CN117645845A - Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device - Google Patents

Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device Download PDF

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Publication number
CN117645845A
CN117645845A CN202311120838.XA CN202311120838A CN117645845A CN 117645845 A CN117645845 A CN 117645845A CN 202311120838 A CN202311120838 A CN 202311120838A CN 117645845 A CN117645845 A CN 117645845A
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China
Prior art keywords
adhesive sheet
layer
meth
adhesive
semiconductor wafer
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CN202311120838.XA
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Chinese (zh)
Inventor
梅泽昌弘
安达一政
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Lintec Corp
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Lintec Corp
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Publication of CN117645845A publication Critical patent/CN117645845A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/255—Polyesters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • C09D175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
    • C09D175/16—Polyurethanes having carbon-to-carbon unsaturated bonds having terminal carbon-to-carbon unsaturated bonds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
    • C09D4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09D159/00 - C09D187/00
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C09D7/62—Additives non-macromolecular inorganic modified by treatment with other compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C09J4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/122—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2467/00—Presence of polyester
    • C09J2467/006—Presence of polyester in the substrate

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Wood Science & Technology (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Dicing (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
  • Adhesive Tapes (AREA)
  • Paints Or Removers (AREA)

Abstract

The present invention relates to an adhesive sheet for semiconductor processing, which has, in order, a surface coating layer, a buffer layer, a base material, and an adhesive layer, wherein the surface coating layer is a layer containing a resin component and hydrophobicized silica, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.

Description

Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
Technical Field
The present invention relates to an adhesive sheet for semiconductor processing and a method for manufacturing a semiconductor device.
Background
In the rapid progress of thinning, miniaturization, and multifunction of information terminal apparatuses, there is also a demand for thinning and densification of semiconductor devices mounted on these apparatuses.
As a method for thinning a semiconductor device, a method of grinding the back surface of a semiconductor wafer used in the semiconductor device has been performed. The back surface grinding of the semiconductor wafer is performed in a state in which an adhesive sheet for semiconductor processing (hereinafter, also referred to as "back grinding sheet") for back surface grinding is attached to the surface of the semiconductor wafer, and the surface of the semiconductor wafer is protected by the sheet. The back grinding sheet is peeled off from the surface of the semiconductor wafer after back grinding.
In recent years, as a grinding and singulation method for thinning a semiconductor chip while suppressing damage to the semiconductor chip, a prior dicing method, a stealth prior dicing method, or the like has been put into practical use. The dicing method is a method in which after a groove of a predetermined depth is formed in the front surface of a semiconductor wafer by a dicing blade or the like, the semiconductor wafer is ground from the back surface side until reaching the groove, and the semiconductor wafer is singulated. In the stealth dicing method, a modified region is formed inside a semiconductor wafer by irradiation of laser light, and then the semiconductor wafer is ground from the back side, and the semiconductor wafer is diced using the modified region as a dicing starting point, whereby the semiconductor wafer is singulated. A back grinding sheet for protecting the surface of the semiconductor wafer is also used in these methods.
Along with development of these thinning techniques, there is also a demand for a function for thinning a semiconductor chip yield in a satisfactory manner for an adhesive sheet for semiconductor processing, and various studies have been made.
In patent document 1, as an adhesive sheet for protecting a semiconductor wafer surface applicable to a dicing-first method or a stealth dicing-first method, an adhesive sheet for protecting a semiconductor wafer surface has been developed, which has a base film, an intermediate layer formed of an adhesive provided on at least one surface side of the base film, and an outermost adhesive layer provided on an outermost layer of the intermediate layer on a side opposite to the base film, wherein the intermediate layer is formed of a material that is cured by a curing treatment after the adhesive sheet is formed.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2015-56446
Disclosure of Invention
Problems to be solved by the invention
According to the adhesive sheet for protecting the surface of a semiconductor wafer of patent document 1, it is considered that notch offset, which is originally caused by breakage of the chip space after dicing the semiconductor wafer into chips, can be suppressed, contamination by the grinding dust of the semiconductor wafer can be suppressed, and the residual glue on the chips can be prevented when the surface protective tape is peeled off.
On the other hand, in back grinding, a back grinding sheet attached to a semiconductor wafer is fixed to a surface (hereinafter, also referred to as "back surface") opposite to the surface attached to the semiconductor wafer by a support device such as a chuck table. Further, the back surface of the semiconductor wafer fixed to the table of the supporting device via the back grinding sheet is ground while cooling water for removing heat and grinding dust generated by grinding is supplied to the grinding surface.
When the back grinding is performed, if the grinding chip exists between the back grinding sheet and the table of the supporting device, cracks may occur in the semiconductor wafer or the semiconductor chip from an impact when the semiconductor wafer is fixed to the table, pressurization and vibration during the back grinding, or the like, with the portion where the grinding chip exists as a starting point. Since the chips adhere to the back surface of the back grinding sheet in a state of being contained in the cooling water, it is necessary to reduce the amount of the chips adhering to the back surface of the back grinding sheet in order to suppress the occurrence of the cracks.
However, the pressure-sensitive adhesive sheet for protecting the surface of a semiconductor wafer of patent document 1 does not sufficiently cope with the demand for reducing the amount of the abrasive dust adhering to the back surface of the back grinding sheet.
The present invention has been made in view of the above-described background, and an object of the present invention is to provide an adhesive sheet for semiconductor processing in which the amount of adhesion of grinding dust is reduced, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.
Means for solving the problems
As a result of intensive studies, the present inventors have found that the above problems can be solved by using an adhesive sheet for semiconductor processing having a specific surface coating layer, a buffer layer, a base material and an adhesive layer in this order, and have completed the present invention as follows.
That is, the present invention relates to the following [1] to [18].
[1] An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a buffer layer, a base material and an adhesive layer in this order,
the surface coating layer is a layer containing a resin component and a hydrophobicized silica.
[2] The pressure-sensitive adhesive sheet for semiconductor processing as described in the above [1], wherein,
in the surface coating layer, the content of the hydrophobicized silica is 1 to 150 parts by mass based on 100 parts by mass of the resin component.
[3] The pressure-sensitive adhesive sheet for semiconductor processing as described in the above [1] or [2], wherein,
the resin component is a polymer of a compound having 1 or more ethylenically unsaturated bonds.
[4] The pressure-sensitive adhesive sheet for semiconductor processing as described in the above [3], wherein,
the compound having 1 or more ethylenically unsaturated bonds is a styrene compound.
[5] The adhesive sheet for semiconductor processing according to any one of the above [1] to [4], wherein the thickness of the surface coating layer is 0.05 to 10. Mu.m.
[6] The adhesive sheet for semiconductor processing according to any one of the above [1] to [5], wherein the buffer layer is a layer formed from a buffer layer forming composition containing urethane (meth) acrylate.
[7] The adhesive sheet for semiconductor processing according to any one of the above [1] to [6], which is used for back grinding of a semiconductor wafer.
[8] A method of manufacturing a semiconductor device, the method comprising:
a step of adhering the adhesive sheet for semiconductor processing described in any one of the above [1] to [7] to a surface of a semiconductor wafer with the adhesive layer as an adhering surface; and
and grinding the back surface of the semiconductor wafer while fixing the surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer by a supporting means.
[9] A method of manufacturing a semiconductor device, the method comprising:
a dividing line forming step of: a step a of forming a groove in a surface of a semiconductor wafer, or a step b of forming a modified region from a front surface or a back surface of the semiconductor wafer into the semiconductor wafer;
and a sheet sticking process: after the step a, or before or after the step b, adhering the adhesive sheet for semiconductor processing described in any one of the above [1] to [7] to the surface of the semiconductor wafer with the adhesive layer as an adhering surface; and
grinding and singulation: the back surface of the semiconductor wafer is ground in a state where the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting means, and the semiconductor wafer is singulated into a plurality of semiconductor chips starting from the groove or the modified region.
[10] An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a buffer layer, a base material and an adhesive layer in this order,
wherein the static contact angle of 1-bromonaphthalene at 23 ℃ relative to the surface coating is more than 19 degrees.
[11] The pressure-sensitive adhesive sheet for semiconductor processing as described in the above [10], wherein,
The surface coating layer is an organic layer containing a resin component.
[12] The pressure-sensitive adhesive sheet for semiconductor processing as described in [11], wherein,
the resin component is a polymer of a compound having 1 or more ethylenically unsaturated bonds.
[13] The adhesive sheet for semiconductor processing according to the item [12], wherein,
the compound having 1 or more ethylenically unsaturated bonds is a styrene compound.
[14] The adhesive sheet for semiconductor processing according to any one of the above [10] to [13], wherein the thickness of the surface coating layer is 0.05 to 10. Mu.m.
[15] The adhesive sheet for semiconductor processing according to any one of the above [10] to [14], wherein the buffer layer is a layer formed from a buffer layer forming composition containing urethane (meth) acrylate.
[16] The adhesive sheet for semiconductor processing according to any one of the above [10] to [15], which is used for back grinding of a semiconductor wafer.
[17] A method of manufacturing a semiconductor device, the method comprising:
a step of adhering the adhesive sheet for semiconductor processing described in any one of the above [10] to [16] to a surface of a semiconductor wafer with the adhesive layer as an adhering surface; and
and grinding the back surface of the semiconductor wafer while fixing the surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer by a supporting means.
[18] A method of manufacturing a semiconductor device, the method comprising:
a dividing line forming step of: a step a of forming a groove in a surface of a semiconductor wafer, or a step b of forming a modified region from a front surface or a back surface of the semiconductor wafer into the semiconductor wafer;
and a sheet sticking process: after the step a, or before or after the step b, adhering the adhesive sheet for semiconductor processing described in any one of the above [10] to [16] to the surface of the semiconductor wafer with the adhesive layer as an adhering surface; and
grinding and singulation: the back surface of the semiconductor wafer is ground in a state where the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting means, and the semiconductor wafer is singulated into a plurality of semiconductor chips starting from the groove or the modified region.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide an adhesive sheet for semiconductor processing in which the amount of adhering grinding dust is reduced, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.
Detailed Description
In the present specification, the lower limit value and the upper limit value described in layers may be independently combined with each other with respect to a preferable numerical range. For example, according to the description of "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit value (10)" and the "more preferable upper limit value (60)" may be combined to obtain "10 to 60".
