WO2023190559A1 - Heat-dissipating structure - Google Patents
Heat-dissipating structure Download PDFInfo
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- WO2023190559A1 WO2023190559A1 PCT/JP2023/012597 JP2023012597W WO2023190559A1 WO 2023190559 A1 WO2023190559 A1 WO 2023190559A1 JP 2023012597 W JP2023012597 W JP 2023012597W WO 2023190559 A1 WO2023190559 A1 WO 2023190559A1
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- Prior art keywords
- heat dissipation
- dissipation structure
- plate
- heat
- insulating plate
- Prior art date
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Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
Definitions
- the present disclosure relates to a heat dissipation structure.
- Power modules that control large currents are used in fields such as automobiles, electric railways, industrial equipment, and power generation.
- Semiconductor elements, ceramic circuit boards, and the like are used in such power modules.
- electronic devices such as personal computers and servers become smaller, thinner, and lighter, there is a demand for higher performance heat dissipation members incorporated into the electronic devices.
- Patent Document 1 discloses a heat dissipation structure for an electric circuit device, which includes a heat dissipation plate exposed to the outside of the electric circuit device, a heat transfer member, and a cooler arranged so as to form a laminated structure.
- the heat transfer member is a ceramic resin composite in which a resin composition is impregnated into a sintered body in which ceramic primary particles form a three-dimensional integral structure, and the heat transfer member includes the heat sink and the cooling member.
- Disclosed is a heat dissipation structure for an electric circuit device, characterized in that the heat dissipation structure is arranged so as to be stacked in direct contact with at least one of the devices.
- thermosetting resin composition containing an epoxy resin
- the above-mentioned semi-cured thermosetting resin composition is cured by laminating and heat-treating the members, and the members are bonded together.
- equipment for curing the thermosetting resin composition is required, and the expected performance may not be exhibited depending on the curing conditions at that time, so it is also necessary to adjust the curing conditions.
- a possible method is to use a ceramic resin composite in which a thermosetting resin composition containing an epoxy resin is completely cured in advance. If such a response were possible, the above-mentioned equipment would become unnecessary. Furthermore, since the performance of the ceramic resin composite that becomes the insulating layer can be specified at the time of shipment, adjustment of curing conditions, etc. may be unnecessary. However, according to the studies conducted by the present inventors, a heat dissipation structure using a ceramic resin composite that has been completely cured in advance has better performance than a heat dissipation structure manufactured using a conventional semi-cured resin. It may decrease.
- the above-mentioned heat dissipation structure is required to have sufficiently excellent reliability depending on the application in which it is used. Even when exposed to heat cycles under harsh conditions, such as power devices, it is required to maintain sufficient reliability.
- An object of the present disclosure is to provide a heat dissipation structure with excellent heat cycle characteristics.
- the present disclosure provides the following [1] to [6].
- An electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element; a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween; A heat dissipation structure comprising a fastener that holds the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction,
- the insulating board includes a porous sintered nitride board and a resin filled in the pores of the sintered nitride board, A heat dissipation structure having a thermal resistance of 0.30° C./W or less in the lamination direction.
- One aspect of the present disclosure includes: an electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element; a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween; A heat dissipation structure comprising: a fastener for holding the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction, the insulating plate being a porous sintered nitride plate; , and a resin filled in the pores of the nitride sintered plate, and the heat radiation structure has a thermal resistance of 0.30° C./W or less in the stacking direction.
- the heat dissipation structure has a thermal resistance within a predetermined range in the stacking direction.
- the fact that the thermal resistance is within the above range means that the adhesiveness between the insulating plate and the electric circuit device and the heat sink is high.
- the heat dissipation structure can suppress fluctuations in performance values such as thermal resistance before and after a heat cycle test, and exhibit excellent heat cycle characteristics.
- the porosity of the sintered nitride plate may be 25 to 65% by volume.
- the filling rate of the resin in the pores may be 90% by volume or more.
- the thickness of the insulating plate may be 0.35 mm or less.
- the pressure in the stacking direction by the tightening tool may be 10 MPa or more.
- a heat dissipation structure with excellent heat cycle characteristics can be provided.
- FIG. 1 is a schematic cross-sectional view showing an example of a heat dissipation structure.
- the materials exemplified in this specification can be used alone or in combination of two or more. If there are multiple substances corresponding to each component in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. .
- the heat dissipation structure includes an electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element, and a pair of coolers stacked on the heat sink via an insulating plate. and a fastener that holds the circuit device, the insulating plate, and the cooler in a pressurized state in the stacking direction.
- the insulating plate includes a porous sintered nitride plate and a resin filled in the pores of the sintered nitride plate.
- the heat dissipation structure has a thermal resistance of 0.30° C./W or less in the stacking direction of the circuit device, the insulating plate, and the cooler.
- FIG. 1 is a schematic cross-sectional view showing an example of a heat dissipation structure.
- the heat dissipation structure 100 shown in FIG. An insulating plate 20 provided so as to be in direct contact with the insulating plate 20 and an electric circuit device 10 disposed so as to be sandwiched between the pair of insulating plates 20 are stacked.
- the electric circuit device 10, the insulating plate 20, and the cooler 30 are held under pressure in the stacking direction by a fastener 40 inserted into the through hole of the cooler 30.
- the electric circuit device 10 includes a heat generating element 2, a heat sink 4 provided on both main surfaces of the heat generating element 2, and a sealing material 6 provided so as to cover at least a portion of the heat generating element 2 and the heat sink 4. It is configured.
- the pair of coolers 30 in FIG. 1 are shown as having the same shape, they may have different shapes, and pressure may not be applied between the coolers 30 by the fastener 40. If possible, the through holes may be formed in only one
- the heating element 2 incorporated in the electric circuit device 10 may be an element that generates heat as it is used.
- the heating element 2 may be, for example, an element that generates heat when used by passing an electric current through it.
- the heating element 2 may be, for example, a semiconductor element or a power semiconductor element.
- the power semiconductor element is, for example, an element responsible for power-related control such as drive control of a motor or the like and power conversion of a lighting device or the like.
- the heat sink 4 incorporated in the electric circuit device 10 radiates heat generated from the heating element 2 to the outside.
- the heat sink 4 may be placed near the heating element 2, but is preferably placed in direct contact with the heating element 2. It is also preferable that the heat sink 4 is placed in direct contact with the insulating plate 20. It is desirable that the heat sink 4 has an exposed surface exposed to the outside of the electric circuit device 10. With such a configuration, heat is transferred from the heat sink 4 to the cooler 30 via the insulating plate 20, thereby providing the heat sink structure 100 with even better heat dissipation performance.
- the heat sink 4 may be, for example, a metal plate.
- the metal constituting the heat sink 4 include copper, aluminum, titanium, and alloys thereof. From the viewpoint of improving heat dissipation, the metal constituting the heat dissipation plate 4 preferably contains copper, and is more preferably copper.
- the upper limit of the thickness of the heat sink 4 may be, for example, 3.2 mm or less, 3.0 mm or less, 2.7 mm or less, 2.5 mm or less, or 2.0 mm or less. By setting the upper limit of the thickness of the heat sink 4 within the above range, it is possible to further improve the heat diffusion performance of the heat sink while maintaining the weight reduction of the heat sink structure.
- the lower limit of the thickness of the heat sink 4 may be, for example, 0.3 mm or more, 0.5 mm or more, 0.7 mm or more, or 1.0 mm or more. By setting the lower limit of the thickness of the heat sink 4 within the above range, it is possible to further lower the thermal resistance of the heat sink structure while maintaining the ability of the heat sink to diffuse heat generated from the heating element.
- the thickness of the heat sink 4 may be adjusted within the above-mentioned range, and may be, for example, 0.3 to 3.2 mm, or 0.3 to 3.0 mm.
- the sealing material 6 protects the heat generating element 2 from light, heat, water, and the like.
- the sealing material 6 may be a cured resin.
- the cured resin may be, for example, an epoxy resin or a silicone resin.
- the insulating board 20 is a resin-filled board that includes a nitride sintered board and a resin that fills the pores of the nitride sintered board.
- the sintered nitride plate contains nitride particles and pores formed by sintering primary particles of nitride.
- the nitride constituting the nitride particles may include, for example, at least one selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride.
- the nitride constituting the nitride particles may include boron nitride, and preferably boron nitride, from the viewpoint of improving the heat dissipation properties of the insulating plate 20.
- the average pore diameter of the sintered nitride plate may be, for example, 4.0 ⁇ m or less, 3.8 ⁇ m or less, 3.6 ⁇ m or less, or 3.5 ⁇ m or less. Since such a sintered nitride board has small pores, it is possible to maintain a sufficiently large contact area between the nitride particles and further improve the heat dissipation performance of the insulating board 20.
- the average pore diameter of the nitride sintered plate is, for example, 0.8 ⁇ m or more, 1.0 ⁇ m or more, 1.2 ⁇ m or more, 1.4 ⁇ m or more, 1.6 ⁇ m or more, 1.7 ⁇ m or more, 1.8 ⁇ m or more, 2.
- nitride sintered plate may be 0 ⁇ m or more, 2.5 ⁇ m or more, or 3.0 ⁇ m or more.
- a nitride sintered plate can be sufficiently deformed when pressure is applied when bonding, so when stacked with the electric circuit device 10 and the cooler 30, the conformability of the interface can be further improved, which is advantageous.
- the heat cycle characteristics of the heat dissipation structure can be further improved.
- the average pore diameter of the sintered nitride plate may be adjusted within the above-mentioned range, for example, from 1.0 to 4.0 ⁇ m, or from 3.0 to 3.5 ⁇ m.
- the average pore diameter (median pore diameter) of a sintered nitride plate can be measured using the following procedure. First, a nitride sintered plate is obtained by heating the insulating plate 20 to burn and remove the resin. Then, using a mercury porosimeter, the pore size distribution is determined when the nitride sintered plate is pressurized while increasing the pressure from 0.0042 MPa to 206.8 MPa. When the horizontal axis is the pore diameter and the vertical axis is the cumulative pore volume, the pore diameter when the cumulative pore volume reaches 50% of the total pore volume is the average pore diameter. As the mercury porosimeter, for example, one manufactured by Shimadzu Corporation can be used.
- the upper limit of the porosity of the nitride sintered plate that is, the volume ratio of pores in the nitride sintered plate, may be, for example, 65 volume % or less, 60 volume % or less, or 58 volume % or less.
- the upper limit of the porosity of the nitride sintered body is within the above range, a decrease in mechanical strength of the nitride sintered board can be more fully suppressed, and an insulating board 20 with better handling properties can be provided.
- the lower limit of the porosity of the nitride sintered plate is, for example, 25 volume% or more, 28 volume% or more, 30 volume% or more, 32 volume% or more, 34 volume% or more, 36 volume% or more, 38 volume% or more, It may be 40 volume% or more, 42 volume% or more, 44 volume% or more, or 46 volume% or more. Since the upper limit of the porosity of the nitride sintered body is within the above range, the resin content is improved, the flexibility of the insulating plate 20 is improved, and it is laminated with the electric circuit device 10 and the cooler 30. At the same time, the followability of the interface can be further improved, and the heat cycle characteristics of the resulting heat dissipation structure can be further improved.
- the porosity of the sintered nitride plate may be adjusted within the above-mentioned range, for example, 25-65% by volume, 30-65% by volume, or 40-60% by volume.
- the upper limit of the bulk density of the nitride sintered plate may be, for example, 1700 kg/m 3 or less, 1600 kg/m 3 or less, 1500 kg/m 3 or less, 1400 kg/m 3 or less, or 1300 kg/m 3 or less.
- the lower limit of the bulk density of the nitride sintered plate may be, for example, 1000 kg/m 3 or more, 1100 kg/m 3 or more, or 1200 kg/m 3 or more.
- the porosity in this specification is calculated by calculating the bulk density [Y (kg/m 3 )] from the volume and mass of the nitride sintered plate, and combining this bulk density with the theoretical density of nitride [X (kg/m 3 )]. )], it can be determined by the following formula (1).
- the theoretical density X is 2280 kg/m 3 .
- the theoretical density X is 3260 kg/m 3 .
- the nitride constituting the nitride sintered plate is silicon nitride
- the theoretical density X is 3170 kg/m 3 .
- the bulk density Y may be 800 to 1500 kg/m 3 or 1000 to 1400 kg/m 3 .
- the bulk density Y is within the above range, it is possible to achieve both the strength of the nitride sintered plate and the improvement of the heat cycle characteristics of the heat dissipation structure due to the improvement in the filling amount of the resin at a higher level.
- the resin filling the pores of the sintered nitride plate may be, for example, a relatively flexible resin.
- the resin include silicone resins and thermoplastic resins having a softening point of 80° C. or higher.
- silicone resin include addition reaction silicone.
- Addition reaction type silicones include, for example, one-component reaction type silicone resins containing organopolysiloxanes having both vinyl groups and hydrosilyl groups (H-Si groups) in one molecule, and silicone resins having vinyl groups at terminals or side chains. Examples include two-component reactive silicone resins containing an organopolysiloxane and an organopolysiloxane having two or more hydrosilyl groups at the terminal or side chain.
- addition reaction silicone examples include "XE14-B8530A/B” (trade name) manufactured by MOMENTIVE, "YE5822” (trade name) manufactured by GE Toshiba Silicone, and the like.
- thermoplastic resin having a softening point of 80° C. or higher examples include hydrocarbon cooligomer (manufactured by Henkel, trade name: "PSX-Pm”).
- PSX-Pm hydrocarbon cooligomer
- the softening point of the thermoplastic resin may be 100°C or higher, 120°C or higher, or 150°C or higher.
- the filling rate of the resin in the pores of the nitride sintered plate is adjusted from the viewpoint of improving the followability of the main surface of the insulating plate 20 to the main surfaces of the electric circuit device 10 and the cooler 30. It's fine.
- the lower limit of the filling rate of the resin in the pores of the nitride sintered plate may be, for example, 90 volume % or more, 92 volume % or more, 94 volume % or more, or 96 volume % or more.
- the upper limit of the filling rate of the resin in the pores of the nitride sintered plate is not particularly limited, and may be 100 volume% or more, 99 volume% or less, or 98 volume% or less. good.
- the filling rate of the resin in the pores of the sintered nitride plate may be adjusted within the above-mentioned range, and may be, for example, 90 to 99% by volume.
- the resin filling rate means the ratio of the volume filled with resin to the total volume of the pores of the nitride sintered board.
- the resin filling rate in the insulating plate 20 shall be measured by the method described in the Examples of this specification.
- the lower limit of the elastic modulus of the insulating plate 20 may be, for example, 200 MPa or more, 250 MPa or more, 300 MPa or more, or 350 MPa or more.
- the upper limit of the elastic modulus of the insulating plate 20 may be, for example, 2300 MPa or less, 2000 MPa or less, 1700 MPa or less, or 1500 MPa or less.
- the heat dissipation structure can be appropriately deformed by applying pressure with the fastener 40 when preparing the heat dissipation structure, and the main surface of the electric circuit device 10 and the cooler 30 can be The followability can be further improved, and the heat cycle characteristics of the resulting heat dissipation structure can be further improved.
- the elastic modulus of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 200 to 2300 MPa.
- the elastic modulus in this specification means a value measured by the following method.
- a nitride sintered body for example, a boron nitride sintered body
- the compression elastic modulus of the measurement sample at 200° C. is measured using a compression testing machine in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compression properties”. Measurements shall be performed under the conditions shown below.
- As the compression tester for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used. Compression speed: 0.1mm/min Load cell: 100kN Test temperature: 200°C
- the upper limit of the thickness of the insulating plate 20 may be, for example, 0.35 mm or less, 0.32 mm or less, 0.30 mm or less, or 0.25 mm or less.
- the lower limit of the thickness of the insulating plate 20 may be, for example, 0.10 mm or more, 0.15 mm or more, 0.17 mm or more, or 0.20 mm or more.
- the thickness of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 0.10 to 0.35 mm, or 0.20 to 0.35 mm.
- the upper limit of the bulk density of the insulating plate 20 may be, for example, 2000 kg/m 3 or less, 1900 kg/m 3 or less, or 1800 kg/m 3 or less.
- the resistance can be lower.
- the lower limit of the bulk density of the insulating plate 20 may be, for example, 1500 kg/m 3 or more, 1600 kg/m 3 or more, or 1700 kg/m 3 or more.
- the heat dissipation performance of the insulating plate can be further improved and the thermal resistance of the heat dissipation structure can be further reduced.
- the bulk density of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 1500 to 2000 kg/m 3 .
- the lower limit of the thermal conductivity of the insulating plate 20 may be, for example, 25 W/mK or more, or 30 W/mK or more. When the lower limit of the thermal conductivity is within the above range, the thermal resistance can be lowered more than the conventional insulating heat dissipating material obtained from a resin composition in which a resin and a filler are mixed.
- the upper limit of the thermal conductivity of the insulating plate 20 may be, for example, 90 W/mK or less, 85 W/mK or less, or 80 W/mK or less.
- the fact that the upper limit of the thermal conductivity is within the above range also corresponds to the low bulk density of the insulating plate, and it is possible to flexibly deform, reducing the voids at the interface with the electric circuit device and cooler. can be further reduced.
- the thermal conductivity of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 25 to 90 W/mK.
- Thermal conductivity in this specification means a value calculated by the following method.
- the thermal diffusivity A (unit: m 2 /sec) of the nitride sintered plate is determined.
- the bulk density B (unit: kg/m 3 ) of the sample is determined from the volume and mass of the sample.
- the specific heat capacity C (unit: J/(kg ⁇ K)) of the above sample is measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg is taken from the sample, crushed, and molded into pellets to obtain a molded body. The obtained molded body is filled into a platinum pan, and the specific heat capacity is measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214).
- the specific heat capacity measurement conditions were: heating from 25°C to 300°C at a temperature increase rate of 10°C/min and a nitrogen atmosphere, and from 300°C to 25°C at a cooling rate of 20°C/min and a nitrogen atmosphere.
- the temperature is assumed to drop to °C.
- the thermal conductivity in the thickness direction of the above sample is calculated from the following formula (2).
- the upper limit of the compressive strength of the insulating plate 20 is, for example, 20.0 MPa or less, 18.0 MPa or less, 16.0 MPa or less, 14.0 MPa or less, 12.0 MPa or less, 10.0 MPa or less, or 8.0 MPa or less. It's good.
- the upper limit of the compressive strength is within the above range, the heat dissipation structure can be more easily deformed by the tightening pressure when preparing the heat dissipation structure, and the heat cycle characteristics of the heat dissipation structure can be further improved.
- the lower limit of the compressive strength of the insulating plate 20 may be, for example, 4.0 MPa or more, 4.5 MPa or more, 5.0 MPa or more, or 5.5 MPa or more.
- the compressive strength of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 2.0 to 20 MPa, or 2.0 to 10.0 MPa.
- Compressive strength in this specification means a value measured by the following method.
- a nitride sintered body for example, a boron nitride sintered body
- the compressive strength of the measurement sample at 200° C. is measured using a compression tester in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compressive properties”. Measurements shall be performed under the conditions shown below.
- As the compression tester for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used.
- the cooler 30 has a function of cooling the heat transmitted from the heating element 2 via the insulating plate 20.
