノプロピルトリエトキシシラン、３－（２－アミノエチル）アミノプロピルトリエトキシシラン、３－アミノプロピルトリメトキシシラン、３－（２－アミノエチル）アミノプロピルトリメトキシシラン、Ｎ－フェニル－３－アミノプロピルトリメトキシシラン、３－メルカプトトリエトキシシラン、及び、３－ウレイドプロピルトリエトキシシランが挙げられる。
　また、シランカップリング剤は、多官能基型シランカップリング剤であってもよい。例えば、シランカップリング剤Ｘ－１２シリーズ（例えば、Ｘ－１２－１０４８、Ｘ－１２－１０５０、Ｘ－１２－９８１Ｓ及びＸ－１２－９８４Ｓ等、信越化学工業社製）が挙げられる。 The silane coupling agent is, for example, a compound having a hydrolyzable group directly bonded to the Si atom.
Examples of the hydrolyzable group include alkoxy groups (preferably having 1 to 10 carbon atoms) and halogen atoms such as chlorine atoms.
The number of hydrolyzable groups directly bonded to Si atoms in the silane coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, and it is, for example, 10,000 or less.
The silane coupling agent also preferably has a reactive group.
Specific examples of the reactive groups include epoxy groups, oxetanyl groups, vinyl groups, (meth)acryl groups, styryl groups, amino groups, isocyanate groups, mercapto groups, and acid anhydride groups.
The number of reactive groups possessed by the silane coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, and it is, for example, 10,000 or less.
Silane coupling agents include, for example, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, Methoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptotriethoxysilane, and 3-ureidopropyltriethoxysilane.
Also, the silane coupling agent may be a polyfunctional silane coupling agent. Examples thereof include the X-12 series of silane coupling agents (eg, X-12-1048, X-12-1050, X-12-981S and X-12-984S, manufactured by Shin-Etsu Chemical Co., Ltd.).
　表面修飾剤は、１種単独又は２種以上で用いてもよい。
　第１熱伝導層が表面修飾剤を含む場合、表面修飾剤の含有量は、第１熱伝導層全質量に対して、０．００５～５質量％が好ましく、０．０５～３質量％がより好ましい。
　第１熱伝導層が表面修飾剤を含む場合、表面修飾剤の含有量は、全第１熱伝導性無機粒子に対して、０．０１～１０質量％が好ましく、０．１０～５質量％がより好ましい。
　表面修飾第１熱伝導性無機粒子中における、表面修飾剤と第１熱伝導性無機粒子との質量比（第１熱伝導性無機粒子表面上に吸着している表面修飾剤の質量／第１熱伝導性無機粒子の質量）は、０．００００１～０．５が好ましく、０．０００１～０．１がより好ましい。
　第１熱伝導層が表面修飾第１熱伝導性無機粒子を含む場合、表面修飾第１熱伝導性無機粒子の含有量は、第１熱伝導層全体積に対して、５０．０～８０．０体積％が好ましく、５５．０～７５．０体積％がより好ましく、６０．０～７０．０体積％が更に好ましい。
　第１熱伝導層が表面修飾窒化物（好ましくは表面修飾窒化ホウ素）を含む場合、表面修飾窒化物（好ましくは表面修飾窒化ホウ素）の含有量は、全表面修飾第１熱伝導性無機粒子に対して、１０～１００質量％が好ましく、４０～１００質量％がより好ましく、６０～１００質量％が更に好ましい。 The surface modifiers may be used singly or in combination of two or more.
When the first thermally conductive layer contains a surface modifier, the content of the surface modifier is preferably 0.005 to 5% by mass, more preferably 0.05 to 3% by mass, based on the total mass of the first thermally conductive layer. more preferred.
When the first thermally conductive layer contains a surface modifier, the content of the surface modifier is preferably 0.01 to 10% by mass, more preferably 0.10 to 5% by mass, with respect to all the first thermally conductive inorganic particles. is more preferred.
The mass ratio of the surface modifier to the first thermally conductive inorganic particles in the surface-modified first thermally conductive inorganic particles (the mass of the surface modifier adsorbed on the surface of the first thermally conductive inorganic particles/the first The mass of the thermally conductive inorganic particles) is preferably 0.00001 to 0.5, more preferably 0.0001 to 0.1.
When the first thermally conductive layer contains the surface-modified first thermally conductive inorganic particles, the content of the surface-modified first thermally conductive inorganic particles is 50.0 to 80.0 with respect to the total area of the first thermally conductive layer. 0% by volume is preferred, 55.0 to 75.0% by volume is more preferred, and 60.0 to 70.0% by volume is even more preferred.
When the first thermally conductive layer contains a surface-modified nitride (preferably surface-modified boron nitride), the content of the surface-modified nitride (preferably surface-modified boron nitride) is On the other hand, 10 to 100% by mass is preferable, 40 to 100% by mass is more preferable, and 60 to 100% by mass is even more preferable.
　第１熱伝導性無機粒子が無機窒化物である場合（例えば、第１熱伝導性無機粒子が凝集状窒化ホウ素である場合）、第１熱伝導性無機粒子の平均粒径は、１．０～３００．０μｍが好ましく、５．０～１００．０μｍがより好ましく、１０．０～８０．０μｍが更に好ましい。
　第１熱伝導性無機粒子が無機酸化物である場合、第１熱伝導性無機粒子の平均粒径は、０．１～３０．０μｍが好ましく、１．０～１５．０μｍがより好ましく、２．０～１０．０μｍが更に好ましく、２．０～７．０μｍが特に好ましい。
　第１熱伝導性無機粒子が無機窒化物及び無機酸化物の両方を含む場合、それぞれが上記好適態様であることが好ましい。
　第１熱伝導性無機粒子の平均粒径は、例えば、走査型電子顕微鏡（ＳＥＭ：Ｓｃａｎｎｉｎｇ　Ｅｌｅｃｔｒｏｎ　Ｍｉｃｒｏｓｃｏｐｅ）又はレーザー回折式粒子径分布測定装置を用いて測定できる。走査型電子顕微鏡としては、例えば、透過型顕微鏡ＨＴ７７００（日立ハイテクノロジーズ社製）を使用できる。
　走査型電子顕微鏡を用いて得た粒子像の最大長（Ｄｍａｘ：粒子画像の輪郭上の２点における最大長さ）及び最大長垂直長（ＤＶ－ｍａｘ：最大長に平行な２本の直線で画像を挟んだ時、２直線間を垂直に結ぶ最短の長さ）を測長し、その相乗平均値（Ｄｍａｘ×ＤＶ－ｍａｘ）１／２を粒径とした。この方法で１００個の粒子の粒径を測定し、その算術平均値を粒子の平均粒径とした。 When the first thermally conductive inorganic particles are inorganic nitrides (for example, when the first thermally conductive inorganic particles are aggregated boron nitride), the average particle size of the first thermally conductive inorganic particles is 1.0. ~300.0 μm is preferable, 5.0 to 100.0 μm is more preferable, and 10.0 to 80.0 μm is even more preferable.
When the first thermally conductive inorganic particles are an inorganic oxide, the average particle size of the first thermally conductive inorganic particles is preferably 0.1 to 30.0 μm, more preferably 1.0 to 15.0 μm. 0 to 10.0 μm is more preferable, and 2.0 to 7.0 μm is particularly preferable.
When the first thermally conductive inorganic particles contain both an inorganic nitride and an inorganic oxide, it is preferable that each of them is in the preferred embodiment described above.
The average particle size of the first thermally conductive inorganic particles can be measured using, for example, a scanning electron microscope (SEM) or a laser diffraction particle size distribution analyzer. As a scanning electron microscope, for example, a transmission microscope HT7700 (manufactured by Hitachi High-Technologies Corporation) can be used.
The maximum length of the particle image obtained using a scanning electron microscope (Dmax: the maximum length at two points on the contour of the particle image) and the maximum vertical length (DV-max: two straight lines parallel to the maximum length The shortest length vertically connecting two straight lines when the image was sandwiched was measured, and the geometric mean value (Dmax×DV-max) 1/2 was taken as the grain size. The particle size of 100 particles was measured by this method, and the arithmetic average value was taken as the average particle size of the particles.
　第１熱伝導性無機粒子は、無機窒化物を含むことが好ましく、窒化ホウ素を含むことがより好ましく、窒化ホウ素を含み、平均アスペクト比が１．０～１．６である酸化アルミニウム（熱伝導性無機粒子Ｘに該当する）を含まないことが更に好ましく、窒化ホウ素のみからなることが特に好ましい。 The first thermally conductive inorganic particles preferably contain an inorganic nitride, more preferably contain boron nitride, contain boron nitride, and have an average aspect ratio of 1.0 to 1.6. It is more preferable not to contain organic particles X), and it is particularly preferable to consist only of boron nitride.
　第１熱伝導性無機粒子は、１種単独又は２種以上で用いてもよい。
　第１熱伝導性無機粒子の含有量は、第１熱伝導層全体積に対して、５０．０～８０．０体積％が好ましく、５５．０～７５．０体積％がより好ましく、６０．０～７０．０体積％が更に好ましい。 The first thermally conductive inorganic particles may be used singly or in combination of two or more.
The content of the first thermally conductive inorganic particles is preferably 50.0 to 80.0% by volume, more preferably 55.0 to 75.0% by volume, with respect to the total volume of the first thermally conductive layer. 0 to 70.0% by volume is more preferable.
＜硬化性化合物＞
　第１熱伝導層は、硬化性化合物を含んでいてもよい。
　硬化性化合物は、架橋性基を有する化合物である。
　架橋性基としては、例えば、ビニル基、（メタ）アリル基及び（メタ）アクリロイル基等のエチレン性不飽和結合を有する基；エポキシ基及びオキセタン基等の環状エーテル基；フェノール性ヒドロキシ基及びメチロール基等のヒドロキシ基；無水カルボン酸基が挙げられる。 <Curable compound>
The first thermally conductive layer may contain a curable compound.
A curable compound is a compound having a crosslinkable group.
Examples of crosslinkable groups include groups having ethylenically unsaturated bonds such as vinyl groups, (meth)allyl groups and (meth)acryloyl groups; cyclic ether groups such as epoxy groups and oxetane groups; phenolic hydroxy groups and methylol. hydroxy groups such as groups; carboxylic anhydride groups;
　硬化性化合物としては、例えば、ラジカル、酸、塩基及び／又は熱により架橋可能な公知の化合物であればよく、具体的には、エポキシ化合物、マレイミド化合物、フェノール化合物及び酸無水物が挙げられる。
　硬化性化合物は、エポキシ化合物、マレイミド化合物、フェノール化合物及び酸無水物からなる群から選択される１種以上を含むことが好ましく、エポキシ化合物、マレイミド化合物及びフェノール化合物からなる群から選択される１種以上を含むことがより好ましく、エポキシ化合物及びマレイミド化合物からなる群から選択される１種以上を含むことが更に好ましい。 The curable compound may be, for example, a known compound that can be crosslinked by radicals, acids, bases and/or heat, and specific examples thereof include epoxy compounds, maleimide compounds, phenolic compounds and acid anhydrides.
The curable compound preferably contains one or more selected from the group consisting of epoxy compounds, maleimide compounds, phenol compounds and acid anhydrides, and one selected from the group consisting of epoxy compounds, maleimide compounds and phenol compounds. More preferably, it contains at least one selected from the group consisting of epoxy compounds and maleimide compounds.
（エポキシ化合物）
　エポキシ化合物は、１分子中に、１つ以上のエポキシ基を有する化合物である。
　エポキシ基は、オキシラン環から１つ以上の水素原子（好ましくは１つの水素原子）を除いてなる基である。上記エポキシ基は、可能な場合、更に置換基（例えば、直鎖状又は分岐鎖状の炭素数１～５のアルキル基等）を有していてもよい。 (epoxy compound)
An epoxy compound is a compound having one or more epoxy groups in one molecule.
An epoxy group is a group having one or more hydrogen atoms (preferably one hydrogen atom) removed from an oxirane ring. If possible, the epoxy group may further have a substituent (eg, a straight-chain or branched-chain alkyl group having 1 to 5 carbon atoms, etc.).
　エポキシ化合物が有するエポキシ基の数は、１分子中、２以上が好ましく、２～１０００がより好ましく、２～４０が更に好ましい。 The number of epoxy groups possessed by the epoxy compound is preferably 2 or more, more preferably 2 to 1000, and even more preferably 2 to 40, in one molecule.
　エポキシ化合物の分子量は、１５０以上が好ましく、３００以上がより好ましい。上限は、１０００００以下が好ましく、１００００以下がより好ましい。
　なお、上記分子量に分子量分布がある場合、上記分子量は重量平均分子量である。
　重量平均分子量は、ゲルパーミエーションクロマトグラフィ（ＧＰＣ）によるポリスチレン換算で求めた重量平均分子量である。 The molecular weight of the epoxy compound is preferably 150 or more, more preferably 300 or more. The upper limit is preferably 100,000 or less, more preferably 10,000 or less.
In addition, when the said molecular weight has molecular weight distribution, the said molecular weight is a weight average molecular weight.
The weight average molecular weight is the weight average molecular weight obtained by gel permeation chromatography (GPC) in terms of polystyrene.
　エポキシ化合物のエポキシ基含有量は、２．０～２０．０ｍｍｏｌ／ｇが好ましく、５．０～１５．０ｍｍｏｌ／ｇがより好ましい。
　なお、上記エポキシ基含有量は、エポキシ化合物１ｇが有するエポキシ基の数を意味する。
　エポキシ化合物は、芳香環基（好ましくは芳香族炭化水素環基）を有することも好ましい。 The epoxy group content of the epoxy compound is preferably 2.0 to 20.0 mmol/g, more preferably 5.0 to 15.0 mmol/g.
In addition, the said epoxy group content means the number of epoxy groups which 1g of epoxy compounds have.
The epoxy compound also preferably has an aromatic ring group (preferably an aromatic hydrocarbon ring group).
　エポキシ化合物は、液晶性を示してもよく示さなくてもよい。
　つまり、エポキシ化合物は、液晶化合物であってよい。換言すると、エポキシ基を有する液晶化合物であってもよい。 The epoxy compound may or may not exhibit liquid crystallinity.
That is, the epoxy compound may be a liquid crystal compound. In other words, it may be a liquid crystal compound having an epoxy group.
　エポキシ化合物としては、例えば、ビスフェノールＡ、Ｆ、Ｓ及びＡＤ等のグリシジルエーテルであるビスフェノールＡ型エポキシ化合物、ビスフェノールＦ型エポキシ化合物、ビスフェノールＳ型エポキシ化合物並びにビスフェノールＡＤ型エポキシ化合物；水素添加したビスフェノールＡ型エポキシ化合物及び水素添加したビスフェノールＡＤ型エポキシ化合物；フェノールノボラック型のグリシジルエーテル（フェノールノボラック型エポキシ化合物）、クレゾールノボラック型のグリシジルエーテル（クレゾールノボラック型エポキシ化合物）及びビスフェノールＡノボラック型のグリシジルエーテル；ジシクロペンタジエン型のグリシジルエーテル（ジシクロペンタジエン型エポキシ化合物）；ジヒドロキシペンタジエン型のグリシジルエーテル（ジヒドロキシペンタジエン型エポキシ化合物）；レゾルシノール等のジヒドロキシベンゼンのグリシジルエーテルのようなポリヒドロキシベンゼン型のグリシジルエーテル（ポリヒドロキシベンゼン型エポキシ化合物）；ベンゼンポリカルボン酸型のグリシジルエステル（ベンゼンポリカルボン酸型エポキシ化合物）；トリスフェノールメタン型エポキシ化合物；フェノキシ樹脂；並びに側鎖にエポキシ基を有するアクリル樹脂が挙げられる。上述の各化合物におけるグリシジルエーテル基及び／又はグリシジルエステル基の１つ又は２つ以上が、ジグリシジルアミノ基又はジグリシジルアミノアルキレン基（ジグリシジルアミノメチレン基等）に置き換わった化合物をエポキシ化合物として用いてもよい。
　上述の各化合物は、置換基を有していてもよい。例えば、上述の各化合物に含まれる芳香環基、シクロアルカン環基及び／又はアルキレン基等が、グリシジルエーテル基、グリシジルエステル基、ジグリシジルアミノ基及び／又はジグリシジルアミノアルキレン基以外の置換基を有していてもよい。 Examples of epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, and bisphenol AD type epoxy compounds, which are glycidyl ethers of bisphenol A, F, S and AD; hydrogenated bisphenol A; type epoxy compound and hydrogenated bisphenol AD type epoxy compound; phenol novolac type glycidyl ether (phenol novolac type epoxy compound), cresol novolac type glycidyl ether (cresol novolac type epoxy compound) and bisphenol A novolac type glycidyl ether; Cyclopentadiene type glycidyl ether (dicyclopentadiene type epoxy compound); dihydroxypentadiene type glycidyl ether (dihydroxypentadiene type epoxy compound); polyhydroxybenzene type glycidyl ether such as glycidyl ether of dihydroxybenzene such as resorcinol (polyhydroxy benzene-type epoxy compounds); benzenepolycarboxylic acid-type glycidyl esters (benzenepolycarboxylic acid-type epoxy compounds); trisphenolmethane-type epoxy compounds; phenoxy resins; A compound in which one or more of the glycidyl ether groups and/or glycidyl ester groups in each of the above compounds is replaced with a diglycidylamino group or a diglycidylaminoalkylene group (such as a diglycidylaminomethylene group) is used as an epoxy compound. may
Each compound described above may have a substituent. For example, an aromatic ring group, a cycloalkane ring group and/or an alkylene group contained in each of the above compounds may be substituted with a substituent other than a glycidyl ether group, a glycidyl ester group, a diglycidylamino group and/or a diglycidylaminoalkylene group. may have.
　エポキシ化合物は、１種単独又は２種以上で用いてもよい。
　エポキシ化合物の含有量は、第１熱伝導層全質量に対して、１．０～９０．０質量％が好ましく、２．０～５０．０質量％がより好ましく、４．０～２０．０質量％が更に好ましい。 You may use an epoxy compound individually by 1 type or in 2 or more types.