In the present specification, the term "active ingredient" refers to a component other than a diluent solvent among components contained in a composition to be subjected to the formulation.
In the present specification, "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid", for example, and other similar expressions are also used.
In the present specification, the term "energy ray" means a ray having energy in an electromagnetic wave or a charged particle beam, and examples thereof include ultraviolet rays, radiation rays, and electron beams. For example, an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like may be used as an ultraviolet light source to irradiate ultraviolet rays. As for the electron beam, an electron beam generated by an electron beam accelerator or the like may be irradiated.
In the present specification, "energy ray polymerizability" means a property of polymerization by irradiation with energy rays. The term "energy ray curability" refers to a property that is cured by irradiation with energy rays, and the term "non-energy ray curability" refers to a property that is not energy ray curable.
In the present specification, the "front surface" of the semiconductor wafer means a surface on which a circuit is formed, and the "back surface" means a surface on which a circuit is not formed.
The mechanism of action described in the present specification is presumed, and the mechanism for achieving the effect of the adhesive sheet for semiconductor processing of the present invention is not limited.
[ adhesive sheet for semiconductor processing ]
The adhesive sheet for semiconductor processing according to the first embodiment of the present invention is an adhesive sheet for semiconductor processing which has a surface coating layer, a buffer layer, a base material, and an adhesive layer in this order, and the surface coating layer is a layer containing a resin component and a hydrophobicized silica.
The adhesive sheet for semiconductor processing according to the second embodiment of the present invention is an adhesive sheet for semiconductor processing which has a surface coating layer, a buffer layer, a base material, and an adhesive layer in this order, and has a static contact angle of 1-bromonaphthalene at 23 ℃ with respect to the surface coating layer of 19 ° or more.
Hereinafter, unless otherwise specified, the term "adhesive sheet of the present embodiment" refers to both of the adhesive sheet for semiconductor processing according to the first embodiment of the present invention and the adhesive sheet for semiconductor processing according to the second embodiment of the present invention.
The adhesive sheet of the present embodiment is attached to a surface of a semiconductor device as a work, and is used to perform a predetermined process on the semiconductor device while protecting the surface. After a predetermined process is performed on the workpiece, the adhesive sheet of the present embodiment is peeled off from the semiconductor device.
In the present embodiment, the term "semiconductor device" refers to all devices that can function by utilizing semiconductor characteristics, and examples thereof include: a semiconductor wafer, a semiconductor chip, an electronic component including the semiconductor chip, an electronic device including the electronic component, and the like. The adhesive sheet of the present embodiment is suitable for processing a semiconductor wafer.
The reason why the amount of adhering chips is reduced in the adhesive sheet of the present embodiment is not yet determined, but it is estimated as follows.
The surface coating layer of the adhesive sheet according to the first embodiment of the present invention contains a hydrophobicized silica. The hydrophobicized silica is thought to be present on the surface of the surface coating layer because of its hydrophobicity, and thus imparts water repellency to the surface coating layer. As a result, it is presumed that the surface coating is less likely to be wetted with water containing the shavings, and the amount of shavings adhering thereto is reduced.
In addition, the surface coating layer of the adhesive sheet according to the second embodiment of the present invention has a static contact angle with 1-bromonaphthalene of 19 ° or more at 23 ℃, and it is presumed that the surface coating layer having a static contact angle with 1-bromonaphthalene of 19 ° or more at 23 ℃ is less likely to be wetted with water containing the chips, and as a result, the amount of the attached chips is reduced.
The pressure-sensitive adhesive sheet of the present embodiment may have layers other than the top coat layer, the buffer layer, the base material, and the pressure-sensitive adhesive layer, or may not have these layers. Examples of the layer other than the surface coating layer, the buffer layer, the base material, and the adhesive layer include: an intermediate layer provided between the substrate and the pressure-sensitive adhesive layer, a release sheet provided on the side of the pressure-sensitive adhesive layer opposite to the substrate, and the like.
The following describes the respective members constituting the pressure-sensitive adhesive sheet of the present embodiment in order.
< surface coating >
The surface coating layer is a layer provided on the opposite side of the buffer layer from the substrate, and is fixed by the supporting device when the semiconductor device is processed.
The surface coating layer of the adhesive sheet according to the first embodiment of the present invention contains a resin component and a hydrophobicized silica. On the other hand, the surface coating layer of the adhesive sheet according to the second embodiment of the present invention may be an inorganic layer or an organic layer, but from the viewpoint of productivity and handling properties of the adhesive sheet, the surface coating layer is preferably an organic layer, more preferably an organic layer containing a resin component, and further preferably a silica having been subjected to a hydrophobization treatment.
(resin component)
The resin component is preferably a thermoplastic resin from the viewpoint of reducing the amount of the adhering chips.
The resin component may be used alone or in combination of two or more.
[ thermoplastic resin ]
The thermoplastic resin is preferably a polymer of a compound having 1 or more ethylenically unsaturated bonds (hereinafter, also referred to as "polymer (1)") from the viewpoint of further reducing the amount of adhering chips.
In the present embodiment, "ethylenically unsaturated bond" means a carbon-carbon double bond capable of undergoing an addition reaction, and a double bond of an aromatic ring is not included therein.
The content of the structural unit derived from the compound having 1 or more ethylenically unsaturated bonds in the polymer (1) is not particularly limited, but is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. When the content of the structural unit derived from the compound having 1 or more ethylenically unsaturated bonds is equal to or greater than the lower limit, the amount of the attached abrasive grains tends to be further reduced.
The content of the structural unit derived from the compound having 1 or more ethylenically unsaturated bonds in the polymer (1) may be 100 mass%, but may be 99.5 mass% or less or 99 mass% or less, for example, in order to contain the structural unit derived from another monomer.
Examples of the compound having 1 or more ethylenically unsaturated bonds include: styrene compounds such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, chlorostyrene, and methoxystyrene; chain monoolefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene and the like; chain non-conjugated dienes (non-conjugated dienes) such as 1, 4-hexadiene, 4-methyl-1, 4-hexadiene, and 5-methyl-1, 4-hexadiene; 1, 3-butadiene, isoprene, 1, 3-pentadiene, 2, 3-dimethyl-1, 3-butadiene, 2-phenyl-1, 3-butanediumConjugated dienes (conjugated dienes) such as olefins and 1, 3-hexadienes; cyclic mono-olefins such as cyclobutene, cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, cyclooctene, and the like; cyclic dienes such as cyclohexadiene, methylcyclohexadiene, cyclooctadiene, methylcyclooctadiene, and phenylcyclooctadiene; norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, tetracyclo [7.4.0.1 ] 10,13 .0 2,7 ]Tridecyl-2,4,6,11-tetraene and other polycyclic olefins; monomers having an oxygen atom and an ethylenic unsaturated bond such as maleic anhydride and vinyl acetate, and monomers having a nitrogen atom and an ethylenic unsaturated bond such as maleimide compounds and nitrile monomers.
In the above options, the polymer (1) preferably contains a structural unit derived from a styrenic compound. Hereinafter, the polymer (1) containing a structural unit derived from a styrene compound is referred to as "styrene resin".
The content of the structural unit derived from the styrene compound in the styrene resin is not particularly limited, but is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more.
When the content of the structural unit derived from the styrene compound in the styrene resin is not less than the lower limit, the heat resistance of the surface coating layer tends to be good.
The content of the structural unit derived from the styrene compound in the styrene resin is not particularly limited, but is preferably 80% by mass or less, more preferably 75% by mass or less, and still more preferably 70% by mass or less.
When the content of the structural unit derived from the styrene compound in the styrene resin is equal to or less than the upper limit, the balance between the amount of adhering the chips and the heat resistance tends to be improved by introducing the structural unit other than the structural unit derived from the styrene compound.
Examples of the structural unit other than the structural unit derived from the styrene compound that may be contained in the styrene resin include: structural units derived from compounds other than styrene compounds are exemplified as the compounds having 1 or more ethylenically unsaturated bonds. Of these, the styrene-based resin more preferably contains a structural unit derived from a conjugated diene.
The structural unit derived from the conjugated diene means a structural unit formed by addition polymerization of the conjugated diene, a structural unit formed by hydrogenation of a structural unit formed by addition polymerization of the conjugated diene, and the like.
Examples of the structural unit formed by hydrogenating the structural unit formed by addition polymerization of the conjugated diene include: an ethylene-propylene unit formed by hydrogenating a structural unit formed by addition polymerization of isoprene, an ethylene-butene unit formed by hydrogenating a structural unit formed by addition polymerization of 1, 3-butadiene, and the like.
When the styrene-based resin contains a structural unit derived from a conjugated diene, the content thereof in the styrene-based resin is not particularly limited, but is preferably 20 to 50% by mass, more preferably 25 to 45% by mass, and still more preferably 30 to 40% by mass.
When the content of the conjugated diene-derived structural unit in the styrene-based resin is equal to or greater than the lower limit, the amount of the adhering chips tends to be further reduced. In addition, when the content of the conjugated diene-derived structural unit in the styrene-based resin is equal to or less than the upper limit, the handling property after the work processing tends to be good.
The styrene resin is preferably one or more selected from the group consisting of styrene-butadiene block copolymers, styrene-ethylene-propylene block copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers (hereinafter also referred to as "SEBS") and styrene-ethylene-propylene-styrene block copolymers (hereinafter also referred to as "SEPS") from the viewpoint of the amount of adhering chips and heat resistance, and more preferably one or more selected from the group consisting of styrene-ethylene-butylene-styrene block copolymers and styrene-ethylene-propylene-styrene block copolymers.
Examples of the polymer (1) other than the styrene resin include: homopolymers such as polyethylene, polypropylene, and polybutadiene; ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-maleic anhydride copolymers, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylate copolymers, ethylene-tetracyclododecene copolymers, propylene-butene copolymers, propylene-maleic anhydride copolymers, propylene-vinyl acetate copolymers, propylene- (meth) acrylate copolymers, propylene-tetracyclododecene copolymers, and the like; multipolymers such as ethylene-maleic anhydride-vinyl acetate copolymers, ethylene-maleic anhydride- (meth) acrylate copolymers, ethylene-vinyl acetate- (meth) acrylate copolymers, propylene-maleic anhydride-vinyl acetate copolymers, propylene-maleic anhydride- (meth) acrylate copolymers, propylene-vinyl acetate- (meth) acrylate copolymers, ethylene-propylene-maleic anhydride copolymers, ethylene-propylene-vinyl acetate copolymers, ethylene-propylene- (meth) acrylate copolymers, ethylene-butene-maleic anhydride copolymers, ethylene-butene-vinyl acetate copolymers, ethylene-butene- (meth) acrylate copolymers, propylene-butene-maleic anhydride copolymers, propylene-butene-vinyl acetate copolymers, propylene-butene- (meth) acrylate copolymers; etc.