- Cooler 30 may be made of metal. Examples of metals include aluminum, copper, and titanium.
- the cooler 30 is not particularly limited as long as it can secure a sufficient contact area with the insulating plate 20, and is not limited to a plate shape, and may have irregularities formed on the surface opposite to the insulating plate 20 side. It may have cooling fins, and may also have piping through which a cooling medium (for example, cooling water) flows.
- a cooling medium for example, cooling water
- the fastener 40 is not particularly limited as long as it can apply pressure between the pair of coolers 30.
- a jig composed of a bolt and a nut is shown as a specific example of the fastening tool 40.
- a nut is screwed into a through hole of a cooler 30 placed at the lower side in FIG. It is possible to adjust so that a desired pressure is applied between the coolers 30.
- the lower limit of the pressure in the stacking direction (tightening pressure) by the tightening tool 40 may be, for example, 5 MPa or more, 7 MPa or more, 10 MPa or more, 15 MPa or more, or 20 MPa or more.
- the upper limit of the tightening pressure may be, for example, 35 MPa or less, 30 MPa or less, 27 MPa or less, or 25 MPa or less.
- the pressure in the stacking direction by the fastener 40 may be adjusted within the above-mentioned range, and may be, for example, 5 to 35 MPa.
- the insulating plate 20 has appropriate flexibility and has excellent followability to other members. Due to the excellent adhesion of the interface between the insulating plate 20, the electric circuit device 10, and the cooler 30, the heat dissipation structure 100 has a low thermal resistance in the stacking direction. The heat dissipation structure has a thermal resistance of 0.30° C./W or less in the stacking direction of the circuit device, the insulating plate, and the cooler.
- the upper limit of the thermal resistance in the stacking direction of the heat dissipation structure 100 may be, for example, 0.25°C/W or less, 0.20°C/W or less, or 0.15°C/W or less.
- the fact that the upper limit value of the thermal resistance is within the above range means that the adhesion between the insulating plate 20 and the electric circuit device 10 and the cooler 30 is better, and the resulting heat dissipation structure 100 is heated. Cycle characteristics can be further improved.
- the lower limit value of thermal resistance in the lamination direction of the heat dissipation structure 100 is not particularly limited, but is, for example, 0.01°C/W or more, 0.03°C/W or more, 0.04°C/W or more.
- the thermal resistance in the stacking direction of the heat dissipation structure may be adjusted within the above-mentioned range, and may be, for example, 0.01 to 0.30°C/W, or 0.04 to 0.30°C/W.
- the thermal resistance in the stacking direction of the heat dissipation structure 100 may be 0.30° C./W or less when the heat dissipation plate 4 is made of a copper plate with a thickness of 3.0 mm.
- the thermal resistance in the stacking direction of the heat dissipation structure means the thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler.
- the lower limit of the dielectric breakdown voltage of the heat dissipation structure 100 may be, for example, 20 kV/mm or more, or 25 kV/mm or more. By setting the lower limit of the dielectric breakdown voltage within the above range, it becomes easier to control current switching using the element.
- the dielectric breakdown strength of the heat dissipation structure in this specification is described in JIS C 2110-1:2016 "Solid electrical insulating materials - Test method for dielectric breakdown strength - Part 1: Test by application of commercial frequency AC voltage" means the value measured based on the method of
- the above-described heat dissipation structure can be manufactured, for example, by the following manufacturing method. That is, one embodiment of the method for manufacturing a heat dissipation structure includes stacking a first cooler, a first insulating plate, an electric circuit device, a second insulating plate, and a second cooler in this order, and then using a fastener. The method includes a step of pressurizing the circuit device, the insulating plate, and the cooler in the stacking direction.
- the electric circuit device includes a heat generating element and a heat sink provided on both main surfaces of the heat generating element.
- the insulating board may be a resin-filled board including a porous sintered nitride board and a resin filled in the pores of the sintered nitride board.
- the insulating plate one prepared by the manufacturing method described below can be used.
- the method for preparing the insulating board varies depending on the resin that is impregnated into the insulating board and cured or solidified.
- the method for preparing an insulating board includes a sintering step of firing a molded board containing a nitride to obtain a sintered nitride board, and adding a silane compound and a sintered board to the sintered nitride board.
- the method includes a step of impregnating a mixture containing at least one of the siloxane compounds to obtain an impregnated body, and a curing step of heat-treating the impregnated body and polymerizing the mixture to obtain a resin-filled plate.
- the resin in the resin-filled plate includes silicone resin, which is a polymer of siloxane compounds.
- the method for preparing the insulating board includes a sintering step of firing a molded board containing a nitride to obtain a sintered nitride board;
- the method includes a resin impregnation step in which the nitride sintered plate is melted and impregnated with the thermoplastic resin, and a solidification step in which the resin after impregnation is solidified.
- the resin included in the insulating plate includes silicone resin will be described.
- the molded plate in the sintering process may be obtained by molding raw material powder containing nitride.
- the nitride contained in the raw material powder may contain, for example, at least one type of nitride selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride.
- the boron nitride may be amorphous boron nitride or hexagonal boron nitride.
- the raw material powder is, for example, an amorphous boron nitride powder with an average particle size of 0.5 to 10.0 ⁇ m, or an average particle size of 3.0 to 3.0 ⁇ m.
- a hexagonal boron nitride powder having a diameter of 40.0 ⁇ m can be used.
- the method for molding the raw material powder to obtain a compact may be, for example, uniaxial pressing, cold isostatic pressing (CIP), or doctor blade method.
- a sintering aid may be added to the raw material powder before molding. Examples of the sintering aid include metal oxides such as yttrium oxide, aluminum oxide and magnesium oxide, alkali metal carbonates such as lithium carbonate and sodium carbonate, and boric acid.
- the blending amount of the sintering aid is, for example, 0.01 parts by mass or more, or 0.10 parts by mass, based on a total of 100 parts by mass of the nitride and the sintering aid. It may be more than parts by mass.
- the blending amount of the sintering aid is, for example, 20.00 parts by mass or less, 15.00 parts by mass or less, or 10.00 parts by mass or less, based on a total of 100 parts by mass of the nitride and the sintering aid. good.
- the firing temperature in the sintering step may be, for example, 1600°C or higher, or 1700°C or higher.
- the firing temperature may be, for example, 2200°C or lower, or 2000°C or lower.
- the firing time may be, for example, 1 hour or more and 30 hours or less.
- the atmosphere of the sintering process may be, for example, an inert gas atmosphere such as nitrogen, helium, and argon.
- a batch type furnace, a continuous type furnace, etc. can be used for sintering.
- batch furnaces include muffle furnaces, tube furnaces, and atmospheric furnaces.
- continuous furnaces include rotary kilns, screw conveyor furnaces, tunnel furnaces, belt furnaces, pusher furnaces, and large continuous furnaces. In this way, a sintered nitride plate can be obtained.
- a mixture containing at least one of a silane compound and a siloxane compound is impregnated into the pores of the nitride sintered plate to obtain an impregnated body.
- the mixture can be impregnated smoothly.
- the above mixture may also contain a polysiloxane compound and the like.
- addition reaction type silicone can be suitably used.
- Specific examples of addition reaction type silicones include one-component reaction type silicone resins containing organopolysiloxanes having both vinyl groups and hydrosilyl groups (H-Si groups) in one molecule, and silicone resins containing vinyl groups at the ends or side chains. and an organopolysiloxane having two or more hydrosilyl groups at the terminal or side chain.
- the addition reaction silicone may be, for example, "XE14-B8530A/B" (trade name) manufactured by Momentive Performance Materials.
- addition reaction silicone contains both a vinyl group and a hydrosilyl group in one molecule.
- the weight average molecular weight of the organopolysiloxane having a vinyl group and the organopolysiloxane having a vinyl group at the terminal or side chain may be adjusted.
- the weight average molecular weight of the vinyl group-containing organopolysiloxane may be, for example, 10,000 to 30,000, or 15,000 to 25,000, or 400,000 to 600,000, or 450,000 to 550,000.
- the organopolysiloxanes having vinyl groups having different weight average molecular weights for example, the organopolysiloxanes having vinyl groups having a weight average molecular weight of 10,000 to 30,000, and A mixture of the vinyl group-containing organopolysiloxane with an average molecular weight of 400,000 to 600,000, or a mixture of the vinyl group-containing organopolysiloxane with a weight average molecular weight of 15,000 to 25,000 and a weight average molecular weight of 450,000 to 450,000. 550,000 and the above organopolysiloxane having a vinyl group can be used.
- the above-mentioned mixture may contain, for example, a curing agent in addition to at least one of the silane compound and the siloxane compound.
- the curing agent may be a catalyst that accelerates the curing reaction of the polysiloxane compound.
- hardening agents include "RD-1" (trade name) manufactured by DuPont-Toray Specialty Materials Co., Ltd. and "XC-86-250" (trade name) manufactured by Momentive Performance Materials Japan LLC. etc. can be used.
- the blending amount of the curing agent is, for example, 0.01 to 5.00 parts by mass, 0.03 to 4.00 parts by mass, or 0.05 to 2 parts by mass, based on a total of 100 parts by mass of the silane compound and siloxane compound. .00 parts by mass.
- the impregnated body is heat-treated to polymerize the mixture (at least one of a silane compound and a siloxane compound) to obtain a resin-filled plate.
- the temperature of the heat treatment in the curing step may be, for example, 50 to 250°C, 70 to 200°C, 90 to 150°C, or 100 to 130°C.
- the heating time in the curing step may be, for example, 3 to 24 hours or 5 to 12 hours.
- Example 1 [Preparation of sintered nitride plate] 100 parts by mass of orthoboric acid manufactured by Nippon Denko Corporation and 35 parts by mass of acetylene black (trade name: HS100) manufactured by Denka Corporation were mixed using a Henschel mixer. The obtained raw material mixture was filled into a graphite crucible and heated in an arc furnace at 2200° C. in an argon atmosphere for 5 hours to obtain bulk boron carbide (B 4 C). The obtained lumps were coarsely crushed using a jaw crusher to obtain coarse powder. This coarse powder was further pulverized using a ball mill having silicon carbide balls ( ⁇ 10 mm) to obtain a pulverized powder.
- HS100 acetylene black
- the prepared pulverized powder was filled into a boron nitride crucible. Thereafter, it was heated in a nitrogen gas atmosphere at 2000° C. and 0.85 MPa for 10 hours using a resistance heating furnace. In this way, a fired product containing boron carbonitride (B 4 CN 4 ) was obtained.
- a sintering aid was prepared by blending powdered boric acid and calcium carbonate. In preparation, 50.0 parts by mass of calcium carbonate was blended with 100 parts by mass of boric acid. The atomic ratio of boron and calcium at this time was 17.5 atomic % of calcium to 100 atomic % of boron. 20 parts by mass of a sintering aid was added to 100 parts by mass of the fired product, and mixed using a Henschel mixer to prepare a powdery mixture.
- the compact was placed in a boron nitride container and introduced into a batch type high frequency furnace. In a batch type high frequency furnace, heating was performed for 5 hours at normal pressure, nitrogen flow rate of 5 L/min, and 2000°C. Thereafter, the boron nitride sintered plate was taken out from the boron nitride container. In this way, a sheet-shaped boron nitride sintered plate was obtained. The thickness of the boron nitride sintered plate was 0.32 mm.
- the porosity of the obtained boron nitride sintered plate was determined.
- the bulk density [Y (kg/m 3 )] is calculated from the volume and mass of the boron nitride sintered plate, and from this bulk density and the theoretical density of nitride [X (kg/m 3 )], the following It was determined using equation (1). The results are shown in Table 1.
- the theoretical density X of the boron nitride sintered plate was 2280 kg/m 3 .
- Porosity (volume%) [1-(Y/X)] x 100 (1)
- a boron nitride sintered plate impregnated with the above mixture was heat-treated at 150°C for 24 hours to perform a curing reaction, thereby curing the impregnated mixture and making it into a resin, thereby preparing an insulating plate (resin-impregnated body). .
- the bulk density of the insulating plate is the volume calculated from the length of each side of the insulating plate (measured with a caliper) in accordance with JIS Z 8807:2012 "Method of measuring density and specific gravity by geometric measurement", It was determined based on the mass of the insulating plate measured using an electronic balance (see section 9 of JIS Z 8807:2012). The theoretical density of the insulating plate was determined by the following formula (5).
- Theoretical density of the insulating plate Bulk density of boron nitride sintered plate + True density of resin ⁇ (1 - Bulk density of boron nitride sintered plate / True density of boron nitride) ...Formula (5)
- the thermal conductivity H of the insulating plate was determined according to the following method.
- the thermal diffusivity A of the obtained sample was measured by a laser flash method using a xenon flash analyzer (manufactured by NETZSCH, trade name: LFA467NanoFlash).
- the bulk density B (unit: kg/m 3 ) of the sample was determined from the volume and mass of the sample.
- the specific heat capacity C (unit: J/(kg ⁇ K)) of the above sample was measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg of the above sample was taken, crushed, and molded into pellets to obtain a molded body. The obtained molded body was filled in a platinum pan, and the specific heat capacity was measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214).
- the obtained measurement sample was tested using a compression tester (Autograph AG-X (300kN) manufactured by Shimadzu Corporation) in accordance with the description of JIS K 7181:2001 "Plastics - How to determine compression properties".
- the compressive strength at 200°C was measured using the following. The measurements were conducted under the following conditions. Compression speed: 0.1mm/min Load cell: 100kN Test temperature: 200°C
- An electric circuit device was prepared in which a 3.0 mm thick copper plate, a semiconductor element, and a 3.0 mm thick copper plate were laminated in this order and sealed with a sealing material.
- an aluminum plate was prepared as a cooler.
- a pipe through which cold water flows is arranged on one main surface of the aluminum plate (the surface located at the outermost layer of the heat dissipation structure), and cooling is performed by circulating the cold water through the pipe.
- stack the aluminum plate, insulating plate, electric circuit device, insulating plate, and aluminum plate in this order and adjust the bolts and nuts so that a tightening pressure of 10 MPa is applied between the aluminum plates.
- a heat dissipation structure was manufactured.
- thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler was measured based on the following method.
- the calorific value of the electric circuit device was set to 310 W
- the inlet temperature of the cooling water sent to the cooler was set to 65° C.
- the flow rate of the cooling water was set to 5 L/min.
- Thermocouples were inserted into the outer surface of the heat sink and the cooler to measure the temperature. Based on the measured values, the value of thermal resistance was determined from the following formula (3).
- Thermal resistance (°C/W) [Outer surface temperature of heat sink (°C) - Outer surface temperature of cooler (°C)] / 310 (W) ... Formula (3)
- the heat cycle characteristics of the heat dissipation structure were evaluated using the following method.
- an ultrasonic flaw detection image of the joint portion was obtained using an ultrasonic flaw detection device for the obtained heat dissipation structure.
- the initial bond area ratio can be calculated by taking advantage of the fact that the areas where the insulating plate, heat sink, and cooler are not bonded (delamination has occurred) are represented by black areas. Decided.
- the initial bonding area ratio is the area that is actually bonded to the area to be bonded (i.e., the area of the insulating plate) (the area obtained by subtracting the area of the black part from the area of the insulating plate in the ultrasonic flaw detection image: initial bonding area) ) means the ratio (area %).
- the heat dissipation structure to be measured was subjected to a heat cycle test in which one cycle was holding at -40°C for 30 minutes and then holding at 175°C for 30 minutes, and this was repeated 1000 cycles. . Thereafter, the adhesion state was confirmed using an ultrasonic flaw detector.
- the bonding rate is determined as the ratio of the bonding area to the initial bonding area (value of ⁇ [bonding area after heat cycle test]/[initial bonding area] ⁇ x 100) in the ultrasonic flaw detection image obtained after the heat cycle test. did. From the obtained initial bonding area ratio and bonding rate, the heat cycle characteristics of the heat dissipation structure were evaluated based on the following criteria.
- Example 2 In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating plate was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate prepared in this manner was used. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
- Example 3 In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating board was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate thus prepared was used and the tightening pressure was 20 MPa. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
- thermosetting resin composition 10 parts by mass of a commercially available curing agent (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name: Akmex H-8) was added to 100 parts by mass of a commercially available epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: Epicote 807).
- a commercially available curing agent manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name: Akmex H-8
- epoxy resin manufactured by Mitsubishi Chemical Corporation, trade name: Epicote 807
- the obtained resin-impregnated plate was further heated at 200° C. for 24 hours to cure the semi-cured resin, thereby preparing a resin-filled plate.
- the obtained resin-filled board (insulating board) was evaluated in the same manner as the insulating board of Example 1. The results are shown in Table 1.
- Example 3 The procedure was the same as in Example 1, except that a sintered silicon nitride plate (thickness: 0.32 mm, bulk density: 3.2 g/cm 3 , thermal conductivity: 80 W/mK) was used instead of the insulating plate. A heat dissipation structure was prepared.
- a heat dissipation structure with excellent heat cycle characteristics can be provided.
- Heat generating element 4... Heat dissipation plate, 6... Sealing material, 10... Electric circuit device, 20... Insulating board, 30... Cooler, 40... Fastener, 100... Heat dissipation structure.
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Abstract
An aspect of the present disclosure provides a heat-dissipating structure including an electric circuit device including a heat-generating element and heatsinks provided on both principal surfaces of the heat-generating element, a pair of coolers stacked on the heatsinks via respective insulating plates, and clamps that hold the electric circuit device, the insulating plates, and the coolers in a pressurized state in the stacking direction, wherein the insulating plates include a porous nitride sintered plate and a resin filling the pores of the nitride sintered plate, and the thermal resistance in the stacking direction is 0.30°C/W or less.
Description
本開示は、放熱構造体に関する。
The present disclosure relates to a heat dissipation structure.
自動車、電鉄、産業用機器、及び発電関係等の分野では、大電流を制御するパワーモジュールが用いられている。このようなパワーモジュールには、半導体素子及びセラミック回路基板等が用いられている。パワーモジュールは、高出力化に伴って、高い放熱性を有することが求められている。また、パーソナルコンピュータ及びサーバー等の電子機器においても、小型化、薄型化及び軽量化に伴って、電子機器に組み込まれる放熱部材の高性能化が求められている。
Power modules that control large currents are used in fields such as automobiles, electric railways, industrial equipment, and power generation. Semiconductor elements, ceramic circuit boards, and the like are used in such power modules. As power modules increase in output, they are required to have high heat dissipation properties. Further, as electronic devices such as personal computers and servers become smaller, thinner, and lighter, there is a demand for higher performance heat dissipation members incorporated into the electronic devices.
特許文献１には、電気回路装置の外部へ露出する放熱板と、伝熱部材と、冷却器とが積層構造をなすように配置されて含まれる、電気回路装置の放熱構造であって、上記伝熱部材が、セラミックス一次粒子が３次元的に一体構造をなしている焼結体に樹脂組成物が含浸しているセラミックス樹脂複合体であり、上記伝熱部材が、上記放熱板および上記冷却器のうちの少なくとも一方と直接接触して積層するように配置されることを特徴とする、電気回路装置の放熱構造が開示されている。
Patent Document 1 discloses a heat dissipation structure for an electric circuit device, which includes a heat dissipation plate exposed to the outside of the electric circuit device, a heat transfer member, and a cooler arranged so as to form a laminated structure. The heat transfer member is a ceramic resin composite in which a resin composition is impregnated into a sintered body in which ceramic primary particles form a three-dimensional integral structure, and the heat transfer member includes the heat sink and the cooling member. Disclosed is a heat dissipation structure for an electric circuit device, characterized in that the heat dissipation structure is arranged so as to be stacked in direct contact with at least one of the devices.