The content of the epoxy compound is preferably 1.0 to 90.0% by mass, more preferably 2.0 to 50.0% by mass, and 4.0 to 20.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred.
（マレイミド化合物）
　第１熱伝導層は、マレイミド化合物を含んでいてもよい。
　第１熱伝導層は、マレイミド化合物がフェノール化合物との付加反応及び／又は上記付加反応で生じた高分子構造が組成物中のその他成分で形成される高分子構造に対して相互侵入網目構造の形成して、第１熱伝導層の高分子構造の密度をより向上させ、熱伝導シートの熱伝導性及び耐熱性（Ｔｇ）をより高められる、と考えられている。
　また、第１熱伝導層中により密な高分子構造が形成されるため、熱伝導シート中に水が浸入しにくくなり吸湿性も抑制され、加えて、熱伝導シートが高温に晒された場合において構成成分が熱分解して熱伝導シート中に揮発性の低分子が生成されることも抑制される。その結果、熱伝導シートを高温下に置いた場合でも、熱伝導シートから揮発性成分が気化して接着性が低下することが抑制され、熱伝導シードのハンダ耐熱性がより向上する、と考えられている。 (maleimide compound)
The first heat conductive layer may contain a maleimide compound.
The first heat conductive layer has an interpenetrating network structure with respect to the polymer structure formed by the addition reaction of the maleimide compound with the phenol compound and/or the polymer structure formed by the above addition reaction with the other components in the composition. It is believed that forming a higher density polymer structure of the first thermally conductive layer can further enhance the thermal conductivity and heat resistance (Tg) of the thermally conductive sheet.
In addition, since a denser polymer structure is formed in the first heat conductive layer, it is difficult for water to enter the heat conductive sheet, and hygroscopicity is suppressed. It is also suppressed that the constituent components are thermally decomposed in the heat conductive sheet to generate volatile low molecular weight molecules. As a result, even when the thermal conductive sheet is placed at high temperatures, the evaporation of volatile components from the thermal conductive sheet and the decrease in adhesiveness are suppressed, and the solder heat resistance of the thermal conductive seed is further improved. It is
　マレイミド化合物とは、１つ以上のマレイミド基を有する化合物を意味する。
　なかでも、マレイミド化合物としては、１つ又は２つのマレイミド基を有する化合物が好ましく、２つのマレイミド基を有する化合物（ビスマレイミド化合物）がより好ましい。 A maleimide compound means a compound having one or more maleimide groups.
Among them, the maleimide compound is preferably a compound having one or two maleimide groups, and more preferably a compound having two maleimide groups (bismaleimide compound).
　マレイミド化合物が有するマレイミド基の数は、１以上であり、１～１００が好ましく、２～１０がより好ましく、２が更に好ましい。
　マレイミド化合物は、高分子化合物及び低分子化合物のいずれであってもよい。
　マレイミド化合物の分子量は、１００～３０００が好ましく、２００～２０００がより好ましく、３００～１０００が更に好ましい。 The number of maleimide groups possessed by the maleimide compound is 1 or more, preferably 1 to 100, more preferably 2 to 10, and still more preferably 2.
The maleimide compound may be either a high molecular weight compound or a low molecular weight compound.
The molecular weight of the maleimide compound is preferably from 100 to 3,000, more preferably from 200 to 2,000, even more preferably from 300 to 1,000.
　マレイミド化合物が有するマレイミド基としては、式（Ｍ）で表される基が好ましい。 The maleimide group possessed by the maleimide compound is preferably a group represented by formula (M).
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　式（Ｍ）中、＊は、結合位置を表す。Ｘ及びＹは、それぞれ独立に、水素原子又は置換基を表す。 In formula (M), * represents a binding position. X and Y each independently represent a hydrogen atom or a substituent.
　Ｘ及びＹは、それぞれ独立に、水素原子又は置換基を表す。
　上記置換基としては、例えば、公知の置換基（例えば、アルキル基等）が挙げられる。
　Ｘ及びＹとしては、水素原子が好ましい。 X and Y each independently represent a hydrogen atom or a substituent.
Examples of the substituent include known substituents (eg, alkyl group, etc.).
X and Y are preferably hydrogen atoms.
　マレイミド化合物は、芳香環基（例えば、ベンゼン環基等）を１つ以上（好ましくは１～１０つ）有する化合物であることも好ましい。
　マレイミド化合物は、式（１）で表される化合物であることが好ましい。 The maleimide compound is also preferably a compound having one or more (preferably 1 to 10) aromatic ring groups (eg, benzene ring group, etc.).
The maleimide compound is preferably a compound represented by Formula (1).
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　式（１）中、ｍは、０又は１を表す。ｍとしては、１が好ましい。
　ｎは０又は１を表す。ｎとしては、１が好ましい。 In formula (1), m represents 0 or 1. As m, 1 is preferable.
n represents 0 or 1; As n, 1 is preferable.
　式（１）中、Ｒ１及びＲ２は、それぞれ独立に、水素原子又は置換基を表す。
　上記置換基としては、アルキル基が好ましい。上記アルキル基は、直鎖状でも分岐鎖状でもよく、上記アルキル基の炭素数としては１～１０が好ましい。
　Ｒ１及び／又はＲ２が置換基を表す場合、Ｒ１及び／又はＲ２は、ベンゼン環基上においてマレイミド基と隣接した位置に存在することも好ましい。
　Ｒ１及びＲ２が両方とも置換基を表す場合、Ｒ１及びＲ２はそれぞれ異なる置換基であることが好ましく、Ｒ１がメチル基を表し、Ｒ２がエチル基を表すことがより好ましい。 In formula (1), R 1 and R 2 each independently represent a hydrogen atom or a substituent.
As the substituent, an alkyl group is preferable. The alkyl group may be linear or branched, and preferably has 1 to 10 carbon atoms.
When R 1 and/or R 2 represent a substituent, it is also preferred that R 1 and/or R 2 are present at a position adjacent to the maleimide group on the benzene ring group.
When both R 1 and R 2 represent substituents, R 1 and R 2 preferably represent different substituents, more preferably R 1 represents a methyl group and R 2 represents an ethyl group.
　式（１）中、Ｌ１は２価の連結基を表す。
　上記２価の連結基としては、２価の連結基としては、例えば、エーテル基（－Ｏ－）、カルボニル基（－ＣＯ－）、エステル基（－ＣＯＯ－）、チオエーテル基（－Ｓ－）、－ＳＯ２－、－ＮＲ－（Ｒは、水素原子又はアルキル基）、２価の脂肪族炭化水素基（例えば、アルキレン基、シクロアルキレン基、アルケニレン基（－ＣＨ＝ＣＨ－等）、アルキニレン基（－Ｃ≡Ｃ－等））及び２価の芳香環基（アリーレン基及びヘテロアリーレン基）並びにこれらを組み合わせた基が挙げられる。
　式（１）中、Ｌ１で表される２価の連結基の炭素数は、１以上が好ましく、１～１００がより好ましく、３～１５が更に好ましい。 In formula (1), L 1 represents a divalent linking group.
Examples of the divalent linking group include an ether group (--O--), a carbonyl group (--CO--), an ester group (--COO--), and a thioether group (--S--). , —SO 2 —, —NR— (R is a hydrogen atom or an alkyl group), divalent aliphatic hydrocarbon group (e.g., alkylene group, cycloalkylene group, alkenylene group (—CH═CH— etc.), alkynylene groups (—C≡C—, etc.), divalent aromatic ring groups (arylene groups and heteroarylene groups), and groups in which these are combined.
In formula (1), the number of carbon atoms in the divalent linking group represented by L 1 is preferably 1 or more, more preferably 1-100, even more preferably 3-15.
　なかでも、Ｌ１は、「＊ｐ－（Ｌ２－Ａｒ）ｋ－＊ｑ」で表される基が好ましい。
　＊ｑは、マレイミド基と直接結合する側の結合位置を表し、＊ｐは、反対側の結合位置を表す。
　ｋは、１以上の整数を表し、１～１０の整数が好ましく、１がより好ましい。
　Ｌ２は、単結合、－Ｃ（Ｒ３）（Ｒ４）－、－Ｏ－又は－ＣＯ－を表し、－Ｃ（Ｒ３）（Ｒ４）－が好ましい。
　Ｒ３及びＲ４は、それぞれ独立に、水素原子又は置換基を表し、アルキル基（直鎖状でも分岐鎖状でもよく、炭素数は１～１０）が好ましい。
　Ａｒは、アリーレン基を表す。上記アリーレン基の環員原子の数は、６～１５が好ましく、６がより好ましい。上記アリーレン基が置換基を有する場合、置換基の数は、１～４が好ましく、１～２がより好ましい。上記アリーレン基が有していてもよい置換基としては、アルキル基（直鎖状でも分岐鎖状でもよく、炭素数は１～１０）が好ましい。Ａｒがなり得る構造としては、例えば、式（１）中に明示される、Ｒ１及びＲ２と結合するベンゼン環基がなり得る構造も挙げられる。
　Ｌ２及びＡｒが複数存在する場合、複数存在するＬ２同士及び複数存在するＡｒ同士は、それぞれ同一でも異なっていてもよい。 Among them, L 1 is preferably a group represented by “* p —(L 2 —Ar) k —* q ”.
* q represents the bonding position on the side directly bonded to the maleimide group, and * p represents the bonding position on the opposite side.
k represents an integer of 1 or more, preferably an integer of 1 to 10, more preferably 1.
L 2 represents a single bond, -C(R 3 )(R 4 )-, -O- or -CO-, preferably -C(R 3 )(R 4 )-.
R 3 and R 4 each independently represent a hydrogen atom or a substituent, preferably an alkyl group (which may be linear or branched and has 1 to 10 carbon atoms).
Ar represents an arylene group. The number of ring member atoms in the arylene group is preferably 6 to 15, more preferably 6. When the arylene group has a substituent, the number of substituents is preferably 1-4, more preferably 1-2. As the substituent that the arylene group may have, an alkyl group (which may be linear or branched and has 1 to 10 carbon atoms) is preferable. Structures that Ar can have include, for example, structures that can have a benzene ring group bonded to R 1 and R 2 , which are clearly shown in formula (1).
When there are a plurality of L 2 and Ar, the plurality of L 2 and the plurality of Ar may be the same or different.
　ｎが１の場合、Ｒ１及びＲ２と結合するベンゼン環基上において、マレイミド基と、「－（Ｌ１）ｍ－マレイミド基」で表される基との２つの基は、互いに、オルト位に配置されてもよく、メタ位に配置されてもよく、パラ位に配置されてもよい。なかでも、上記２つの基は、メタ位又はパラ位に配置されていることが好ましい。 When n is 1, two groups, a maleimido group and a group represented by "-(L 1 ) m -maleimido group", on the benzene ring group bonded to R 1 and R 2 are mutually ortho It may be placed at the meta-position, it may be placed at the para-position. Among others, the above two groups are preferably arranged at the meta-position or the para-position.
　なかでも、式（１）で表される化合物は、ｍが１を表し、ｎが１を表し、かつ、Ｌ１で表される２価の連結基の炭素数が３～１５であることが好ましい。 Among them, in the compound represented by formula (1), m represents 1, n represents 1, and the divalent linking group represented by L1 has 3 to 15 carbon atoms. preferable.
　マレイミド化合物は、１種単独又は２種以上で用いてもよい。
　マレイミド化合物の含有量は、第１熱伝導層全質量に対して、０．１～４０．０質量％が好ましく、１．０～１５．０質量％がより好ましく、５．０～２０．０質量％が更に好ましい。 You may use a maleimide compound individually by 1 type or in 2 or more types.
The content of the maleimide compound is preferably 0.1 to 40.0% by mass, more preferably 1.0 to 15.0% by mass, and 5.0 to 20.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred.
（フェノール化合物）
　フェノール化合物は、１つ以上のフェノール性ヒドロキシ基を有する化合物である。
　フェノール化合物が有するフェノール性ヒドロキシ基の数は、２以上が好ましく、２～１０がより好ましい。
　フェノール化合物は、トリアジン骨格を有することが好ましい。
　トリアジン骨格を有するとは、フェノール化合物が、分子内に１つ以上（好ましくは、１～５つ）のトリアジン環基を有することを意味する。 (phenol compound)
A phenolic compound is a compound with one or more phenolic hydroxy groups.
The number of phenolic hydroxy groups possessed by the phenol compound is preferably 2 or more, more preferably 2-10.
The phenol compound preferably has a triazine skeleton.
Having a triazine skeleton means that the phenol compound has one or more (preferably 1 to 5) triazine ring groups in the molecule.
－式（Ｚ１）で表される化合物－
　フェノール化合物は、式（Ｚ１）で表される化合物であることも好ましい。
　フェノール化合物は、式（Ｚ１）で表される化合物を含むことが好ましく、フェノール化合物が式（Ｚ１）で表される化合物そのものであってもよい。
　式（Ｚ１）で表される化合物の含有量は、フェノール化合物の全質量に対して、１０～１００質量％が好ましく、２５～１００質量％がより好ましく、５０～１００質量％が更に好ましい。 -Compound represented by formula (Z1)-
The phenol compound is also preferably a compound represented by Formula (Z1).
The phenol compound preferably contains a compound represented by formula (Z1), and the phenol compound may be the compound represented by formula (Z1) itself.
The content of the compound represented by formula (Z1) is preferably 10 to 100% by mass, more preferably 25 to 100% by mass, and even more preferably 50 to 100% by mass, based on the total mass of the phenol compound.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　式（Ｚ１）中、ｒは０以上の整数を表す。
　ｒとしては、０～２０の整数が好ましく、０～１０の整数がより好ましい。
　Ｌは、２価の有機基を表す。上記２価の有機基としては、例えば、置換基を有していてもよい２価の芳香環基、置換基を有していてもよい２価の脂肪族炭化水素基、置換基を有していてもよい２価の脂肪族環基、－Ｏ－、－Ｓ－、－Ｎ（ＲＮ）－又は－ＣＯ－、及び、これらを組み合わせた基が挙げられる。
　ＲＮは、水素原子又は置換基を表す。ＲＮの表す置換基としては、例えば、炭素数１～５の直鎖状のアルキル基及び分岐鎖状のアルキル基が挙げられる。
　また、Ｌで表される、芳香環基、脂肪族炭化水素基及び脂肪族環基が有していてもよい置換基としては、例えば、炭素数１～５の直鎖状のアルキル基及び分岐鎖状のアルキル基が挙げられる。
　ＲＺは、水素原子又は置換基を表す。
　ＲＺで表される置換基としては、炭素数１～６の置換基が好ましく、炭素数１～６の炭化水素基がより好ましく、炭素数１～６の直鎖状又は分岐鎖状のアルキル基が更に好ましい。
　式（Ｚ１）中、（３＋ｒ）個存在するＲＺのうち、置換基を表すＲＺの割合〔（置換基を表すＲＺの個数／（３＋ｒ）個存在するＲＺの個数）×１００〕は、３０％以上が好ましく、５０％以上がより好ましく、６５％以上が更に好ましい。上限は、９０％以下が好ましく、８０％以下がより好ましい。
　式（Ｚ１）中に（３＋ｒ）個存在するＲＺの少なくとも１つ（例えば、１～２つ等）は水素原子を表してもよい。
　式（Ｚ１）中におけるＲｚ（好ましくは置換基であるＲｚ）及びＯＨが結合したベンゼン環基において、上記Ｒｚ（好ましくは置換基であるＲｚ）は、上記ベンゼン環基が結合するＮＨに対するパラ位に存在していることも好ましい。 In formula (Z1), r represents an integer of 0 or more.
r is preferably an integer of 0 to 20, more preferably an integer of 0 to 10.
L represents a divalent organic group. Examples of the divalent organic group include a divalent aromatic ring group optionally having a substituent, a divalent aliphatic hydrocarbon group optionally having a substituent, and a substituent divalent aliphatic cyclic groups, -O-, -S-, -N(R N )- or -CO-, and groups combining these.
RN represents a hydrogen atom or a substituent. Examples of substituents represented by RN include straight-chain alkyl groups and branched-chain alkyl groups having 1 to 5 carbon atoms.
In addition, the substituents which the aromatic ring group, the aliphatic hydrocarbon group and the aliphatic ring group represented by L may have include, for example, a linear alkyl group having 1 to 5 carbon atoms and a branched A chain alkyl group is mentioned.
R Z represents a hydrogen atom or a substituent.
The substituent represented by R Z is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and a linear or branched alkyl having 1 to 6 carbon atoms. groups are more preferred.
In the formula (Z1), the ratio of R Z representing a substituent among (3+r) R Zs present [(number of R Zs representing a substituent/(3+r) number of R Zs present)×100] is preferably 30% or more, more preferably 50% or more, and even more preferably 65% or more. The upper limit is preferably 90% or less, more preferably 80% or less.
At least one of (3+r) R 2 Zs present in the formula (Z1) (eg, 1 to 2) may represent a hydrogen atom.
In the benzene ring group to which R z (preferably R z which is a substituent) and OH in formula (Z1) are bonded, the R z (preferably R z which is a substituent) is bonded to the benzene ring group It is also preferred to be in the para position to NH.
　フェノール化合物としては、上記以外に、その他フェノール化合物を含んでいてもよい。
　その他フェノール化合物としては、例えば、ビスフェノールＡ、Ｆ、Ｓ、ＡＤ、ベンゼンジオール及びベンゼントリオール等のベンゼンポリオール、ビフェニルアラルキル型フェノール樹脂、フェノールノボラック樹脂、クレゾールノボラック樹脂、芳香族炭化水素ホルムアルデヒド樹脂変性フェノール樹脂、ジシクロペンタジエンフェノール付加型樹脂、フェノールアラルキル樹脂、多価ヒドロキシ化合物とホルムアルデヒドとから合成される多価フェノールノボラック樹脂、ナフトールアラルキル樹脂、トリメチロールメタン樹脂、テトラフェニロールエタン樹脂、ナフトールノボラック樹脂、ナフトールフェノール共縮ノボラック樹脂、ナフトールクレゾール共縮ノボラック樹脂、ビフェニル変性フェノール樹脂、ビフェニル変性ナフトール樹脂、アミノトリアジン変性フェノール樹脂、並びに、アルコキシ基含有芳香環変性ノボラック樹脂が挙げられる。 As the phenol compound, other phenol compounds may be included in addition to the above.