The weight average molecular weight (Mw) of the thermoplastic resin is not particularly limited, but is preferably 10,000 ～ 600,000, more preferably 15,000 ～ 500,000, and further preferably 20,000 ～ 400,000.
When the weight average molecular weight (Mw) of the thermoplastic resin is equal to or greater than the lower limit, the handling properties after processing the workpiece tend to be more excellent. When the weight average molecular weight (Mw) of the thermoplastic resin is equal to or less than the upper limit, the solvent solubility of the thermoplastic resin tends to be improved, and the formation of a surface coating layer by application tends to be easy.
In the present embodiment, the weight average molecular weight (Mw) is a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC), and specifically, is a value measured by the method described in examples.
The content of the resin component in the surface coating layer is not particularly limited, but is preferably 30 to 95% by mass, more preferably 40 to 90% by mass, and still more preferably 45 to 80% by mass, relative to the total amount (100% by mass) of the surface coating layer.
When the content of the resin component is within the above range, the adhesion amount of the chips tends to be further reduced.
(hydrophobized silica)
By incorporating the surface coating layer with the hydrophobicized silica, the amount of the adhering chips of the adhesive sheet of the present embodiment can be reduced.
The hydrophobicized silica may be used alone or in combination of two or more.
Examples of the hydrophobicized silica include: and a silica obtained by surface-treating a raw silica with a hydrophobizing agent.
The raw material silica to be subjected to hydrophobization may be, for example, wet-process silica produced by a wet process such as a precipitation process, a gel process, or a sol-gel process, or may be dry-process silica such as fumed silica or fused silica. Among these, wet-process silica is preferred, and precipitation-process silica is more preferred, from the viewpoint of easy hydrophobization.
Examples of the hydrophobizing agent include: organosilicon compounds, fatty acids, fatty acid metal salts, and the like.
The hydrophobizing agent may be used alone or in combination of two or more.
Examples of the method for surface-treating the raw silica with the hydrophobizing agent include: a method of bringing raw silica into contact with a hydrophobizing agent in a solvent, a method of bringing vapor of a hydrophobizing agent carried by a carrier gas such as nitrogen into contact with raw silica, a method of bringing a stock solution of a hydrophobizing agent into direct contact with raw silica, and the like.
The shape of the hydrophobicized silica is not particularly limited, and examples thereof include spherical and irregular shapes. Among them, the irregular shape is preferable from the viewpoint of further reducing the amount of the adhering abrasive dust.
Examples of the hydrophobicized silica include "AEROSIL (registered trademark) series" manufactured by Evonik corporation, "QSG series" manufactured by siegesbeck chemical industry corporation, "Nipsil (registered trademark) SS series" manufactured by eastern Cao Guihua corporation, and "sylophicic (registered trademark) series" manufactured by Fuji Silysia Chemical corporation.
The content of the hydrophobicized silica in the surface coating layer is not particularly limited, but is preferably 1 to 150 parts by mass, more preferably 10 to 120 parts by mass, still more preferably 20 to 100 parts by mass, and still more preferably 30 to 90 parts by mass, based on 100 parts by mass of the resin component.
When the content of the hydrophobized silica is not less than the lower limit, the amount of adhering chips tends to be further reduced. When the content of the hydrophobicized silica is not more than the upper limit, the film forming property of the surface coating tends to be improved.
The surface coating layer may contain components other than the resin component and the hydrophobicized silica.
For example, from the viewpoint of further improving adhesion to the buffer layer, the surface coating layer is preferably a layer formed by irradiating a composition containing a resin component and hydrophobicized silica, and containing an energy ray polymerizable polyfunctional compound and a photopolymerization initiator with energy rays.
In the following description, the composition for forming a surface coating layer is sometimes referred to as a "composition for forming a surface coating layer".
(energy ray polymerizable multifunctional Compound)
The energy ray polymerizable polyfunctional compound is a compound having 2 or more energy ray polymerizable functional groups.
The energy ray polymerizable polyfunctional compound may be used singly or in combination of two or more.
The number of the energy ray polymerizable functional groups of the energy ray polymerizable polyfunctional compound is preferably 2 to 10, more preferably 3 to 8, and still more preferably 4 to 7.
The energy ray polymerizable functional group of the energy ray polymerizable polyfunctional compound is preferably a (meth) acryl group.
The energy ray polymerizable polyfunctional compound is preferably a polyfunctional (meth) acrylate monomer.
Examples of the polyfunctional (meth) acrylate monomer include: 2-functional (meth) acrylate monomers such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, di (acryloyloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, and isocyanuric acid ethylene oxide-modified diacrylate; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, bis (acryloxyethyl) hydroxyethyl isocyanurate, isocyanuric ethylene oxide modified triacrylate, epsilon-caprolactone modified tris (acryloxyethyl) isocyanurate, diglycerol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, and the like. Among them, dipentaerythritol hexa (meth) acrylate and dipentaerythritol penta (meth) acrylate are preferable, and dipentaerythritol hexa-acrylate and dipentaerythritol penta-acrylate are more preferable.
When the composition for forming a surface coating layer contains the energy ray-polymerizable polyfunctional compound, the content of the energy ray-polymerizable polyfunctional compound is preferably 10 to 60 parts by mass, more preferably 14 to 40 parts by mass, and still more preferably 17 to 30 parts by mass, per 100 parts by mass of the resin component.
When the content of the energy ray polymerizable polyfunctional compound is not less than the lower limit, the adhesion between the surface coating layer and the buffer layer tends to be excellent. When the content of the energy ray-polymerizable polyfunctional compound is equal to or less than the upper limit, the balance between adhesion to the buffer layer and the amount of adhering chips tends to be easily improved.
(photopolymerization initiator)
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and the like, and more specifically, examples thereof include: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like.
The photopolymerization initiator may be used alone or in combination of two or more.
When the composition for forming a surface coating layer contains a photopolymerization initiator, the content thereof is not particularly limited, but from the viewpoint of homogenizing and sufficiently performing the energy ray polymerization reaction, the content is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the energy ray polymerizable polyfunctional compound.
(other Components)
The surface coating layer may contain other components than those described above within a range that does not impair the effects of the present invention. Examples of the other components include: resins other than the above; additives such as antistatic agents, antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, and the like; etc.
(contact angle of 1-bromonaphthalene)
The adhesive sheet according to the second embodiment of the present invention has a surface coating layer having a static contact angle with 1-bromonaphthalene (hereinafter, also simply referred to as "1-bromonaphthalene contact angle") of 19 ° or more at 23 ℃. The adhesive sheet according to the first embodiment of the present invention preferably has a surface coating layer having a 1-bromonaphthalene contact angle of 19 ° or more.
When the 1-bromonaphthalene contact angle of the surface coating is 19 ° or more, the adhesion amount of the chips tends to be further reduced.
From the viewpoint of further reducing the amount of the adhering abrasive dust, the contact angle of 1-bromonaphthalene of the surface coating is preferably 20 ° or more, more preferably 21 ° or more. The upper limit of the 1-bromonaphthalene contact angle of the surface coating is not particularly limited, and may be, for example, 50 ° or less, 40 ° or less, or 35 ° or less from the viewpoint of ease of production or the like.
The 1-bromonaphthalene contact angle of the surface coating layer was measured based on JIS R3257:1999, and specifically, it was measured by the method described in examples.
(thickness of surface coating)
The thickness of the surface coating layer is not particularly limited, but is preferably 0.05 to 10. Mu.m, more preferably 0.2 to 7. Mu.m, and still more preferably 1 to 4. Mu.m.
When the thickness of the surface coating is equal to or greater than the lower limit, a uniform layer can be formed, and the amount of adhering chips can be further reduced. When the thickness of the surface coating layer is equal to or less than the upper limit, the effect of absorbing the irregularities such as foreign matter on the chuck table by the buffer layer tends to be easily obtained.
< buffer layer >
The buffer layer is a layer provided between the substrate and the surface coating layer, and serves to absorb vibration, impact, and the like generated during back grinding and prevent cracking of the workpiece. Further, by providing the buffer layer, it is possible to absorb irregularities such as foreign matter present on the table of the supporting device, and to improve the holding property of the supporting device with respect to the adhesive sheet.
(composition for Forming buffer layer)
The buffer layer may be formed from a buffer layer forming composition.
The buffer layer is preferably a layer obtained by energy ray curing a composition for forming a buffer layer containing an energy ray polymerizable compound from the viewpoint of obtaining physical properties suitable for the buffer layer.
The composition for forming a buffer layer preferably contains a urethane (meth) acrylate (a 1) as the energy ray-polymerizable compound. By containing the urethane (meth) acrylate (a 1) in the composition for forming a buffer layer, the storage modulus and the like of the buffer layer tend to be adjusted to a good range.
From the same viewpoint, the composition for forming a buffer layer preferably contains one or more kinds of polymerizable compounds (a 2) selected from alicyclic groups or heterocyclic groups having 6 to 20 ring-forming atoms and polymerizable compounds (a 3) having functional groups in addition to the urethane (meth) acrylate (a 1), and more preferably contains the polymerizable compounds (a 2) having alicyclic groups or heterocyclic groups having 6 to 20 ring-forming atoms and the polymerizable compounds (a 3) having functional groups in addition to the urethane (meth) acrylate (a 1).
In the present specification, the number of ring-forming atoms refers to the number of atoms constituting the ring itself in a compound having a structure in which atoms are bonded in a ring, and atoms not constituting the ring (for example, hydrogen atoms bonded to atoms constituting the ring) and atoms contained in a substituent in the case where the ring is substituted with a substituent are not included in the number of ring-forming atoms.
[ urethane (meth) acrylate (a 1) ]
The urethane (meth) acrylate (a 1) is a compound having a (meth) acryloyl group and a urethane bond, and has a property of polymerizing by irradiation with energy rays.