上述のセラミックス樹脂複合体としては、窒化ホウ素焼結体に、エポキシ樹脂を含む熱硬化性樹脂組成物を半硬化させたものが使用されている。電気回路装置の放熱構造を形成する際に、部材を積層し加熱処理することで上述の半硬化された熱硬化性樹脂組成物が硬化すると共に、部材間を接着するような態様をとっている。しかし、熱硬化性樹脂組成物を硬化させるための設備が必要になり、その際の硬化条件等によっては想定される性能が発揮されない場合が生じ得ることから、硬化条件の調整も必要となる。
As the above-mentioned ceramic resin composite, a boron nitride sintered body semi-cured with a thermosetting resin composition containing an epoxy resin is used. When forming the heat dissipation structure of an electric circuit device, the above-mentioned semi-cured thermosetting resin composition is cured by laminating and heat-treating the members, and the members are bonded together. . However, equipment for curing the thermosetting resin composition is required, and the expected performance may not be exhibited depending on the curing conditions at that time, so it is also necessary to adjust the curing conditions.
そこで、エポキシ樹脂を含む熱硬化性樹脂組成物を予め完全に硬化させたセラミックス樹脂複合体を使用する手段が考えられる。このような対応が可能であれば、上述のような設備が不要になる。また、絶縁層となるセラミックス樹脂複合体の性能を出荷時に特定できるため、硬化条件の調整等も不要となり得る。しかし、本発明者らの検討によれば、予め完全に硬化させたセラミックス樹脂複合体を用いた放熱構造体では、従来の半硬化樹脂を用いて製造される放熱構造体の性能よりも性能が低下する場合がある。
Therefore, a possible method is to use a ceramic resin composite in which a thermosetting resin composition containing an epoxy resin is completely cured in advance. If such a response were possible, the above-mentioned equipment would become unnecessary. Furthermore, since the performance of the ceramic resin composite that becomes the insulating layer can be specified at the time of shipment, adjustment of curing conditions, etc. may be unnecessary. However, according to the studies conducted by the present inventors, a heat dissipation structure using a ceramic resin composite that has been completely cured in advance has better performance than a heat dissipation structure manufactured using a conventional semi-cured resin. It may decrease.
また、上述の放熱構造は用いられる用途に応じて信頼性に十分に優れることが求められる。パワーデバイス等のように、過酷な条件でのヒートサイクルに曝された場合であっても十分な信頼性を維持することが求められる。
Furthermore, the above-mentioned heat dissipation structure is required to have sufficiently excellent reliability depending on the application in which it is used. Even when exposed to heat cycles under harsh conditions, such as power devices, it is required to maintain sufficient reliability.
本開示は、ヒートサイクル特性に優れる放熱構造体を提供することを目的とする。
An object of the present disclosure is to provide a heat dissipation structure with excellent heat cycle characteristics.
本発明者らの検討によれば、従来のエポキシ樹脂を含む熱硬化性樹脂組成物を、窒化物焼結板に含浸させ完全硬化させた部材を絶縁層として用いた場合、上記部材が硬く、柔軟性に欠けるため、電気回路装置及び冷却器表面への追従性が弱く、界面に空隙が生じる等して十分な放熱性が発揮されないこと、また界面に空隙があるためヒートサイクル試験の前後で性状の変化を招いていること、さらには、上述のようなエポキシ樹脂を完全硬化させた部材を絶縁層として用いた場合に生じる他部材との間の空隙を低減する目的で締め付け圧力を高めると部材の破損を招くこと等を見出した。本開示は、これらの知見に基づく。
According to the studies of the present inventors, when a member obtained by impregnating a nitride sintered board with a conventional thermosetting resin composition containing an epoxy resin and completely curing it is used as an insulating layer, the member becomes hard; Due to the lack of flexibility, the ability to follow the surface of electric circuit devices and coolers is weak, and sufficient heat dissipation is not achieved due to the formation of voids at the interface. Furthermore, if the tightening pressure is increased in order to reduce the voids between the completely cured epoxy resin and other parts that occur when using a completely cured epoxy resin as an insulating layer. It was discovered that this may lead to damage to parts. The present disclosure is based on these findings.
本開示は、以下の［１］～［６］を提供する。
The present disclosure provides the following [1] to [6].
［１］ 発熱素子及び前記発熱素子の両主面上に設けられた放熱板を含む電気回路装置と、
絶縁板を介して前記放熱板上に積層された一対の冷却器と、
前記電気回路装置、前記絶縁板及び前記冷却器を積層方向に加圧した状態に保持する締め付け具と、を有する放熱構造体であって、
前記絶縁板は、多孔質の窒化物焼結板と、前記窒化物焼結板の気孔に充填された樹脂と、を含み、
積層方向における熱抵抗が０．３０℃／Ｗ以下である、放熱構造体。
［２］ 前記窒化物焼結板の気孔率は２５～６５体積％である、［１］に記載の放熱構造体。
［３］ 前記気孔に対する前記樹脂の充填率は９０体積％以上である、［１］又は［２］に記載の放熱構造体。
［４］ 前記絶縁板の厚さが０．３５ｍｍ以下である、［１］～［３］のいずれかに記載の放熱構造体。
［５］ 前記締め付け具による積層方向の圧力が１０ＭＰａ以上である、［１］～［４］のいずれかに記載の放熱構造体。
［６］ 前記樹脂が、シリコーン樹脂、及び、軟化点が８０℃以上である熱可塑性樹脂からなる群より選択される少なくとも一種を含む、［１］～［５］のいずれかに記載の放熱構造体。 [1] An electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element;
a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween;
A heat dissipation structure comprising a fastener that holds the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction,
The insulating board includes a porous sintered nitride board and a resin filled in the pores of the sintered nitride board,
A heat dissipation structure having a thermal resistance of 0.30° C./W or less in the lamination direction.
[2] The heat dissipation structure according to [1], wherein the sintered nitride plate has a porosity of 25 to 65% by volume.
[3] The heat dissipation structure according to [1] or [2], wherein the filling rate of the resin with respect to the pores is 90% by volume or more.
[4] The heat dissipation structure according to any one of [1] to [3], wherein the insulating plate has a thickness of 0.35 mm or less.
[5] The heat dissipation structure according to any one of [1] to [4], wherein the pressure in the stacking direction by the fastener is 10 MPa or more.
[6] The heat dissipation structure according to any one of [1] to [5], wherein the resin includes at least one selected from the group consisting of a silicone resin and a thermoplastic resin having a softening point of 80° C. or higher. body.
絶縁板を介して前記放熱板上に積層された一対の冷却器と、
前記電気回路装置、前記絶縁板及び前記冷却器を積層方向に加圧した状態に保持する締め付け具と、を有する放熱構造体であって、
前記絶縁板は、多孔質の窒化物焼結板と、前記窒化物焼結板の気孔に充填された樹脂と、を含み、
積層方向における熱抵抗が０．３０℃／Ｗ以下である、放熱構造体。
［２］ 前記窒化物焼結板の気孔率は２５～６５体積％である、［１］に記載の放熱構造体。
［３］ 前記気孔に対する前記樹脂の充填率は９０体積％以上である、［１］又は［２］に記載の放熱構造体。
［４］ 前記絶縁板の厚さが０．３５ｍｍ以下である、［１］～［３］のいずれかに記載の放熱構造体。
［５］ 前記締め付け具による積層方向の圧力が１０ＭＰａ以上である、［１］～［４］のいずれかに記載の放熱構造体。
［６］ 前記樹脂が、シリコーン樹脂、及び、軟化点が８０℃以上である熱可塑性樹脂からなる群より選択される少なくとも一種を含む、［１］～［５］のいずれかに記載の放熱構造体。 [1] An electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element;
a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween;
A heat dissipation structure comprising a fastener that holds the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction,
The insulating board includes a porous sintered nitride board and a resin filled in the pores of the sintered nitride board,
A heat dissipation structure having a thermal resistance of 0.30° C./W or less in the lamination direction.
[2] The heat dissipation structure according to [1], wherein the sintered nitride plate has a porosity of 25 to 65% by volume.
[3] The heat dissipation structure according to [1] or [2], wherein the filling rate of the resin with respect to the pores is 90% by volume or more.
[4] The heat dissipation structure according to any one of [1] to [3], wherein the insulating plate has a thickness of 0.35 mm or less.
[5] The heat dissipation structure according to any one of [1] to [4], wherein the pressure in the stacking direction by the fastener is 10 MPa or more.
[6] The heat dissipation structure according to any one of [1] to [5], wherein the resin includes at least one selected from the group consisting of a silicone resin and a thermoplastic resin having a softening point of 80° C. or higher. body.
本開示の一側面は、発熱素子及び上記発熱素子の両主面上に設けられた放熱板を含む電気回路装置と、絶縁板を介して上記放熱板上に積層された一対の冷却器と、上記電気回路装置、上記絶縁板及び上記冷却器を積層方向に加圧した状態に保持する締め付け具と、を有する放熱構造体であって、上記絶縁板は、多孔質の窒化物焼結板と、上記窒化物焼結板の気孔に充填された樹脂と、を含み、当該放熱構造体の積層方向における熱抵抗が０．３０℃／Ｗ以下である、放熱構造体を提供する。
One aspect of the present disclosure includes: an electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element; a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween; A heat dissipation structure comprising: a fastener for holding the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction, the insulating plate being a porous sintered nitride plate; , and a resin filled in the pores of the nitride sintered plate, and the heat radiation structure has a thermal resistance of 0.30° C./W or less in the stacking direction.
上記放熱構造体は、積層方向における熱抵抗が所定の範囲内のものとなっている。熱抵抗が上記範囲内となることは、絶縁板と、電気回路装置及び放熱板との密着性が高いことを意味する。このような構成を有することで、上記放熱構造体は、ヒートサイクル試験の前後での熱抵抗等の性能値の変動が抑制され、優れたヒートサイクル特性を発揮し得る。
The heat dissipation structure has a thermal resistance within a predetermined range in the stacking direction. The fact that the thermal resistance is within the above range means that the adhesiveness between the insulating plate and the electric circuit device and the heat sink is high. With such a configuration, the heat dissipation structure can suppress fluctuations in performance values such as thermal resistance before and after a heat cycle test, and exhibit excellent heat cycle characteristics.
上記窒化物焼結板の気孔率は２５～６５体積％であってよい。
The porosity of the sintered nitride plate may be 25 to 65% by volume.
上記気孔に対する上記樹脂の充填率は９０体積％以上であってよい。
The filling rate of the resin in the pores may be 90% by volume or more.
上記絶縁板の厚さは０．３５ｍｍ以下であってよい。
The thickness of the insulating plate may be 0.35 mm or less.
上記締め付け具による積層方向の圧力が１０ＭＰａ以上であってよい。
The pressure in the stacking direction by the tightening tool may be 10 MPa or more.
本開示によれば、ヒートサイクル特性に優れる放熱構造体を提供できる。
According to the present disclosure, a heat dissipation structure with excellent heat cycle characteristics can be provided.
以下、場合によって図面を参照して、本開示の実施形態を説明する。ただし、以下の実施形態は、本開示を説明するための例示であり、本開示を以下の内容に限定する趣旨ではない。説明において、同一要素又は同一機能を有する要素には同一符号を用い、場合によって重複する説明は省略する。また、上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。さらに、各要素の寸法比率は図示の比率に限られるものではない。
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same reference numerals will be used for the same elements or elements having the same function, and redundant description will be omitted in some cases. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratio of each element is not limited to the ratio shown in the drawings.
本明細書において例示する材料は特に断らない限り、１種を単独で又は２種以上を組み合わせて用いることができる。組成物中の各成分の含有量は、組成物中の各成分に該当する物質が複数存在する場合には、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。
Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. If there are multiple substances corresponding to each component in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. .
放熱構造体の一実施形態は、発熱素子及び上記発熱素子の両主面上に設けられた放熱板を含む電気回路装置と、絶縁板を介して上記放熱板上に積層された一対の冷却器と、上記回路装置、上記絶縁板及び上記冷却器を積層方向に加圧した状態に保持する締め付け具と、を有する。上記放熱構造体において、上記絶縁板は、多孔質の窒化物焼結板と、上記窒化物焼結板の気孔に充填された樹脂と、を含む。そして、上記放熱構造体は、上記回路装置、上記絶縁板及び上記冷却器の積層方向における熱抵抗が０．３０℃／Ｗ以下である。
One embodiment of the heat dissipation structure includes an electric circuit device including a heat generating element and a heat sink provided on both main surfaces of the heat generating element, and a pair of coolers stacked on the heat sink via an insulating plate. and a fastener that holds the circuit device, the insulating plate, and the cooler in a pressurized state in the stacking direction. In the heat dissipation structure, the insulating plate includes a porous sintered nitride plate and a resin filled in the pores of the sintered nitride plate. The heat dissipation structure has a thermal resistance of 0.30° C./W or less in the stacking direction of the circuit device, the insulating plate, and the cooler.
図１は、放熱構造体の一例を示す模式断面図である。図１に示す放熱構造体１００は、端部に締め付け具４０が挿入される貫通孔を有する冷却器３０と、冷却器３０の上記貫通孔よりも中央寄りの領域において、冷却器３０の主面と直接接するように設けられた絶縁板２０と、一対の絶縁板２０によって挟持されるように配置された電気回路装置１０とが積層されている。そして、電気回路装置１０、絶縁板２０及び冷却器３０は、冷却器３０の貫通孔に挿入された締め付け具４０によって、積層方向に加圧された状態で保持されている。電気回路装置１０は、発熱素子２及び発熱素子２の両主面上に設けられた放熱板４、並びに発熱素子２及び放熱板４の少なくとも一部を覆うように設けられた封止材６で構成されている。なお、図１における一対の冷却器３０は、互いに同じ形状を有する例で示したが、互いに異なる形状を有してもよく、また締め付け具４０によって冷却器３０の間に圧力を加えられることができれば、貫通孔は一方の冷却器３０のみに形成されていてよい。
FIG. 1 is a schematic cross-sectional view showing an example of a heat dissipation structure. The heat dissipation structure 100 shown in FIG. An insulating plate 20 provided so as to be in direct contact with the insulating plate 20 and an electric circuit device 10 disposed so as to be sandwiched between the pair of insulating plates 20 are stacked. The electric circuit device 10, the insulating plate 20, and the cooler 30 are held under pressure in the stacking direction by a fastener 40 inserted into the through hole of the cooler 30. The electric circuit device 10 includes a heat generating element 2, a heat sink 4 provided on both main surfaces of the heat generating element 2, and a sealing material 6 provided so as to cover at least a portion of the heat generating element 2 and the heat sink 4. It is configured. Although the pair of coolers 30 in FIG. 1 are shown as having the same shape, they may have different shapes, and pressure may not be applied between the coolers 30 by the fastener 40. If possible, the through holes may be formed in only one cooler 30.
電気回路装置１０に組み入れられている発熱素子２は使用に伴って熱を生じる素子であってよい。発熱素子２は、例えば、電流を流して使用する際に熱を発生する素子であってよい。発熱素子２としては、例えば、半導体素子であってよく、パワー半導体素子であってよい。パワー半導体素子は、例えば、モーター等の駆動制御及び照明装置等の電力変換などの電力関係の制御を担う素子である。
The heating element 2 incorporated in the electric circuit device 10 may be an element that generates heat as it is used. The heating element 2 may be, for example, an element that generates heat when used by passing an electric current through it. The heating element 2 may be, for example, a semiconductor element or a power semiconductor element. The power semiconductor element is, for example, an element responsible for power-related control such as drive control of a motor or the like and power conversion of a lighting device or the like.
電気回路装置１０に組み入れられている放熱板４は発熱素子２から発生した熱を外部へと放出する。放熱板４は、発熱素子２の近傍に配置されていてよいが、好ましくは、発熱素子２に直接接するように配置される。放熱板４はまた、絶縁板２０と直接接するように配置することが好ましい。放熱板４は、電気回路装置１０の外部に露出する露出面を有することが望ましい。このような構成とすることで、放熱板４から絶縁板２０を介して冷却器３０と熱を伝えることで、より放熱性に優れる放熱構造体１００とすることができる。
The heat sink 4 incorporated in the electric circuit device 10 radiates heat generated from the heating element 2 to the outside. The heat sink 4 may be placed near the heating element 2, but is preferably placed in direct contact with the heating element 2. It is also preferable that the heat sink 4 is placed in direct contact with the insulating plate 20. It is desirable that the heat sink 4 has an exposed surface exposed to the outside of the electric circuit device 10. With such a configuration, heat is transferred from the heat sink 4 to the cooler 30 via the insulating plate 20, thereby providing the heat sink structure 100 with even better heat dissipation performance.
放熱板４は、例えば、金属板であってよい。放熱板４を構成する金属としては、例えば、銅、アルミニウム、チタン、又はこれらの合金等が挙げられる。放熱板４を構成する金属は、放熱性を向上させる観点から、好ましくは銅を含み、より好ましくは銅である。
The heat sink 4 may be, for example, a metal plate. Examples of the metal constituting the heat sink 4 include copper, aluminum, titanium, and alloys thereof. From the viewpoint of improving heat dissipation, the metal constituting the heat dissipation plate 4 preferably contains copper, and is more preferably copper.
放熱板４の厚さの上限値は、例えば、３．２ｍｍ以下、３．０ｍｍ以下、２．７ｍｍ以下、２．５ｍｍ以下、又は２．０ｍｍ以下であってよい。放熱板４の厚さの上限値を上記範囲内とすることで、放熱構造体の軽量化を維持したまま、放熱板における熱の拡散性能をより向上させることができる。放熱板４の厚さの下限値は、例えば、０．３ｍｍ以上、０．５ｍｍ以上、０．７ｍｍ以上、又は１．０ｍｍ以上であってよい。放熱板４の厚さの下限値を上記範囲内とすることで、発熱素子から発生する熱の放熱板による拡散性能を維持しつつ、放熱構造体の熱抵抗をより低くすることができる。放熱板４の厚さは上述の範囲内で調整してよく、例えば、０．３～３．２ｍｍ、又は０．３～３．０ｍｍであってよい。
The upper limit of the thickness of the heat sink 4 may be, for example, 3.2 mm or less, 3.0 mm or less, 2.7 mm or less, 2.5 mm or less, or 2.0 mm or less. By setting the upper limit of the thickness of the heat sink 4 within the above range, it is possible to further improve the heat diffusion performance of the heat sink while maintaining the weight reduction of the heat sink structure. The lower limit of the thickness of the heat sink 4 may be, for example, 0.3 mm or more, 0.5 mm or more, 0.7 mm or more, or 1.0 mm or more. By setting the lower limit of the thickness of the heat sink 4 within the above range, it is possible to further lower the thermal resistance of the heat sink structure while maintaining the ability of the heat sink to diffuse heat generated from the heating element. The thickness of the heat sink 4 may be adjusted within the above-mentioned range, and may be, for example, 0.3 to 3.2 mm, or 0.3 to 3.0 mm.