Other phenolic compounds include, for example, bisphenol A, F, S, AD, benzenepolyols such as benzenediol and benzenetriol, biphenylaralkyl-type phenolic resins, phenolic novolak resins, cresol novolak resins, aromatic hydrocarbon formaldehyde resins, modified phenolic resins. , dicyclopentadiene phenol addition type resin, phenol aralkyl resin, polyhydric phenol novolac resin synthesized from polyhydric hydroxy compound and formaldehyde, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin, naphthol novolak resin, naphthol Phenol co-condensed novolac resins, naphthol cresol co-condensed novolac resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and alkoxy group-containing aromatic ring-modified novolac resins can be mentioned.
　フェノール化合物の分子量は、２２５～２０００が好ましく、２２５～１０００がより好ましい。
　なお、上記分子量に分子量分布がある場合、上記分子量は重量平均分子量である。 The molecular weight of the phenol compound is preferably 225-2000, more preferably 225-1000.
In addition, when the said molecular weight has molecular weight distribution, the said molecular weight is a weight average molecular weight.
　フェノール化合物のヒドロキシ基含有量は、２．０ｍｍｏｌ／ｇ以上が好ましく、４．０ｍｍｏｌ／ｇ以上がより好ましい。上限は、２５．０ｍｍｏｌ／ｇ以下が好ましく、１０．０ｍｍｏｌ／ｇ以下がより好ましい。
　なお、上記ヒドロキシ基含有量は、フェノール化合物１ｇが有する、ヒドロキシ基（好ましくはフェノール性ヒドロキシ基）の数を意味する。
　また、フェノール化合物は、ヒドロキシ基以外にも、エポキシ化合物と重合反応できる活性水素含有基（例えば、カルボキシ基等）を有していてもよいし、有していなくてもよい。フェノール化合物の活性水素の含有量（ヒドロキシ基及びカルボキシ基等における水素原子の合計含有量）は、２．０ｍｍｏｌ／ｇ以上が好ましく、４．０ｍｍｏｌ／ｇ以上がより好ましい。上限は、２５．０ｍｍｏｌ／ｇ以下が好ましく、１０．０ｍｍｏｌ／ｇ以下がより好ましい。 The hydroxy group content of the phenol compound is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more. The upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.
The hydroxy group content means the number of hydroxy groups (preferably phenolic hydroxy groups) possessed by 1 g of the phenol compound.
In addition to the hydroxy group, the phenol compound may or may not have an active hydrogen-containing group (for example, a carboxyl group) capable of polymerizing with the epoxy compound. The content of active hydrogen in the phenol compound (the total content of hydrogen atoms in hydroxy groups, carboxy groups, etc.) is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more. The upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.
　本発明の組成物は、上記フェノール化合物以外に、エポキシ化合物と反応可能な基を有する化合物（以下、「その他活性水素含有化合物」ともいう。）を含んでいてもよい。
　フェノール化合物の含有量に対する、その他活性水素含有化合物の含有量の質量比（その他活性水素含有化合物の含有量／フェノール化合物の含有量）は、０～１が好ましく、０～０．１がより好ましく、０～０．０５が更に好ましい。 The composition of the present invention may contain, in addition to the phenol compound, a compound having a group capable of reacting with an epoxy compound (hereinafter also referred to as "other active hydrogen-containing compounds").
The mass ratio of the content of other active hydrogen-containing compounds to the content of phenolic compounds (content of other active hydrogen-containing compounds/content of phenolic compounds) is preferably 0 to 1, more preferably 0 to 0.1. , 0 to 0.05 are more preferred.
　フェノール化合物は、１種単独又は２種以上で用いてもよい。
　フェノール化合物の含有量は、第１熱伝導層全質量に対して、１．０～９０．０質量％が好ましく、１．０～５０．０質量％がより好ましく、２．０～３０．０質量％が更に好ましく、３．０～１０．０質量％が特に好ましい。 You may use a phenol compound individually by 1 type or in 2 or more types.
The content of the phenol compound is preferably 1.0 to 90.0% by mass, more preferably 1.0 to 50.0% by mass, and 2.0 to 30.0% by mass with respect to the total mass of the first heat conductive layer. % by mass is more preferred, and 3.0 to 10.0% by mass is particularly preferred.
　マレイミド化合物の含有量は、エポキシ化合物とフェノール化合物との合計含有量に対して、１～２００質量％が好ましく、５～１００質量％よりが好ましく、１０～８０質量％が更に好ましく、２０～８０質量％が更に好ましい。
　マレイミド化合物の含有量は、フェノール化合物の含有量に対して、１～５００質量％が好ましく、２０～３００質量％がより好ましく、５０～２００質量％が更に好ましく、７０～１８０質量％が特に好ましい。 The content of the maleimide compound is preferably 1 to 200% by mass, more preferably 5 to 100% by mass, more preferably 10 to 80% by mass, more preferably 20 to 80% by mass, based on the total content of the epoxy compound and the phenol compound. % by mass is more preferred.
The content of the maleimide compound is preferably 1 to 500% by mass, more preferably 20 to 300% by mass, still more preferably 50 to 200% by mass, and particularly preferably 70 to 180% by mass, relative to the content of the phenol compound. .
　エポキシ化合物とフェノール化合物との合計含有量は、第１熱伝導層全質量に対して、３～９０質量％が好ましく、５～５０質量％がより好ましく、７～４０質量％が更に好ましい。 The total content of the epoxy compound and the phenol compound is preferably 3-90% by mass, more preferably 5-50% by mass, and even more preferably 7-40% by mass, relative to the total mass of the first heat conductive layer.
　フェノール化合物に含まれるヒドロキシ基（好ましくはフェノール性ヒドロキシ基）の数に対する、エポキシ化合物に含まれる合計のエポキシ基の数との比（エポキシ基の数／ヒドロキシ基の数）は、３／９７～９７／３が好ましく、３０／７０～７０／３０がより好ましく、４０／６０～６０／４０が更に好ましく、４５／５５～５５／４５が特に好ましい。
　つまり、フェノール化合物とエポキシ化合物との含有量の比は、上記「エポキシ基の数／フェノール性ヒドロキシ基の数」が上記範囲内になるような比であることが好ましい。 The ratio of the total number of epoxy groups contained in the epoxy compound to the number of hydroxy groups (preferably phenolic hydroxy groups) contained in the phenol compound (number of epoxy groups/number of hydroxy groups) is 3/97 to 97/3 is preferred, 30/70 to 70/30 is more preferred, 40/60 to 60/40 is even more preferred, and 45/55 to 55/45 is particularly preferred.
That is, the content ratio of the phenolic compound and the epoxy compound is preferably such that the "number of epoxy groups/number of phenolic hydroxy groups" is within the above range.
　エポキシ化合物のエポキシ基と、活性水素（フェノール性ヒドロキシ基に由来する活性水素であってもよく、その他活性水素含有化合物の活性水素であってもよい）との当量比（エポキシ基の数／活性水素の数）は、３／９７～９７／３が好ましく、３０／７０～７０／３０がより好ましく、４０／６０～６０／４０が更に好ましく、４５／５５～５５／４５が特に好ましい。 Equivalent ratio (number of epoxy groups/activity The number of hydrogen atoms) is preferably 3/97 to 97/3, more preferably 30/70 to 70/30, still more preferably 40/60 to 60/40, and particularly preferably 45/55 to 55/45.
（酸無水物）
　第１熱伝導層は、酸無水物を含んでいてもよい。
　酸無水物は、１つ以上の酸無水物基（－ＣＯ－Ｏ－ＣＯ－で表される基）を有する化合物である。 (acid anhydride)
The first thermally conductive layer may contain an acid anhydride.
An acid anhydride is a compound having one or more acid anhydride groups (groups represented by --CO--O--CO--).
　酸無水物が有する酸無水物基の数は、１以上であり、２以上が好ましく、３以上がより好ましい。上記数の上限は、例えば、１０００以下である。
　酸無水物の分子量（分子量分布がある場合は重量平均分子量）は、１００以上が好ましく、２０００以上がより好ましく、６０００以上が更に好ましい。上記分子量の上限は、１０００００以下が好ましく、３００００以下がより好ましく、１７０００以下が更に好ましい。
　酸無水物は、低分子化合物であっても高分子化合物であってもよい。
　低分子化合物である酸無水物としては、例えば、無水マレイン酸、無水フタル酸、無水ピロメリット酸及び無水トリメリット酸が挙げられる。
　高分子化合物である酸無水物において、酸無水物基は、主鎖に組み込まれて存在していてもよく、側鎖に存在していてもよい。なお、例えば、上記高分子化合物がマレイン酸に基づく繰り返し単位を有する場合、上記繰り返し単位に含まれる酸無水物基は、主鎖に組み込まれているものとする。 The number of acid anhydride groups possessed by the acid anhydride is 1 or more, preferably 2 or more, and more preferably 3 or more. The upper limit of the above number is, for example, 1000 or less.
The molecular weight of the acid anhydride (the weight average molecular weight if there is a molecular weight distribution) is preferably 100 or more, more preferably 2000 or more, and even more preferably 6000 or more. The upper limit of the molecular weight is preferably 100,000 or less, more preferably 30,000 or less, and even more preferably 17,000 or less.
The acid anhydride may be a low-molecular-weight compound or a high-molecular-weight compound.
Acid anhydrides that are low-molecular-weight compounds include, for example, maleic anhydride, phthalic anhydride, pyromellitic anhydride, and trimellitic anhydride.
In the acid anhydride, which is a polymer compound, the acid anhydride group may be incorporated in the main chain or may be present in the side chain. For example, when the polymer compound has repeating units based on maleic acid, the acid anhydride groups contained in the repeating units are assumed to be incorporated in the main chain.
　酸無水物としては、市販品を用いてもよい。市販品である酸無水物としては、例えば、巴工業社製のＳＭＡシリーズ（Ｐｏｌｙｓｃｏｐｅ　ＰｏｌｙｍｅｒｓＢＶ社製のＸＩＲＡＮシリーズ）、アルケマ社製のＯＲＥＶＡＣ　Ｔシリーズ及び荒川化学工業社製のアラスターシリーズが挙げられる。 A commercially available product may be used as the acid anhydride. Commercially available acid anhydrides include, for example, the SMA series manufactured by Tomoe Industries (XIRAN series manufactured by Polyscope Polymers BV), the OREVAC T series manufactured by Arkema, and the Alastor series manufactured by Arakawa Chemical Industries.
　酸無水物は、１種単独又は２種以上で用いてもよい。
　酸無水物の含有量は、第１熱伝導層全質量に対して、０．０１～４０．０質量％が好ましく、０．１～１０．０質量％がより好ましく、０．６～５．０質量％が更に好ましい。 You may use an acid anhydride individually by 1 type or in 2 or more types.
The content of the acid anhydride is preferably 0.01-40.0% by mass, more preferably 0.1-10.0% by mass, and 0.6-5. 0% by mass is more preferred.
＜硬化促進剤＞
　第１熱伝導層は、硬化促進剤を含むことが好ましい。
　硬化促進剤としては、例えば、トリスオルトトリルホスフィン、トリフェニルホスフィン、三フッ化ホウ素アミン錯体、特開２０１２－０６７２２５号公報の段落［００５２］に記載の化合物、テトラフェニルホスホニウムテトラフェニルボレート（ＴＰＰ－Ｋ）、テトラフェニルホスホニウムテトラ－ｐ－トリルボラート（ＴＰＰ－ＭＫ）、テトラ－ｎ－ブチルホスホニウムラウレート（ＴＢＰ－ＬＡ）、ビス（テトラ－ｎ－ブチルホスホニウム）ピロメリテート及びテトラフェニルホスホニウムのビス（ナフタレン－２，３－ジオキシ）フェニルシリケート付加物等の四級ホスホニウム系化合物（ホスホニウム塩）等のオニウム塩系硬化促進剤が挙げられる。 <Curing accelerator>
The first thermally conductive layer preferably contains a curing accelerator.
Examples of curing accelerators include trisorthotolylphosphine, triphenylphosphine, boron trifluoride amine complex, compounds described in paragraph [0052] of JP-A-2012-067225, tetraphenylphosphonium tetraphenylborate (TPP- K), tetraphenylphosphonium tetra-p-tolylborate (TPP-MK), tetra-n-butylphosphonium laurate (TBP-LA), bis(tetra-n-butylphosphonium) pyromellitate and bis(naphthalene- Onium salt curing accelerators such as quaternary phosphonium compounds (phosphonium salts) such as 2,3-dioxy)phenyl silicate adducts.
　硬化促進剤は、リン原子を有する化合物又はホスホニウム塩を含むことが好ましく、リン原子を有する化合物を含むことがより好ましい。
　硬化促進剤は、リン原子を有する化合物又はホスホニウム塩そのものであってもよい。硬化促進剤がホスホニウム塩を含む場合、第１熱伝導層の保存安定性が優れる。 The curing accelerator preferably contains a phosphorus atom-containing compound or a phosphonium salt, more preferably a phosphorus atom-containing compound.
The curing accelerator may be a compound having a phosphorus atom or the phosphonium salt itself. When the curing accelerator contains a phosphonium salt, the storage stability of the first heat conductive layer is excellent.
　硬化促進剤は、１種単独又は２種以上で用いてもよい。
　硬化促進剤の含有量は、第１熱伝導層全質量に対して、０．００２質量％以上が好ましく、０．０２質量％以上がより好ましく、０．０７質量％以上が更に好ましい。上限は、第１熱伝導層全質量に対して、５．０質量％以下が好ましく、２．０質量％以下がより好ましく、１．０質量％以下が更に好ましい。 You may use a hardening accelerator by 1 type individual or 2 or more types.
The content of the curing accelerator is preferably 0.002% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.07% by mass or more, relative to the total mass of the first heat conductive layer. The upper limit is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less with respect to the total mass of the first heat conductive layer.
　第１熱伝導層は、樹脂を含んでいてもよい。
　樹脂としては、例えば、上述した硬化性化合物の硬化物が挙げられる。具体的には、エポキシ化合物及びマレイミド化合物からなる群から選択される１種以上と、フェノール化合物との硬化物が挙げられる。なお、この硬化物は、エポキシ基及びマレイミド基からなる群から選択される１種以上と、フェノール性ヒドロキシ基とを有することが好ましい。 The first heat conductive layer may contain resin.
Examples of resins include cured products of the above-described curable compounds. Specifically, one or more selected from the group consisting of an epoxy compound and a maleimide compound and a cured product of a phenol compound can be mentioned. The cured product preferably has one or more selected from the group consisting of epoxy groups and maleimide groups, and phenolic hydroxy groups.
　硬化性化合物及びその硬化物の合計含有量は、第１熱伝導層全体積に対して、２０～５０体積％が好ましく、２５～４５体積％がより好ましく、３０～４０体積％が更に好ましい。 The total content of the curable compound and its cured product is preferably 20-50% by volume, more preferably 25-45% by volume, and even more preferably 30-40% by volume, relative to the total volume of the first heat conductive layer.
　なお、後述するように、第１熱伝導層は、加圧処理が施された層であってもよい。加圧処理を施されることにより、第１熱伝導層中のボイド等が除去され、結果として、貼合後の熱伝導シートの熱伝導性が優れる。 As will be described later, the first thermally conductive layer may be a layer subjected to pressure treatment. The pressure treatment removes voids and the like in the first heat conductive layer, and as a result, the thermal conductivity of the heat conductive sheet after lamination is excellent.
〔第２熱伝導層〕
　熱伝導シートは、第１熱伝導層の２つの主面のうち一方の主面上のみに配置された、第２熱伝導層を有する。　第２熱伝導層は、第２熱伝導性無機粒子及び硬化性化合物を含む。
　第２熱伝導層は、表面修飾剤を含み、第２熱伝導性無機粒子が、第２熱伝導性無機粒子の表面上に吸着した表面修飾剤とともに、表面修飾第２熱伝導性無機粒子を構成していることが好ましい。表面修飾第２熱伝導性無機粒子を構成する第２熱伝導性無機粒子としては、凝集状窒化ホウ素が好ましい。
　上記凝集状窒化ホウ素、上記表面修飾剤及び表面修飾第２熱伝導性無機粒子は、それぞれ第１熱伝導性無機粒子が含み得る、凝集状窒化ホウ素、表面修飾剤及び表面修飾第１熱伝導性無機粒子のうち第２熱伝導性無機粒子で構成される表面修飾無機粒子と同義であり、好適態様も同じである。 [Second heat conductive layer]
The thermally conductive sheet has a second thermally conductive layer disposed on only one of the two major surfaces of the first thermally conductive layer. The second thermally conductive layer includes second thermally conductive inorganic particles and a curable compound.
The second thermally conductive layer contains a surface modifier, and the second thermally conductive inorganic particles are surface-modified second thermally conductive inorganic particles together with the surface modifier adsorbed on the surface of the second thermally conductive inorganic particles. preferably configured. Agglomerated boron nitride is preferable as the second thermally conductive inorganic particles constituting the surface-modified second thermally conductive inorganic particles.
The aggregated boron nitride, the surface modifier, and the surface-modified second thermally conductive inorganic particles are aggregated boron nitride, the surface modifier, and the surface-modified first thermally conductive inorganic particles, respectively, which the first thermally conductive inorganic particles may contain. Of the inorganic particles, it is synonymous with surface-modified inorganic particles composed of second thermally conductive inorganic particles, and the preferred embodiments are also the same.