The urethane (meth) acrylate (a 1) may be used singly or in combination of two or more.
The weight average molecular weight (Mw) of the urethane (meth) acrylate (a 1) is not particularly limited, but is preferably 1,000 ～ 100,000, more preferably 2,000 to 60,000, and further preferably 3,000 to 20,000.
The number of (meth) acryloyl groups present in 1 molecule of the urethane (meth) acrylate (a 1) is not particularly limited, but is preferably 1 to 4, more preferably 1 to 3, still more preferably 1 or 2.
The urethane (meth) acrylate (a 1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyisocyanate compound with a (meth) acrylate having a hydroxyl group.
The polyol compound is not particularly limited as long as it has 2 or more hydroxyl groups.
Specific examples of the polyol compound include: alkylene glycols, polyether polyols, polyester polyols, polycarbonate polyols, and the like. Among them, polyester polyols are preferable.
The polyol compound may be any of 2-functional diol, 3-functional triol, and 4-functional or more polyol, and is preferably 2-functional diol, more preferably polyester diol.
The polyhydric alcohol compound may be used singly or in combination of two or more.
Examples of the polyisocyanate compound include: aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4, 4' -diisocyanate, dicyclohexylmethane-2, 4' -diisocyanate, and ω, ω ' -diisocyanate-dimethylcyclohexane; aromatic diisocyanates such as 4,4' -diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, dimethylbiphenyl diisocyanate, tetramethylene xylylene diisocyanate, naphthalene-1, 5-diisocyanate, etc.; etc. Among them, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate are preferable.
The polyisocyanate compound may be used singly or in combination of two or more.
The (meth) acrylate having a hydroxyl group which reacts with the terminal isocyanate urethane prepolymer is not particularly limited as long as it is a compound having a hydroxyl group and a (meth) acryloyl group in at least 1 molecule.
Examples of the (meth) acrylate having a hydroxyl group include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and the like; hydroxyl group-containing (meth) acrylamides such as N-methylol (meth) acrylamides; vinyl alcohol, vinyl phenol, a reactant obtained by reacting (meth) acrylic acid with diglycidyl ester of bisphenol a; etc. Among them, hydroxyalkyl (meth) acrylates are preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.
The (meth) acrylic acid ester having a hydroxyl group may be used singly or in combination of two or more.
The conditions for reacting the terminal isocyanate urethane prepolymer with the (meth) acrylate having a hydroxyl group are not particularly limited, and for example, the conditions may be such that the reaction is carried out at 60 to 100℃for 1 to 4 hours in the presence of an organic solvent, a catalyst or the like, which are added as needed.
The content of the urethane (meth) acrylate (a 1) in the composition for forming a buffer layer is not particularly limited, but is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass, based on the total amount (100% by mass) of the active ingredients of the composition for forming a buffer layer.
[ polymerizable Compound (a 2) having an alicyclic group or heterocyclic group having 6 to 20 ring members ]
When the buffer layer-forming composition contains the polymerizable compound (a 2) having an alicyclic group or heterocyclic group having 6 to 20 ring-forming atoms (hereinafter, also referred to as "polymerizable compound (a 2) having an alicyclic group or heterocyclic group)"), the film-forming property of the buffer layer-forming composition tends to be improved.
Examples of the atom forming the ring structure of the heterocyclic group include: carbon atom, nitrogen atom, oxygen atom, sulfur atom, etc.
The polymerizable compound (a 2) having an alicyclic group or a heterocyclic group may be used singly or in combination of two or more.
The polymerizable compound (a 2) having an alicyclic group or a heterocyclic group is preferably a compound having a (meth) acryloyl group.
The number of (meth) acryloyl groups in 1 molecule of the polymerizable compound (a 2) having an alicyclic group or a heterocyclic group is not particularly limited, but is preferably 1 or more, more preferably 1 or 2, and further preferably 1.
The number of ring-forming atoms of the alicyclic group or heterocyclic group of the polymerizable compound (a 2) having an alicyclic group or heterocyclic group is 6 to 20, preferably 6 to 18, more preferably 6 to 16, and still more preferably 7 to 12.
Examples of the polymerizable compound (a 2) having an alicyclic group or a heterocyclic group include: alicyclic group-containing (meth) acrylates such as isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, adamantyl (meth) acrylate, and the like; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and morpholino (meth) acrylate; etc. Among them, alicyclic group-containing (meth) acrylate is preferable, and isobornyl (meth) acrylate is more preferable.
The content of the polymerizable compound (a 2) having an alicyclic group or a heterocyclic group in the composition for forming a buffer layer is not particularly limited, but is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 50% by mass, based on the total amount (100% by mass) of the active ingredients of the composition for forming a buffer layer.
[ polymerizable Compound (a 3) having functional group ]
By containing the polymerizable compound (a 3) having a functional group in the composition for forming a buffer layer, the viscosity of the composition for forming a buffer layer can be adjusted to a proper range.
The polymerizable compound (a 3) having a functional group may be used singly or in combination of two or more.
Examples of the functional group of the polymerizable compound (a 3) having a functional group include: hydroxy, epoxy, amido, amino, and the like.
The number of functional groups in 1 molecule of the polymerizable compound (a 3) having functional groups is 1 or more, preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.
The polymerizable compound (a 3) having a functional group is preferably a compound having a functional group and a (meth) acryloyl group.
The number of (meth) acryloyl groups in 1 molecule of the polymerizable compound (a 3) having a functional group is not particularly limited, but is preferably 1 or more, more preferably 1 or 2, and still more preferably 1.
Examples of the polymerizable compound (a 3) having a functional group include: a hydroxyl group-containing polymerizable compound, an epoxy group-containing polymerizable compound, an amide group-containing polymerizable compound, an amino group-containing polymerizable compound, and the like.
Examples of the hydroxyl group-containing polymerizable compound include: hydroxy-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; vinyl ether compounds such as hydroxyethyl vinyl ether and hydroxybutyl vinyl ether; etc.
Examples of the epoxy group-containing polymerizable compound include: glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether, and the like.
Examples of the amide group-containing polymerizable compound include: (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol propane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-vinylformamide, and the like.
Examples of the amino group-containing polymerizable compound include: amino group-containing (meth) acrylates such as primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.
Among these compounds, hydroxyl group-containing (meth) acrylates are preferable, and hydroxyl group-containing (meth) acrylates having an aromatic ring such as 2-hydroxy-3-phenoxypropyl (meth) acrylate are more preferable.
The content of the functional group-containing polymerizable compound (a 3) in the composition for forming a buffer layer is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 25% by mass, based on the total amount (100% by mass) of the active ingredients of the composition for forming a buffer layer.
[ other polymerizable Compound ]
The composition for forming a buffer layer may contain other polymerizable compounds than the components (a 1) to (a 3) within a range that does not impair the effects of the present invention.
Examples of the other polymerizable compound include: alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms; vinyl compounds such as styrene, N-vinylpyrrolidone and N-vinylcaprolactam; etc.
The other polymerizable compounds may be used alone or in combination of two or more.
The content of the other polymerizable compound in the composition for forming a buffer layer is not particularly limited, but is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 2% by mass, relative to the total amount (100% by mass) of the active ingredients of the composition for forming a buffer layer.
[ photopolymerization initiator ]
The composition for forming a buffer layer containing an energy ray polymerizable compound preferably further contains a photopolymerization initiator from the viewpoint of reducing the polymerization time and the energy ray irradiation amount by the energy ray irradiation.
The photopolymerization initiator may be used alone or in combination of two or more.
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and the like, and more specifically, examples thereof include: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like. Among them, 1-hydroxycyclohexyl phenyl ketone is preferable.
The content of the photopolymerization initiator in the composition for forming a buffer layer is not particularly limited, but is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the energy ray polymerizable compound, from the viewpoint of homogenizing and sufficiently conducting the energy ray curing reaction.
(other Components)
The composition for forming a buffer layer may contain other components within a range that does not impair the effects of the present invention. Examples of the other components include: a resin component other than the above resin; antistatic agents, antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, and other additives; etc.
(Young's modulus of buffer layer)
The Young's modulus of the buffer layer at 23 ℃ is smaller than that of the substrate at 23 ℃, specifically, preferably lower than 1,200MPa, more preferably lower than 1,000MPa, and further preferably lower than 900MPa. The Young's modulus of the buffer layer at 23℃is preferably 50MPa or more, more preferably 100MPa or more.
When the Young's modulus of the buffer layer at 23℃is not more than the upper limit, the effect of absorbing vibration, impact, and the like generated during back grinding and the holding property of the adhesive sheet tend to be improved. Further, when the Young's modulus of the buffer layer at 23℃is equal to or higher than the lower limit, excessive deformation of the buffer layer during processing of the workpiece tends to be suppressed.
The Young's modulus of the buffer layer at 23℃can be measured under the conditions of a test speed of 200 mm/min based on JIS K7127:1999.
(stress relaxation Rate of buffer layer)
The stress relaxation rate of the buffer layer is not particularly limited, but is preferably 70 to 100%, more preferably 75 to 100%, and even more preferably 78 to 98%.
When the stress relaxation rate of the buffer layer is in the above range, the effect of absorbing vibration, impact, and the like generated at the time of back grinding and the holding property of the adhesive sheet tend to be improved.
The stress relaxation rate of the buffer layer was determined as follows: a buffer layer having a thickness of 200 μm was cut into 15 mm. Times.140 mm and used as a test piece, and stress A (N/m) was used when the test piece was stretched by 10% at 200 mm/min by 20mm grasping both ends of the test piece 2 ) And stress B (N/m after 1 minute from the stop of stretching 2 ) The value of (2) is obtained by the following equation.
Stress relaxation rate (%) =100× (a-B)/a (%)
(thickness of buffer layer)
The thickness of the buffer layer is not particularly limited, but is preferably 5 to 70. Mu.m, more preferably 7 to 50. Mu.m, and still more preferably 10 to 40. Mu.m.
When the thickness of the buffer layer is equal to or greater than the lower limit, the effect of absorbing vibration, impact, and the like generated at the time of back grinding and the holding property of the adhesive sheet tend to be improved. When the thickness of the buffer layer is equal to or less than the upper limit, excessive deformation of the buffer layer during processing of the workpiece tends to be suppressed.