封止材６は、光、熱、及び水等から発熱素子２を保護する。封止材６は硬化樹脂であってよい。硬化樹脂としては、例えば、エポキシ樹脂及びシリコーン樹脂等であってよい。
The sealing material 6 protects the heat generating element 2 from light, heat, water, and the like. The sealing material 6 may be a cured resin. The cured resin may be, for example, an epoxy resin or a silicone resin.
絶縁板２０は、窒化物焼結板と、窒化物焼結板の有する気孔に充填された樹脂とを有する樹脂充填板である。窒化物焼結板は、窒化物の一次粒子同士が焼結して構成される窒化物粒子と気孔とを含有する。上記窒化物粒子を構成する窒化物としては、例えば、窒化ホウ素、窒化アルミニウム、又は窒化ケイ素からなる群から選択される少なくとも一種を含んでよい。上記窒化物粒子を構成する窒化物としては、絶縁板２０の放熱性により優れる観点から、窒化ホウ素を含んでよく、好ましくは窒化ホウ素である。
The insulating board 20 is a resin-filled board that includes a nitride sintered board and a resin that fills the pores of the nitride sintered board. The sintered nitride plate contains nitride particles and pores formed by sintering primary particles of nitride. The nitride constituting the nitride particles may include, for example, at least one selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride. The nitride constituting the nitride particles may include boron nitride, and preferably boron nitride, from the viewpoint of improving the heat dissipation properties of the insulating plate 20.
窒化物焼結板の平均気孔径は、例えば、４．０μｍ以下、３．８μｍ以下、３．６μｍ以下、又は３．５μｍ以下であってよい。このような窒化物焼結板は、気孔のサイズが小さいことから、窒化物粒子の粒子同士の接触面積を十分に大きく維持し、絶縁板２０の放熱性をより向上させることができる。窒化物焼結板の平均気孔径は、例えば、０．８μｍ以上、１．０μｍ以上、１．２μｍ以上、１．４μｍ以上、１．６μｍ以上、１．７μｍ以上、１．８μｍ以上、２．０μｍ以上、２．５μｍ以上、又は３．０μｍ以上であってよい。このような窒化物焼結板は、接着する際に加圧すると十分に変形できるため、電気回路装置１０及び冷却器３０と積層させた際に界面の追従性をより向上させることができ、得られる放熱構造体のヒートサイクル特性をより向上させることができる。窒化物焼結板の平均気孔径は上述の範囲内で調整してよく、例えば、１．０～４．０μｍ、又は３．０～３．５μｍであってよい。
The average pore diameter of the sintered nitride plate may be, for example, 4.0 μm or less, 3.8 μm or less, 3.6 μm or less, or 3.5 μm or less. Since such a sintered nitride board has small pores, it is possible to maintain a sufficiently large contact area between the nitride particles and further improve the heat dissipation performance of the insulating board 20. The average pore diameter of the nitride sintered plate is, for example, 0.8 μm or more, 1.0 μm or more, 1.2 μm or more, 1.4 μm or more, 1.6 μm or more, 1.7 μm or more, 1.8 μm or more, 2. It may be 0 μm or more, 2.5 μm or more, or 3.0 μm or more. Such a nitride sintered plate can be sufficiently deformed when pressure is applied when bonding, so when stacked with the electric circuit device 10 and the cooler 30, the conformability of the interface can be further improved, which is advantageous. The heat cycle characteristics of the heat dissipation structure can be further improved. The average pore diameter of the sintered nitride plate may be adjusted within the above-mentioned range, for example, from 1.0 to 4.0 μm, or from 3.0 to 3.5 μm.
窒化物焼結板の平均気孔径（メジアン気孔径）は、以下の手順で測定することができる。まず、絶縁板２０を加熱して樹脂を燃焼させ除去することで窒化物焼結板を得る。そして、水銀ポロシメーターを用い、０．００４２ＭＰａから２０６．８ＭＰａまで圧力を増やしながら窒化物焼結板を加圧したときの気孔径分布を求める。横軸を気孔径、縦軸を累積気孔容積としたときに、累積気孔容積が全気孔容積の５０％に達するときの気孔径が平均気孔径である。水銀ポロシメーターとしては、例えば、株式会社島津製作所製のものを用いることができる。
The average pore diameter (median pore diameter) of a sintered nitride plate can be measured using the following procedure. First, a nitride sintered plate is obtained by heating the insulating plate 20 to burn and remove the resin. Then, using a mercury porosimeter, the pore size distribution is determined when the nitride sintered plate is pressurized while increasing the pressure from 0.0042 MPa to 206.8 MPa. When the horizontal axis is the pore diameter and the vertical axis is the cumulative pore volume, the pore diameter when the cumulative pore volume reaches 50% of the total pore volume is the average pore diameter. As the mercury porosimeter, for example, one manufactured by Shimadzu Corporation can be used.
窒化物焼結板の気孔率、すなわち、窒化物焼結板における気孔の体積の比率、の上限値は、例えば、６５体積％以下、６０体積％以下、又は５８体積％以下であってよい。窒化物焼結体の気孔率の上限値が上記範囲内であることで、窒化物焼結板の機械強度の低下をより十分に抑制し、取扱い性により優れた絶縁板２０を提供できる。窒化物焼結板の気孔率の下限値は、例えば、２５体積％以上、２８体積%以上、３０体積％以上、３２体積%以上、３４体積％以上、３６体積％以上、３８体積％以上、４０体積％以上、４２体積％以上、４４体積％以上、又は４６体積％以上であってよい。窒化物焼結体の気孔率の上限値が上記範囲内であることで、樹脂の含有量を向上させ、絶縁板２０の柔軟性を向上させ、電気回路装置１０及び冷却器３０と積層させた際に界面の追従性をより向上させることができ、得られる放熱構造体のヒートサイクル特性をより向上させることができる。窒化物焼結板の気孔率は上述の範囲内で調整してよく、例えば、２５～６５体積％、３０～６５体積％、又は４０～６０体積％であってよい。
The upper limit of the porosity of the nitride sintered plate, that is, the volume ratio of pores in the nitride sintered plate, may be, for example, 65 volume % or less, 60 volume % or less, or 58 volume % or less. When the upper limit of the porosity of the nitride sintered body is within the above range, a decrease in mechanical strength of the nitride sintered board can be more fully suppressed, and an insulating board 20 with better handling properties can be provided. The lower limit of the porosity of the nitride sintered plate is, for example, 25 volume% or more, 28 volume% or more, 30 volume% or more, 32 volume% or more, 34 volume% or more, 36 volume% or more, 38 volume% or more, It may be 40 volume% or more, 42 volume% or more, 44 volume% or more, or 46 volume% or more. Since the upper limit of the porosity of the nitride sintered body is within the above range, the resin content is improved, the flexibility of the insulating plate 20 is improved, and it is laminated with the electric circuit device 10 and the cooler 30. At the same time, the followability of the interface can be further improved, and the heat cycle characteristics of the resulting heat dissipation structure can be further improved. The porosity of the sintered nitride plate may be adjusted within the above-mentioned range, for example, 25-65% by volume, 30-65% by volume, or 40-60% by volume.
窒化物焼結板のかさ密度の上限値は、例えば、１７００ｋｇ／ｍ３以下、１６００ｋｇ／ｍ３以下、１５００ｋｇ／ｍ３以下、１４００ｋｇ／ｍ３以下、又は１３００ｋｇ／ｍ３以下であってよい。窒化物焼結板のかさ密度の下限値は、例えば、１０００ｋｇ／ｍ３以上、１１００ｋｇ／ｍ３以上、又は１２００ｋｇ／ｍ３以上であってよい。
The upper limit of the bulk density of the nitride sintered plate may be, for example, 1700 kg/m 3 or less, 1600 kg/m 3 or less, 1500 kg/m 3 or less, 1400 kg/m 3 or less, or 1300 kg/m 3 or less. The lower limit of the bulk density of the nitride sintered plate may be, for example, 1000 kg/m 3 or more, 1100 kg/m 3 or more, or 1200 kg/m 3 or more.
本明細書における気孔率は、窒化物焼結板の体積及び質量から、かさ密度［Ｙ（ｋｇ／ｍ３）］を算出し、このかさ密度と窒化物の理論密度［Ｘ（ｋｇ／ｍ３）］とから、下記式（１）によって求めることができる。窒化物焼結板を構成する窒化物が、窒化ホウ素の場合、理論密度Ｘは２２８０ｋｇ／ｍ３である。窒化物焼結板を構成する窒化物が、窒化アルミニウムの場合、理論密度Ｘは３２６０ｋｇ／ｍ３である。窒化物焼結板を構成する窒化物が、窒化ケイ素の場合、理論密度Ｘは３１７０ｋｇ／ｍ３である。なお、絶縁板２０は樹脂を含浸したものであることから、絶縁板２０を測定対象とする場合、予め８００℃以上で５時間加熱処理することによって、樹脂を燃焼させ除去したうえで得られる窒化物焼結板を測定対象とすることができる。
気孔率（体積％）＝［１－（Ｙ／Ｘ）］×１００ （１） The porosity in this specification is calculated by calculating the bulk density [Y (kg/m 3 )] from the volume and mass of the nitride sintered plate, and combining this bulk density with the theoretical density of nitride [X (kg/m 3 )]. )], it can be determined by the following formula (1). When the nitride constituting the nitride sintered plate is boron nitride, the theoretical density X is 2280 kg/m 3 . When the nitride constituting the sintered nitride plate is aluminum nitride, the theoretical density X is 3260 kg/m 3 . When the nitride constituting the nitride sintered plate is silicon nitride, the theoretical density X is 3170 kg/m 3 . In addition, since the insulatingplate 20 is impregnated with resin, when the insulating plate 20 is to be measured, heat treatment is performed at 800°C or higher for 5 hours in advance to burn and remove the resin. A sintered material plate can be measured.
Porosity (volume%) = [1-(Y/X)] x 100 (1)
気孔率（体積％）＝［１－（Ｙ／Ｘ）］×１００ （１） The porosity in this specification is calculated by calculating the bulk density [Y (kg/m 3 )] from the volume and mass of the nitride sintered plate, and combining this bulk density with the theoretical density of nitride [X (kg/m 3 )]. )], it can be determined by the following formula (1). When the nitride constituting the nitride sintered plate is boron nitride, the theoretical density X is 2280 kg/m 3 . When the nitride constituting the sintered nitride plate is aluminum nitride, the theoretical density X is 3260 kg/m 3 . When the nitride constituting the nitride sintered plate is silicon nitride, the theoretical density X is 3170 kg/m 3 . In addition, since the insulating
Porosity (volume%) = [1-(Y/X)] x 100 (1)
窒化物焼結板が窒化ホウ素焼結板である場合、かさ密度Ｙは、８００～１５００ｋｇ／ｍ３であってよく、１０００～１４００ｋｇ／ｍ３であってもよい。かさ密度Ｙが上述の範囲内であることで、窒化物焼結板の強度と、樹脂の充填量の向上による放熱構造体のヒートサイクル特性の向上とをより高水準で両立することができる。
When the nitride sintered plate is a boron nitride sintered plate, the bulk density Y may be 800 to 1500 kg/m 3 or 1000 to 1400 kg/m 3 . When the bulk density Y is within the above range, it is possible to achieve both the strength of the nitride sintered plate and the improvement of the heat cycle characteristics of the heat dissipation structure due to the improvement in the filling amount of the resin at a higher level.
窒化物焼結板の有する気孔に充填された樹脂は、例えば、比較的柔軟性の高い樹脂であってよい。樹脂としては、例えば、シリコーン樹脂、及び、軟化点が８０℃以上である熱可塑性樹脂等が挙げられる。シリコーン樹脂は、例えば、付加反応型シリコーン等が挙げられる。付加反応型シリコーンは、例えば、一分子中にビニル基及びヒドロシリル基（Ｈ－Ｓｉ基）の両方を有するオルガノポリシロキサンを含む一液反応型シリコーン樹脂、並びに、末端若しくは側鎖にビニル基を有するオルガノポリシロキサンと、末端又は側鎖に２個以上のヒドロシリル基を有するオルガノポリシロキサンと、を含む二液反応型シリコーン樹脂等が挙げられる。付加反応型シリコーンは、具体的には、ＭＯＭＥＮＴＩＶＥ社製の「ＸＥ１４－Ｂ８５３０Ａ／Ｂ」（商品名）、ＧＥ東芝シリコーン社製の「ＹＥ５８２２」（商品名）等が挙げられる。軟化点が８０℃以上である熱可塑性樹脂としては、例えば、炭化水素系のコオリゴマー（Ｈｅｎｋｅｌ社製、商品名：「ＰＳＸ―Ｐｍ」）等が挙げられる。上記熱可塑性樹脂の軟化点は、１００℃以上、１２０℃以上、又は１５０℃以上であってよい。
The resin filling the pores of the sintered nitride plate may be, for example, a relatively flexible resin. Examples of the resin include silicone resins and thermoplastic resins having a softening point of 80° C. or higher. Examples of the silicone resin include addition reaction silicone. Addition reaction type silicones include, for example, one-component reaction type silicone resins containing organopolysiloxanes having both vinyl groups and hydrosilyl groups (H-Si groups) in one molecule, and silicone resins having vinyl groups at terminals or side chains. Examples include two-component reactive silicone resins containing an organopolysiloxane and an organopolysiloxane having two or more hydrosilyl groups at the terminal or side chain. Specific examples of the addition reaction silicone include "XE14-B8530A/B" (trade name) manufactured by MOMENTIVE, "YE5822" (trade name) manufactured by GE Toshiba Silicone, and the like. Examples of the thermoplastic resin having a softening point of 80° C. or higher include hydrocarbon cooligomer (manufactured by Henkel, trade name: "PSX-Pm"). The softening point of the thermoplastic resin may be 100°C or higher, 120°C or higher, or 150°C or higher.
絶縁板２０において、窒化物焼結板の上記気孔に対する上記樹脂の充填率は、絶縁板２０の主面における電気回路装置１０及び冷却器３０の主面への追従性を向上させる観点から調整してよい。窒化物焼結板の上記気孔に対する上記樹脂の充填率の下限値は、例えば、９０体積％以上、９２体積％以上、９４体積％以上、又は９６体積％以上であってよい。窒化物焼結板の上記気孔に対する上記樹脂の充填率の上限値は、特に限定されるものではなく、１００体積％以上であってもよく、９９体積％以下、又は９８体積％以下であってよい。窒化物焼結板の上記気孔に対する上記樹脂の充填率は上述の範囲内で調整してよく、例えば、９０～９９体積％であってよい。
In the insulating plate 20, the filling rate of the resin in the pores of the nitride sintered plate is adjusted from the viewpoint of improving the followability of the main surface of the insulating plate 20 to the main surfaces of the electric circuit device 10 and the cooler 30. It's fine. The lower limit of the filling rate of the resin in the pores of the nitride sintered plate may be, for example, 90 volume % or more, 92 volume % or more, 94 volume % or more, or 96 volume % or more. The upper limit of the filling rate of the resin in the pores of the nitride sintered plate is not particularly limited, and may be 100 volume% or more, 99 volume% or less, or 98 volume% or less. good. The filling rate of the resin in the pores of the sintered nitride plate may be adjusted within the above-mentioned range, and may be, for example, 90 to 99% by volume.
本明細書における樹脂の充填率とは、窒化物焼結板の有する気孔の全体積に対する樹脂が充填されている体積の割合を意味する。絶縁板２０における樹脂の充填率は、本明細書の実施例に記載の方法で測定するものとする。
In this specification, the resin filling rate means the ratio of the volume filled with resin to the total volume of the pores of the nitride sintered board. The resin filling rate in the insulating plate 20 shall be measured by the method described in the Examples of this specification.
絶縁板２０の弾性率の下限値は、例えば、２００ＭＰａ以上、２５０ＭＰａ以上、３００ＭＰａ以上、又は３５０ＭＰａ以上であってよい。上記弾性率の下限値が上記範囲内であることで、絶縁板２０の取扱い性が向上すると共に、締め付け具４０による加圧による放熱構造体の破損等の発生を抑制できる。絶縁板２０の弾性率の上限値は、例えば、２３００ＭＰａ以下、２０００ＭＰａ以下、１７００ＭＰａ以下、又は１５００ＭＰａ以下であってよい。上記弾性率の上限値が上記範囲内であることで、放熱構造体を調製する際の締め付け具４０による加圧によって適度に変形可能であり、電気回路装置１０及び冷却器３０の主面への追従性をより向上し、得られる放熱構造体のヒートサイクル特性をより向上させることができる。絶縁板２０の弾性率は上述の範囲内で調整してよく、例えば、２００～２３００ＭＰａであってよい。
The lower limit of the elastic modulus of the insulating plate 20 may be, for example, 200 MPa or more, 250 MPa or more, 300 MPa or more, or 350 MPa or more. When the lower limit of the elastic modulus is within the above range, handling of the insulating plate 20 is improved, and damage to the heat dissipation structure due to pressure applied by the fastener 40 can be suppressed. The upper limit of the elastic modulus of the insulating plate 20 may be, for example, 2300 MPa or less, 2000 MPa or less, 1700 MPa or less, or 1500 MPa or less. Since the upper limit value of the elastic modulus is within the above range, the heat dissipation structure can be appropriately deformed by applying pressure with the fastener 40 when preparing the heat dissipation structure, and the main surface of the electric circuit device 10 and the cooler 30 can be The followability can be further improved, and the heat cycle characteristics of the resulting heat dissipation structure can be further improved. The elastic modulus of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 200 to 2300 MPa.