　第２熱伝導性無機粒子は、凝集状窒化ホウ素と、熱伝導性無機粒子Ｘとを含む。
　熱伝導性無機粒子Ｘは、平均アスペクト比が１．０～１．６であり、上記凝集状窒化ホウ素とは異なる熱伝導性無機粒子である。
　熱伝導性無機粒子Ｘを構成し得る熱伝導性無機粒子としては、上述した第１熱伝導無機粒子で例示した無機粒子（具体的には、無機窒化物及び無機酸化物等）が挙げられる。
　熱伝導性無機粒子Ｘとしては、例えば、第１熱伝導性無機粒子のうち、凝集状窒化ホウ素以外の無機窒化物及び無機酸化物であって、平均アスペクト比が１．０～１．６である熱伝導性無機粒子が挙げられる。
　熱伝導性無機粒子Ｘとしては、平均アスペクト比が１．０～１．６である無機酸化物が好ましく、平均アスペクト比が１．０～１．６である酸化アルミニウムがより好ましい。 The second thermally conductive inorganic particles include agglomerated boron nitride and thermally conductive inorganic particles X.
The thermally conductive inorganic particles X have an average aspect ratio of 1.0 to 1.6 and are thermally conductive inorganic particles different from the aggregated boron nitride.
Thermally conductive inorganic particles that can form the thermally conductive inorganic particles X include the inorganic particles exemplified above for the first thermally conductive inorganic particles (specifically, inorganic nitrides, inorganic oxides, etc.).
As the thermally conductive inorganic particles X, for example, among the first thermally conductive inorganic particles, inorganic nitrides and inorganic oxides other than aggregated boron nitride and having an average aspect ratio of 1.0 to 1.6. Certain thermally conductive inorganic particles are included.
As the thermally conductive inorganic particles X, inorganic oxides having an average aspect ratio of 1.0 to 1.6 are preferable, and aluminum oxide having an average aspect ratio of 1.0 to 1.6 is more preferable.
　第２熱伝導性無機粒子は、凝集状窒化ホウ素及び熱伝導性無機粒子Ｘ以外に、その他熱伝導性無機粒子を含んでいてもよい。
　上記その他熱伝導性無機粒子としては、凝集状窒化ホウ素及び熱伝導性無機粒子Ｘ以外であれば特に制限されない。 In addition to the aggregated boron nitride and the thermally conductive inorganic particles X, the second thermally conductive inorganic particles may contain other thermally conductive inorganic particles.
The other thermally conductive inorganic particles are not particularly limited as long as they are other than the aggregated boron nitride and the thermally conductive inorganic particles X.
　熱伝導性無機粒子Ｘの平均粒径は、０．１～３００．０μｍの場合が多く、１．０～１００．０μｍが好ましく、１．０～１５．０μｍがより好ましく、２．０～１０．０μｍが更に好ましく、２．０～７．０μｍが特に好ましい。
　熱伝導性無機粒子Ｘの平均アスペクト比は、１．０～１．６であり、１．０～１．５５好ましく、１．０～１．５０がより好ましい。
　本明細書において、平均アスペクト比は、ＴＥＭ（透過型電子顕微鏡）又はＳＥＭ（走査型電子顕微鏡）にて観察された任意の１００個の無機粒子毎に、長径と短径とを測定して、無機粒子毎のアスペクト比（長径／短径）を計算し、１００個のアスペクト比を算術平均して求められる。なお、粒子の長径とは粒子の長軸方向の長さを意味し、粒子の短径とは粒子の長軸方向に直交する粒子の長さを意味する。 The average particle size of the thermally conductive inorganic particles X is often 0.1 to 300.0 μm, preferably 1.0 to 100.0 μm, more preferably 1.0 to 15.0 μm, and 2.0 to 10 μm. 0 μm is more preferred, and 2.0 to 7.0 μm is particularly preferred.
The average aspect ratio of the thermally conductive inorganic particles X is 1.0 to 1.6, preferably 1.0 to 1.55, more preferably 1.0 to 1.50.
In this specification, the average aspect ratio is obtained by measuring the major axis and minor axis of any 100 inorganic particles observed with a TEM (transmission electron microscope) or SEM (scanning electron microscope), The aspect ratio (major axis/minor axis) of each inorganic particle is calculated, and the arithmetic mean of 100 aspect ratios is obtained. The major diameter of the particles means the length in the major axis direction of the particles, and the minor diameter of the particles means the length of the particles orthogonal to the major axis direction of the particles.
　第２熱伝導性無機粒子の含有量は、第２熱伝導層全体積に対して、４０．０～６０．０体積％であり、４５．０～５５．０体積％が好ましく、５０．０～５５．０体積％がより好ましい。第２熱伝導性無機粒子の含有量とは、例えば、第２熱伝導性無機粒子が凝集状窒化ホウ素と熱伝導性無機粒子Ｘとからなる場合、凝集状窒化ホウ素及び熱伝導性無機粒子Ｘの合計含有量を意味する。
　凝集状窒化ホウ素の含有量は、第２熱伝導層全体積に対して、２５．０～５５．０体積％が好ましく、３０．０～５５．０体積％がより好ましく、３５．０～５０．０体積％が更に好ましい。
　熱伝導性無機粒子Ｘの含有量は、第２熱伝導層全体積に対して、５．０～３０．０体積％が好ましく、７．５～２７．５体積％がより好ましく、１０．０～２５．０体積％が更に好ましい。
　第２熱伝導層中、熱伝導性無機粒子Ｘに対する凝集状窒化ホウ素の体積比（凝集状窒化ホウ素の体積／熱伝導性無機粒子Ｘの体積）は、２．５～１０．５が好ましく、２．８～５．０がより好ましい。 The content of the second thermally conductive inorganic particles is 40.0 to 60.0% by volume, preferably 45.0 to 55.0% by volume, and 50.0% by volume with respect to the total volume of the second thermally conductive layer. ~55.0% by volume is more preferred. The content of the second thermally conductive inorganic particles is, for example, when the second thermally conductive inorganic particles consist of aggregated boron nitride and thermally conductive inorganic particles X, the aggregated boron nitride and thermally conductive inorganic particles X means the total content of
The content of aggregated boron nitride is preferably 25.0 to 55.0% by volume, more preferably 30.0 to 55.0% by volume, more preferably 35.0 to 50%, relative to the total volume of the second heat conductive layer. 0 vol % is more preferred.
The content of the thermally conductive inorganic particles X is preferably 5.0 to 30.0% by volume, more preferably 7.5 to 27.5% by volume, and 10.0% by volume with respect to the total volume of the second thermally conductive layer. ~25.0% by volume is more preferred.
In the second thermally conductive layer, the volume ratio of aggregated boron nitride to thermally conductive inorganic particles X (volume of aggregated boron nitride/volume of thermally conductive inorganic particles X) is preferably 2.5 to 10.5. 2.8 to 5.0 is more preferred.
　硬化性化合物は、第１熱伝導層が含む得る硬化性化合物と同義であり、好適態様も同じである。 The curable compound is synonymous with the curable compound that the first heat conductive layer may contain, and the preferred embodiments are also the same.
　第２熱伝導層は、硬化性化合物の硬化物を含んでいてもよい。具体的には、エポキシ化合物及びマレイミド化合物からなる群から選択される１種以上と、フェノール化合物との硬化物が挙げられる。なお、この硬化物は、エポキシ基及びマレイミド基からなる群から選択される１種以上と、フェノール性ヒドロキシ基とを有することが好ましい。
　第２熱伝導層は、上記以外に、第１熱伝導層が含み得る成分（例えば、硬化促進剤等）を含んでいてもよい。 The second heat conductive layer may contain a cured product of a curable compound. Specifically, one or more selected from the group consisting of an epoxy compound and a maleimide compound and a cured product of a phenol compound can be mentioned. The cured product preferably has one or more selected from the group consisting of epoxy groups and maleimide groups, and phenolic hydroxy groups.
In addition to the above, the second heat conductive layer may contain components that the first heat conductive layer may contain (for example, a curing accelerator, etc.).
〔第１熱伝導層及び第２熱伝導層の関係〕
　第１熱伝導層及び第２熱伝導層は、要件Ａ及び要件Ｂを満たす。 [Relationship between first thermally conductive layer and second thermally conductive layer]
The first thermally conductive layer and the second thermally conductive layer satisfy requirement A and requirement B.
　要件Ａ：第１熱伝導層の平均膜厚が第２熱伝導層の平均膜厚よりも大きい。
　第１熱伝導層の平均膜厚が第２熱伝導層の平均膜厚よりも大きければ、特に制限されない。なかでも、第１熱伝導層の平均膜厚から第２熱伝導層の平均膜厚を引いた値は、５５～１９０μｍが好ましく、６５～１７０μｍがより好ましく、７５～１５０μｍが更に好ましい。
　第１熱伝導層の平均膜厚は、７０～２５０μｍが好ましく、８５～２２５μｍがより好ましく、１００～２００μｍが更に好ましく、１００～１５０μｍが特に好ましい。
　第２熱伝導層の平均膜厚は、５～１００μｍが好ましく、１０～８０μｍがより好ましく、１０～７０μｍが更に好ましい。
　第１熱伝導層及び第２熱伝導層の平均膜厚の測定方法としては、例えば、熱伝導シートの断面を切り出し、ＳＥＭで上記断面を観察して測定する方法が挙げられる。
　第１熱伝導層及び第２熱伝導層の平均膜厚を調整する方法としては、例えば、各層形成用組成物の使用量及び各層を形成した後に任意の圧力で加圧する方法が挙げられる。 Requirement A: The average thickness of the first thermally conductive layer is greater than the average thickness of the second thermally conductive layer.
There is no particular limitation as long as the average thickness of the first thermally conductive layer is greater than the average thickness of the second thermally conductive layer. In particular, the value obtained by subtracting the average thickness of the second heat conductive layer from the average thickness of the first heat conductive layer is preferably 55 to 190 μm, more preferably 65 to 170 μm, and even more preferably 75 to 150 μm.
The average film thickness of the first heat conductive layer is preferably 70-250 μm, more preferably 85-225 μm, even more preferably 100-200 μm, and particularly preferably 100-150 μm.
The average film thickness of the second heat conductive layer is preferably 5 to 100 μm, more preferably 10 to 80 μm, even more preferably 10 to 70 μm.
As a method for measuring the average film thickness of the first thermally conductive layer and the second thermally conductive layer, for example, a method of cutting out a section of the thermally conductive sheet and observing the section with an SEM for measurement can be mentioned.
Examples of the method for adjusting the average film thickness of the first thermally conductive layer and the second thermally conductive layer include a method of applying an arbitrary pressure after forming the amount of each layer-forming composition and forming each layer.
　要件Ｂ：第１熱伝導層全体積に対する第１熱伝導性無機粒子の含有量が、第２熱伝導層全体積に対する第２熱伝導性無機粒子の含有量よりも大きい。
　第１熱伝導層全体積に対する第１熱伝導性無機粒子の含有量が、第２熱伝導層全体積に対する第２熱伝導性無機粒子の含有量よりも大きければ、特に制限されない。なかでも、第１熱伝導層全体積に対する第１熱伝導性無機粒子の含有量から第２熱伝導層全体積に対する第２熱伝導性無機粒子の含有量を引いた値は、５．０～６５．０体積％が好ましく、８．０～４５．０体積％がより好ましく、１０．０～２５．０体積％が更に好ましい。
　各熱伝導層における各熱伝導性無機粒子の含有量は、上述したとおりである。 Requirement B: The content of the first thermally conductive inorganic particles in the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles in the total area of the second thermally conductive layer.
There is no particular limitation as long as the content of the first thermally conductive inorganic particles relative to the total volume of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total volume of the second thermally conductive layer. Above all, the value obtained by subtracting the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer from the content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is 5.0 to 65.0% by volume is preferred, 8.0 to 45.0% by volume is more preferred, and 10.0 to 25.0% by volume is even more preferred.
The content of each thermally conductive inorganic particle in each thermally conductive layer is as described above.
〔基材〕
　熱伝導シートは、基材を有していてもよい。
　基材は、熱伝導シートを支持する部材であり、最終的に剥離されてもよい。
　基材は、単層構造及び多層構造のいずれであってもよい。
　基材の形状は、シート状であることが好ましい。
　基材としては、例えば、プラスチック材料、金属材料及びガラスが挙げられる。プラスチック材料としては、例えば、ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル、ポリカーボネート、アクリル樹脂、エポキシ樹脂、ポリウレタン、ポリアミド、ポリオレフィン、セルロース誘導体及びシリコーンが挙げられる。金属材料としては、例えば、銅及びアルミニウムが挙げられる。
　基材は、表面処理されていることが好ましい。表面処理としては、例えば、離型処理及び粗化処理が挙げられる。
　基材の膜厚は、５０～３００μｍが好ましく、７５～２５０μｍがより好ましい。 〔Base material〕
The thermally conductive sheet may have a base material.
The base material is a member that supports the heat conductive sheet, and may be finally peeled off.
The substrate may have either a single layer structure or a multilayer structure.
The shape of the substrate is preferably sheet-like.
Substrates include, for example, plastic materials, metal materials, and glass. Examples of plastic materials include polyesters such as polyethylene terephthalate (PET), polycarbonates, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cellulose derivatives, and silicones. Metal materials include, for example, copper and aluminum.
The substrate is preferably surface-treated. Surface treatments include, for example, release treatment and roughening treatment.
The film thickness of the substrate is preferably 50-300 μm, more preferably 75-250 μm.
　熱伝導シートは、絶縁性（電気絶縁性）であることが好ましい。
　熱伝導シートの２３℃相対湿度６５％における体積抵抗率は、１０１０Ω・ｃｍ以上が好ましく、１０１２Ω・ｃｍ以上がより好ましく、１０１４Ω・ｃｍ以上が更に好ましい。上限は、１０１８Ω・ｃｍ以下が好ましい。
　熱伝導シートの熱伝導率は、等方性であることが好ましい。 The heat conductive sheet is preferably insulating (electrically insulating).
The volume resistivity of the heat conductive sheet at 23° C. and 65% relative humidity is preferably 10 10 Ω·cm or more, more preferably 10 12 Ω·cm or more, and still more preferably 10 14 Ω·cm or more. The upper limit is preferably 10 18 Ω·cm or less.
The thermal conductivity of the thermally conductive sheet is preferably isotropic.
〔熱伝導シートの製造方法〕
　熱伝導シートの製造方法としては、例えば、公知の方法が挙げられる。
　具体的には、熱伝導シートの製造方法としては、第１基材上に第１熱伝導層形成用組成物を塗布して第１熱伝導層を形成する第１熱伝導層形成工程と、
　第２基材上に第２熱伝導層形成用組成物を塗布して第２熱伝導層を形成する第２熱伝導層形成工程と、
　第１熱伝導層の第１基材とは反対側の表面と、第２熱伝導層の第２基材とは反対側の表面とを貼り合わせる貼合工程と、を有する製造方法が好ましい。 [Method for producing thermally conductive sheet]
Examples of the method for producing the heat conductive sheet include known methods.
Specifically, the method for producing a thermally conductive sheet includes a first thermally conductive layer forming step of applying a composition for forming a first thermally conductive layer on a first substrate to form a first thermally conductive layer;
a second thermally conductive layer forming step of applying a composition for forming a second thermally conductive layer on a second substrate to form a second thermally conductive layer;
A manufacturing method including a bonding step of bonding together the surface of the first thermally conductive layer opposite to the first substrate and the surface of the second thermally conductive layer opposite to the second substrate is preferred.
　熱伝導シートの製造方法は、表面修飾剤を用いて第１熱伝導性無機粒子又は第２熱伝導性無機粒子の表面を修飾する工程（表面修飾工程）を更に含むことが好ましい。また、熱伝導シートの製造方法は、第１熱伝導性無機粒子又は第２熱伝導性無機粒子を表面処理して変性無機物粒子を得る工程（変性工程）を更に含むことも好ましい。上記変性工程を含む場合、変性工程は、表面修飾工程前に実施することが好ましい。つまり、上記変性無機物粒子の表面に対して、上記表面修飾工程を実施することが好ましい。
　以下、各工程について詳述する。 It is preferable that the method for producing a thermally conductive sheet further includes a step of modifying the surface of the first thermally conductive inorganic particles or the second thermally conductive inorganic particles using a surface modifier (surface modification step). It is also preferable that the method for producing a thermally conductive sheet further includes a step of surface-treating the first thermally conductive inorganic particles or the second thermally conductive inorganic particles to obtain modified inorganic particles (modification step). When the modification step is included, the modification step is preferably performed before the surface modification step. That is, it is preferable to perform the surface modification step on the surface of the modified inorganic particles.
Each step will be described in detail below.
＜変性工程＞
　変性工程は、第１熱伝導性無機粒子又は第２熱伝導性無機粒子を表面処理して変性無機物粒子を得る工程である。
　上記変性工程は、水溶液中で、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と酸化剤とを接触させて、変性無機物粒子を得る工程が好ましい。
　上記変性工程に供する第１熱伝導性無機粒子又は第２熱伝導性無機粒子は、上述したとおりである。 <Degeneration step>
The modification step is a step of surface-treating the first thermally conductive inorganic particles or the second thermally conductive inorganic particles to obtain modified inorganic particles.
The modification step is preferably a step of bringing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles into contact with an oxidizing agent in an aqueous solution to obtain modified inorganic particles.
The first thermally conductive inorganic particles or the second thermally conductive inorganic particles to be subjected to the modification step are as described above.
　上記水溶液は、アルカリ性水溶液が好ましい。上記アルカリ性水溶液のｐＨは、８以上の場合が多く、１２以上が好ましく、１２超がより好ましく、１３以上が更に好ましく、１３超が特に好ましい。上限は、１４以下が好ましい。上記水溶液のｐＨは、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と上記酸化剤とを含んでいる状態における上記水溶液のｐＨを意味する。つまり、上記水溶液は、必要に応じてアルカリ化合物と、水と、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と、酸化剤とを含む。 The above aqueous solution is preferably an alkaline aqueous solution. The pH of the alkaline aqueous solution is often 8 or more, preferably 12 or more, more preferably more than 12, even more preferably 13 or more, and particularly preferably more than 13. The upper limit is preferably 14 or less. The pH of the aqueous solution means the pH of the aqueous solution containing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent. That is, the aqueous solution contains an alkali compound, water, the first thermally conductive inorganic particles or the second thermally conductive inorganic particles, and an oxidizing agent, if necessary.