< adhesive layer >
The pressure-sensitive adhesive layer is a layer provided on the opposite side of the base material from the buffer layer, and is a layer to be adhered to a work.
The adhesive layer is preferably a layer formed of an energy ray curable adhesive. By forming the adhesive layer from an energy ray-curable adhesive, the surface of the workpiece can be well protected with sufficient adhesiveness before energy ray curing, and the peeling force can be reduced after energy ray curing, thereby achieving easy peeling from the workpiece.
Examples of the energy ray-curable adhesive include: the following X-type adhesive composition, Y-type adhesive composition, XY-type adhesive composition, and the like.
Adhesive composition of type X: energy ray-curable adhesive composition containing non-energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin I") and energy ray-curable compound other than adhesive resin
Adhesive composition of the Y type: energy ray-curable adhesive composition containing energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin II") having unsaturated groups introduced into side chains of non-energy ray-curable adhesive resin and containing no energy ray-curable compound other than adhesive resin
XY type adhesive composition: energy ray-curable adhesive composition containing the energy ray-curable adhesive resin II and an energy ray-curable compound other than the adhesive resin
Among them, the energy ray-curable adhesive is preferably an XY-type adhesive composition. By using an XY-type adhesive composition, there is a tendency that the adhesive composition has sufficient adhesiveness before curing and can sufficiently reduce the peeling force with respect to a work after curing.
The adhesive forming the adhesive layer may be a layer formed of a non-energy ray-curable adhesive which does not cure even when irradiated with energy rays.
Examples of the non-energy ray-curable binder include: an adhesive containing an adhesive resin I and no adhesive resin II and an energy ray-curable compound.
Next, each component constituting the adhesive layer will be described in more detail.
In the following description, the term "adhesive resin" used means one or both of adhesive resin I and adhesive resin II. In the following description, the term "adhesive composition" is merely referred to as "adhesive composition", and is also intended to include the concepts of an X-type adhesive composition, a Y-type adhesive composition, an XY-type adhesive composition, and adhesive compositions other than these.
Examples of the adhesive resin include: acrylic resins, urethane resins, rubber resins, silicone resins, and the like. Among them, acrylic resins are preferable.
(acrylic resin)
The acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate.
Examples of the alkyl (meth) acrylate include: alkyl (meth) acrylate in which the alkyl group has 1 to 20 carbon atoms.
The alkyl group of the alkyl (meth) acrylate may be linear or branched.
From the viewpoint of further improving the adhesive force of the adhesive layer, the acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate having 4 or more carbon atoms as an alkyl group.
The structural units derived from the alkyl (meth) acrylate having 4 or more carbon atoms in the alkyl group contained in the acrylic resin may be one kind or two or more kinds.
The alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms preferably has 4 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, and still more preferably 4 to 6 carbon atoms.
Examples of the alkyl (meth) acrylate in which the alkyl group has 4 or more carbon atoms include: butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, and the like. Of these, butyl (meth) acrylate is preferable, and butyl acrylate is more preferable.
When the acrylic resin contains a structural unit derived from a (meth) acrylic acid alkyl ester having 4 or more carbon atoms as an alkyl group, the content thereof in the acrylic resin is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 60% by mass, from the viewpoint of further improving the adhesive force of the adhesive layer.
From the viewpoint of improving the storage modulus G' and the adhesive property of the adhesive layer, the acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate having 4 or more carbon atoms in the alkyl group and a structural unit derived from an alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group.
The structural units of the alkyl (meth) acrylate having 1 to 3 carbon atoms derived from the alkyl group contained in the acrylic resin may be one kind or two or more kinds.
Examples of the alkyl (meth) acrylate in which the alkyl group has 1 to 3 carbon atoms include: methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, and the like. Among them, methyl (meth) acrylate is preferable, ethyl (meth) acrylate is more preferable, methyl (meth) acrylate is more preferable, and methyl methacrylate is still more preferable.
When the acrylic resin contains a structural unit derived from an alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group, the content thereof in the acrylic resin is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, and still more preferably 15 to 25% by mass.
The acrylic resin preferably further contains a structural unit derived from a functional group-containing monomer.
By incorporating structural units derived from functional group-containing monomers into the acrylic resin, functional groups that are the crosslinking start points of reaction with the crosslinking agent or functional groups that can react with unsaturated group-containing compounds to introduce unsaturated groups into the side chains of the acrylic resin can be introduced.
The structural units derived from the functional group-containing monomer contained in the acrylic resin may be one kind alone or two or more kinds.
Examples of the functional group-containing monomer include: hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like. Among them, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferable, and hydroxyl group-containing monomers are more preferable.
Examples of the hydroxyl group-containing monomer include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, butyl 2-hydroxy (meth) acrylate, butyl 3-hydroxy (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; etc.
Examples of the carboxyl group-containing monomer include: ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid, and anhydrides thereof; 2-carboxyethyl methacrylate; etc.
When the acrylic resin contains a structural unit derived from a functional group-containing monomer, the content thereof is not particularly limited, but is preferably 5 to 45% by mass, more preferably 15 to 40% by mass, and still more preferably 25 to 35% by mass in the acrylic resin.
The acrylic resin may contain, in addition to the above-described structural units, structural units derived from other monomers copolymerizable with the acrylic monomer.
The structural units derived from the other monomers contained in the acrylic resin may be one kind alone or two or more kinds.
Examples of the other monomer include: styrene, alpha-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide, and the like.
In the acrylic resin, an unsaturated group having energy ray polymerizability may be further introduced to impart energy ray curability.
The unsaturated group can be introduced, for example, by reacting a functional group of an acrylic resin containing a structural unit derived from a functional group-containing monomer with a reactive substituent of a compound having a reactive substituent and an unsaturated group (hereinafter, also referred to as an "unsaturated group-containing compound") reactive with the functional group. The unsaturated group-containing compound may be used singly or in combination of two or more.
Examples of the unsaturated group included in the unsaturated group-containing compound include: (meth) acryl, vinyl, allyl, and the like. Among them, a (meth) acryl group is preferable.
Examples of the reactive substituent of the unsaturated group-containing compound include: isocyanate groups, glycidyl groups, and the like.
Examples of the unsaturated group-containing compound include: (meth) acryloyloxyethyl isocyanate, (meth) acryloyloxyisocyanate, (meth) glycidyl acrylate, and the like.
When the acrylic resin containing the structural unit derived from the functional group-containing monomer is reacted with the unsaturated group-containing compound, the ratio of the functional groups to be reacted with the unsaturated group-containing compound in the total number of functional groups in the acrylic resin is not particularly limited, but is preferably 60 to 98 mol%, more preferably 70 to 95 mol%, still more preferably 80 to 93 mol%.
When the ratio of the functional group reactive with the unsaturated group-containing compound is within the above range, sufficient energy ray curability can be imparted to the acrylic resin, and the functional group that has not reacted with the unsaturated group-containing compound can be reacted with the crosslinking agent to crosslink the acrylic resin.
The weight average molecular weight (Mw) of the acrylic resin is not particularly limited, but is preferably 30 to 150 tens of thousands, more preferably 35 to 100 tens of thousands, and still more preferably 40 to 60 tens of thousands.
When the weight average molecular weight (Mw) of the acrylic resin is in the above range, the adhesive force and cohesive force of the adhesive layer tend to be more excellent.
(energy ray-curable Compound)
The energy ray-curable compound contained in the X-type or XY-type adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and curable by irradiation with energy rays.
Examples of the energy ray-curable compound include: a polyvalent (meth) acrylate monomer such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and 1, 6-hexanediol di (meth) acrylate; oligomers such as urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and epoxy (meth) acrylate; etc. Among them, urethane (meth) acrylate oligomer is preferable from the viewpoint of having a high molecular weight and being less likely to cause a decrease in the elastic modulus of the adhesive layer.
The molecular weight of the energy ray-curable compound is not particularly limited, but is preferably 100 to 12,000, more preferably 200 to 10,000, further preferably 400 to 8,000, and still further preferably 600 to 6,000. In the case where the energy ray-curable compound is an oligomer, the molecular weight refers to a weight average molecular weight (Mw).
The content of the energy ray-curable compound in the X-type adhesive composition is not particularly limited, but is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 60 to 90 parts by mass, relative to 100 parts by mass of the adhesive resin.
When the content of the energy ray-curable compound in the X-type adhesive composition is within the above range, the balance between the adhesive force before the irradiation with energy rays and the peelability after the irradiation with energy rays tends to be good.
The content of the energy ray-curable compound in the XY-type adhesive composition is not particularly limited, but is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and further preferably 3 to 15 parts by mass, relative to 100 parts by mass of the adhesive resin.
When the content of the energy ray-curable compound in the XY-type adhesive composition is within the above range, the balance between the adhesive force before the irradiation with energy rays and the peelability after the irradiation with energy rays tends to be good. Since the adhesive resin is energy ray-curable in the XY-type adhesive composition, the peeling force tends to be sufficiently reduced after irradiation with energy rays even if the content of the energy ray-curable compound is small.
(crosslinking agent)
The adhesive composition preferably further contains a crosslinking agent.
The crosslinking agent is, for example, a component that crosslinks the adhesive resins by reacting with functional groups derived from the functional group-containing monomer that the adhesive resins have.
The crosslinking agent may be used alone or in combination of two or more.
Examples of the crosslinking agent include: isocyanate-based crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, and adducts thereof; epoxy crosslinking agents such as ethylene glycol glycidyl ether; aziridine crosslinking agents such as hexa [1- (2-methyl) -aziridinyl ] triphosphoric acid triazine; chelate crosslinking agents such as aluminum chelates; etc. Among them, the isocyanate-based crosslinking agent is preferable from the viewpoint of further improving the cohesive force and the adhesive force, and from the viewpoint of easy acquisition.
When the pressure-sensitive adhesive composition contains a crosslinking agent, the content thereof is not particularly limited, but from the viewpoint of properly conducting the crosslinking reaction, the content is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass, relative to 100 parts by mass of the pressure-sensitive adhesive resin.
(photopolymerization initiator)
In the case where the adhesive is an energy ray curable adhesive, the adhesive composition preferably further contains a photopolymerization initiator. By incorporating the photopolymerization initiator in the energy ray-curable adhesive, the curing reaction of the energy ray-curable adhesive tends to be sufficiently progressed even by using energy rays of relatively low energy such as ultraviolet rays.