本明細書における弾性率とは、以下の方法によって測定される値を意味する。まず、窒化物焼結体（例えば、窒化ホウ素焼結体）を加工して、角柱形状の測定用試料（縦×横×高さ＝１０ｍｍ×１０ｍｍ×０．４ｍｍ）を調製する。そして、当該測定用試料に対して、ＪＩＳ Ｋ ７１８１：２００１「プラスチック－圧縮特性の求め方」の記載に準拠して、圧縮試験機を用いて、２００℃における圧縮弾性率を測定する。測定は、以下に示す条件で行うものとする。なお、圧縮試験機としては、例えば、株式会社島津製作所製の「オートグラフ ＡＧ－Ｘ（３００ｋＮ）」（商品名）等を使用できる。
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ The elastic modulus in this specification means a value measured by the following method. First, a nitride sintered body (for example, a boron nitride sintered body) is processed to prepare a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). Then, the compression elastic modulus of the measurement sample at 200° C. is measured using a compression testing machine in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compression properties”. Measurements shall be performed under the conditions shown below. As the compression tester, for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ The elastic modulus in this specification means a value measured by the following method. First, a nitride sintered body (for example, a boron nitride sintered body) is processed to prepare a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). Then, the compression elastic modulus of the measurement sample at 200° C. is measured using a compression testing machine in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compression properties”. Measurements shall be performed under the conditions shown below. As the compression tester, for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
絶縁板２０の厚さの上限値は、例えば、０．３５ｍｍ以下、０．３２ｍｍ以下、０．３０ｍｍ以下、又は０．２５ｍｍ以下であってよい。絶縁板２０の厚さの上限値が上記範囲内であることで、電気回路装置及び冷却器の表面における凹凸に対する絶縁板の追従性がより向上し、放熱構造体の熱抵抗をより低下させることができる。絶縁板２０の厚さの下限値は、例えば、０．１０ｍｍ以上、０．１５ｍｍ以上、０．１７ｍｍ以上、又は０．２０ｍｍ以上であってよい。絶縁板２０の厚さの下限値が上記範囲内であることで、絶縁板が割れることなどをより抑制し、ハンドリング性を向上させることができる。絶縁板２０の厚さは上述の範囲内で調整してよく、例えば、０．１０～０．３５ｍｍ、又は０．２０～０．３５ｍｍであってよい。
The upper limit of the thickness of the insulating plate 20 may be, for example, 0.35 mm or less, 0.32 mm or less, 0.30 mm or less, or 0.25 mm or less. By setting the upper limit of the thickness of the insulating plate 20 within the above range, the ability of the insulating plate to follow unevenness on the surface of the electric circuit device and the cooler is further improved, and the thermal resistance of the heat dissipation structure is further reduced. I can do it. The lower limit of the thickness of the insulating plate 20 may be, for example, 0.10 mm or more, 0.15 mm or more, 0.17 mm or more, or 0.20 mm or more. When the lower limit of the thickness of the insulating plate 20 is within the above range, cracking of the insulating plate can be further suppressed and handling properties can be improved. The thickness of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 0.10 to 0.35 mm, or 0.20 to 0.35 mm.
絶縁板２０のかさ密度の上限値は、例えば、２０００ｋｇ／ｍ３以下、１９００ｋｇ／ｍ３以下、又は１８００ｋｇ／ｍ３以下であってよい。絶縁板２０のかさ密度の上限値が上記範囲内であると、絶縁板の柔軟性をより向上し、電気回路装置及び冷却器の表面に対する絶縁板の追従性を向上させ、放熱構造体の熱抵抗をより低くすることができる。絶縁板２０のかさ密度の下限値は、例えば、１５００ｋｇ／ｍ３以上、１６００ｋｇ／ｍ３以上、又は１７００ｋｇ／ｍ３以上であってよい。絶縁板２０のかさ密度の下限値が上記範囲内であると、絶縁板の放熱性をより向上させ、放熱構造体の熱抵抗をより低下させることができる。絶縁板２０のかさ密度は上述の範囲内で調整してよく、例えば、１５００～２０００ｋｇ／ｍ３であってよい。
The upper limit of the bulk density of the insulating plate 20 may be, for example, 2000 kg/m 3 or less, 1900 kg/m 3 or less, or 1800 kg/m 3 or less. When the upper limit of the bulk density of the insulating plate 20 is within the above range, the flexibility of the insulating plate is further improved, the conformability of the insulating plate to the surface of the electric circuit device and the cooler is improved, and the heat of the heat dissipation structure is improved. The resistance can be lower. The lower limit of the bulk density of the insulating plate 20 may be, for example, 1500 kg/m 3 or more, 1600 kg/m 3 or more, or 1700 kg/m 3 or more. When the lower limit of the bulk density of the insulating plate 20 is within the above range, the heat dissipation performance of the insulating plate can be further improved and the thermal resistance of the heat dissipation structure can be further reduced. The bulk density of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 1500 to 2000 kg/m 3 .
絶縁板２０の熱伝導率の下限値は、例えば、２５Ｗ／ｍＫ以上、又は３０Ｗ／ｍＫ以上であってよい。上記熱伝導率の下限値が上記範囲内であることで、樹脂とフィラーとを混合した樹脂組成物から得られる従来の絶縁放熱材料よりも、熱抵抗をより低下させることができる。絶縁板２０の熱伝導率の上限値は、例えば、９０Ｗ／ｍＫ以下、８５Ｗ／ｍＫ以下、又は８０Ｗ／ｍＫ以下であってよい。上記熱伝導率の上限値が上記範囲内であることは絶縁板のかさ密度が低いことにも対応し、柔軟に変形が可能であることで、電気回路装置及び冷却器との界面の空隙をより低減することができる。絶縁板２０の熱伝導率は上述の範囲内で調整してよく、例えば、２５～９０Ｗ／ｍＫであってよい。
The lower limit of the thermal conductivity of the insulating plate 20 may be, for example, 25 W/mK or more, or 30 W/mK or more. When the lower limit of the thermal conductivity is within the above range, the thermal resistance can be lowered more than the conventional insulating heat dissipating material obtained from a resin composition in which a resin and a filler are mixed. The upper limit of the thermal conductivity of the insulating plate 20 may be, for example, 90 W/mK or less, 85 W/mK or less, or 80 W/mK or less. The fact that the upper limit of the thermal conductivity is within the above range also corresponds to the low bulk density of the insulating plate, and it is possible to flexibly deform, reducing the voids at the interface with the electric circuit device and cooler. can be further reduced. The thermal conductivity of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 25 to 90 W/mK.
本明細書における熱伝導率は、以下の方法によって算出される値を意味する。まず、窒化物焼結板の熱拡散率Ａ（単位：ｍ２／ｓｅｃ）を求める。この際、窒化物焼結体（例えば、窒化ホウ素焼結体）を、縦×横×厚み＝１０ｍｍ×１０ｍｍ×０．４０ｍｍのサイズに加工した試料を調製し、レーザーフラッシュ法によって、上記試料の熱拡散率Ａを測定する。上記試料のかさ密度Ｂ（単位：ｋｇ／ｍ３）を上記試料の体積及び質量から決定する。さらに、上記試料の比熱容量Ｃ（単位：Ｊ／（ｋｇ・Ｋ））を、ＪＩＳ Ｋ ７１２３－１９８７「プラスチックの比熱容量測定方法」の記載に準拠して測定する。より具体的には、上記試料から２５ｍｇを採取、粉砕し、ペレット状に成型して成型体を得る。得られた成型体を白金製のパンに充填し、示差走査熱量計（ネッチ社製、商品名：ＤＳＣ２１４）を用いて比熱容量を測定する。比熱容量の測定条件は、昇温速度１０℃／分、且つ窒素雰囲気の条件下で２５℃から３００℃まで昇温し、降温速度２０℃／分、且つ窒素雰囲気の条件下で３００℃から２５℃まで降温するものとする。このようにして得られる、熱拡散率Ａ、かさ密度Ｂ、及び比熱容量Ｃ（２５℃の結果を適用）の値に基づいて、下記式（２）から上記試料の厚さ方向の熱伝導率Ｈを算出するものとする。なお、熱拡散率Ａの測定に使用する測定装置としては、例えば、キセノンフラッシュアナライザ（ＮＥＴＺＳＣＨ社製、商品名：ＬＦＡ４６７ＮａｎｏＦｌａｓｈ）等を使用できる。
Ｈ＝Ａ×Ｂ×Ｃ …式（２） Thermal conductivity in this specification means a value calculated by the following method. First, the thermal diffusivity A (unit: m 2 /sec) of the nitride sintered plate is determined. At this time, a sample was prepared by processing a nitride sintered body (for example, a boron nitride sintered body) into a size of length x width x thickness = 10 mm x 10 mm x 0.40 mm, and the laser flash method was used to process the sample. Measure the thermal diffusivity A. The bulk density B (unit: kg/m 3 ) of the sample is determined from the volume and mass of the sample. Furthermore, the specific heat capacity C (unit: J/(kg·K)) of the above sample is measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg is taken from the sample, crushed, and molded into pellets to obtain a molded body. The obtained molded body is filled into a platinum pan, and the specific heat capacity is measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214). The specific heat capacity measurement conditions were: heating from 25°C to 300°C at a temperature increase rate of 10°C/min and a nitrogen atmosphere, and from 300°C to 25°C at a cooling rate of 20°C/min and a nitrogen atmosphere. The temperature is assumed to drop to ℃. Based on the values of thermal diffusivity A, bulk density B, and specific heat capacity C (applying the results at 25°C) obtained in this way, the thermal conductivity in the thickness direction of the above sample is calculated from the following formula (2). Let us calculate H. As a measuring device used to measure the thermal diffusivity A, for example, a xenon flash analyzer (manufactured by NETZSCH, trade name: LFA467NanoFlash) can be used.
H=A×B×C…Formula (2)
Ｈ＝Ａ×Ｂ×Ｃ …式（２） Thermal conductivity in this specification means a value calculated by the following method. First, the thermal diffusivity A (unit: m 2 /sec) of the nitride sintered plate is determined. At this time, a sample was prepared by processing a nitride sintered body (for example, a boron nitride sintered body) into a size of length x width x thickness = 10 mm x 10 mm x 0.40 mm, and the laser flash method was used to process the sample. Measure the thermal diffusivity A. The bulk density B (unit: kg/m 3 ) of the sample is determined from the volume and mass of the sample. Furthermore, the specific heat capacity C (unit: J/(kg·K)) of the above sample is measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg is taken from the sample, crushed, and molded into pellets to obtain a molded body. The obtained molded body is filled into a platinum pan, and the specific heat capacity is measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214). The specific heat capacity measurement conditions were: heating from 25°C to 300°C at a temperature increase rate of 10°C/min and a nitrogen atmosphere, and from 300°C to 25°C at a cooling rate of 20°C/min and a nitrogen atmosphere. The temperature is assumed to drop to ℃. Based on the values of thermal diffusivity A, bulk density B, and specific heat capacity C (applying the results at 25°C) obtained in this way, the thermal conductivity in the thickness direction of the above sample is calculated from the following formula (2). Let us calculate H. As a measuring device used to measure the thermal diffusivity A, for example, a xenon flash analyzer (manufactured by NETZSCH, trade name: LFA467NanoFlash) can be used.
H=A×B×C…Formula (2)
絶縁板２０の圧縮強さの上限値は、例えば、２０．０ＭＰａ以下、１８．０ＭＰａ以下、１６．０ＭＰａ以下、１４．０ＭＰａ以下、１２．０ＭＰａ以下、１０．０ＭＰａ以下、又は８．０ＭＰａ以下であってよい。上記圧縮強さの上限値が上記範囲内であることで、放熱構造体を調製する際の締め付け圧力による変形がより容易となり、放熱構造体のヒートサイクル特性をより向上し得る。絶縁板２０の圧縮強さの下限値は、例えば、４．０ＭＰａ以上、４．５ＭＰａ以上、５．０ＭＰａ以上、又は５．５ＭＰａ以上であってよい。上記圧縮強さの下限値が上記範囲内であることで、放熱構造体の調製の際に絶縁板２０が破損することをより十分に抑制し得る。絶縁板２０の圧縮強さは上述の範囲内で調整してよく、例えば、２．０～２０ＭＰａ、又は２．０～１０．０ＭＰａであってよい。
The upper limit of the compressive strength of the insulating plate 20 is, for example, 20.0 MPa or less, 18.0 MPa or less, 16.0 MPa or less, 14.0 MPa or less, 12.0 MPa or less, 10.0 MPa or less, or 8.0 MPa or less. It's good. When the upper limit of the compressive strength is within the above range, the heat dissipation structure can be more easily deformed by the tightening pressure when preparing the heat dissipation structure, and the heat cycle characteristics of the heat dissipation structure can be further improved. The lower limit of the compressive strength of the insulating plate 20 may be, for example, 4.0 MPa or more, 4.5 MPa or more, 5.0 MPa or more, or 5.5 MPa or more. When the lower limit of the compressive strength is within the above range, damage to the insulating plate 20 during preparation of the heat dissipation structure can be more fully suppressed. The compressive strength of the insulating plate 20 may be adjusted within the above-mentioned range, and may be, for example, 2.0 to 20 MPa, or 2.0 to 10.0 MPa.
本明細書における圧縮強さは、以下の方法によって測定される値を意味する。まず、窒化物焼結体（例えば、窒化ホウ素焼結体）を加工して、角柱形状の測定用試料（縦×横×高さ＝１０ｍｍ×１０ｍｍ×０．４ｍｍ）を調製する。そして、当該測定用試料に対して、ＪＩＳ Ｋ ７１８１：２００１「プラスチック－圧縮特性の求め方」の記載に準拠して、圧縮試験機を用いて、２００℃における圧縮強さを測定する。測定は、以下に示す条件で行うものとする。なお、圧縮試験機としては、例えば、株式会社島津製作所製の「オートグラフ ＡＧ－Ｘ（３００ｋＮ）」（商品名）等を使用できる。
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ Compressive strength in this specification means a value measured by the following method. First, a nitride sintered body (for example, a boron nitride sintered body) is processed to prepare a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). Then, the compressive strength of the measurement sample at 200° C. is measured using a compression tester in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compressive properties”. Measurements shall be performed under the conditions shown below. As the compression tester, for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ Compressive strength in this specification means a value measured by the following method. First, a nitride sintered body (for example, a boron nitride sintered body) is processed to prepare a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). Then, the compressive strength of the measurement sample at 200° C. is measured using a compression tester in accordance with the description in JIS K 7181:2001 “Plastics - How to determine compressive properties”. Measurements shall be performed under the conditions shown below. As the compression tester, for example, "Autograph AG-X (300 kN)" (trade name) manufactured by Shimadzu Corporation can be used.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
冷却器３０は、絶縁板２０を介して発熱素子２から伝わる熱を冷却する機能を有する。冷却器３０は、金属で構成されていてよい。金属としては、例えば、アルミニウム、銅、及びチタン等が挙げられる。冷却器３０は、絶縁板２０との接触面積を十分に確保することができれば、特に制限されるものではなく、板状に限られず、絶縁板２０側とは反対側の面に凹凸が形成されていてもよく、冷却フィンを有していてもよく、また冷却用媒体（例えば、冷却水）等を流す配管を備えていてもよい。
The cooler 30 has a function of cooling the heat transmitted from the heating element 2 via the insulating plate 20. Cooler 30 may be made of metal. Examples of metals include aluminum, copper, and titanium. The cooler 30 is not particularly limited as long as it can secure a sufficient contact area with the insulating plate 20, and is not limited to a plate shape, and may have irregularities formed on the surface opposite to the insulating plate 20 side. It may have cooling fins, and may also have piping through which a cooling medium (for example, cooling water) flows.
締め付け具４０は、一対の冷却器３０の間に圧力を加えることができるものであれば、特に限定されるものではない。図１においては、締め付け具４０の具体例として、ボルトとナットとで構成される治具を示した。この例では、図１の下方に配置された冷却器３０の貫通孔に螺合され、上方に配置された冷却器３０の貫通孔に挿入されたボルトに対して、ナットを螺合し締め付けることによって、冷却器３０の間に所望の圧力が加わるように調整することができる。
The fastener 40 is not particularly limited as long as it can apply pressure between the pair of coolers 30. In FIG. 1, a jig composed of a bolt and a nut is shown as a specific example of the fastening tool 40. In this example, a nut is screwed into a through hole of a cooler 30 placed at the lower side in FIG. It is possible to adjust so that a desired pressure is applied between the coolers 30.
締め付け具４０による積層方向の圧力（締め付け圧力）の下限値は、例えば、５ＭＰａ以上、７ＭＰａ以上、１０ＭＰａ以上、１５ＭＰａ以上、又は２０ＭＰａ以上であってよい。上記締め付け圧力の下限値が上記範囲内であることで、放熱構造体を構成する部材間の密着性をより向上させることができる。上記締め付け圧力の上限値は、例えば、３５ＭＰａ以下、３０ＭＰａ以下、２７ＭＰａ以下、又は２５ＭＰａ以下であってよい。上記締め付け圧力の上限値が上記範囲内であることで、絶縁板が割れることなどをより抑制し、電気回路装置及び冷却器との界面の空隙をより低減することができる。締め付け具４０による積層方向の圧力は上述の範囲内で調整してよく、例えば、５～３５ＭＰａであってよい。
The lower limit of the pressure in the stacking direction (tightening pressure) by the tightening tool 40 may be, for example, 5 MPa or more, 7 MPa or more, 10 MPa or more, 15 MPa or more, or 20 MPa or more. When the lower limit of the tightening pressure is within the above range, it is possible to further improve the adhesion between the members that constitute the heat dissipation structure. The upper limit of the tightening pressure may be, for example, 35 MPa or less, 30 MPa or less, 27 MPa or less, or 25 MPa or less. By setting the upper limit value of the tightening pressure within the above range, cracking of the insulating plate can be further suppressed, and voids at the interface with the electric circuit device and the cooler can be further reduced. The pressure in the stacking direction by the fastener 40 may be adjusted within the above-mentioned range, and may be, for example, 5 to 35 MPa.
本開示に係る絶縁板２０は適度な柔軟性を有し、他部材への追従性に優れたものとなっている。絶縁板２０と、電気回路装置１０及び冷却器３０との界面の密着性に優れることで、上記放熱構造体１００は、積層方向における熱抵抗が低く抑制されている。上記放熱構造体は、上記回路装置、上記絶縁板及び上記冷却器の積層方向における熱抵抗が０．３０℃／Ｗ以下である。
The insulating plate 20 according to the present disclosure has appropriate flexibility and has excellent followability to other members. Due to the excellent adhesion of the interface between the insulating plate 20, the electric circuit device 10, and the cooler 30, the heat dissipation structure 100 has a low thermal resistance in the stacking direction. The heat dissipation structure has a thermal resistance of 0.30° C./W or less in the stacking direction of the circuit device, the insulating plate, and the cooler.
上記放熱構造体１００の積層方向における熱抵抗の上限値は、例えば、０．２５℃／Ｗ以下、０．２０℃／Ｗ以下、又は０．１５℃／Ｗ以下であってよい。上記熱抵抗の上限値が上記範囲内であることは、絶縁板２０と、電気回路装置１０及び冷却器３０との密着性がより優れていることを意味し、得られる放熱構造体１００のヒートサイクル特性をより向上させ得る。上記放熱構造体１００の積層方向における熱抵抗の下限値は、特に限定されるものではないが、例えば、０．０１℃／Ｗ以上、０．０３℃／Ｗ以上、０．０４℃／Ｗ以上、０．０５℃／Ｗ以上、又は０．０６℃／Ｗ以上であってよい。上記放熱構造体の積層方向における熱抵抗は上述の範囲内で調整してよく、例えば、０．０１～０．３０℃／Ｗ、又は０．０４～０．３０℃／Ｗであってよい。例えば放熱構造体１００の積層方向における熱抵抗は、放熱板４が厚さ３．０ｍｍの銅板で構成されている際に、０．３０℃／Ｗ以下であってもよい。
The upper limit of the thermal resistance in the stacking direction of the heat dissipation structure 100 may be, for example, 0.25°C/W or less, 0.20°C/W or less, or 0.15°C/W or less. The fact that the upper limit value of the thermal resistance is within the above range means that the adhesion between the insulating plate 20 and the electric circuit device 10 and the cooler 30 is better, and the resulting heat dissipation structure 100 is heated. Cycle characteristics can be further improved. The lower limit value of thermal resistance in the lamination direction of the heat dissipation structure 100 is not particularly limited, but is, for example, 0.01°C/W or more, 0.03°C/W or more, 0.04°C/W or more. , 0.05°C/W or more, or 0.06°C/W or more. The thermal resistance in the stacking direction of the heat dissipation structure may be adjusted within the above-mentioned range, and may be, for example, 0.01 to 0.30°C/W, or 0.04 to 0.30°C/W. For example, the thermal resistance in the stacking direction of the heat dissipation structure 100 may be 0.30° C./W or less when the heat dissipation plate 4 is made of a copper plate with a thickness of 3.0 mm.