　上記水溶液中で、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と酸化剤とを接触させる時間は、０．１～２４時間が好ましく、０．５～１０時間がより好ましく、１．５～６時間が更に好ましい。
　また、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と酸化剤とを接触させる際の上記水溶液の温度は、１～９５℃が好ましく、２５～８０℃がより好ましく、４５～６５℃が更に好ましい。 The time for contacting the first thermally conductive inorganic particles or the second thermally conductive inorganic particles with the oxidizing agent in the aqueous solution is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours. .5 to 6 hours is more preferred.
The temperature of the aqueous solution when the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent are brought into contact is preferably 1 to 95°C, more preferably 25 to 80°C, and 45 to 65°C. °C is more preferred.
　上記水溶液中で、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と酸化剤とを接触させる方法としては、例えば、混合液中で接触させる方法が挙げられる。 As a method of contacting the first thermally conductive inorganic particles or the second thermally conductive inorganic particles with the oxidizing agent in the above aqueous solution, for example, a method of contacting them in a mixed liquid can be mentioned.
　有機溶媒としては、例えば、メタノール、エタノール、２－プロパノール、アセトニトリル、シクロペンタノン、シクロヘキサノン、酢酸エチル、メチルエチルケトン、ジクロロメタン及びテトラヒドロフランが挙げられる。
　有機溶媒は、１種単独又は２種以上で用いてもよい。 Organic solvents include, for example, methanol, ethanol, 2-propanol, acetonitrile, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane and tetrahydrofuran.
You may use an organic solvent individually by 1 type or in 2 or more types.
　第１熱伝導性無機粒子又は第２熱伝導性無機粒子及び酸化剤を接触させる方法としては、例えば、スリーワンモーター等のメカニカルスターラー又はマグネチックスターラー等を用いて撹拌処理しながら接触させる方法及び第１熱伝導性無機粒子又は第２熱伝導性無機粒子を充填したカートリッジに、酸化剤を含む溶液をポンプ等で循環させながら接触させる方法が挙げられる。 As a method of contacting the first thermally conductive inorganic particles or the second thermally conductive inorganic particles and the oxidizing agent, for example, a method of contacting while stirring using a mechanical stirrer such as a three-one motor, a magnetic stirrer, or the like; For example, a solution containing an oxidizing agent is brought into contact with a cartridge filled with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles while being circulated by a pump or the like.
　上記水溶液中で、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と酸化剤とを接触させた後、得られた変性無機物粒子を上記水溶液中から取り出すことが好ましい。
　上記水溶液から変性無機物粒子を取り出す方法としては、例えば、上記水溶液をろ過して、ろ物として変性無機物粒子を分取する方法が挙げられる。
　取り出された変性無機物粒子を、水及び／又は有機溶媒等で洗浄することも好ましい。洗浄後の無機物粒子は、オーブン等を乾燥処理されることも好ましい。 After bringing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles into contact with the oxidizing agent in the aqueous solution, it is preferable to remove the obtained modified inorganic particles from the aqueous solution.
Examples of the method for extracting the modified inorganic particles from the aqueous solution include a method of filtering the aqueous solution and fractionating the modified inorganic particles as filtered matter.
It is also preferable to wash the removed modified inorganic particles with water and/or an organic solvent. After washing, the inorganic particles are preferably dried in an oven or the like.
　上記水溶液中、水の含有量は、上記水溶液の全質量に対して、２０～９９質量％が好ましく、５０～９５質量％がより好ましく、６５～９０質量％が更に好ましい。 The content of water in the aqueous solution is preferably 20 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 65 to 90% by mass, relative to the total mass of the aqueous solution.
（酸化剤）
　変性工程に用いられる酸化剤としては、例えば、過硫酸ナトリウム、過硫酸カリウム及び過硫酸アンモニウム等の過硫酸塩；硝酸セリウムアンモニウム、硝酸ナトリウム及び硝酸アンモニウム等の硝酸塩；過酸化水素及びｔｅｒｔ－ブチルヒドロペルオキシド等の過酸化物；２価の銅化合物及びマンガン化合物等の遷移金属化合物；過ヨウ素酸カリウム及び過ヨウ素酸ナトリウム等の超原子価ヨウ素化合物；ベンゾキノン、ナフトキノン、アントラキノン及びクロラニル等のキノン化合物；並びに、次亜塩素酸ナトリウム及び亜塩素酸ナトリウム等のハロゲンオキソ酸の塩が挙げられる。
　酸化剤は、過硫酸塩を含むことが好ましく、過硫酸塩であることがより好ましい。
　また、酸化剤の作用を補助するために、酸化剤とは別に触媒を用いてもよい。上記触媒としては、例えば、２価の鉄化合物（例えば、ＦｅＳＯ４等）及び３価の鉄化合物が挙げられる。なお、酸化剤及び／又は触媒は、水和物であってもよい。 (Oxidant)
Examples of the oxidizing agent used in the modification step include persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; nitrates such as cerium ammonium nitrate, sodium nitrate and ammonium nitrate; hydrogen peroxide and tert-butyl hydroperoxide. transition metal compounds such as divalent copper compounds and manganese compounds; hypervalent iodine compounds such as potassium periodate and sodium periodate; quinone compounds such as benzoquinone, naphthoquinone, anthraquinone and chloranil; Salts of halogen oxoacids such as sodium hypochlorite and sodium chlorite are included.
The oxidizing agent preferably comprises a persulfate, more preferably a persulfate.
In addition, a catalyst may be used separately from the oxidant in order to assist the action of the oxidant. Examples of the catalyst include divalent iron compounds (such as FeSO4 ) and trivalent iron compounds. Note that the oxidizing agent and/or catalyst may be a hydrate.
　酸化剤の標準酸化還元電位は、０．３０Ｖ以上が好ましく、１．５０Ｖ以上がより好ましく、１．７０Ｖ以上が更に好ましい。上限は、４．００Ｖ以下が好ましく、２．５０Ｖ以下がより好ましい。上記標準酸化還元電位は、標準水素電極を基準とした値である。 The standard oxidation-reduction potential of the oxidizing agent is preferably 0.30 V or higher, more preferably 1.50 V or higher, and even more preferably 1.70 V or higher. The upper limit is preferably 4.00 V or less, more preferably 2.50 V or less. The above standard oxidation-reduction potential is a value based on a standard hydrogen electrode.
　酸化剤は、１種単独又は２種以上で用いてもよい。
　上記水溶液中、酸化剤の含有量は、上記水溶液における水１００質量部に対して、０．０５～２０質量部が好ましく、０．１～２０質量部がより好ましく、１～２０質量部が更に好ましい。 The oxidizing agents may be used singly or in combination of two or more.
The content of the oxidizing agent in the aqueous solution is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and further 1 to 20 parts by mass, relative to 100 parts by mass of water in the aqueous solution. preferable.
　触媒は、１種単独又は２種以上で用いてもよい。
　上記水溶液が触媒を含む場合、その触媒の含有量は、上記水溶液における水１００質量部に対して、０．００５～２質量部が好ましく、０．０１～２質量部がより好ましく、０．１～２質量部が更に好ましい。 The catalyst may be used singly or in combination of two or more.
When the aqueous solution contains a catalyst, the content of the catalyst is preferably 0.005 to 2 parts by mass, more preferably 0.01 to 2 parts by mass, more preferably 0.1 with respect to 100 parts by mass of water in the aqueous solution. ~2 parts by mass is more preferred.
（アルカリ化合物）
　上記水溶液は、上記水溶液のｐＨを調製するために、上述の成分以外にアルカリ化合物を含むことも好ましい。
　上記アルカリ化合物としては、例えば、アルカリ金属水酸化物（例えば、水酸化ナトリウム等）及びアルカリ土類金属水酸化物等の無機塩基；並びに、有機塩基が挙げられる。
　上記水溶液中、アルカリ化合物の含有量は、上記水溶液のｐＨを所望の値に適宜調整する量であればよく、例えば、上記水溶液における水１００質量部に対して、０．１～１０質量部が挙げられる。 (alkali compound)
In order to adjust the pH of the aqueous solution, the aqueous solution preferably contains an alkaline compound in addition to the components described above.
Examples of the alkali compound include inorganic bases such as alkali metal hydroxides (eg, sodium hydroxide, etc.) and alkaline earth metal hydroxides; and organic bases.
The content of the alkaline compound in the aqueous solution may be an amount that appropriately adjusts the pH of the aqueous solution to a desired value. mentioned.
＜表面修飾工程＞
　表面修飾工程は、表面修飾剤を用いて第１熱伝導性無機粒子又は第２熱伝導性無機粒子の表面を修飾する工程である。
　表面修飾工程は、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と表面修飾剤とを接触させることが好ましい。第１熱伝導性無機粒子又は第２熱伝導性無機粒子と表面修飾剤とを接触させる方法は、上記変性工程と同様の方法が挙げられる。
　第１熱伝導性無機粒子又は第２熱伝導性無機粒子と接触させる表面修飾剤は、表面修飾剤の加水分解物又は加水分解縮合物が好ましい。つまり、表面修飾剤は、第１熱伝導性無機粒子又は第２熱伝導性無機粒子と接触させる前に、加水分解処理を施すことが好ましい。 <Surface modification step>
The surface modification step is a step of modifying the surface of the first thermally conductive inorganic particles or the second thermally conductive inorganic particles using a surface modifier.
In the surface modification step, the first thermally conductive inorganic particles or the second thermally conductive inorganic particles are preferably brought into contact with the surface modifier. The method for bringing the first thermally conductive inorganic particles or the second thermally conductive inorganic particles into contact with the surface modifying agent includes the same method as in the modification step.
The surface modifier to be brought into contact with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles is preferably a hydrolyzate or hydrolyzed condensate of the surface modifier. That is, the surface modifier is preferably hydrolyzed before being brought into contact with the first thermally conductive inorganic particles or the second thermally conductive inorganic particles.
（加水分解処理）
　加水分解処理は、表面修飾剤を加水分解する処理である。
　表面修飾剤がシランカップ剤である場合、加水分解処理によって、シランカップリング剤のアルコキシシリル基が加水分解されてシラノール基が生成され、上記シラノール基が第１熱伝導性無機粒子又は第２熱伝導性無機粒子の表面と結合を形成し得る。 (Hydrolysis treatment)
Hydrolysis treatment is treatment for hydrolyzing the surface modifier.
When the surface modifier is a silane coupling agent, the hydrolysis treatment hydrolyzes the alkoxysilyl groups of the silane coupling agent to generate silanol groups, and the silanol groups form the first thermally conductive inorganic particles or the second thermally conductive particles. It can form a bond with the surface of the conductive inorganic particles.
　加水分解の方法は、表面修飾剤が加水分解される条件であれば、特に制限されない。
　具体的には、酸性溶液（例えば、塩酸及び酢酸水溶液等）を用いて実施することが好ましい。上記酸性溶液は、有機溶媒を含んでいてもよい。 The hydrolysis method is not particularly limited as long as the conditions are such that the surface modifier is hydrolyzed.
Specifically, it is preferable to use an acidic solution (eg, aqueous hydrochloric acid and acetic acid solution). The acidic solution may contain an organic solvent.
　第１基材及び第２基材は、上記基材と同義であり、好適態様も同じである。
　第１基材及び第２基材は、同一又は異なっていてもよい。
　第１熱伝導層形成用組成物及び第２熱伝導層形成用組成物については、後段で詳述する。 The first base material and the second base material are synonymous with the above base material, and the preferred embodiments are also the same.
The first substrate and the second substrate may be the same or different.
The composition for forming the first thermally conductive layer and the composition for forming the second thermally conductive layer will be described in detail later.
　第１熱伝導層形成用組成物又は第２熱伝導層形成用組成物（以下、単に「組成物」ともいう。）を塗布する方法としては、例えば、公知の方法が挙げられる。
　具体的には、印刷法、スプレー法、ロールコート法、バーコート法、カーテンコート法、スピンコート法及びダイコート法（スリットコート法）が挙げられる。 Examples of the method of applying the composition for forming the first thermally conductive layer or the composition for forming the second thermally conductive layer (hereinafter also simply referred to as "composition") include known methods.
Specific examples include a printing method, a spray method, a roll coating method, a bar coating method, a curtain coating method, a spin coating method and a die coating method (slit coating method).
　組成物を塗布した後、必要に応じて、得られた塗膜に対して乾燥処理を施してもよい。乾燥処理としては、加熱処理が好ましい。
　加熱処理の温度としては、硬化性化合物の硬化反応が進行しづらい温度が好ましく、５０～１３０℃がより好ましい。 After applying the composition, the obtained coating film may be subjected to a drying treatment, if necessary. Heat treatment is preferable as the drying treatment.
The temperature of the heat treatment is preferably a temperature at which the curing reaction of the curable compound hardly progresses, more preferably 50 to 130°C.
　また、得られた塗膜に半硬化処理を施して、半硬化状態にしてもよい。つまり、第１熱伝導層及び第２熱伝導層は、半硬化膜であってもよい。特に、貼合後の熱伝導シートの熱伝導性が優れる点で、第１熱伝導層は、半硬化処理が施された層であることが好ましい。半硬化処理としては、加熱処理が挙げられ、加熱条件としては硬化性化合物の硬化が進行する温度以上が好ましい。
　また、第１熱伝導層は、加圧処理（例えば、プレス加工処理）が施された層であることが好ましい。加圧処理が施されることにより、第１熱伝導層中のボイドが低減し、貼合後の熱伝導シートの熱伝導性が優れる。
　半硬化処理及び加圧処理は、別々に実施してもよいし、同時に実施してもよい。
　例えば、基材上に組成物を塗布して塗膜を形成した後、そのまま無加圧で基材上の塗膜を加熱等して半硬化状態の半硬化物としてもよいし、プレス加工を併用しながら基材上の塗膜を加熱等して半硬化物としてもよい。
　プレス加工をする場合、プレス加工は、上記半硬化処理の前後に実施してもよいし、上記加熱等中に実施してもよい。
　半硬化処理においてプレス加工を実施すると、得られる半硬化物の膜厚の調整及び／又は半硬化物中のボイド量の低減をしやすい場合がある。 Further, the obtained coating film may be semi-cured by subjecting it to a semi-cured state. That is, the first thermally conductive layer and the second thermally conductive layer may be semi-cured films. In particular, the first thermally conductive layer is preferably a layer subjected to a semi-curing treatment in terms of excellent thermal conductivity of the thermally conductive sheet after lamination. The semi-curing treatment includes heat treatment, and the heating condition is preferably a temperature at which curing of the curable compound proceeds or higher.
Moreover, it is preferable that the first heat conductive layer is a layer subjected to pressure treatment (for example, pressing treatment). The pressure treatment reduces voids in the first thermally conductive layer, resulting in excellent thermal conductivity of the thermally conductive sheet after lamination.
Semi-curing treatment and pressure treatment may be performed separately or simultaneously.
For example, after forming a coating film by applying a composition on a substrate, the coating film on the substrate may be heated as it is without pressure to obtain a semi-cured product in a semi-cured state, or press processing may be performed. A semi-cured product may be obtained by heating the coating film on the base material while using them together.
When press working is performed, the press working may be performed before or after the semi-hardening treatment, or may be performed during the heating or the like.
If pressing is performed in the semi-curing treatment, it may be easier to adjust the thickness of the resulting semi-cured product and/or reduce the amount of voids in the semi-cured product.
　また、加圧処理（プレス加工処理）中は、常圧下及び減圧下のいずれであってもよい。
　プレス加工に使用するプレスとしては、例えば、平板プレスを用いてもよいしロールプレスを用いてもよい。
　ロールプレスを使用する場合、例えば、基材上に塗膜を形成して得た塗膜付き基材を、２本のロールが対向する１対のロールに挟持し、上記１対のロールを回転させて上記塗膜付き基材を通過させながら、上記塗膜付き基材の膜厚方向に圧力を付加することが好ましい。上記塗膜付き基材は、塗膜の片面にのみ基材が存在していてもよいし、塗膜の両面に基材が存在していてもよい。上記塗膜付き基材は、ロールプレスに１回だけ通過させてもよいし複数回通過させてもよい。
　半硬化処理及び／又は本硬化処理等における硬化処理の際に、平板プレスによる処理とロールプレスによる処理とは一方のみを実施してもよいし両方を実施してもよい。 Moreover, during the pressure treatment (pressing treatment), it may be under normal pressure or under reduced pressure.
As a press used for pressing, for example, a flat plate press or a roll press may be used.
When using a roll press, for example, a substrate with a coating film obtained by forming a coating film on the substrate is sandwiched between a pair of rolls facing each other, and the pair of rolls is rotated. It is preferable to apply pressure in the film thickness direction of the substrate with the coating film while allowing the substrate with the coating film to pass through. The base material with the coating film may have the base material on only one side of the coating film, or may have the base material on both sides of the coating film. The coated substrate may be passed through the roll press only once or may be passed multiple times.
At the time of hardening treatment such as the semi-hardening treatment and/or the main hardening treatment, either one or both of flat press treatment and roll press treatment may be performed.
　貼合工程としては、例えば、第１熱伝導層の第１基材とは反対側の表面と、第２熱伝導層の第２基材とは反対側の表面とを接触させて圧着する方法が挙げられる。
　圧着方法としては、例えば、ラミネート及びロール等による加圧及び加熱する方法が好ましい。具体的には、上記硬化処理で用いられるプレス加工が挙げられる。 As the lamination step, for example, a method in which the surface of the first thermally conductive layer opposite to the first substrate and the surface of the second thermally conductive layer opposite to the second substrate are brought into contact with each other and pressed together. are mentioned.
As the press-bonding method, for example, a method of pressurizing and heating by lamination, rolls, or the like is preferable. Specifically, press working used in the above-described hardening treatment is exemplified.