The photopolymerization initiator may be used alone or in combination of two or more.
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and the like, and more specifically, examples thereof include: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like.
When the adhesive composition contains the photopolymerization initiator, the content thereof is not particularly limited, but from the viewpoint of homogenizing and sufficiently conducting the energy ray curing reaction, the content is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the adhesive resin.
(other additives)
The adhesive composition may contain other additives within a range that does not impair the effects of the present invention. As other additives, for example, there may be mentioned: antistatic agents, antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, and the like.
(organic solvent)
From the viewpoint of further improving the coatability to a substrate, a release sheet, or the like, the adhesive composition may be diluted with an organic solvent to be prepared in the form of a solution.
Examples of the organic solvent include: methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, diAn alkane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol, etc. />
The organic solvent may be used alone or in combination of two or more.
The organic solvent may be used as it is, or one or more organic solvents other than the organic solvent used in the synthesis may be added.
The storage modulus G' of the pressure-sensitive adhesive layer at 23℃is not particularly limited, but is preferably 0.05 to 0.5MPa, more preferably 0.1 to 0.4MPa, and still more preferably 0.12 to 0.3MPa.
When the storage modulus G' of the adhesive layer is in the above range at 23 ℃, even when the surface of the work has irregularities, an adhesive layer excellent in the following property to the irregularities can be obtained, and the surface of the work can be more favorably protected during processing.
In the case where the adhesive layer is formed of an energy ray-curable adhesive, the storage modulus G 'of the adhesive layer means the storage modulus G' before curing by irradiation with energy rays.
The storage modulus G' of the adhesive layer at 23 ℃ can be determined as follows: the adhesive layer having a thickness of 3mm was cut into a circular shape having a diameter of 8mm, and the resultant was used as a test piece, and the measurement was performed under the conditions of a frequency of 1Hz and a measurement temperature of 23℃by a torsional shear method using a viscoelasticity measuring device.
The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 5 to 100. Mu.m, more preferably 10 to 80. Mu.m, and still more preferably 15 to 60. Mu.m.
When the thickness of the adhesive layer is equal to or greater than the lower limit, excellent adhesion can be obtained, and the surface of the workpiece can be more favorably protected during processing. When the thickness of the pressure-sensitive adhesive layer is equal to or less than the upper limit, generation of the chip at the time of cutting the pressure-sensitive adhesive sheet can be suppressed, and breakage of the work piece can be prevented more favorably.
< substrate >
Examples of the base material include various resin films. Examples of the resin constituting the resin film include: polyethylene such as Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), and High Density Polyethylene (HDPE); polyolefins such as polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, and norbornene resin; ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid ester copolymers, and other ethylene copolymers; polyvinyl chloride, polyvinyl chloride copolymers, and the like; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and wholly aromatic polyesters; polyurethanes, polyimides, polyamides, polycarbonates, fluororesins, polyacetals, modified polyphenylene oxides, polyphenylene sulfides, polysulfones, polyether ketones, acrylic polymers; etc.
The base material may be a single-layer film of a resin film formed from one or more resins selected from these resins, or may be a laminated film obtained by laminating two or more of these resin films. Further, the resin may be a modified film such as a crosslinked film or an ionomer film.
Among these resin films, the base material is preferably at least one selected from the group consisting of a polyester film, a polyamide film, a polyimide film and a biaxially oriented polypropylene film, more preferably a polyester film, and still more preferably a polyethylene terephthalate film.
The Young's modulus of the substrate is not particularly limited, but is preferably 1,000MPa or more, more preferably 1,800 to 30,000MPa, and still more preferably 2,500 to 6,000MPa.
When the young's modulus of the base material is equal to or greater than the lower limit value, the vibration suppressing effect during work tends to be further improved. When the young's modulus of the base material is equal to or less than the upper limit, workability in adhering to a workpiece and workability in peeling from the workpiece tend to be good.
The Young's modulus of the substrate can be measured under the conditions of a test speed of 200 mm/min based on JIS K7127:1999.
The thickness of the base material is not particularly limited, but is preferably 10 to 200. Mu.m, more preferably 25 to 100. Mu.m, and still more preferably 30 to 70. Mu.m.
When the thickness of the base material is equal to or greater than the lower limit, strength sufficient to function as a support for the adhesive sheet tends to be obtained. When the thickness of the base material is equal to or less than the upper limit, moderate flexibility and improved handleability tend to be obtained.
The "thickness of the substrate" refers to the thickness of the entire substrate, and when the substrate is a substrate composed of a plurality of layers, the "thickness of the substrate" refers to the total thickness of all the layers constituting the substrate.
The base material may contain a plasticizer, a lubricant, an infrared absorber, an ultraviolet absorber, a filler, a colorant, an antistatic agent, an antioxidant, a catalyst, and the like within a range that does not impair the effects of the present invention.
The substrate may be transparent or opaque, and may be colored or vapor deposited as desired.
From the viewpoint of improving the adhesion to other layers, at least one surface of the substrate may be subjected to a surface treatment such as corona treatment, or a coating layer for the purpose of improving the adhesion may be provided.
< Release sheet >
The pressure-sensitive adhesive sheet of the present embodiment may be formed by attaching a release sheet to at least one of the surface of the pressure-sensitive adhesive layer and the surface of the surface coating layer. The release sheet protects the surface of the adhesive sheet before use by being attached thereto in a releasable manner, and is peeled off and removed when the adhesive sheet is used.
The release sheet may be a release sheet subjected to a single-sided release treatment or a release sheet subjected to a double-sided release treatment.
The release sheet is preferably a release sheet having a release agent coated on a release sheet substrate.
The base material for the release sheet is preferably a resin film, and examples of the resin film include: polyester films such as polyethylene terephthalate films, polybutylene terephthalate films, and polyethylene naphthalate films; polyolefin films such as polypropylene films and polyethylene films; etc.
Examples of the release agent include: rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins; long chain alkyl resins, alkyd resins, fluorine resins, and the like.
The thickness of the release sheet is not particularly limited, but is preferably 5 to 200. Mu.m, more preferably 10 to 100. Mu.m, and still more preferably 20 to 50. Mu.m.
< total thickness of adhesive sheet >
The total thickness of the pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, but is preferably 30 to 300. Mu.m, more preferably 40 to 220. Mu.m, and still more preferably 45 to 160. Mu.m.
When the total thickness of the adhesive sheet is equal to or greater than the lower limit, the adhesive performance of the adhesive layer, the impact absorbing performance of the buffer layer, and the like can be appropriately maintained, and the function as an adhesive sheet for semiconductor processing tends to be sufficiently exhibited. When the total thickness of the adhesive sheet is equal to or less than the upper limit value, the peeling force at the time of peeling the work from the adhesive sheet tends to be reduced.
In the present embodiment, the "total thickness of the adhesive sheet" refers to a thickness from the surface of the surface coating layer of the adhesive sheet to the surface of the adhesive layer, and when the release sheet is provided, the thickness of the release sheet is not included in the total thickness.
< method for producing adhesive sheet >
The method for producing the pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, and can be produced by a known method.
The pressure-sensitive adhesive sheet of the present embodiment can be produced, for example, by a method including the steps of: a step of forming an adhesive layer on one surface side of the substrate (hereinafter, also referred to as "adhesive layer forming step"); a step of forming a buffer layer on the other surface side of the substrate (hereinafter, also referred to as "buffer layer forming step"); and a step of forming a surface coating layer on the surface of the buffer layer opposite to the substrate (hereinafter, also referred to as "surface coating layer forming step"). The order of these steps is not particularly limited, and may be performed simultaneously if they can be performed simultaneously.
As a method for forming the adhesive layer, the buffer layer, or the surface coating layer, for example, there can be mentioned: after applying the adhesive composition, the buffer layer-forming composition, or the surface coating layer-forming composition to a predetermined position by a known method, energy ray irradiation, heat drying, or the like is performed as needed.
Examples of the method for applying the adhesive composition, the composition for forming a buffer layer, or the composition for forming a surface coating layer include: spin coating, spray coating, bar coating, blade coating, roll coating, blade coating, die coating, gravure coating, and the like.
The pressure-sensitive adhesive layer forming step may be, for example, a method of bonding a pressure-sensitive adhesive layer formed on a release sheet to the surface of a substrate, or a method of forming a pressure-sensitive adhesive layer by directly applying a pressure-sensitive adhesive composition to the surface of a substrate.
In the buffer layer forming step, the buffer layer forming composition may be coated on the release sheet or directly on the surface of the substrate. When the composition for forming a buffer layer is coated on the release sheet, a layer formed from the composition for forming a buffer layer (hereinafter, also referred to as "composition layer for forming a buffer layer") on the release sheet is then adhered to the surface of the substrate. The buffer layer-forming composition layer on the release sheet may be the buffer layer itself, or may be an uncured or semi-cured product of the buffer layer-forming composition having curability when the buffer layer-forming composition is a curable composition. When an uncured or semi-cured product of the composition for forming a buffer layer is formed on a substrate, a treatment for completely curing the composition for forming a buffer layer is thereafter performed.
In the surface coating layer forming step, the composition for forming a surface coating layer may be applied to the release sheet or directly to the surface of the buffer layer. When the composition for forming a surface coating layer is coated on the release sheet, a layer formed from the composition for forming a surface coating layer (hereinafter, also referred to as a "composition layer for forming a surface coating layer") on the release sheet is then adhered to the surface of the buffer layer. The surface coating layer forming composition layer on the release sheet may be the surface coating itself, or may be an uncured or semi-cured product of the surface coating layer forming composition having curability in the case where the surface coating layer forming composition is a curable composition. When an uncured or semi-cured product of the composition for forming a surface coating layer is formed on the buffer layer, a treatment for completely curing the composition for forming a surface coating layer is then performed.
The buffer layer forming step and the surface coating layer forming step may be a method of sequentially disposing a surface coating layer and a buffer layer on a release sheet and then bonding the buffer layer to the surface of the substrate.
When the composition for forming a buffer layer contains an energy ray polymerizable compound, the buffer layer forming step preferably includes a step of irradiating the composition for forming a buffer layer with energy rays.
In the case where the composition for forming a buffer layer contains an energy ray polymerizable compound, the curing treatment by irradiation with energy rays may be performed at one time or may be performed in a plurality of times.