本明細書における、上記放熱構造体の積層方向における熱抵抗は、放熱構造体の放熱板の外側表面から冷却器の外側表面に至る経路の熱抵抗を意味する。当該熱抵抗は、以下の方法に基づいて測定する。まず電気回路装置の発熱量を３１０Ｗとし、冷却器に送る冷却水の入り口温度を６５℃、冷却水の流量を５Ｌ／分間となるように設定する。放熱板の外側表面と冷却器の外側表面に熱電対を挿入し、温度を測定する。測定値に基づいて、下記式（３）から、熱抵抗の値を決定する。
熱抵抗（℃／Ｗ）＝［放熱板の外側表面温度（℃）－冷却器の外側表面温度（℃）］／３１０（Ｗ） …式（３） In this specification, the thermal resistance in the stacking direction of the heat dissipation structure means the thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler. The thermal resistance is measured based on the following method. First, the heat generation amount of the electric circuit device is set to 310 W, the inlet temperature of the cooling water sent to the cooler is set to 65° C., and the flow rate of the cooling water is set to be 5 L/min. Thermocouples are inserted into the outer surface of the heat sink and the outer surface of the cooler to measure the temperature. Based on the measured value, the value of thermal resistance is determined from the following equation (3).
Thermal resistance (℃/W) = [Outer surface temperature of heat sink (℃) - Outer surface temperature of cooler (℃)] / 310 (W) ... Formula (3)
熱抵抗（℃／Ｗ）＝［放熱板の外側表面温度（℃）－冷却器の外側表面温度（℃）］／３１０（Ｗ） …式（３） In this specification, the thermal resistance in the stacking direction of the heat dissipation structure means the thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler. The thermal resistance is measured based on the following method. First, the heat generation amount of the electric circuit device is set to 310 W, the inlet temperature of the cooling water sent to the cooler is set to 65° C., and the flow rate of the cooling water is set to be 5 L/min. Thermocouples are inserted into the outer surface of the heat sink and the outer surface of the cooler to measure the temperature. Based on the measured value, the value of thermal resistance is determined from the following equation (3).
Thermal resistance (℃/W) = [Outer surface temperature of heat sink (℃) - Outer surface temperature of cooler (℃)] / 310 (W) ... Formula (3)
上記放熱構造体１００の絶縁破壊電圧の下限値は、例えば、２０ｋＶ／ｍｍ以上、又は２５ｋＶ／ｍｍ以上であってよい。上記絶縁破壊電圧の下限値を上記範囲内とすることで、素子を用いた電流のスイッチングの制御がより容易なものとなる。
The lower limit of the dielectric breakdown voltage of the heat dissipation structure 100 may be, for example, 20 kV/mm or more, or 25 kV/mm or more. By setting the lower limit of the dielectric breakdown voltage within the above range, it becomes easier to control current switching using the element.
本明細書における放熱構造体の絶縁破壊強さは、ＪＩＳ Ｃ ２１１０－１：２０１６「固体電気絶縁材料－絶縁破壊の強さの試験方法－第１部：商用周波数交流電圧印加による試験」に記載の方法に基づいて測定される値を意味する。
The dielectric breakdown strength of the heat dissipation structure in this specification is described in JIS C 2110-1:2016 "Solid electrical insulating materials - Test method for dielectric breakdown strength - Part 1: Test by application of commercial frequency AC voltage" means the value measured based on the method of
上述の放熱構造体は、例えば、以下のような製造方法によって製造することができる。すなわち、放熱構造体の製造方法の一実施形態は、第一の冷却器、第一の絶縁板、電気回路装置、第二の絶縁板、及び第二の冷却器をこの順に積層し、締め付け具によって、上記回路装置、上記絶縁板及び上記冷却器を積層方向に加圧した状態とする工程を有する。ここで、電気回路装置は、発熱素子及び上記発熱素子の両主面上に設けられた放熱板を含む。
The above-described heat dissipation structure can be manufactured, for example, by the following manufacturing method. That is, one embodiment of the method for manufacturing a heat dissipation structure includes stacking a first cooler, a first insulating plate, an electric circuit device, a second insulating plate, and a second cooler in this order, and then using a fastener. The method includes a step of pressurizing the circuit device, the insulating plate, and the cooler in the stacking direction. Here, the electric circuit device includes a heat generating element and a heat sink provided on both main surfaces of the heat generating element.
上記絶縁板は、多孔質の窒化物焼結板と、上記窒化物焼結板の気孔に充填された樹脂と、を含む樹脂充填板であってよい。絶縁板は、後述する製法によって調製されたものを用いることができる。
The insulating board may be a resin-filled board including a porous sintered nitride board and a resin filled in the pores of the sintered nitride board. As the insulating plate, one prepared by the manufacturing method described below can be used.
絶縁板の調製方法は、絶縁板に含浸させ、硬化又は固化させる樹脂によって異なる。例えば、樹脂がシリコーン樹脂を含む場合、絶縁板の調製方法は、窒化物を含む成形板を焼成して、窒化物焼結板を得る焼結工程と、窒化物焼結板に、シラン化合物及びシロキサン化合物の少なくとも一方を含む混合物を含浸して含浸体を得る工程と、上記含浸体を加熱処理して上記混合物を重合させることで樹脂充填板を得る硬化工程とを有する。樹脂充填板における樹脂は、シロキサン化合物の重合体であるシリコーン樹脂を含む。また、樹脂が、８０℃以上の軟化点を有する熱可塑性樹脂を含む場合、絶縁板の調製方法は、窒化物を含む成形板を焼成して、窒化物焼結板を得る焼結工程と、窒化物焼結板に上記熱可塑性樹脂を溶融させ、含浸させる樹脂含浸工程と、含浸後の樹脂を固化させる固化工程とを有する。以下、絶縁板が有する樹脂が、樹脂がシリコーン樹脂を含む場合について説明する。
The method for preparing the insulating board varies depending on the resin that is impregnated into the insulating board and cured or solidified. For example, when the resin includes a silicone resin, the method for preparing an insulating board includes a sintering step of firing a molded board containing a nitride to obtain a sintered nitride board, and adding a silane compound and a sintered board to the sintered nitride board. The method includes a step of impregnating a mixture containing at least one of the siloxane compounds to obtain an impregnated body, and a curing step of heat-treating the impregnated body and polymerizing the mixture to obtain a resin-filled plate. The resin in the resin-filled plate includes silicone resin, which is a polymer of siloxane compounds. Further, when the resin includes a thermoplastic resin having a softening point of 80° C. or higher, the method for preparing the insulating board includes a sintering step of firing a molded board containing a nitride to obtain a sintered nitride board; The method includes a resin impregnation step in which the nitride sintered plate is melted and impregnated with the thermoplastic resin, and a solidification step in which the resin after impregnation is solidified. Hereinafter, a case where the resin included in the insulating plate includes silicone resin will be described.
焼結工程における成形板は、窒化物を含む原料粉末を成形して得られた物であってよい。原料粉末に含まれる窒化物は、例えば、窒化ホウ素、窒化アルミニウム、及び窒化ケイ素からなる群から選択される少なくとも一種の窒化物を含有してよい。窒化ホウ素を含有する場合、窒化ホウ素は、アモルファス状の窒化ホウ素であってよく、六方晶状の窒化ホウ素であってもよい。窒化物焼結板として窒化ホウ素焼結板を調製する場合、原料粉末として、例えば、平均粒径が０．５～１０．０μｍであるアモルファス窒化ホウ素粉末、又は、平均粒径が３．０～４０．０μｍである六方晶窒化ホウ素粉末を用いることができる。
The molded plate in the sintering process may be obtained by molding raw material powder containing nitride. The nitride contained in the raw material powder may contain, for example, at least one type of nitride selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride. When containing boron nitride, the boron nitride may be amorphous boron nitride or hexagonal boron nitride. When preparing a boron nitride sintered board as a nitride sintered board, the raw material powder is, for example, an amorphous boron nitride powder with an average particle size of 0.5 to 10.0 μm, or an average particle size of 3.0 to 3.0 μm. A hexagonal boron nitride powder having a diameter of 40.0 μm can be used.
原料粉末を成形して成形体を得る方法は、例えば、一軸加圧で行ってよく、冷間等方加圧（ＣＩＰ）法で行ってもよく、ドクターブレード法で行ってもよい。成形の前に、焼結助剤を原料粉末に配合してもよい。焼結助剤としては、例えば、酸化イットリウム、酸化アルミニウム及び酸化マグネシウム等の金属酸化物、炭酸リチウム及び炭酸ナトリウム等のアルカリ金属の炭酸塩、並びにホウ酸等が挙げられる。
The method for molding the raw material powder to obtain a compact may be, for example, uniaxial pressing, cold isostatic pressing (CIP), or doctor blade method. A sintering aid may be added to the raw material powder before molding. Examples of the sintering aid include metal oxides such as yttrium oxide, aluminum oxide and magnesium oxide, alkali metal carbonates such as lithium carbonate and sodium carbonate, and boric acid.
焼結助剤を配合する場合は、焼結助剤の配合量は、例えば、窒化物及び焼結助剤の合計１００質量部に対して、例えば、０．０１質量部以上、又は０．１０質量部以上であってよい。焼結助剤の配合量は、窒化物及び焼結助剤の合計１００質量部に対して、例えば、２０．００質量部以下、１５．００質量部以下又は１０．００質量部以下であってよい。焼結助剤の添加量を上記範囲内とすることで、窒化物焼結板の平均気孔径の調整がより容易なものとなる。
When blending a sintering aid, the blending amount of the sintering aid is, for example, 0.01 parts by mass or more, or 0.10 parts by mass, based on a total of 100 parts by mass of the nitride and the sintering aid. It may be more than parts by mass. The blending amount of the sintering aid is, for example, 20.00 parts by mass or less, 15.00 parts by mass or less, or 10.00 parts by mass or less, based on a total of 100 parts by mass of the nitride and the sintering aid. good. By adjusting the amount of the sintering aid added within the above range, the average pore diameter of the nitride sintered plate can be adjusted more easily.
焼結工程の焼成温度は、例えば、１６００℃以上、又は１７００℃以上であってもよい。焼成温度は、例えば、２２００℃以下、又は２０００℃以下であってもよい。焼成時間は、例えば、１時間以上であってよく、３０時間以下であってもよい。焼結工程の雰囲気は、例えば、窒素、ヘリウム、及びアルゴン等の不活性ガス雰囲気下であってよい。
The firing temperature in the sintering step may be, for example, 1600°C or higher, or 1700°C or higher. The firing temperature may be, for example, 2200°C or lower, or 2000°C or lower. The firing time may be, for example, 1 hour or more and 30 hours or less. The atmosphere of the sintering process may be, for example, an inert gas atmosphere such as nitrogen, helium, and argon.
焼結には、例えば、バッチ式炉及び連続式炉等を用いることができる。バッチ式炉としては、例えば、マッフル炉、管状炉、及び雰囲気炉等を挙げることができる。連続式炉としては、例えば、ロータリーキルン、スクリューコンベア炉、トンネル炉、ベルト炉、プッシャー炉、及び大形連続炉等を挙げることができる。このようにして、窒化物焼結板を得ることができる。
For example, a batch type furnace, a continuous type furnace, etc. can be used for sintering. Examples of batch furnaces include muffle furnaces, tube furnaces, and atmospheric furnaces. Examples of continuous furnaces include rotary kilns, screw conveyor furnaces, tunnel furnaces, belt furnaces, pusher furnaces, and large continuous furnaces. In this way, a sintered nitride plate can be obtained.
含浸工程では、シラン化合物及びシロキサン化合物の少なくとも一方を含む混合物を窒化物焼結板の気孔中に含浸して含浸体を得る。窒化物焼結体の厚さを小さくすることで、混合物の含浸を円滑にすることができる。
In the impregnation step, a mixture containing at least one of a silane compound and a siloxane compound is impregnated into the pores of the nitride sintered plate to obtain an impregnated body. By reducing the thickness of the nitride sintered body, the mixture can be impregnated smoothly.
上述の混合物は、ポリシロキサン化合物等を含んでもよい。上述の混合物としては、例えば、付加反応型シリコーンが好適に使用できる。付加反応型シリコーンの具体例としては、一分子中にビニル基及びヒドロシリル基（Ｈ－Ｓｉ基）の両方を有するオルガノポリシロキサンを含む一液反応型シリコーン樹脂、並びに、末端又は側鎖にビニル基を有するオルガノポリシロキサンと、末端又は側鎖に２個以上のヒドロシリル基を有するオルガノポリシロキサンと、を含む二液反応型シリコーン樹脂等が挙げられる。付加反応型シリコーンとしては、例えば、モメンティブ・パフォーマンス・マテリアルズ社製の「ＸＥ１４－Ｂ８５３０Ａ／Ｂ」（商品名）等であってよい。
The above mixture may also contain a polysiloxane compound and the like. As the above-mentioned mixture, for example, addition reaction type silicone can be suitably used. Specific examples of addition reaction type silicones include one-component reaction type silicone resins containing organopolysiloxanes having both vinyl groups and hydrosilyl groups (H-Si groups) in one molecule, and silicone resins containing vinyl groups at the ends or side chains. and an organopolysiloxane having two or more hydrosilyl groups at the terminal or side chain. The addition reaction silicone may be, for example, "XE14-B8530A/B" (trade name) manufactured by Momentive Performance Materials.
絶縁板の製造の際の窒化物焼結板の気孔への含浸性、及び、絶縁板の絶縁性を向上させる観点から、付加反応型シリコーンにおける、一分子中にビニル基及びヒドロシリル基の両方を有するオルガノポリシロキサン、及び、末端又は側鎖にビニル基を有するオルガノポリシロキサン（両者を合わせて、「ビニル基を有するオルガノポリシロキサン」と表記する）の重量平均分子量を調整してもよい。上記ビニル基を有するオルガノポリシロキサンの重量平均分子量は、例えば、１００００～３００００、又は１５０００～２５０００であってよく、また、４０００００～６０００００、又は４５００００～５５００００であってよい。上述の観点から、重量平均分子量の異なる上記ビニル基を有するオルガノポリシロキサンを混合して用いることがより好ましく、例えば、重量平均分子量が１００００～３００００である上記ビニル基を有するオルガノポリシロキサンと、重量平均分子量が４０００００～６０００００である上記ビニル基を有するオルガノポリシロキサンと、を混合したもの、又は、重量平均分子量が１５０００～２５０００である上記ビニル基を有するオルガノポリシロキサンと、重量平均分子量が４５００００～５５００００である上記ビニル基を有するオルガノポリシロキサンと、を混合したものを用いることができる。
From the viewpoint of impregnating the pores of the sintered nitride board during the production of the insulating board and improving the insulation properties of the insulating board, addition reaction silicone contains both a vinyl group and a hydrosilyl group in one molecule. The weight average molecular weight of the organopolysiloxane having a vinyl group and the organopolysiloxane having a vinyl group at the terminal or side chain (both collectively referred to as "organopolysiloxane having a vinyl group") may be adjusted. The weight average molecular weight of the vinyl group-containing organopolysiloxane may be, for example, 10,000 to 30,000, or 15,000 to 25,000, or 400,000 to 600,000, or 450,000 to 550,000. From the above point of view, it is more preferable to use a mixture of the organopolysiloxanes having vinyl groups having different weight average molecular weights, for example, the organopolysiloxanes having vinyl groups having a weight average molecular weight of 10,000 to 30,000, and A mixture of the vinyl group-containing organopolysiloxane with an average molecular weight of 400,000 to 600,000, or a mixture of the vinyl group-containing organopolysiloxane with a weight average molecular weight of 15,000 to 25,000 and a weight average molecular weight of 450,000 to 450,000. 550,000 and the above organopolysiloxane having a vinyl group can be used.
上述の混合物は、シラン化合物及びシロキサン化合物の少なくとも一方の他に、例えば、硬化剤を含んでもよい。硬化剤は、ポリシロキサン化合物の硬化反応を促進する触媒であってよい。硬化剤は、例えば、デュポン・東レ・スペシャルティ・マテリアル株式会社製の「ＲＤ－１」（商品名）、モメンティブ・パフォーマンス・マテリアルズ・ジャパン合同会社製の「ＸＣ－８６－２５０」（商品名）等を使用できる。
The above-mentioned mixture may contain, for example, a curing agent in addition to at least one of the silane compound and the siloxane compound. The curing agent may be a catalyst that accelerates the curing reaction of the polysiloxane compound. Examples of hardening agents include "RD-1" (trade name) manufactured by DuPont-Toray Specialty Materials Co., Ltd. and "XC-86-250" (trade name) manufactured by Momentive Performance Materials Japan LLC. etc. can be used.
硬化剤の配合量は、上記シラン化合物及びシロキサン化合物の合計１００質量部に対して、例えば、０．０１～５．００質量部、０．０３～４．００質量部、又は０．０５～２．００質量部であってよい。
The blending amount of the curing agent is, for example, 0.01 to 5.00 parts by mass, 0.03 to 4.00 parts by mass, or 0.05 to 2 parts by mass, based on a total of 100 parts by mass of the silane compound and siloxane compound. .00 parts by mass.
硬化工程は、上記含浸体を加熱処理して上記混合物（シラン化合物及びシロキサン化合物の少なくとも一方）を重合させることで樹脂充填板を得る。
In the curing step, the impregnated body is heat-treated to polymerize the mixture (at least one of a silane compound and a siloxane compound) to obtain a resin-filled plate.
硬化工程における加熱処理の温度は、例えば、５０～２５０℃、７０～２００℃、９０～１５０℃、又は１００～１３０℃であってよい。硬化工程における加熱時間は、例えば、３～２４時間、又は５～１２時間であってよい。
The temperature of the heat treatment in the curing step may be, for example, 50 to 250°C, 70 to 200°C, 90 to 150°C, or 100 to 130°C. The heating time in the curing step may be, for example, 3 to 24 hours or 5 to 12 hours.
以上、本開示の幾つかの実施形態について説明したが、本開示は上述した実施形態に何ら限定されるものではない。また、上述した実施形態についての説明内容は、互いに適用することができる。
Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. Further, the descriptions of the embodiments described above can be applied to each other.
以下、本開示について、実施例及び比較例を用いてより詳細に説明する。なお、本開示は以下の実施例に限定されるものではない。
Hereinafter, the present disclosure will be described in more detail using Examples and Comparative Examples. Note that the present disclosure is not limited to the following examples.