　熱伝導シートの製造方法は、更に、第１熱伝導層形成工程、第２熱伝導層形成工程及び／又は貼合工程を有していてもよい。つまり、１つ以上の第１熱伝導層と１つ以上の第２熱伝導層と有する熱伝導シートであってもよい。 The method for manufacturing the heat conductive sheet may further include a first heat conductive layer forming step, a second heat conductive layer forming step and/or a lamination step. That is, it may be a thermally conductive sheet having one or more first thermally conductive layers and one or more second thermally conductive layers.
　熱伝導シートの別の製造方法としては、第１基材上に第１熱伝導層形成用組成物を塗布して第１熱伝導層を形成する工程と、
　上記第１熱伝導層上に、更に、第２熱伝導層形成用組成物を塗布して第２熱伝導層を形成する工程と、を有する製造方法も好ましい。
　また、第１熱伝導層形成用組成物及び第２熱伝導層形成用組成物を基板上に同時に重層塗布し、第１熱伝導層及び第２熱伝導層を形成する製造方法であってもよい。 Another method for producing a thermally conductive sheet includes a step of applying a composition for forming a first thermally conductive layer onto a first substrate to form a first thermally conductive layer;
Also preferred is a manufacturing method comprising the step of further applying a composition for forming a second heat conductive layer on the first heat conductive layer to form a second heat conductive layer.
In addition, even in a manufacturing method in which the composition for forming the first thermally conductive layer and the composition for forming the second thermally conductive layer are simultaneously coated on the substrate to form the first thermally conductive layer and the second thermally conductive layer, good.
〔第１熱伝導層形成用組成物及び第２熱伝導層形成用組成物〕
　組成物（第１熱伝導層形成用組成物及び第２熱伝導層形成用組成物）は、各熱伝導層に含まれる成分と、溶媒とを含む。
　なお、第１熱伝導層形成用組成物は、第１熱伝導層を形成するための組成物であり、上述した第１熱伝導性無機粒子を少なくとも含む。
　第１熱伝導層形成用組成物は、第１熱伝導性無機粒子以外の他の成分（例えば、硬化性化合物等）を含んでいてもよい。
　なお、第２熱伝導層形成用組成物は、第２熱伝導層を形成するための組成物であり、上述した第２熱伝導性無機粒子及び硬化性化合物を少なくとも含む。
　第２熱伝導層形成用組成物は、第２熱伝導性無機粒子及び硬化性化合物以外の他の成分を含んでいてもよい。 [Composition for Forming First Thermally Conductive Layer and Composition for Forming Second Thermally Conductive Layer]
The compositions (the composition for forming the first thermally conductive layer and the composition for forming the second thermally conductive layer) contain components contained in each thermally conductive layer and a solvent.
The composition for forming the first thermally conductive layer is a composition for forming the first thermally conductive layer, and contains at least the first thermally conductive inorganic particles described above.
The composition for forming the first thermally conductive layer may contain components other than the first thermally conductive inorganic particles (for example, a curable compound, etc.).
The composition for forming the second thermally conductive layer is a composition for forming the second thermally conductive layer, and contains at least the second thermally conductive inorganic particles and the curable compound described above.
The composition for forming the second thermally conductive layer may contain components other than the second thermally conductive inorganic particles and the curable compound.
＜溶媒＞
　組成物は、溶媒を含むことが好ましい。
　溶媒としては、有機溶媒が好ましい。有機溶媒としては、例えば、シクロペンタノン、シクロヘキサノン、酢酸エチル、メチルエチルケトン、ジクロロメタン及びテトラヒドロフランが挙げられる。
　組成物が溶媒を含む場合、溶媒の含有量は、組成物の固形分濃度を、２０～９０質量％とする量が好ましく、３０～８５質量％とする量がより好ましく、５０～８０質量％とする量が更に好ましい。組成物の「固形分」とは、組成物を用いて形成される各熱伝導層を形成する成分を意味し、組成物が溶媒を含む場合、溶媒を除いた全ての成分を意味する。また、各熱伝導層を形成する成分であれば、液体状の成分も固形分とする。
　溶媒の含有量は、組成物の全質量に対して、１０～８０質量％が好ましく、１５～７０質量％がより好ましく、２０～５０質量％が更に好ましい。 <Solvent>
The composition preferably contains a solvent.
Organic solvents are preferred as solvents. Organic solvents include, for example, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane and tetrahydrofuran.
When the composition contains a solvent, the content of the solvent is preferably an amount that makes the solid content concentration of the composition 20 to 90% by mass, more preferably 30 to 85% by mass, and 50 to 80% by mass. is more preferable. The "solid content" of the composition means the components forming each thermally conductive layer formed using the composition, and when the composition contains a solvent, it means all components excluding the solvent. In addition, as long as it is a component that forms each heat conductive layer, a liquid component is also considered as a solid content.
The solvent content is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, even more preferably 20 to 50% by mass, relative to the total mass of the composition.
　組成物の製造方法としては、例えば、公知の方法が挙げられる。
　組成物の製造方法としては、例えば、各熱伝導層に含まれる成分と、溶媒とを混合する製造方法が挙げられる。混合する際には、各成分を一括混合しても、順次混合してもよい。
　成分を混合する方法としては、例えば、公知の方法を使用できる。混合に使用する混合装置は、液中分散機が好ましく、例えば、自転公転ミキサー、高速回転せん断型撹拌機等の撹拌機、コロイドミル、ロールミル、高圧噴射式分散機、超音波分散機、ビーズミル及びホモジナイザーが挙げられる。混合装置は、１種単独又は２種以上で用いてもよい。混合の前後に及び／又は同時に、脱気処理を実施してもよい。 Methods for producing the composition include, for example, known methods.
Examples of the method for producing the composition include a method for mixing components contained in each heat conductive layer with a solvent. When mixing, each component may be mixed all at once or sequentially.
As a method for mixing the components, for example, a known method can be used. The mixing device used for mixing is preferably a submerged disperser. A homogenizer is mentioned. You may use a mixing apparatus individually by 1 type or in 2 or more types. Degassing may be performed before, after and/or simultaneously with mixing.
〔熱伝導材料の用途〕
　本発明の熱伝導シートは、例えば、放熱材として使用でき、各種デバイスの放熱用途に使用できる。具体的には、デバイス上に熱伝導シートを配置して熱伝導シート付きデバイスを作製して、デバイスからの発熱を効率的に熱伝導シートの熱伝導層で放熱できる。特に本発明の熱伝導シートは、低圧力で貼合した際にも、デバイスとの密着性に優れるため、低圧力でデバイス上に熱伝導シートを配置でき、デバイスの破損リスクを軽減できる。
　上記熱伝導層は、後述する熱伝導性多層シートを含む熱伝導層であってもよい。
　本発明の熱伝導シートは、パーソナルコンピュータ、一般家電及び自動車等の電気機器に用いられているパワー半導体デバイスの放熱用途に適している。 [Applications of thermal conductive materials]
The thermally conductive sheet of the present invention can be used, for example, as a heat dissipation material, and can be used for heat dissipation of various devices. Specifically, a device with a heat conductive sheet is produced by arranging a heat conductive sheet on the device, and heat generated from the device can be efficiently dissipated through the heat conductive layer of the heat conductive sheet. In particular, the heat conductive sheet of the present invention has excellent adhesion to the device even when laminated at low pressure, so that the heat conductive sheet can be placed on the device at low pressure, and the risk of damage to the device can be reduced.
The thermally conductive layer may be a thermally conductive layer containing a thermally conductive multilayer sheet to be described later.
The heat conductive sheet of the present invention is suitable for heat dissipation of power semiconductor devices used in electrical equipment such as personal computers, general household appliances and automobiles.
　本発明の熱伝導シートの好適用途の一つとして、半導体モジュールが挙げられる。
　本発明の熱伝導シートを含む半導体モジュールの好適態様の一つとして、図２に示す態様が挙げられる。
　半導体モジュール１００Ａは、いわゆるケース型半導体モジュールであり、ヒートシンク３０と、金属層３２と、本発明の熱伝導シート１０と、２つのデバイス３４と、デバイス３４が実装された領域を囲うために設けられたケース枠３６と、ケース枠３６内に配置された封止材料３８とを含む。
　ヒートシンク３０と金属層３２との間には、導電ペースト層が配置されていてもよい。
　熱伝導シート１０中の第２熱伝導層１４がデバイス３４側に配置されている。
　また、デバイス３４の構成は特に制限されないが、半導体チップを含むことが好ましく、熱伝導シート１０側から回路部と導電ペースト層と半導体チップとが積層された態様であることがより好ましい。
　半導体モジュール１００Ａにおいては、デバイス３４は２つ記載されているが、その数は特に制限されず、各種用途に応じて最適な数が選択される。また、デバイス３４への電気接続は、図示しない金属電極やワイヤボンドを用いて行ってもよい。
　封止材料３８としては、例えば、シリコーンゲルが挙げられる。
　半導体モジュール１００Ａにおいては、デバイス３４で発生した熱が熱伝導シート１０を介してヒートシンク３０に伝熱され、半導体モジュール１００Ａ系外に放熱される構成となっている。 A semiconductor module is one of the preferred uses of the heat conductive sheet of the present invention.
One preferred embodiment of a semiconductor module containing the heat conductive sheet of the present invention is the embodiment shown in FIG.
The semiconductor module 100A is a so-called case-type semiconductor module, and includes a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, two devices 34, and a region in which the devices 34 are mounted. and a sealing material 38 disposed within the case frame 36 .
A conductive paste layer may be disposed between the heat sink 30 and the metal layer 32 .
The second heat conductive layer 14 in the heat conductive sheet 10 is arranged on the device 34 side.
Although the configuration of the device 34 is not particularly limited, it preferably includes a semiconductor chip, and more preferably has a configuration in which a circuit section, a conductive paste layer, and a semiconductor chip are laminated from the heat conductive sheet 10 side.
Although two devices 34 are shown in the semiconductor module 100A, the number is not particularly limited, and an optimum number is selected according to various uses. Also, electrical connection to the device 34 may be made using metal electrodes or wire bonds (not shown).
Examples of the sealing material 38 include silicone gel.
In the semiconductor module 100A, the heat generated in the device 34 is transferred to the heat sink 30 through the heat conductive sheet 10 and radiated outside the semiconductor module 100A system.
　本発明の熱伝導シートを含む半導体モジュールの他の好適態様の一つとして、図３に示す態様が挙げられる。
　半導体モジュール１００Ｂは、いわゆるモールド型半導体モジュールであり、ヒートシンク３０と、金属層３２と、本発明の熱伝導シート１０と、２つのデバイス３４と、デバイス３４を封止する封止樹脂４０とを含む。
　モールド型半導体モジュールである半導体モジュール１００Ｂのほうが、ケース型半導体モジュールである半導体モジュール１００Ａよりも、デバイス３４をより強固に固定および封止できる。
　半導体モジュール１００Ｂの製造方法は特に制限されず、例えば、半導体モジュール１００Ｂの封止材料４０以外の構成を備えた積層体のデバイス上に樹脂ペレットを配置して、樹脂ペレットに加熱加圧処理を施して封止樹脂４０を形成して半導体モジュールを製造する方法、および、金型に半導体モジュール１００Ｂの封止材料４０以外の構成を備えた積層体を置き、そこにモールド樹脂を流し込み、熱を加えることによって硬化させて半導体モジュールを製造するトランスファーモール工程を実施する方法が挙げられる。
　ヒートシンク３０と金属層３２との間には、導電ペースト層が配置されていてもよい。
　半導体モジュール１００Ｂにおいては、デバイス３４は２つ記載されているが、その数は特に制限されず、各種用途に応じて最適な数が選択される。また、デバイス３４への電気接続は、図示しない金属電極やワイヤボンドを用いて行ってもよい。　封止樹脂４０としては、例えば、エポキシ樹脂を熱硬化して得られる樹脂が挙げられる。
　半導体モジュール１００Ｂにおいては、デバイス３４で発生した熱が熱伝導シート１０を介してヒートシンク３０に伝熱され、半導体モジュール１００Ｂ系外に放熱される構成となっている。 Another preferred embodiment of the semiconductor module containing the heat conductive sheet of the present invention is shown in FIG.
The semiconductor module 100B is a so-called molded semiconductor module, and includes a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, two devices 34, and a sealing resin 40 that seals the devices 34. .
The semiconductor module 100B, which is a mold-type semiconductor module, can fix and seal the device 34 more firmly than the semiconductor module 100A, which is a case-type semiconductor module.
The method of manufacturing the semiconductor module 100B is not particularly limited. and a method of manufacturing a semiconductor module by forming a sealing resin 40 in a mold, and placing a laminate having a configuration other than the sealing material 40 of the semiconductor module 100B in a mold, pouring the mold resin there, and applying heat. A method of carrying out a transfer molding process in which a semiconductor module is manufactured by hardening by curing.
A conductive paste layer may be disposed between the heat sink 30 and the metal layer 32 .
Although two devices 34 are shown in the semiconductor module 100B, the number is not particularly limited, and an optimum number is selected according to various uses. Also, electrical connection to the device 34 may be made using metal electrodes or wire bonds (not shown). As the sealing resin 40, for example, a resin obtained by thermosetting an epoxy resin can be used.
In the semiconductor module 100B, the heat generated in the device 34 is transferred to the heat sink 30 through the heat conductive sheet 10 and radiated outside the system of the semiconductor module 100B.
　なお、半導体モジュール１００Ｂにおいてはヒートシンク３０と熱伝導シート１０との間に金属層３２が配置されている態様であったが、図４に示す半導体モジュール１００Ｃのように、金属層３２は配置されていなくてもよい。
　なお、半導体モジュール１００Ｃにおいては、ヒートシンク３０と熱伝導シート１０との間には、導電ペースト層が配置されていてもよい。 In the semiconductor module 100B, the metal layer 32 is arranged between the heat sink 30 and the heat conductive sheet 10, but the metal layer 32 is not arranged as in the semiconductor module 100C shown in FIG. It doesn't have to be.
A conductive paste layer may be arranged between the heat sink 30 and the thermally conductive sheet 10 in the semiconductor module 100C.
　また、半導体モジュールの他の好適態様の一つとして、図５に示すように、２つの半導体モジュールが対向するように配置された態様であってもよい。
　半導体モジュール１００Ｄにおいては、ヒートシンク３０と、金属層３２と、本発明の熱伝導シート１０と、デバイス３４とを含む積層体が対向するように配置されており、この２つの積層体中のデバイス３４を封止するように２つの積層体の間に封止樹脂４０が配置されている。
　このような態様においては、半導体モジュール１００Ｄの両面側から放熱される構成となっている。 Moreover, as one of the other preferred aspects of the semiconductor module, as shown in FIG. 5, two semiconductor modules may be arranged so as to face each other.
In the semiconductor module 100D, laminates including a heat sink 30, a metal layer 32, the thermally conductive sheet 10 of the present invention, and a device 34 are arranged to face each other, and the device 34 in these two laminates is arranged to face each other. A sealing resin 40 is arranged between the two laminates so as to seal the .
In such a mode, heat is dissipated from both sides of the semiconductor module 100D.
　また、半導体モジュールの他の好適態様の一つとして、図６に示すように、１つのデバイス３４の両側に熱伝導シート１０を配置する態様であってもよい。
　半導体モジュール１００Ｅは、デバイス３４と、デバイス３４の一方の面側に配置された、熱伝導シート１０と、金属層３２と、ヒートシンク３０と、デバイス３４の他方の面側に配置された、熱伝導シート１０と、金属層３２と、ヒートシンク３０と、デバイス３４を封止する封止樹脂４０とを含む。
　半導体モジュール１００Ｅにおいては、デバイス３４で発生した熱が、デバイス３４の両面に配置された熱伝導シート１０を介して２つのヒートシンク３０に伝熱され、半導体モジュール１００Ｅ系外に放熱される構成となっている。 Moreover, as another preferred mode of the semiconductor module, as shown in FIG.
The semiconductor module 100E includes a device 34, a heat-conducting sheet 10 arranged on one side of the device 34, a metal layer 32, a heat sink 30, and a heat-conducting sheet 100 arranged on the other side of the device 34. It includes a sheet 10 , a metal layer 32 , a heat sink 30 and an encapsulating resin 40 encapsulating the device 34 .
In the semiconductor module 100E, the heat generated in the device 34 is transferred to the two heat sinks 30 via the heat conductive sheets 10 arranged on both sides of the device 34, and is radiated outside the semiconductor module 100E system. ing.
　以下に実施例に基づいて本発明を更に詳細に説明する。以下の実施例に示す材料、使用量、割合、処理内容及び処理手順等は、本発明の趣旨を逸脱しない限り適宜変更できる。したがって、本発明の範囲は以下に示す実施例により限定的に解釈されるべきではない。 The present invention will be described in more detail below based on examples. The materials, amounts used, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the examples shown below.
［組成物の調製及び評価］
〔各種成分〕
　以下に、実施例及び比較例で使用した各種成分を示す。 [Preparation and Evaluation of Composition]
[Various components]
Various components used in Examples and Comparative Examples are shown below.
＜熱伝導性無機粒子＞
・ＨＰ４０ＭＦ１００：凝集状窒化ホウ素（平均粒径：４０μｍ、水島合金鉄社製）
・表面修飾ＢＮ：後述する製造方法Ａにより製造された表面修飾凝集状窒化ホウ素
・ＡＡ－５：酸化アルミニウム（平均粒径：５．０μｍ、平均アスペクト比：１．１、住友化学社製）
・ＡＡ－７：酸化アルミニウム（平均粒径：０．７μｍ、平均アスペクト比：１．０５、住友化学社製）
・ＡＡ－２：酸化アルミニウム（平均粒径：２．０μｍ、平均アスペクト比：１．１、住友化学社製）
・ＡＡ－１０：酸化アルミニウム（平均粒径：１０．０μｍ、平均アスペクト比：１．４、住友化学社製）
・ＡＡ－１８：酸化アルミニウム（平均粒径：１８．０μｍ、平均アスペクト比：１．６、住友化学社製） <Thermal conductive inorganic particles>
・HP40MF100: Agglomerated boron nitride (average particle size: 40 μm, manufactured by Mizushima Ferroalloy Co., Ltd.)