In the case of performing the curing treatment by irradiation with energy rays once, the buffer layer forming composition may be completely cured by irradiation with energy rays after a coating film of the buffer layer forming composition is formed on the substrate, or the buffer layer forming composition may be completely cured on a release sheet and then bonded to the substrate.
When the composition for forming a surface coating layer contains an energy ray polymerizable compound, the step of forming a surface coating layer preferably includes a step of irradiating the composition for forming a surface coating layer with energy rays. The irradiation time of the energy ray to the surface coating layer forming composition is not particularly limited, and may be any time before or after the composition for forming a surface coating layer is laminated on the buffer layer or the composition for forming a buffer layer.
In the case of the curing treatment of the buffer layer forming composition in multiple steps, after the coating film of the buffer layer forming composition is formed on the release sheet, the buffer layer forming composition may be completely cured on the release sheet by bonding the layer of the buffer layer forming composition provided on the release sheet after curing the layer to a semi-cured state, and then radiating energy rays again. When the composition for forming a surface coating layer contains an energy ray polymerizable compound, the composition for forming a surface coating layer can be simultaneously cured by radiating energy rays to completely cure the composition for forming a buffer layer.
The energy rays irradiated during the curing treatment of the composition for forming a buffer layer and the composition for forming a surface coating layer are preferably ultraviolet rays.
When the composition for forming a buffer layer and the composition for forming a surface coating layer are cured by irradiation with energy rays, the composition for forming a buffer layer and the composition for forming a surface coating layer may be exposed to the outside, but it is preferable to irradiate energy rays in a state where both surfaces are covered with a member such as a release sheet or a base material and are not exposed to the outside.
< use of adhesive sheet >
Examples of the processing of the work in a state where the pressure-sensitive adhesive sheet of the present embodiment is attached include: back grinding for grinding the other surface of the semiconductor device with the adhesive sheet attached to one surface of the semiconductor device, dicing for singulating the semiconductor device with the adhesive sheet attached to one surface of the semiconductor device, handling of the semiconductor device, picking up of the semiconductor chip, and the like. Among these processes, the adhesive sheet of the present embodiment is suitable for back grinding, and is more suitable for back grinding in which the back surface of the semiconductor wafer is ground in a state where the circuit forming surface of the semiconductor wafer is attached with the adhesive sheet of the present embodiment. In particular, the pressure-sensitive adhesive sheet of the present embodiment has an effect of suppressing occurrence of cracks when thinning a semiconductor wafer, and is therefore suitable for processes such as a dicing-first method and a stealth dicing-first method.
[ method for manufacturing semiconductor device ]
The method for manufacturing a semiconductor device according to the present embodiment includes:
a step of adhering the adhesive sheet for semiconductor processing of the present embodiment to the surface of a semiconductor wafer with the adhesive layer as an adhering surface; and
and grinding the back surface of the semiconductor wafer while fixing the surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer by a supporting means.
The method for manufacturing a semiconductor device according to the present embodiment preferably includes:
a dividing line forming step of: a step a of forming a groove in a surface of a semiconductor wafer, or a step b of forming a modified region from a front surface or a back surface of the semiconductor wafer into the semiconductor wafer;
and a sheet sticking process: after the step a, or before or after the step b, the adhesive sheet for semiconductor processing according to the present embodiment is adhered to the surface of the semiconductor wafer with the adhesive layer as an adhering surface; and
grinding and singulation: the back surface of the semiconductor wafer is ground in a state where the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting means, and the semiconductor wafer is singulated into a plurality of semiconductor chips starting from the groove or the modified region.
Further, the method for manufacturing a semiconductor device according to the present embodiment may include a peeling step of peeling the adhesive sheet for semiconductor processing according to the present embodiment from the plurality of semiconductor chips after the grinding and singulation step.
The method of manufacturing the semiconductor device having the step a is a process corresponding to a dicing-first method, and the method of manufacturing the semiconductor device having the step b is a process corresponding to a stealth dicing-first method.
As a semiconductor wafer used in the manufacturing method of the present embodiment, for example, there can be mentioned: silicon wafers, gallium arsenide wafers, gallium nitride wafers, silicon carbide wafers, glass wafers, sapphire wafers, and the like. Among them, a silicon wafer is preferable.
Circuits such as wirings, capacitors, diodes, and transistors are generally formed on the surface of a semiconductor wafer. These circuits can be formed by a conventionally known method such as an etching method or a Lift-Off (Lift-Off) method.
The thickness of the semiconductor wafer before grinding is not particularly limited, and is usually 500 to 1,000. Mu.m.
Each step of the method for manufacturing a semiconductor device according to the present embodiment will be described in detail below.
< procedure for Forming lines to divide >
The dividing line forming step is a step a of forming a groove in the front surface of the semiconductor wafer or a step b of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer.
The step a is a step of forming a groove in the surface of the semiconductor wafer, and is performed before the adhesive sheet is attached to the surface of the semiconductor wafer.
The grooves formed in the surface of the semiconductor wafer in step a are grooves having a depth shallower than the thickness of the semiconductor wafer. After the step a, the semiconductor wafer is back-ground to the groove position formed in the step a, and is divided into a plurality of semiconductor chips. Therefore, in the step a, grooves are formed along the dividing lines when the semiconductor wafer is divided and singulated into semiconductor chips.
The grooves may be formed by dicing using a conventionally known wafer dicing apparatus or the like.
The step b is a step of forming a modified region from the front surface or the back surface of the semiconductor wafer to the inside of the semiconductor wafer, and may be performed before or after the adhesive sheet is attached to the front surface of the semiconductor wafer.
In step b, the modified region is formed inside the semiconductor wafer by irradiating the semiconductor wafer with laser light whose focal point is concentrated inside the semiconductor wafer. The modified region is a portion of the semiconductor wafer where embrittlement occurs, and is a region that becomes a starting point at which the semiconductor wafer is singulated into semiconductor chips when the semiconductor wafer is thinned by back grinding or broken by application of a grinding force. Therefore, the modified region is formed along a dividing line when the semiconductor wafer is divided and singulated into semiconductor chips.
The irradiation of the laser light may be performed from the front surface side or the back surface side of the semiconductor wafer. In the case where the step b is performed after the sheet bonding step, the semiconductor wafer may be irradiated with laser light through the adhesive sheet.
< sheet adhesion Process >
The sheet bonding step is a step of bonding the adhesive sheet to the surface of the semiconductor wafer with the adhesive layer as a bonding surface after the step a or before or after the step b.
The method of adhering the pressure-sensitive adhesive sheet is not particularly limited, and a conventionally known method using a laminator or the like can be used, for example.
< grinding and singulation Process >
The grinding and singulation step is a step of grinding the back surface of the semiconductor wafer in a state where the surface coating side of the adhesive sheet attached to the semiconductor wafer is fixed by the supporting means, and singulating the semiconductor wafer into a plurality of semiconductor chips with the grooves or the modified regions as a starting point.
The surface coating side of the adhesive sheet is fixed by a supporting device to the semiconductor wafer to which the adhesive sheet is adhered and in which grooves or modified regions are formed. The support device is not particularly limited, and is preferably a device for holding the object to be fixed by suction, such as a chuck table.
Then, the back surface of the fixed semiconductor wafer is ground, and the semiconductor wafer is singulated into a plurality of semiconductor chips.
In the back grinding, when grooves are formed in the semiconductor wafer in the step a, at least the semiconductor wafer is ground to a position where the grinding surface reaches the bottom of the grooves. By this back grinding, the grooves become through-wafer cuts, and the semiconductor wafer is divided by the cuts and singulated into individual semiconductor chips.
On the other hand, in the case where the modified region is formed in the semiconductor wafer in the step b, the ground surface may reach the modified region, but may not strictly reach the modified region. That is, the semiconductor wafer may be ground to a position close to the modified region, and broken from the modified region and singulated into semiconductor chips. For example, after grinding to a position close to the modified region without singulating the semiconductor wafer, a pick-up tape may be attached to the semiconductor wafer, and the semiconductor chips may be singulated by stretching the pick-up tape.
The semiconductor chip after singulation may have a square shape or an elongated shape such as a rectangular shape.
The thickness of the singulated semiconductor chip is not particularly limited, but is preferably 5 to 100 μm, more preferably 7 to 70 μm, and still more preferably 10 to 45 μm.
The chip size of the singulated semiconductor chip is not particularly limited, and is preferably less than 50mm 2 More preferably less than 30mm 2 More preferably less than 10mm 2 。
< stripping Process >
The peeling step is a step of peeling the adhesive sheet from the plurality of semiconductor chips after the grinding and singulation steps.
When the adhesive layer of the adhesive sheet is formed of an energy ray-curable adhesive, the adhesive is cured by irradiation with energy rays to reduce the peeling force of the adhesive layer, and then the adhesive sheet is peeled off.
In the case of peeling the adhesive sheet, a pickup tape may be used. The pickup tape may be constituted by an adhesive sheet including a base material and an adhesive layer provided on one surface of the base material, for example.
In the case of using the pick-up tape, the pick-up tape is first stuck to the back surface side of the singulated semiconductor wafer, and positional and directional alignment is performed so that the pick-up tape can be picked up. In this case, it is preferable that the annular frame disposed on the outer peripheral side of the semiconductor wafer is also bonded to the pickup tape, and the outer peripheral edge portion of the pickup tape is fixed to the annular frame. Next, the adhesive sheet is peeled from the plurality of semiconductor chips fixed on the pick-up tape.
Then, the plurality of semiconductor chips located on the pickup tape may be picked up and then fixed on a substrate or the like, thereby manufacturing a semiconductor device.
Examples
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The measurement and evaluation methods of the various physical properties are as follows.
[ weight average molecular weight (Mw) ]
The weight average molecular weight (Mw) was measured using a gel permeation chromatography apparatus (product name "HLC-8220" manufactured by Tosoh Co., ltd.) under the following conditions, and was obtained by conversion into standard polystyrene.
(measurement conditions)
Chromatographic column: "TSK guard column HXL-H", "TSK gel GMHXL (. Times.2)", "TSK gel G2000HXL" (manufactured by Tosoh Co., ltd.)