（実施例１）
［窒化物焼結板の調製］
新日本電工株式会社製のオルトホウ酸１００質量部と、デンカ株式会社製のアセチレンブラック（商品名：ＨＳ１００）３５質量部とをヘンシェルミキサーを用いて混合した。得られた原料混合物を、黒鉛製のルツボ中に充填し、アーク炉にて、アルゴン雰囲気で、２２００℃にて５時間加熱し、塊状の炭化ホウ素（Ｂ４Ｃ）を得た。得られた塊状物を、ジョークラッシャーで粗粉砕して粗粉を得た。この粗粉を、炭化珪素製のボール（φ１０ｍｍ）を有するボールミルによってさらに粉砕して粉砕粉を得た。 (Example 1)
[Preparation of sintered nitride plate]
100 parts by mass of orthoboric acid manufactured by Nippon Denko Corporation and 35 parts by mass of acetylene black (trade name: HS100) manufactured by Denka Corporation were mixed using a Henschel mixer. The obtained raw material mixture was filled into a graphite crucible and heated in an arc furnace at 2200° C. in an argon atmosphere for 5 hours to obtain bulk boron carbide (B 4 C). The obtained lumps were coarsely crushed using a jaw crusher to obtain coarse powder. This coarse powder was further pulverized using a ball mill having silicon carbide balls (φ10 mm) to obtain a pulverized powder.
［窒化物焼結板の調製］
新日本電工株式会社製のオルトホウ酸１００質量部と、デンカ株式会社製のアセチレンブラック（商品名：ＨＳ１００）３５質量部とをヘンシェルミキサーを用いて混合した。得られた原料混合物を、黒鉛製のルツボ中に充填し、アーク炉にて、アルゴン雰囲気で、２２００℃にて５時間加熱し、塊状の炭化ホウ素（Ｂ４Ｃ）を得た。得られた塊状物を、ジョークラッシャーで粗粉砕して粗粉を得た。この粗粉を、炭化珪素製のボール（φ１０ｍｍ）を有するボールミルによってさらに粉砕して粉砕粉を得た。 (Example 1)
[Preparation of sintered nitride plate]
100 parts by mass of orthoboric acid manufactured by Nippon Denko Corporation and 35 parts by mass of acetylene black (trade name: HS100) manufactured by Denka Corporation were mixed using a Henschel mixer. The obtained raw material mixture was filled into a graphite crucible and heated in an arc furnace at 2200° C. in an argon atmosphere for 5 hours to obtain bulk boron carbide (B 4 C). The obtained lumps were coarsely crushed using a jaw crusher to obtain coarse powder. This coarse powder was further pulverized using a ball mill having silicon carbide balls (φ10 mm) to obtain a pulverized powder.
調製した粉砕粉を、窒化ホウ素製のルツボに充填した。その後、抵抗加熱炉を用い、窒素ガス雰囲気下で、２０００℃、０．８５ＭＰａの条件で１０時間加熱した。このようにして炭窒化ホウ素（Ｂ４ＣＮ４）を含む焼成物を得た。
The prepared pulverized powder was filled into a boron nitride crucible. Thereafter, it was heated in a nitrogen gas atmosphere at 2000° C. and 0.85 MPa for 10 hours using a resistance heating furnace. In this way, a fired product containing boron carbonitride (B 4 CN 4 ) was obtained.
粉末状のホウ酸と炭酸カルシウムを配合して焼結助剤を調製した。調製にあたっては、１００質量部のホウ酸に対して、炭酸カルシウムを５０．０質量部配合した。このときのホウ素とカルシウムとの原子比率は、ホウ素１００原子％に対してカルシウムが１７．５原子％であった。焼成物１００質量部に対して焼結助剤を２０質量部配合し、ヘンシェルミキサーを用いて混合して粉末状の配合物を調製した。
A sintering aid was prepared by blending powdered boric acid and calcium carbonate. In preparation, 50.0 parts by mass of calcium carbonate was blended with 100 parts by mass of boric acid. The atomic ratio of boron and calcium at this time was 17.5 atomic % of calcium to 100 atomic % of boron. 20 parts by mass of a sintering aid was added to 100 parts by mass of the fired product, and mixed using a Henschel mixer to prepare a powdery mixture.
配合物を、粉末プレス機を用いて、１５０ＭＰａで３０秒間加圧して、シート状（縦×横×厚さ＝５０ｍｍ×５０ｍｍ×０．３５ｍｍ）の成形体を得た。成形体を窒化ホウ素製容器に入れ、バッチ式高周波炉に導入した。バッチ式高周波炉において、常圧、窒素流量５Ｌ／分、２０００℃の条件で５時間加熱した。その後、窒化ホウ素製容器から窒化ホウ素焼結板を取り出した。このようにして、シート状の窒化ホウ素焼結板を得た。窒化ホウ素焼結板の厚さは０．３２ｍｍであった。
The blend was pressed at 150 MPa for 30 seconds using a powder press to obtain a sheet-like molded product (length x width x thickness = 50 mm x 50 mm x 0.35 mm). The compact was placed in a boron nitride container and introduced into a batch type high frequency furnace. In a batch type high frequency furnace, heating was performed for 5 hours at normal pressure, nitrogen flow rate of 5 L/min, and 2000°C. Thereafter, the boron nitride sintered plate was taken out from the boron nitride container. In this way, a sheet-shaped boron nitride sintered plate was obtained. The thickness of the boron nitride sintered plate was 0.32 mm.
＜かさ密度、及び気孔率の測定＞
得られた窒化ホウ素焼結板の気孔率を決定した。まず、窒化ホウ素焼結板の体積及び質量から、かさ密度［Ｙ（ｋｇ／ｍ３）］を算出し、このかさ密度と窒化物の理論密度［Ｘ（ｋｇ／ｍ３）］とから、下記式（１）によって求めた。結果を表１に示す。窒化ホウ素焼結板の理論密度Ｘは２２８０ｋｇ／ｍ３を用いた。
気孔率（体積％）＝［１－（Ｙ／Ｘ）］×１００ （１） <Measurement of bulk density and porosity>
The porosity of the obtained boron nitride sintered plate was determined. First, the bulk density [Y (kg/m 3 )] is calculated from the volume and mass of the boron nitride sintered plate, and from this bulk density and the theoretical density of nitride [X (kg/m 3 )], the following It was determined using equation (1). The results are shown in Table 1. The theoretical density X of the boron nitride sintered plate was 2280 kg/m 3 .
Porosity (volume%) = [1-(Y/X)] x 100 (1)
得られた窒化ホウ素焼結板の気孔率を決定した。まず、窒化ホウ素焼結板の体積及び質量から、かさ密度［Ｙ（ｋｇ／ｍ３）］を算出し、このかさ密度と窒化物の理論密度［Ｘ（ｋｇ／ｍ３）］とから、下記式（１）によって求めた。結果を表１に示す。窒化ホウ素焼結板の理論密度Ｘは２２８０ｋｇ／ｍ３を用いた。
気孔率（体積％）＝［１－（Ｙ／Ｘ）］×１００ （１） <Measurement of bulk density and porosity>
The porosity of the obtained boron nitride sintered plate was determined. First, the bulk density [Y (kg/m 3 )] is calculated from the volume and mass of the boron nitride sintered plate, and from this bulk density and the theoretical density of nitride [X (kg/m 3 )], the following It was determined using equation (1). The results are shown in Table 1. The theoretical density X of the boron nitride sintered plate was 2280 kg/m 3 .
Porosity (volume%) = [1-(Y/X)] x 100 (1)
＜平均気孔径の測定＞
得られた窒化ホウ素焼結板について、株式会社島津製作所製の水銀ポロシメーター（装置名：オートポアＩＶ９５００）を用い、０．００４２ＭＰａから２０６．８ＭＰａまで圧力を増加しながら気孔容積分布を測定した。積算気孔容積が全気孔容積の５０％に達する気孔径を、「平均気孔径」とした。結果を表１に示す。 <Measurement of average pore diameter>
The pore volume distribution of the obtained boron nitride sintered plate was measured using a mercury porosimeter (device name: Autopore IV9500) manufactured by Shimadzu Corporation while increasing the pressure from 0.0042 MPa to 206.8 MPa. The pore diameter where the cumulative pore volume reached 50% of the total pore volume was defined as the "average pore diameter." The results are shown in Table 1.
得られた窒化ホウ素焼結板について、株式会社島津製作所製の水銀ポロシメーター（装置名：オートポアＩＶ９５００）を用い、０．００４２ＭＰａから２０６．８ＭＰａまで圧力を増加しながら気孔容積分布を測定した。積算気孔容積が全気孔容積の５０％に達する気孔径を、「平均気孔径」とした。結果を表１に示す。 <Measurement of average pore diameter>
The pore volume distribution of the obtained boron nitride sintered plate was measured using a mercury porosimeter (device name: Autopore IV9500) manufactured by Shimadzu Corporation while increasing the pressure from 0.0042 MPa to 206.8 MPa. The pore diameter where the cumulative pore volume reached 50% of the total pore volume was defined as the "average pore diameter." The results are shown in Table 1.
［絶縁板の調製］
付加反応型シリコーン（ＭＯＭＥＮＴＩＶＥ社製、商品名：ＸＥ１４－Ｂ８５３０ ２、耐熱温度：２００℃以上）１００質量部に対して、硬化剤（デュポン・東レ・スペシャルティ・マテリアル株式会社、商品名：ＲＤ－１）２質量部を配合して、液体状の混合物を調製した。ディスペンサーを用いて、調製した混合物を窒化ホウ素焼結板の上側の主面上に滴下して、窒化ホウ素焼結板の気孔中に含浸させた。混合物の滴下量は、窒化ホウ素焼結板の気孔の総体積の１．５倍とした。滴下した混合物の一部は、窒化ホウ素焼結板に含浸せず、主面上に残存した。残存分をスキージによって除去した。 [Preparation of insulation board]
For 100 parts by mass of addition reaction silicone (manufactured by MOMENTIVE, product name: XE14-B8530 2, heat-resistant temperature: 200°C or higher), a curing agent (manufactured by DuPont Toray Specialty Materials Co., Ltd., product name: RD-1) is added. ) to prepare a liquid mixture. Using a dispenser, the prepared mixture was dropped onto the upper main surface of the boron nitride sintered board to impregnate it into the pores of the boron nitride sintered board. The amount of the mixture dropped was 1.5 times the total volume of the pores of the boron nitride sintered board. A part of the dropped mixture did not impregnate the boron nitride sintered plate and remained on the main surface. The remaining amount was removed with a squeegee.
付加反応型シリコーン（ＭＯＭＥＮＴＩＶＥ社製、商品名：ＸＥ１４－Ｂ８５３０ ２、耐熱温度：２００℃以上）１００質量部に対して、硬化剤（デュポン・東レ・スペシャルティ・マテリアル株式会社、商品名：ＲＤ－１）２質量部を配合して、液体状の混合物を調製した。ディスペンサーを用いて、調製した混合物を窒化ホウ素焼結板の上側の主面上に滴下して、窒化ホウ素焼結板の気孔中に含浸させた。混合物の滴下量は、窒化ホウ素焼結板の気孔の総体積の１．５倍とした。滴下した混合物の一部は、窒化ホウ素焼結板に含浸せず、主面上に残存した。残存分をスキージによって除去した。 [Preparation of insulation board]
For 100 parts by mass of addition reaction silicone (manufactured by MOMENTIVE, product name: XE14-
上記混合物が含浸した窒化ホウ素焼結板を１５０℃で２４時間加熱処理し、硬化反応を行うことによって、含浸した混合物を硬化させ、樹脂とすることによって、絶縁板（樹脂含浸体）を調製した。
A boron nitride sintered plate impregnated with the above mixture was heat-treated at 150°C for 24 hours to perform a curing reaction, thereby curing the impregnated mixture and making it into a resin, thereby preparing an insulating plate (resin-impregnated body). .
＜絶縁板における樹脂の充填率＞
絶縁板に含まれる樹脂の充填率を、下記式（４）によって求めた。結果は表１に示す。
絶縁板における樹脂の充填率（体積％）＝｛（絶縁板のかさ密度－窒化ホウ素焼結板のかさ密度）／（絶縁板の理論密度－窒化ホウ素焼結板のかさ密度）｝×１００ …式（４） <Filling rate of resin in insulating board>
The filling rate of the resin contained in the insulating plate was determined using the following formula (4). The results are shown in Table 1.
Filling rate of resin in insulating plate (volume %) = {(bulk density of insulating plate - bulk density of boron nitride sintered plate) / (theoretical density of insulating plate - bulk density of boron nitride sintered plate)} x 100... Formula (4)
絶縁板に含まれる樹脂の充填率を、下記式（４）によって求めた。結果は表１に示す。
絶縁板における樹脂の充填率（体積％）＝｛（絶縁板のかさ密度－窒化ホウ素焼結板のかさ密度）／（絶縁板の理論密度－窒化ホウ素焼結板のかさ密度）｝×１００ …式（４） <Filling rate of resin in insulating board>
The filling rate of the resin contained in the insulating plate was determined using the following formula (4). The results are shown in Table 1.
Filling rate of resin in insulating plate (volume %) = {(bulk density of insulating plate - bulk density of boron nitride sintered plate) / (theoretical density of insulating plate - bulk density of boron nitride sintered plate)} x 100... Formula (4)
＜絶縁板のかさ密度＞
絶縁板のかさ密度は、ＪＩＳ Ｚ ８８０７：２０１２の「幾何学的測定による密度及び比重の測定方法」に準拠して、絶縁板の各辺の長さ（ノギスによって測定）から計算した体積と、電子天秤によって測定した絶縁板の質量に基づいて求めた（ＪＩＳ Ｚ ８８０７：２０１２の９項参照）。絶縁板の理論密度は、下記式（５）によって求めた。
絶縁板の理論密度＝窒化ホウ素焼結板のかさ密度＋樹脂の真密度×（１－窒化ホウ素焼結板のかさ密度／窒化ホウ素の真密度） …式（５） <Bulk density of insulation board>
The bulk density of the insulating plate is the volume calculated from the length of each side of the insulating plate (measured with a caliper) in accordance with JIS Z 8807:2012 "Method of measuring density and specific gravity by geometric measurement", It was determined based on the mass of the insulating plate measured using an electronic balance (see section 9 of JIS Z 8807:2012). The theoretical density of the insulating plate was determined by the following formula (5).
Theoretical density of the insulating plate = Bulk density of boron nitride sintered plate + True density of resin × (1 - Bulk density of boron nitride sintered plate / True density of boron nitride) ...Formula (5)
絶縁板のかさ密度は、ＪＩＳ Ｚ ８８０７：２０１２の「幾何学的測定による密度及び比重の測定方法」に準拠して、絶縁板の各辺の長さ（ノギスによって測定）から計算した体積と、電子天秤によって測定した絶縁板の質量に基づいて求めた（ＪＩＳ Ｚ ８８０７：２０１２の９項参照）。絶縁板の理論密度は、下記式（５）によって求めた。
絶縁板の理論密度＝窒化ホウ素焼結板のかさ密度＋樹脂の真密度×（１－窒化ホウ素焼結板のかさ密度／窒化ホウ素の真密度） …式（５） <Bulk density of insulation board>
The bulk density of the insulating plate is the volume calculated from the length of each side of the insulating plate (measured with a caliper) in accordance with JIS Z 8807:2012 "Method of measuring density and specific gravity by geometric measurement", It was determined based on the mass of the insulating plate measured using an electronic balance (see section 9 of JIS Z 8807:2012). The theoretical density of the insulating plate was determined by the following formula (5).
Theoretical density of the insulating plate = Bulk density of boron nitride sintered plate + True density of resin × (1 - Bulk density of boron nitride sintered plate / True density of boron nitride) ...Formula (5)
窒化ホウ素焼結板及び樹脂の真密度は、ＪＩＳ Ｚ ８８０７：２０１２の「気体置換法による密度及び比重の測定方法」に準拠し、乾式自動密度計を用いて測定した窒化ホウ素焼結板及び樹脂の体積及び質量から求めた（ＪＩＳ Ｚ ８８０７：２０１２の１１項の式（１４）～（１７）参照）。
The true density of the boron nitride sintered plate and resin was measured using a dry automatic density meter in accordance with JIS Z 8807:2012 "Method for measuring density and specific gravity by gas displacement method". (see equations (14) to (17) in section 11 of JIS Z 8807:2012).
＜絶縁板の熱伝導率＞
絶縁板の熱伝導率Ｈは、以下の方法に沿って決定した。上記絶縁板から、縦×横×厚み＝１０ｍｍ×１０ｍｍ×０．４０ｍｍのサイズに加工した試料を調製した。得られた当該試料に対して、キセノンフラッシュアナライザ（ＮＥＴＺＳＣＨ社製、商品名：ＬＦＡ４６７ＮａｎｏＦｌａｓｈ）を用い、レーザーフラッシュ法によって、上記試料の熱拡散率Ａを測定した。上記試料のかさ密度Ｂ（単位：ｋｇ／ｍ３）を上記試料の体積及び質量から決定した。さらに、上記試料の比熱容量Ｃ（単位：Ｊ／（ｋｇ・Ｋ））は、ＪＩＳ Ｋ ７１２３－１９８７「プラスチックの比熱容量測定方法」の記載に準拠して測定した。より具体的には、上記試料から２５ｍｇを採取、粉砕し、ペレット状に成型して成型体を得た。得られた成型体を白金製のパンに充填し、示差走査熱量計（ネッチ社製、商品名：ＤＳＣ２１４）を用いて比熱容量を測定した。比熱容量の測定条件は、昇温速度１０℃／分、且つ窒素雰囲気の条件下で２５℃から３００℃まで昇温し、降温速度２０℃／分、且つ窒素雰囲気の条件下で３００℃から２５℃まで降温するものとした。このようにして得られた、熱拡散率Ａ、かさ密度Ｂ、及び比熱容量Ｃの値に基づいて、下記式（２）から上記試料の厚さ方向の熱伝導率Ｈを算出した。
Ｈ＝Ａ×Ｂ×Ｃ …式（２） <Thermal conductivity of insulating plate>
The thermal conductivity H of the insulating plate was determined according to the following method. A sample was prepared from the above insulating plate by processing it into a size of length x width x thickness = 10 mm x 10 mm x 0.40 mm. The thermal diffusivity A of the obtained sample was measured by a laser flash method using a xenon flash analyzer (manufactured by NETZSCH, trade name: LFA467NanoFlash). The bulk density B (unit: kg/m 3 ) of the sample was determined from the volume and mass of the sample. Furthermore, the specific heat capacity C (unit: J/(kg·K)) of the above sample was measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg of the above sample was taken, crushed, and molded into pellets to obtain a molded body. The obtained molded body was filled in a platinum pan, and the specific heat capacity was measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214). The specific heat capacity measurement conditions were: heating from 25°C to 300°C at a temperature increase rate of 10°C/min and a nitrogen atmosphere, and from 300°C to 25°C at a cooling rate of 20°C/min and a nitrogen atmosphere. The temperature was assumed to drop to ℃. Based on the values of thermal diffusivity A, bulk density B, and specific heat capacity C thus obtained, the thermal conductivity H in the thickness direction of the sample was calculated from the following formula (2).