・Surface-modified BN: surface-modified aggregated boron nitride produced by production method A described later ・AA-5: aluminum oxide (average particle size: 5.0 μm, average aspect ratio: 1.1, manufactured by Sumitomo Chemical Co., Ltd.)
AA-7: aluminum oxide (average particle size: 0.7 μm, average aspect ratio: 1.05, manufactured by Sumitomo Chemical Co., Ltd.)
AA-2: aluminum oxide (average particle size: 2.0 μm, average aspect ratio: 1.1, manufactured by Sumitomo Chemical Co., Ltd.)
AA-10: aluminum oxide (average particle size: 10.0 μm, average aspect ratio: 1.4, manufactured by Sumitomo Chemical Co., Ltd.)
AA-18: aluminum oxide (average particle size: 18.0 μm, average aspect ratio: 1.6, manufactured by Sumitomo Chemical Co., Ltd.)
（製造方法Ａ）
　ＮａＯＨ水（ＮａＯＨ：４０ｇ／水：４００ｍＬ）に凝集状窒化ホウ素（ＨＰ４０ＭＦ１００）（５０ｇ）を添加して撹拌した。上記ＮａＯＨ水に、更に、過硫酸ナトリウム水（過硫酸ナトリウム：９．６ｇ／水：１００ｍＬ）を添加した後、上記ＮａＯＨ水を５０℃に昇温し、更に３時間撹拌した（変性工程）。撹拌にはスリーワンモーター（新東科学社製）を用いて１５０ｒｐｍで行った。
　上記ＮａＯＨ水を室温まで冷却した後、上記ＮａＯＨ水中の凝集状窒化ホウ素をろ取し、ろ取された凝集状窒化ホウ素を、水（５００ｍＬ）及びアセトニトリル（２５０ｍＬ）で洗浄することで変性凝集状窒化ホウ素１を得た。
　得られた変性凝集状窒化ホウ素１をアセトニトリル（１００ｍＬ）中で撹拌し、上記アセトニトリル中に更に、シランカップリング剤（信越化学社製：Ｘ１２－９８４Ｓ）の加水分解調整液（１．２５ｇ）を添加した。上記アセトニトリルを室温で３時間撹拌して、吸着処理を行った（吸着工程）。
　上記アセトニトリル中の変性凝集状窒化ホウ素１をろ取した後、ろ取された変性凝集状窒化ホウ素１をアセトニトリル（１００ｍＬ）で洗浄し、４０℃のオーブンで乾燥させることで、表面修飾凝集状窒化ホウ素を得た。
　なお、シランカップリング剤の加水分解調整液は、シランカップリング剤（１ｇ）、エタノール（５００μＬ）、２－プロパノール（５００μＬ）、水（７２０μＬ）及び酢酸（１００μＬ）を混合し、１時間撹拌することで調整した。
　また、「Ｘ１２－９８４Ｓ」は、エポキシ基及びエトキシシリル基を有する、ポリマータイプのシランカップリング剤である。
　なお、製造方法１において、ＮａＯＨ水（ＮａＯＨ：４０ｇ／水：４００ｍｌ）、凝集状窒化ホウ素（ＨＰ４０ＭＦ１００、５０ｇ）及び過硫酸ナトリウム水（過硫酸ナトリウム：９．６ｇ／水：１００ｍｌ）が混合された液（水溶液）のｐＨは、１４だった。
　表面修飾ＢＮ中の表面修飾剤の含有量は、表面修飾ＢＮの全質量に対して、０質量％超１質量％未満であった。 (Manufacturing method A)
Aggregated boron nitride (HP40MF100) (50 g) was added to NaOH water (NaOH: 40 g/water: 400 mL) and stirred. After adding sodium persulfate water (sodium persulfate: 9.6 g/water: 100 mL) to the NaOH water, the NaOH water was heated to 50°C and further stirred for 3 hours (denaturation step). Stirring was performed at 150 rpm using a three-one motor (manufactured by Shinto Kagaku Co., Ltd.).
After cooling the NaOH water to room temperature, the agglomerated boron nitride in the NaOH water was collected by filtration, and the filtered agglomerated boron nitride was washed with water (500 mL) and acetonitrile (250 mL) to form a denatured agglomerate. Boron nitride 1 was obtained.
The resulting modified aggregated boron nitride 1 was stirred in acetonitrile (100 mL), and a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: X12-984S) hydrolysis adjustment solution (1.25 g) was further added to the acetonitrile. added. The acetonitrile was stirred at room temperature for 3 hours to carry out adsorption treatment (adsorption step).
After filtering the modified aggregated boron nitride 1 in the acetonitrile, the filtered modified aggregated boron nitride 1 was washed with acetonitrile (100 mL) and dried in an oven at 40 ° C., thereby surface-modified aggregated boron nitride. Boron was obtained.
The silane coupling agent hydrolysis adjustment solution is prepared by mixing silane coupling agent (1 g), ethanol (500 μL), 2-propanol (500 μL), water (720 μL) and acetic acid (100 μL) and stirring for 1 hour. adjusted by
"X12-984S" is a polymer-type silane coupling agent having an epoxy group and an ethoxysilyl group.
In production method 1, NaOH water (NaOH: 40 g/water: 400 ml), aggregated boron nitride (HP40MF100, 50 g) and sodium persulfate water (sodium persulfate: 9.6 g/water: 100 ml) were mixed. The pH of the liquid (aqueous solution) was 14.
The content of the surface modifier in the surface-modified BN was more than 0% by mass and less than 1% by mass with respect to the total mass of the surface-modified BN.
＜エポキシ化合物＞
・ＥＸＡ－８３０ＬＶＰ（ＤＩＣ社製） <Epoxy compound>
・EXA-830LVP (manufactured by DIC)
＜マレイミド化合物＞
・ＢＭＩ－７０：ビスマレイミド樹脂（ケイ・アイ化成社製） <Maleimide compound>
・ BMI-70: Bismaleimide resin (manufactured by K-I Kasei Co., Ltd.)
＜フェノール化合物＞ <Phenol compound>
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
＜酸無水物＞
・ＳＭＡ　ＥＦ－４０：スチレン無水マレイン酸共重合体（巴工業社製） <Acid anhydride>
・ SMA EF-40: Styrene maleic anhydride copolymer (manufactured by Tomoe Kogyo Co., Ltd.)
＜硬化促進剤＞
・ＴＰＰ－ＭＫ：テトラフェニルホスホニウムテトラ－ｐ－トリルボラート（北興化学工業社製） <Curing accelerator>
・ TPP-MK: Tetraphenylphosphonium tetra-p-tolylborate (manufactured by Hokko Chemical Industry Co., Ltd.)
＜溶媒＞
・シクロペンタノン（日本ゼオン社製） <Solvent>
・Cyclopentanone (manufactured by Nippon Zeon Co., Ltd.)
〔組成物の調製〕
　下記表１及び表２に従って、下記の手順で第１熱伝導層形成用組成物及び第２熱伝導層形成用組成物を調製した。
　具体的には、まず、エポキシ化合物とフェノール化合物とを、当量（エポキシ化合物のエポキシ基の数と、フェノール化合物のヒドロキシ基の数とが等しくなる量）で配合した混合体を調製した。
　上記混合体及び溶媒を混合した後、酸無水物、硬化促進剤及びマレイミド化合物を混合した。その後、更に各熱伝導性無機粒子を添加した。得られた混合物を自転公転ミキサー（あわとり練太郎ＡＲＥ－３１０、ＴＨＩＮＫＹ社製）で５分間処理して、各実施例及び各比較例の組成物（硬化性組成物）を得た。
　表１及び表２中、第１熱伝導層形成用組成物又は第２熱伝導層形成用組成物の全質量に対する各成分の含有量（質量％）を表す。なお、「残部」とは、他の成分との合計量が１００質量％になるように、溶媒量を調整したことを意味する。 [Preparation of composition]
According to Tables 1 and 2 below, a composition for forming a first thermally conductive layer and a composition for forming a second thermally conductive layer were prepared in the following procedure.
Specifically, first, an epoxy compound and a phenol compound were blended in equivalent amounts (an amount that equalizes the number of epoxy groups in the epoxy compound and the number of hydroxy groups in the phenol compound) to prepare a mixture.
After mixing the above mixture and solvent, an acid anhydride, a curing accelerator and a maleimide compound were mixed. After that, each thermally conductive inorganic particle was further added. The resulting mixture was processed for 5 minutes with a rotation-revolution mixer (Awatori Mixer ARE-310, manufactured by THINKY) to obtain compositions (curable compositions) of each example and each comparative example.
In Tables 1 and 2, the content (% by mass) of each component with respect to the total mass of the composition for forming the first thermally conductive layer or the composition for forming the second thermally conductive layer is shown. In addition, "remainder" means that the amount of solvent was adjusted so that the total amount with other components was 100% by mass.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
［評価］
〔熱伝導シートの作製〕
　マイクロメーター付きアプリケーターを用いて、離型処理したＰＥＴフィルム（ＰＥＴ７５６５０１、リンテック社製、膜厚７５μｍ）の離型面上に、クリアランス４５０μｍで各第１熱伝導層形成用組成物を均一に塗布し、５０℃で４分間乾燥して、膜厚２２０μｍの第１熱伝導層を有する第１積層体を得た。得られた第１積層体を、更に、１２０℃で５分間乾燥した後に、５ｃｍ×５ｃｍに断裁した。得られた断裁物を温度１８８℃及び圧力２０ＭＰａで真空加圧した。
　また、マイクロメーター付きアプリケーターを用いて、離型処理したＰＥＴフィルム（ＰＥＴ７５６５０１、リンテック社製、膜厚７５μｍ）の離型面上に、クリアランス６０μｍで各第２熱伝導層形成用組成物を均一に塗布し、５０℃で２分間乾燥して、膜厚５３μｍの第２熱伝導層を有する第２積層体を得た。得られた第２積層体を、更に、１２０℃で２分間乾燥した後に、５ｃｍ×５ｃｍに断裁した。 [evaluation]
[Preparation of heat conductive sheet]
Using an applicator with a micrometer, each composition for forming the first heat conductive layer was uniformly applied onto the release surface of a release-treated PET film (PET756501, manufactured by Lintec, film thickness 75 μm) with a clearance of 450 μm. , and dried at 50° C. for 4 minutes to obtain a first laminate having a first thermally conductive layer with a film thickness of 220 μm. The obtained first laminate was further dried at 120° C. for 5 minutes, and then cut into 5 cm×5 cm. The resulting cut material was vacuum-pressurized at a temperature of 188° C. and a pressure of 20 MPa.
Also, using an applicator with a micrometer, each composition for forming the second heat conductive layer was uniformly applied with a clearance of 60 μm onto the release surface of a release-treated PET film (PET756501, Lintec, film thickness: 75 μm). It was applied and dried at 50° C. for 2 minutes to obtain a second laminate having a second heat conductive layer with a film thickness of 53 μm. The obtained second laminate was further dried at 120° C. for 2 minutes, and then cut into 5 cm×5 cm.
　上記第２熱伝導層を有する第２積層体のＰＥＴフィルムとは反対側の第２熱伝導層の表面を、上記第１熱伝導層を有する第１積層体のＰＥＴとは反対側の第１熱伝導層の表面に貼り付け、温度１８８℃及び圧力５ＭＰａで真空加圧して樹脂シートを得た。得られた樹脂シートの両面にあるＰＥＴフィルムを剥離して、各実施例及び各比較例の熱伝導シートを得た。いずれの熱伝導シートにおいても、得られた熱伝導シートの第１熱伝導層の膜厚は１２０μｍであり、得られた熱伝導シートの第２熱伝導層の膜厚は、３６μｍであった。 The surface of the second heat conductive layer opposite to the PET film of the second laminate having the second heat conductive layer is replaced with the first heat conductive layer opposite to the PET film of the first heat conductive layer having the first heat conductive layer. It was attached to the surface of the thermally conductive layer and vacuum-pressurized at a temperature of 188° C. and a pressure of 5 MPa to obtain a resin sheet. The PET films on both sides of the obtained resin sheet were peeled off to obtain the thermally conductive sheets of each example and each comparative example. In both thermally conductive sheets, the thickness of the first thermally conductive layer of the obtained thermally conductive sheet was 120 μm, and the thickness of the second thermally conductive layer of the obtained thermally conductive sheet was 36 μm.
〔熱伝導性の評価〕
　上記得られた樹脂シート（ＰＥＴフィルム／第１熱伝導層／第２熱伝導層／ＰＥＴフィルムをこの順で有する積層体）を、空気下で熱プレス（熱板温度１８０℃、圧力５ＭＰａで５分間）処理した後、更に、常圧下で１８０℃９０分間で処理した。得られた積層体の両面のＰＥＴフィルムを剥がし、熱伝導率測定用サンプルを得た。
　各組成物を用いて得られたそれぞれの樹脂シートを用いて、上記と同様に各熱伝導率測定用サンプルを作製して熱伝導性評価を実施した。下記の方法で熱伝導率の測定を行い、下記の基準に従って熱伝導性を評価した。 [Evaluation of thermal conductivity]
The resin sheet obtained above (laminate having PET film/first heat conductive layer/second heat conductive layer/PET film in this order) was hot-pressed under air (hot plate temperature 180° C., pressure 5 MPa, 5 minutes), and then further treated at 180° C. for 90 minutes under normal pressure. The PET films on both sides of the obtained laminate were peeled off to obtain a sample for thermal conductivity measurement.
Each resin sheet obtained using each composition was used to prepare each sample for thermal conductivity measurement in the same manner as described above, and the thermal conductivity was evaluated. Thermal conductivity was measured by the following method, and thermal conductivity was evaluated according to the following criteria.
＜膜厚方向の熱伝導率（Ｗ／ｍｋ）測定＞
（１）ＮＥＴＺＳＣＨ社製の「ＬＦＡ４６７」を用いて、レーザーフラッシュ法で熱伝導率測定用サンプルの厚み方向の熱拡散率を測定した。
（２）メトラー・トレド社製の天秤「ＸＳ２０４」を用いて、熱伝導率測定用サンプルの比重をアルキメデス法（「固体比重測定キット」使用）で測定した。
（３）セイコーインスツル社製の「ＤＳＣ３２０／６２００」を用い、１０℃／分の昇温条件の下、２５℃及び１７５℃における熱伝導率測定用サンプルの比熱を求めた。
（４）得られた熱拡散率に比重及び比熱を乗じて、熱伝導率測定用サンプルの膜厚方向の熱伝導率を算出した。
　熱伝導率測定用サンプルの熱伝導率を、下記基準に照らして区分して熱伝導性を評価とした。
　Ａ：１５Ｗ／ｍＫ以上
　Ｂ：１０Ｗ／ｍＫ以上、１５Ｗ／ｍＫ未満
　Ｃ：１０Ｗ／ｍＫ未満 <Measurement of thermal conductivity (W/mk) in film thickness direction>
(1) Using "LFA467" manufactured by NETZSCH, the thermal diffusivity in the thickness direction of the sample for thermal conductivity measurement was measured by the laser flash method.
(2) Using a balance "XS204" manufactured by Mettler Toledo, the specific gravity of the sample for thermal conductivity measurement was measured by the Archimedes method (using the "solid specific gravity measurement kit").
(3) Using “DSC320/6200” manufactured by Seiko Instruments Inc., the specific heat of the sample for thermal conductivity measurement was obtained at 25° C. and 175° C. under a temperature increase condition of 10° C./min.
(4) The obtained thermal diffusivity was multiplied by the specific gravity and the specific heat to calculate the thermal conductivity in the film thickness direction of the sample for thermal conductivity measurement.
The thermal conductivity of the samples for thermal conductivity measurement was classified according to the following criteria, and the thermal conductivity was evaluated.
A: 15 W/mK or more B: 10 W/mK or more and less than 15 W/mK C: less than 10 W/mK
〔密着性（銅ピール強度）の評価〕
　マイクロメーター付きアプリケーターを用いて、離型処理ＰＥＴフィルム（ＰＥＴ７５６５０１、リンテック社製、膜厚７５μｍ）の離型面上に、クリアランス４５０μｍで各第１熱伝導層形成用組成物を均一に塗布し、５０℃で４分間乾燥して、膜厚２２０μｍの第１熱伝導層を有する積層体を得た。得られた積層体を、更に、１２０℃で５分間乾燥した後に、５ｃｍ×５ｃｍに断裁した。第１熱伝導層の面と、厚さ１ｍｍ、サイズ５ｃｍ×５ｃｍのアルミニウム板を重ねて温度１８８℃及び圧力２０ＭＰａで真空加圧し、離型処理ＰＥＴフィルム（第１層目）／第１熱伝導層（第２層目）／アルミニウム板（第３層目）をこの順に有する第１積層体を得た。
　また、離型処理ＰＥＴフィルムに代えて、表面処理された銅箔上（製品名：表面処理電解銅箔ＣＦ－Ｔ８Ｇ－ＵＮ－３５、福田金属箔粉工業社製、膜厚３５μｍ）に変更し、クリアランス４８μｍで各第２熱伝導層形成用組成物を均一に塗布し、５０℃で３分間乾燥して、膜厚３７μｍの第２熱伝導層を有する第２積層体を得た。
　第１積層体の離型処理ＰＥＴフィルムを剥離して、露出した第１熱伝導層と、第２積層体の露出した第２熱伝導層とを直接合わせて温度１８８℃及び圧力５ＭＰａで真空加圧して、銅箔（第１層目）／第２熱伝導層（第２層目）／第１熱伝導層（第３層目）／アルミニウム板（第４層目）をこの順で有する積層体３を得た。得られた積層体３の第１熱伝導層の膜厚は１２０μｍであり、得られた密着性評価用熱伝導シートの第２熱伝導層の膜厚は、３６μｍであった。更に、積層体３を、幅２．０ｃｍ×長さ５．０ｃｍサイズ、及び、幅０．５ｃｍ×長さ５．０ｃｍサイズに裁断した。
　上記得られた各積層体３の銅箔ピール強度を、デジタルフォースゲージ（ＺＴＳ－２００Ｎ、イマダ社製）と９０度剥離試験治具（Ｐ９０－２００Ｎ－ＢＢ、イマダ社製）を用いて、ＪＩＳ　Ｃ　６４８１に記載の状態での引きはがし強さの測定方法に従って測定した。ピール強度試験における銅箔の剥離は、積層体３に対して９０°の角度で、５０ｍｍ／分の剥離速度で実施した。
　Ａ：５．０Ｎ／ｃｍ以上
　Ｂ：２．５Ｎ／ｃｍ以上、５．０Ｎ／ｃｍ未満
　Ｃ：２．５Ｎ／ｃｍ未満 [Evaluation of adhesion (copper peel strength)]
Using an applicator with a micrometer, each composition for forming the first heat conductive layer was uniformly applied onto the release surface of a release-treated PET film (PET756501, manufactured by Lintec, film thickness 75 µm) with a clearance of 450 µm, After drying at 50° C. for 4 minutes, a laminate having a first heat conductive layer with a film thickness of 220 μm was obtained. The obtained laminate was further dried at 120° C. for 5 minutes, and then cut into 5 cm×5 cm. An aluminum plate with a thickness of 1 mm and a size of 5 cm × 5 cm was superimposed on the surface of the first heat conductive layer, and vacuum pressure was applied at a temperature of 188 ° C. and a pressure of 20 MPa, and the mold release treated PET film (first layer) / first heat conduction A first laminate having a layer (second layer)/aluminum plate (third layer) in this order was obtained.