Column temperature: 40 DEG C
Elution solvent: tetrahydrofuran (THF)
Flow rate: 1.0mL/min
[ measurement of thickness of pressure-sensitive adhesive sheet etc. ]
The total thickness of the adhesive sheet, the thickness of each layer, and the thickness of a test piece produced from them were measured by a constant pressure gauge (trade name "PG-02", manufactured by TECLOCK Co., ltd.). At this time, 10 arbitrary points were measured, and an average value was calculated.
The total thickness of the adhesive sheet is a value obtained by measuring the thickness of the adhesive sheet with the release sheet and subtracting the thickness of the release sheet from the thickness.
The thickness of the buffer layer is a value obtained by subtracting the thickness of the base material from the thickness of the base material with the buffer layer.
The thickness of the surface coating layer is a value obtained by subtracting the thickness of the release sheet from the thickness of the surface coating layer with the release sheet.
The thickness of the adhesive layer is obtained by subtracting the thicknesses of the topcoat layer, the buffer layer, and the substrate from the total thickness of the adhesive sheet.
[ measurement of 1-bromonaphthalene contact angle of surface coating ]
The 1-bromonaphthalene contact angle of the surface coating was measured based on JIS R3257:1999. Specifically, the release sheets on the surface coating side of the pressure-sensitive adhesive sheets produced in examples and comparative examples were peeled off, and the static contact angle when 1-bromonaphthalene was dropped onto the surface of the exposed surface coating layer was measured using a full-automatic contact angle measuring instrument (product name "DM-701" manufactured by synergistic interface science co., ltd.) under the following conditions.
Measurement temperature: 23 DEG C
Drop amount: 2 μl
Measurement time: after 1 second of dripping
Image analysis method: theta/2 process
[ evaluation of the surface coating adhesion amount of grinding chip ]
The pressure-sensitive adhesive sheets having release sheets on both sides thereof produced in examples and comparative examples were cut into a size of 5cm square in plan view, and the release sheets on the surface coating side were peeled off to prepare test pieces with the surface coating exposed. Any 1 of the 4 corners of the test piece was fixed and hung, and immersed in grinding water containing 2 mass% of the grinding dust of the silicon wafer for 10 minutes. The test piece was removed from the grinding water, left in a suspended state, left to stand at 23℃for 24 hours to dry, and then visually observed for the surface coating layer of the test piece, and the adhesion amount of the grinding dust was evaluated according to the following criteria. In the following evaluation criteria, "chip-adhering portion" refers to an island-shaped chip-adhering portion formed by drying droplets of grinding water adhering to the surface coating layer.
A: there are 1 chip-attached portions on the surface coating layer, or the chips are not attached to such an extent that they can be recognized as chip-attached portions.
B: there are 2-5 abrasive dust adhering parts on the surface coating.
C: there are more than 6 chip attachment portions on the surface coating, but the chips do not attach to the entire surface of the surface coating.
D: the whole surface of the surface coating is adhered with the grinding scraps.
[ preparation of urethane acrylate oligomer for buffer layer ]
Production example 1
The terminal isocyanate urethane prepolymer obtained by reacting a polyester diol with isophorone diisocyanate and 2-hydroxyethyl acrylate are reacted to obtain a 2-functional urethane acrylate oligomer having a weight average molecular weight (Mw) of 5,000.
[ preparation of energy ray-curable acrylic resin for adhesive layer ]
Production example 2
An acrylic polymer was obtained by copolymerizing 52 parts by mass of n-butyl acrylate, 20 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate. Then, 2-methacryloyloxyethyl isocyanate was reacted so as to be added to 90 mol% of all hydroxyl groups of the acrylic polymer, thereby obtaining an energy ray-curable acrylic resin having a weight average molecular weight (Mw) of 50 ten thousand.
[ production of adhesive sheet ]
Examples 1 to 4 and comparative examples 1 to 2
Next, an adhesive sheet was produced by the following method. The amounts of the components blended in the following description all represent the amounts of the active ingredients blended.
(1) Preparation of a substrate
As a substrate, a polyethylene terephthalate film (Young's modulus: 2,500 MPa) having a thickness of 50 μm was prepared.
(2) Preparation of a composition for Forming a surface coating
Each component shown in table 1 was dissolved in toluene so that the effective component concentration became 10 mass%, and a composition for forming a surface coating layer was obtained.
(3) Preparation of composition for Forming buffer layer
A buffer layer-forming composition was prepared by blending 40 parts by mass of the urethane acrylate oligomer obtained in production example 1, 40 parts by mass of isobornyl acrylate, 20 parts by mass of 2-hydroxy-3-phenoxypropyl acrylate, 2.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator, and 0.2 parts by mass of a phthalocyanine pigment.
(4) Preparation of adhesive composition
100 parts by mass of the energy ray-curable acrylic resin obtained in production example 2, 6 parts by mass of a polyfunctional urethane acrylate (trade name "Shikou UT-4332", manufactured by mitsubishi chemical Co., ltd., weight average molecular weight (Mw) 4,700) as an energy ray-curable compound, 0.375 part by mass of an isocyanate-based crosslinking agent (trade name "corona L", manufactured by Tosoh Co., ltd.), and 1 part by mass of phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide as a photopolymerization initiator were blended and diluted with an organic solvent to prepare an adhesive composition.
(5) Production of adhesive sheet
The buffer layer-forming composition obtained above was applied to one surface of a substrate as described above so that the thickness of the formed buffer layer became 20. Mu.m, and then the composition was irradiated with light at an illuminance of 30mW/cm 2 Irradiation amount of 60mJ/cm 2 The buffer layer forming composition is semi-cured by irradiation with ultraviolet light, and a layer obtained by semi-curing the buffer layer forming composition is formed on one surface of the substrate.
The surface coating layer-forming composition obtained above was applied to the release treated surface of a release sheet (trade name "SP-PET381031" manufactured by linden corporation) by a meyer rod so that the thickness of the surface coating layer formed became 2 μm, and then heated and dried, whereby a surface coating layer-forming composition layer was formed on the release sheet.
Bonding a surface coating layer forming composition layer on the release sheet to a layer formed by semi-curing a buffer layer forming composition formed on one side of the substrate, followed by irradiation with light of 160mW/cm 2 The irradiation amount was 500mJ/cm 2 The composition for forming a buffer layer and the composition for forming a surface coating layer are cured by irradiation with ultraviolet rays under the conditions of (a) to obtain a laminate having a buffer layer and a surface coating layer in this order on one surface of a substrate.
The pressure-sensitive adhesive composition obtained above was applied to a release treated surface of a release sheet (trade name "SP-PET381031" manufactured by lindeke corporation) so that the thickness after drying became 20 μm, and then dried by heating, to prepare a release sheet with a pressure-sensitive adhesive layer.
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached release sheet was adhered to the surface of the base material provided in the laminate, on which no buffer layer was provided, to thereby obtain a pressure-sensitive adhesive sheet having a release sheet on both surfaces and having a surface coating layer, a buffer layer, a base material, and a pressure-sensitive adhesive layer in this order.
The evaluation results of the adhesive sheets obtained in each example and comparative example are shown in table 1.
Watch (watch)
(resin component)
S2104: hydrogenated styrene thermoplastic elastomer (SEPS), styrene content 65% by mass, KRARARARAY Co., ltd., trade name "SEPTON (registered trademark) 2104"
(hydrophobized silica)
Hydrophobic silica: irregularly shaped precipitated silica having been hydrophobicized
Untreated silica: colloidal silica, trade name "SNOWTEX UP" manufactured by Nissan chemical Co., ltd "
Energy ray polymerizable polyfunctional compound: mixtures of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate, manufactured by Japanese Kagaku Kogyo Co., ltd., trade name "KAYARAD DPHA"
Photopolymerization initiator: 2-hydroxy-2-methyl-1-phenylpropion, manufactured by IGM Resins b.v., trade name "Omnirad1173"
As is clear from table 1, the adhesive sheets of examples 1 to 4 satisfying the constitution of the adhesive sheet of the present embodiment have sufficiently reduced amounts of adhering chips. On the other hand, the adhesive sheets of comparative examples 1 and 2, which do not satisfy the constitution of the adhesive sheet of the present embodiment, do not have sufficient reduction in the amount of adhering chips.

Claims (10)

1. An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a buffer layer, a base material and an adhesive layer in this order,
the surface coating layer is a layer containing a resin component and a hydrophobicized silica.
2. The adhesive sheet for semiconductor processing according to claim 1, wherein,
in the surface coating layer, the content of the hydrophobicized silica is 1 to 150 parts by mass per 100 parts by mass of the resin component.
3. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein,
the resin component is a polymer of a compound having 1 or more ethylenically unsaturated bonds.
4. The adhesive sheet for semiconductor processing according to claim 3, wherein,
the compound having 1 or more ethylenically unsaturated bonds is a styrenic compound.
5. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein,
the thickness of the surface coating is 0.05-10 mu m.
6. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein,
the buffer layer is a layer formed from a buffer layer forming composition containing urethane (meth) acrylate.
7. The adhesive sheet for semiconductor processing according to claim 1 or 2, which is used for back grinding of a semiconductor wafer.
8. A method of manufacturing a semiconductor device, the method comprising:
a step of adhering the adhesive sheet for semiconductor processing according to claim 1 or 2 to a surface of a semiconductor wafer with the adhesive layer as an adhering surface; and
and grinding the back surface of the semiconductor wafer while the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting means.
9. A method of manufacturing a semiconductor device, the method comprising:
a dividing line forming step of: a step a of forming a groove in a surface of a semiconductor wafer, or a step b of forming a modified region from a front surface or a back surface of the semiconductor wafer to an inside of the semiconductor wafer;
And a sheet sticking process: after the step a, or before or after the step b, the adhesive sheet for semiconductor processing according to claim 1 or 2 is adhered to the surface of the semiconductor wafer with the adhesive layer as an adhering surface; and
grinding and singulation: the back surface of the semiconductor wafer is ground in a state where the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting means, and the semiconductor wafer is singulated into a plurality of semiconductor chips starting from the groove or modified region.
10. An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a buffer layer, a base material and an adhesive layer in this order,
wherein the static contact angle of 1-bromonaphthalene at 23 ℃ relative to the surface coating is 19 DEG or more.
CN202311120838.XA 2022-09-02 2023-09-01 Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device Pending CN117645845A (en)

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JP2022-139844 2022-09-02
JP2022-139848 2022-09-02

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