In addition, instead of the release-treated PET film, it was changed to a surface-treated copper foil (product name: surface-treated electrolytic copper foil CF-T8G-UN-35, manufactured by Fukuda Metal Foil & Powder Co., Ltd., film thickness 35 μm). , each composition for forming the second heat conductive layer was uniformly applied with a clearance of 48 μm and dried at 50° C. for 3 minutes to obtain a second laminate having a second heat conductive layer with a thickness of 37 μm.
The release-treated PET film of the first laminate was peeled off, and the exposed first thermally conductive layer and the exposed second thermally conductive layer of the second laminate were directly combined and subjected to vacuum heating at a temperature of 188 ° C. and a pressure of 5 MPa. Lamination having copper foil (first layer) / second thermally conductive layer (second layer) / first thermally conductive layer (third layer) / aluminum plate (fourth layer) in this order by pressing Got 3 bodies. The thickness of the first heat conductive layer of the obtained laminate 3 was 120 μm, and the thickness of the second heat conductive layer of the obtained heat conductive sheet for adhesion evaluation was 36 μm. Furthermore, the laminate 3 was cut into a size of 2.0 cm width×5.0 cm length and a size of 0.5 cm width×5.0 cm length.
The copper foil peel strength of each laminate 3 obtained above was measured using a digital force gauge (ZTS-200N, manufactured by Imada) and a 90-degree peel test jig (P90-200N-BB, manufactured by Imada) according to JIS. It was measured according to the method for measuring peel strength in the state described in C 6481. The peeling of the copper foil in the peel strength test was performed at an angle of 90° with respect to the laminate 3 at a peeling speed of 50 mm/min.
A: 5.0 N/cm or more B: 2.5 N/cm or more and less than 5.0 N/cm C: less than 2.5 N/cm
〔絶縁性の評価〕
　絶縁性の評価として、高温高湿条件での絶縁信頼性測定、及び、高温高湿条件での絶縁信頼性測定を実施した。 [Evaluation of insulation]
Insulation reliability measurement under high temperature and high humidity conditions and insulation reliability measurement under high temperature and high humidity conditions were carried out as insulation evaluation.
＜高温高湿条件での絶縁信頼性測定＞
　絶縁信頼性測定用サンプルは、「熱伝導測定用サンプル」と同様の手順で作製した。
　楠本化成社製の「ＥＴＡＣ絶縁信頼性測定システムＳＩＲ１３」を用いて、８５℃、８５％ＲＨの環境下で絶縁信頼性測定用サンプルに１ｋＶの電圧を印加して、絶縁信頼性測定用サンプルが絶縁破壊されるまでの時間を計測した。
　絶縁信頼性測定用サンプルが絶縁破壊されるまでの時間を、下記基準に照らして区分し、高温高湿条件での絶縁信頼性の評価とした。
　Ａ：５００時間以上
　Ｂ：１００時間以上５００時間未満
　Ｃ：５０時間以上１００時間未満
　Ｄ：５０時間未満 <Insulation reliability measurement under high temperature and high humidity conditions>
A sample for insulation reliability measurement was produced in the same procedure as the "sample for thermal conductivity measurement".
Using "ETAC insulation reliability measurement system SIR13" manufactured by Kusumoto Kasei Co., Ltd., a voltage of 1 kV is applied to the insulation reliability measurement sample in an environment of 85 ° C. and 85% RH, and the insulation reliability measurement sample is The time until dielectric breakdown occurred was measured.
The time until dielectric breakdown occurred in the samples for insulation reliability measurement was classified according to the following criteria, and the insulation reliability was evaluated under high-temperature and high-humidity conditions.
A: 500 hours or more B: 100 hours or more and less than 500 hours C: 50 hours or more and less than 100 hours D: Less than 50 hours
＜絶縁破壊電圧性測定＞
　絶縁破壊電圧性測定用サンプルは、絶縁信頼性測定用サンプルと同様の手順でを作製した。
　ヤマヨ試験器有限会社製の「ＹＳＴ－２４３－１００ＲＨＯ」を用いて、２５℃及び１７５℃の油中で、絶縁破壊電圧性測定用サンプルに１ｋＶを印加し２０秒間破壊しなければ、印加電圧を０．５Ｖずつ昇圧し２０秒間評価する測定を繰り返した。破壊しなかった最大電圧を絶縁破壊電圧とし、下記基準に照らして区分し、絶縁破壊電圧性の評価した。
　Ａ：５ｋＶ以上
　Ｂ：２ｋＶ以上５ｋＶ未満
　Ｃ：２ｋＶ未満 <Dielectric breakdown voltage measurement>
A sample for dielectric breakdown voltage measurement was prepared in the same manner as the sample for insulation reliability measurement.
Using "YST-243-100RHO" manufactured by Yamayo Test Instruments Co., Ltd., apply 1 kV to the dielectric breakdown voltage measurement sample in oil at 25 ° C. and 175 ° C. If it does not break for 20 seconds, the applied voltage is The measurement was repeated by increasing the voltage by 0.5 V and evaluating for 20 seconds. The maximum voltage at which no breakdown occurred was defined as the dielectric breakdown voltage, and the dielectric breakdown voltage property was evaluated by classifying the samples according to the following criteria.
A: 5 kV or more B: 2 kV or more and less than 5 kV C: less than 2 kV
〔ボイド発生抑制性の評価〕
　上記〔熱伝導シート（半硬化膜）の作製〕で得られた熱伝導シートを用いて、トラー・トレド社製の天秤「ＸＳ２０４」を用いて熱伝導シートの比重をアルキメデス法（「固体比重測定キット」使用）で測定した実比重ｇ／ｃｃと、理論比重（樹脂成分１．２ｇ／ｃｃ、アルミナ３．９０ｇ／ｃｃ、窒化ホウ素２．２７ｇ／ｃｃから体積分率で求めた値）を用いて、Ｖを以下の式で算出した。
　Ｖ　＝　（理論比重－実比重）／理論比重×１００
　Ａ：Ｖが、１．０％未満
　Ｂ：Ｖが、１．０％以上２．０％未満
　Ｃ：Ｖが、２．０％以上 [Evaluation of void generation suppression property]
Using the heat conductive sheet obtained in the above [Preparation of heat conductive sheet (semi-cured film)], the specific gravity of the heat conductive sheet is measured using a balance "XS204" manufactured by Tolar Toledo Co., Ltd. The Archimedes method ("solid specific gravity measurement Using the actual specific gravity g/cc measured with the kit" and the theoretical specific gravity (value obtained from the resin component 1.2 g/cc, alumina 3.90 g/cc, and boron nitride 2.27 g/cc by volume fraction) Then, V was calculated by the following formula.
V = (theoretical specific gravity - actual specific gravity) / theoretical specific gravity × 100
A: V is less than 1.0% B: V is 1.0% or more and less than 2.0% C: V is 2.0% or more
［結果］
　以下、評価結果を表３に示す。
　表中、「凝集状窒化ホウ素／酸化アルミニウム」欄は、酸化アルミニウム（熱伝導性無機粒子Ｘ）に対する凝集状窒化ホウ素の体積比を示す。 [result]
The evaluation results are shown in Table 3 below.
In the table, the "aggregated boron nitride/aluminum oxide" column shows the volume ratio of aggregated boron nitride to aluminum oxide (thermally conductive inorganic particles X).
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　表３に示す結果より、本発明の熱伝導シートは、熱伝導性に優れ、密着性にも優れることが確認された。
　第２熱伝導性無機粒子の含有量が、第２熱伝導層全体積に対して、４５．０～５５．０体積％である場合、本発明の効果がより優れることが確認された（実施例１～５等の比較）。
　第２熱伝導層中、熱伝導性無機粒子Ｘに対する凝集状窒化ホウ素の体積比が、２．８～５．０である場合、本発明の効果がより優れることが確認された（実施例１、６～１０等の比較）。
　熱伝導性無機粒子Ｘの平均粒径が、２．０～１０．０μｍである場合、本発明の効果がより優れることが確認された（実施例１、１１～１４等の比較）。
　第１熱伝導層及び第２熱伝導層の少なくとも一方が、更に、表面修飾剤を含み、凝集状窒化ホウ素が、凝集状窒化ホウ素の表面上に吸着した表面修飾剤とともに、表面修飾凝集状窒化ホウ素を構成している（表面修飾第１熱伝導性無機粒子及び／又は表面修飾第１熱伝導性無機粒子を用いた）場合、熱伝導性、密着性、絶縁性及びボイド発生抑制性がより優れることが確認された（実施例３、１１、１５及び１６等の比較）。 From the results shown in Table 3, it was confirmed that the thermally conductive sheet of the present invention has excellent thermal conductivity and adhesion.
It was confirmed that the effect of the present invention is more excellent when the content of the second thermally conductive inorganic particles is 45.0 to 55.0% by volume with respect to the total volume of the second thermally conductive layer (implementation (comparison with Examples 1 to 5, etc.).
It was confirmed that the effect of the present invention is more excellent when the volume ratio of the aggregated boron nitride to the thermally conductive inorganic particles X in the second thermally conductive layer is 2.8 to 5.0 (Example 1 , 6-10, etc.).
It was confirmed that the effects of the present invention are more excellent when the average particle diameter of the thermally conductive inorganic particles X is 2.0 to 10.0 μm (comparison with Examples 1, 11 to 14, etc.).
At least one of the first thermally conductive layer and the second thermally conductive layer further comprises a surface modifier, and the aggregated boron nitride is surface-modified aggregated nitriding with the surface modifier adsorbed on the surface of the aggregated boron nitride. When boron is composed (using the surface-modified first thermally conductive inorganic particles and/or the surface-modified first thermally conductive inorganic particles), the thermal conductivity, adhesion, insulation and void generation suppression are improved. It was confirmed to be excellent (comparison with Examples 3, 11, 15 and 16, etc.).
　１０　　熱伝導シート
　１２　　第１熱伝導層
　１４　　第２熱伝導層
　１６　　第１熱伝導性無機粒子
　１８　　第２熱伝導性無機粒子
　２０　　凝集状窒化ホウ素
　２２　　熱伝導性無機粒子Ｘ
　３０　　ヒートシンク
　３２　　金属層
　３４　　デバイス
　３６　　ケース枠
　３８　　封止材料
　４０　　封止樹脂
　１００Ａ，１００Ｂ，１００Ｃ，１００Ｄ，１００Ｅ　　半導体モジュール REFERENCE SIGNS LIST 10 thermally conductive sheet 12 first thermally conductive layer 14 second thermally conductive layer 16 first thermally conductive inorganic particles 18 second thermally conductive inorganic particles 20 agglomerated boron nitride 22 thermally conductive inorganic particles X
30 heat sink 32 metal layer 34 device 36 case frame 38 sealing material 40 sealing resin 100A, 100B, 100C, 100D, 100E semiconductor module

Claims (11)

  1. 　２つの主面を有する第１熱伝導層と、
    　前記第１熱伝導層の２つの主面のうち一方の主面上のみに配置された、第２熱伝導層とを有し、
    　前記第１熱伝導層の平均膜厚が前記第２熱伝導層の平均膜厚よりも大きく、
    　前記第１熱伝導層が、第１熱伝導性無機粒子を含み、
    　前記第２熱伝導層が、第２熱伝導性無機粒子及び硬化性化合物を含み、
    　前記第１熱伝導層全体積に対する前記第１熱伝導性無機粒子の含有量が、前記第２熱伝導層全体積に対する前記第２熱伝導性無機粒子の含有量よりも大きく、
    　前記第２熱伝導層中の前記第２熱伝導性無機粒子が、凝集状窒化ホウ素と、平均アスペクト比が１．０～１．６であり、前記凝集状窒化ホウ素とは異なる熱伝導性無機粒子Ｘと、を含み、
    　前記第２熱伝導性無機粒子の含有量が、前記第２熱伝導層全体積に対して、４０．０～６０．０体積％である、熱伝導シート。     a first thermally conductive layer having two main surfaces;
    a second thermally conductive layer disposed only on one of the two major surfaces of the first thermally conductive layer;
    The average film thickness of the first thermally conductive layer is greater than the average film thickness of the second thermally conductive layer,
    The first thermally conductive layer contains first thermally conductive inorganic particles,
    the second thermally conductive layer comprises second thermally conductive inorganic particles and a curable compound;
    The content of the first thermally conductive inorganic particles relative to the total area of the first thermally conductive layer is greater than the content of the second thermally conductive inorganic particles relative to the total area of the second thermally conductive layer,
    The second thermally conductive inorganic particles in the second thermally conductive layer are aggregated boron nitride and a thermally conductive inorganic material having an average aspect ratio of 1.0 to 1.6 and different from the aggregated boron nitride a particle X, and
    A thermally conductive sheet, wherein the content of the second thermally conductive inorganic particles is 40.0 to 60.0% by volume with respect to the total volume of the second thermally conductive layer.
  2. 　前記第２熱伝導層中、前記熱伝導性無機粒子Ｘに対する前記凝集状窒化ホウ素の体積比が、２．５～１０．５である、請求項１に記載の熱伝導シート。 The thermally conductive sheet according to claim 1, wherein the second thermally conductive layer has a volume ratio of the aggregated boron nitride to the thermally conductive inorganic particles X of 2.5 to 10.5.
  3. 　前記熱伝導性無機粒子Ｘが、酸化アルミニウムである、請求項１又は２に記載の熱伝導シート。 The thermally conductive sheet according to claim 1 or 2, wherein the thermally conductive inorganic particles X are aluminum oxide.
  4. 　前記熱伝導性無機粒子Ｘの平均粒径が、２．０～１０．０μｍである、請求項１～３のいずれか１項に記載の熱伝導シート。 The thermally conductive sheet according to any one of claims 1 to 3, wherein the thermally conductive inorganic particles X have an average particle size of 2.0 to 10.0 µm.
  5. 　前記硬化性化合物が、エポキシ化合物及びマレイミド化合物からなる群から選択される１種以上を含む、請求項１～４のいずれか１項に記載の熱伝導シート。 The thermally conductive sheet according to any one of claims 1 to 4, wherein the curable compound contains one or more selected from the group consisting of epoxy compounds and maleimide compounds.
  6. 　前記硬化性化合物が、フェノール化合物を含む、請求項１～５のいずれか１項に記載の熱伝導シート。 The heat conductive sheet according to any one of claims 1 to 5, wherein the curable compound contains a phenolic compound.
  7. 　前記第２熱伝導層の平均膜厚が、１０～７０μｍである、請求項１～６のいずれか１項に記載の熱伝導シート。 The thermally conductive sheet according to any one of claims 1 to 6, wherein the second thermally conductive layer has an average thickness of 10 to 70 µm.
  8. 　前記第１熱伝導層の平均膜厚が、１００～１５０μｍである、請求項１～７のいずれか１項に記載の熱伝導シート。 The thermally conductive sheet according to any one of claims 1 to 7, wherein the average film thickness of the first thermally conductive layer is 100 to 150 µm.
  9. 　前記凝集状窒化ホウ素の平均粒径が、１０．０～８０．０μｍである、請求項１～８のいずれか１項に記載の熱伝導シート。 The heat conductive sheet according to any one of Claims 1 to 8, wherein the aggregated boron nitride has an average particle size of 10.0 to 80.0 µm.
  10. 　前記第１熱伝導層及び前記第２熱伝導層の少なくとも一方が、更に、表面修飾剤を含み、
    　前記凝集状窒化ホウ素が、前記凝集状窒化ホウ素の表面上に吸着した前記表面修飾剤とともに、表面修飾凝集状窒化ホウ素を構成している、請求項１～９のいずれか１項に記載の熱伝導シート。     at least one of the first thermally conductive layer and the second thermally conductive layer further comprising a surface modifier;
    The heat of any one of claims 1 to 9, wherein the aggregated boron nitride, together with the surface modifier adsorbed on the surface of the aggregated boron nitride, constitutes a surface-modified aggregated boron nitride. conductive sheet.
  11. 　デバイスと、前記デバイス上に配置された請求項１～１０のいずれか１項に記載の熱伝導シートとを有する、熱伝導シート付きデバイス。 A device with a thermally conductive sheet, comprising a device and the thermally conductive sheet according to any one of claims 1 to 10 arranged on the device.
PCT/JP2022/020969 2021-05-31 2022-05-20 Heat conductive sheet, and device equipped with heat conductive sheet WO2022255130A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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