H=A×B×C…Formula (2)
絶縁板の熱伝導率Ｈは、以下の方法に沿って決定した。上記絶縁板から、縦×横×厚み＝１０ｍｍ×１０ｍｍ×０．４０ｍｍのサイズに加工した試料を調製した。得られた当該試料に対して、キセノンフラッシュアナライザ（ＮＥＴＺＳＣＨ社製、商品名：ＬＦＡ４６７ＮａｎｏＦｌａｓｈ）を用い、レーザーフラッシュ法によって、上記試料の熱拡散率Ａを測定した。上記試料のかさ密度Ｂ（単位：ｋｇ／ｍ３）を上記試料の体積及び質量から決定した。さらに、上記試料の比熱容量Ｃ（単位：Ｊ／（ｋｇ・Ｋ））は、ＪＩＳ Ｋ ７１２３－１９８７「プラスチックの比熱容量測定方法」の記載に準拠して測定した。より具体的には、上記試料から２５ｍｇを採取、粉砕し、ペレット状に成型して成型体を得た。得られた成型体を白金製のパンに充填し、示差走査熱量計（ネッチ社製、商品名：ＤＳＣ２１４）を用いて比熱容量を測定した。比熱容量の測定条件は、昇温速度１０℃／分、且つ窒素雰囲気の条件下で２５℃から３００℃まで昇温し、降温速度２０℃／分、且つ窒素雰囲気の条件下で３００℃から２５℃まで降温するものとした。このようにして得られた、熱拡散率Ａ、かさ密度Ｂ、及び比熱容量Ｃの値に基づいて、下記式（２）から上記試料の厚さ方向の熱伝導率Ｈを算出した。
Ｈ＝Ａ×Ｂ×Ｃ …式（２） <Thermal conductivity of insulating plate>
The thermal conductivity H of the insulating plate was determined according to the following method. A sample was prepared from the above insulating plate by processing it into a size of length x width x thickness = 10 mm x 10 mm x 0.40 mm. The thermal diffusivity A of the obtained sample was measured by a laser flash method using a xenon flash analyzer (manufactured by NETZSCH, trade name: LFA467NanoFlash). The bulk density B (unit: kg/m 3 ) of the sample was determined from the volume and mass of the sample. Furthermore, the specific heat capacity C (unit: J/(kg·K)) of the above sample was measured in accordance with the description of JIS K 7123-1987 "Method for Measuring Specific Heat Capacity of Plastics". More specifically, 25 mg of the above sample was taken, crushed, and molded into pellets to obtain a molded body. The obtained molded body was filled in a platinum pan, and the specific heat capacity was measured using a differential scanning calorimeter (manufactured by Netch Corporation, trade name: DSC214). The specific heat capacity measurement conditions were: heating from 25°C to 300°C at a temperature increase rate of 10°C/min and a nitrogen atmosphere, and from 300°C to 25°C at a cooling rate of 20°C/min and a nitrogen atmosphere. The temperature was assumed to drop to ℃. Based on the values of thermal diffusivity A, bulk density B, and specific heat capacity C thus obtained, the thermal conductivity H in the thickness direction of the sample was calculated from the following formula (2).
H=A×B×C…Formula (2)
＜絶縁板の圧縮強さ＞
上述の「窒化物焼結板の調製」に記載したものと同様の配合物を用いて、粉末プレス機を用いて、１５０ＭＰａで３０秒間加圧して、シート状（縦×横×厚さ＝５０ｍｍ×５０ｍｍ×０．４ｍｍ）の絶縁板を調製した。得られた絶縁板を対象として、絶縁板の圧縮強さを、後述する方法によって測定した。 <Compressive strength of insulation board>
Using the same formulation as described in "Preparation of sintered nitride plate" above, pressurize at 150 MPa for 30 seconds using a powder press to form a sheet (length x width x thickness = 50 mm). An insulating plate of 50 mm x 0.4 mm was prepared. The compressive strength of the obtained insulating board was measured by the method described below.
上述の「窒化物焼結板の調製」に記載したものと同様の配合物を用いて、粉末プレス機を用いて、１５０ＭＰａで３０秒間加圧して、シート状（縦×横×厚さ＝５０ｍｍ×５０ｍｍ×０．４ｍｍ）の絶縁板を調製した。得られた絶縁板を対象として、絶縁板の圧縮強さを、後述する方法によって測定した。 <Compressive strength of insulation board>
Using the same formulation as described in "Preparation of sintered nitride plate" above, pressurize at 150 MPa for 30 seconds using a powder press to form a sheet (length x width x thickness = 50 mm). An insulating plate of 50 mm x 0.4 mm was prepared. The compressive strength of the obtained insulating board was measured by the method described below.
まず、上記絶縁板を加工して、角柱形状の測定用試料（縦×横×高さ＝１０ｍｍ×１０ｍｍ×０．４ｍｍ）を得た。得られた測定用試料に対して、ＪＩＳ Ｋ ７１８１：２００１「プラスチック－圧縮特性の求め方」の記載に準拠して、圧縮試験機（株式会社島津製作所製、オートグラフ ＡＧ－Ｘ（３００ｋＮ））を用いて、２００℃における圧縮強さを測定した。測定は、以下の条件で行った。
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ First, the above insulating plate was processed to obtain a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). The obtained measurement sample was tested using a compression tester (Autograph AG-X (300kN) manufactured by Shimadzu Corporation) in accordance with the description of JIS K 7181:2001 "Plastics - How to determine compression properties". The compressive strength at 200°C was measured using the following. The measurements were conducted under the following conditions.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
圧縮速度：０．１ｍｍ／ｍｉｎ
ロードセル：１００ｋＮ
試験温度：２００℃ First, the above insulating plate was processed to obtain a prismatic measurement sample (length x width x height = 10 mm x 10 mm x 0.4 mm). The obtained measurement sample was tested using a compression tester (Autograph AG-X (300kN) manufactured by Shimadzu Corporation) in accordance with the description of JIS K 7181:2001 "Plastics - How to determine compression properties". The compressive strength at 200°C was measured using the following. The measurements were conducted under the following conditions.
Compression speed: 0.1mm/min
Load cell: 100kN
Test temperature: 200℃
［放熱構造体の製造］
電気回路装置として、厚さ３．０ｍｍの銅板、半導体素子、及び厚さ３．０ｍｍの銅板をこの順に積層し、封止材で封止したものを用意した。また、冷却器としてアルミニウム板を用意した。当該アルミニウム板の一方の主面（放熱構造体の最外層に位置する面）には、冷水を流す管が配置されており、当該管に冷水を循環させることによって、冷却を行う。絶縁板として上述の絶縁板を用い、アルミニウム板、絶縁板、電気回路装置、絶縁板、及びアルミニウム板をこの順に積層し、ボルト及びナットによって、アルミニウム板間に１０ＭＰａの締め付け圧力がかかるように調整して、放熱構造体を製造した。 [Manufacture of heat dissipation structure]
An electric circuit device was prepared in which a 3.0 mm thick copper plate, a semiconductor element, and a 3.0 mm thick copper plate were laminated in this order and sealed with a sealing material. In addition, an aluminum plate was prepared as a cooler. A pipe through which cold water flows is arranged on one main surface of the aluminum plate (the surface located at the outermost layer of the heat dissipation structure), and cooling is performed by circulating the cold water through the pipe. Using the above insulating plate as the insulating plate, stack the aluminum plate, insulating plate, electric circuit device, insulating plate, and aluminum plate in this order, and adjust the bolts and nuts so that a tightening pressure of 10 MPa is applied between the aluminum plates. A heat dissipation structure was manufactured.
電気回路装置として、厚さ３．０ｍｍの銅板、半導体素子、及び厚さ３．０ｍｍの銅板をこの順に積層し、封止材で封止したものを用意した。また、冷却器としてアルミニウム板を用意した。当該アルミニウム板の一方の主面（放熱構造体の最外層に位置する面）には、冷水を流す管が配置されており、当該管に冷水を循環させることによって、冷却を行う。絶縁板として上述の絶縁板を用い、アルミニウム板、絶縁板、電気回路装置、絶縁板、及びアルミニウム板をこの順に積層し、ボルト及びナットによって、アルミニウム板間に１０ＭＰａの締め付け圧力がかかるように調整して、放熱構造体を製造した。 [Manufacture of heat dissipation structure]
An electric circuit device was prepared in which a 3.0 mm thick copper plate, a semiconductor element, and a 3.0 mm thick copper plate were laminated in this order and sealed with a sealing material. In addition, an aluminum plate was prepared as a cooler. A pipe through which cold water flows is arranged on one main surface of the aluminum plate (the surface located at the outermost layer of the heat dissipation structure), and cooling is performed by circulating the cold water through the pipe. Using the above insulating plate as the insulating plate, stack the aluminum plate, insulating plate, electric circuit device, insulating plate, and aluminum plate in this order, and adjust the bolts and nuts so that a tightening pressure of 10 MPa is applied between the aluminum plates. A heat dissipation structure was manufactured.
＜放熱構造体の熱抵抗の測定＞
放熱構造体の放熱板の外側表面から冷却器の外側表面に至る経路の熱抵抗を以下の方法に基づいて測定した。まず電気回路装置の発熱量を３１０Ｗとし、冷却器に送る冷却水の入り口温度を６５℃、冷却水の流量を５Ｌ／分間となるように設定した。放熱板の外側表面と冷却器の外側表面に熱電対を挿入し、温度を測定した。測定値に基づいて、下記式（３）から、熱抵抗の値を決定した。
熱抵抗（℃／Ｗ）＝［放熱板の外側表面温度（℃）－冷却器の外側表面温度（℃）］／３１０（Ｗ） …式（３） <Measurement of thermal resistance of heat dissipation structure>
The thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler was measured based on the following method. First, the calorific value of the electric circuit device was set to 310 W, the inlet temperature of the cooling water sent to the cooler was set to 65° C., and the flow rate of the cooling water was set to 5 L/min. Thermocouples were inserted into the outer surface of the heat sink and the cooler to measure the temperature. Based on the measured values, the value of thermal resistance was determined from the following formula (3).
Thermal resistance (℃/W) = [Outer surface temperature of heat sink (℃) - Outer surface temperature of cooler (℃)] / 310 (W) ... Formula (3)
放熱構造体の放熱板の外側表面から冷却器の外側表面に至る経路の熱抵抗を以下の方法に基づいて測定した。まず電気回路装置の発熱量を３１０Ｗとし、冷却器に送る冷却水の入り口温度を６５℃、冷却水の流量を５Ｌ／分間となるように設定した。放熱板の外側表面と冷却器の外側表面に熱電対を挿入し、温度を測定した。測定値に基づいて、下記式（３）から、熱抵抗の値を決定した。
熱抵抗（℃／Ｗ）＝［放熱板の外側表面温度（℃）－冷却器の外側表面温度（℃）］／３１０（Ｗ） …式（３） <Measurement of thermal resistance of heat dissipation structure>
The thermal resistance of the path from the outer surface of the heat dissipation plate of the heat dissipation structure to the outer surface of the cooler was measured based on the following method. First, the calorific value of the electric circuit device was set to 310 W, the inlet temperature of the cooling water sent to the cooler was set to 65° C., and the flow rate of the cooling water was set to 5 L/min. Thermocouples were inserted into the outer surface of the heat sink and the cooler to measure the temperature. Based on the measured values, the value of thermal resistance was determined from the following formula (3).
Thermal resistance (℃/W) = [Outer surface temperature of heat sink (℃) - Outer surface temperature of cooler (℃)] / 310 (W) ... Formula (3)
＜放熱構造体のヒートサイクル特性の評価＞
放熱構造体のヒートサイクル特性を以下の方法で評価した。まず、得られた放熱構造体に対する超音波探傷装置によって、接合部の超音波探傷像を取得した。取得された超音波探傷像において、絶縁板と放熱板及び冷却器との接合ができていない（はく離が生じている）箇所が黒色部で表されることを利用して、初期接合面積率を決定した。初期接合面積率は、接合すべき面積（すなわち、絶縁板の面積）に対する実際に接合されている面積（超音波探傷像において、絶縁板の面積から黒色部の面積を引いた面積：初期接合面積）の割合（面積％）を意味する。 <Evaluation of heat cycle characteristics of heat dissipation structure>
The heat cycle characteristics of the heat dissipation structure were evaluated using the following method. First, an ultrasonic flaw detection image of the joint portion was obtained using an ultrasonic flaw detection device for the obtained heat dissipation structure. In the obtained ultrasonic flaw detection image, the initial bond area ratio can be calculated by taking advantage of the fact that the areas where the insulating plate, heat sink, and cooler are not bonded (delamination has occurred) are represented by black areas. Decided. The initial bonding area ratio is the area that is actually bonded to the area to be bonded (i.e., the area of the insulating plate) (the area obtained by subtracting the area of the black part from the area of the insulating plate in the ultrasonic flaw detection image: initial bonding area) ) means the ratio (area %).
放熱構造体のヒートサイクル特性を以下の方法で評価した。まず、得られた放熱構造体に対する超音波探傷装置によって、接合部の超音波探傷像を取得した。取得された超音波探傷像において、絶縁板と放熱板及び冷却器との接合ができていない（はく離が生じている）箇所が黒色部で表されることを利用して、初期接合面積率を決定した。初期接合面積率は、接合すべき面積（すなわち、絶縁板の面積）に対する実際に接合されている面積（超音波探傷像において、絶縁板の面積から黒色部の面積を引いた面積：初期接合面積）の割合（面積％）を意味する。 <Evaluation of heat cycle characteristics of heat dissipation structure>
The heat cycle characteristics of the heat dissipation structure were evaluated using the following method. First, an ultrasonic flaw detection image of the joint portion was obtained using an ultrasonic flaw detection device for the obtained heat dissipation structure. In the obtained ultrasonic flaw detection image, the initial bond area ratio can be calculated by taking advantage of the fact that the areas where the insulating plate, heat sink, and cooler are not bonded (delamination has occurred) are represented by black areas. Decided. The initial bonding area ratio is the area that is actually bonded to the area to be bonded (i.e., the area of the insulating plate) (the area obtained by subtracting the area of the black part from the area of the insulating plate in the ultrasonic flaw detection image: initial bonding area) ) means the ratio (area %).
次に、測定対象となる放熱構造体に対して、－４０℃にて３０分間保持し、１７５℃にて３０分間保持することを１サイクルとし、これを１０００サイクル繰り返す、ヒートサイクル試験を行った。その後、超音波探傷装置による接着状態の確認を行った。ヒートサイクル試験後に取得された超音波探傷像における、接合面積の初期接合面積に対する割合（｛［ヒートサイクル試験後後の接合面積］／［初期接合面積］｝×１００の値）として接合率を決定した。得られた初期接合面積率及び接合率から、下記の基準で、放熱構造体のヒートサイクル特性を評価した。
Ａ：初期接合面積率が９０面積％以上であり、接合率が９５％以上である。
Ｂ：初期接合面積率が９０面積％以上であり、接合率が８０％以上９５％未満である。
Ｃ：初期接合面積率が９０面積％以上であり、接合率が６０％以上８０％未満である。
Ｄ：初期接合面積率が９０面積％以上であり、接合率が５０％以上６０％未満である。
Ｅ：初期接合面積率が９０面積％以上であり、接合率が５０％未満である。
Ｆ：初期接合面積率が９０面積％未満である。 Next, the heat dissipation structure to be measured was subjected to a heat cycle test in which one cycle was holding at -40°C for 30 minutes and then holding at 175°C for 30 minutes, and this was repeated 1000 cycles. . Thereafter, the adhesion state was confirmed using an ultrasonic flaw detector. The bonding rate is determined as the ratio of the bonding area to the initial bonding area (value of {[bonding area after heat cycle test]/[initial bonding area]} x 100) in the ultrasonic flaw detection image obtained after the heat cycle test. did. From the obtained initial bonding area ratio and bonding rate, the heat cycle characteristics of the heat dissipation structure were evaluated based on the following criteria.
A: The initial bonding area ratio is 90 area % or more, and the bonding rate is 95% or more.
B: The initial bonding area ratio is 90% by area or more, and the bonding rate is 80% or more and less than 95%.
C: The initial bonding area ratio is 90% by area or more, and the bonding rate is 60% or more and less than 80%.
D: The initial bonding area ratio is 90% by area or more, and the bonding rate is 50% or more and less than 60%.
E: The initial bonding area ratio is 90 area% or more, and the bonding rate is less than 50%.
F: The initial bonding area ratio is less than 90 area %.
Ａ：初期接合面積率が９０面積％以上であり、接合率が９５％以上である。
Ｂ：初期接合面積率が９０面積％以上であり、接合率が８０％以上９５％未満である。
Ｃ：初期接合面積率が９０面積％以上であり、接合率が６０％以上８０％未満である。
Ｄ：初期接合面積率が９０面積％以上であり、接合率が５０％以上６０％未満である。
Ｅ：初期接合面積率が９０面積％以上であり、接合率が５０％未満である。
Ｆ：初期接合面積率が９０面積％未満である。 Next, the heat dissipation structure to be measured was subjected to a heat cycle test in which one cycle was holding at -40°C for 30 minutes and then holding at 175°C for 30 minutes, and this was repeated 1000 cycles. . Thereafter, the adhesion state was confirmed using an ultrasonic flaw detector. The bonding rate is determined as the ratio of the bonding area to the initial bonding area (value of {[bonding area after heat cycle test]/[initial bonding area]} x 100) in the ultrasonic flaw detection image obtained after the heat cycle test. did. From the obtained initial bonding area ratio and bonding rate, the heat cycle characteristics of the heat dissipation structure were evaluated based on the following criteria.
A: The initial bonding area ratio is 90 area % or more, and the bonding rate is 95% or more.
B: The initial bonding area ratio is 90% by area or more, and the bonding rate is 80% or more and less than 95%.
C: The initial bonding area ratio is 90% by area or more, and the bonding rate is 60% or more and less than 80%.
D: The initial bonding area ratio is 90% by area or more, and the bonding rate is 50% or more and less than 60%.
E: The initial bonding area ratio is 90 area% or more, and the bonding rate is less than 50%.
F: The initial bonding area ratio is less than 90 area %.
＜放熱構造体の絶縁破壊強さ＞
放熱構造体の絶縁破壊強さを、ＪＩＳ Ｃ ２１１０－１：２０１６「固体電気絶縁材料－絶縁破壊の強さの試験方法－第１部：商用周波数交流電圧印加による試験」に記載の方法に基づいて測定した。結果を表２に示す。 <Dielectric breakdown strength of heat dissipation structure>
The dielectric breakdown strength of the heat dissipation structure was determined based on the method described in JIS C 2110-1:2016 "Solid electrical insulating materials - Test method for dielectric breakdown strength - Part 1: Test by application of commercial frequency AC voltage" It was measured using The results are shown in Table 2.
放熱構造体の絶縁破壊強さを、ＪＩＳ Ｃ ２１１０－１：２０１６「固体電気絶縁材料－絶縁破壊の強さの試験方法－第１部：商用周波数交流電圧印加による試験」に記載の方法に基づいて測定した。結果を表２に示す。 <Dielectric breakdown strength of heat dissipation structure>
The dielectric breakdown strength of the heat dissipation structure was determined based on the method described in JIS C 2110-1:2016 "Solid electrical insulating materials - Test method for dielectric breakdown strength - Part 1: Test by application of commercial frequency AC voltage" It was measured using The results are shown in Table 2.
（実施例２）
絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を用いたこと以外は、実施例１と同様にして、絶縁板を調製した。このように調製した絶縁板を用いたこと以外は、実施例１と同様にして放熱構造体を製造した。得られた絶縁板及び放熱構造体について、実施例１と同様に各種性状を評価した。結果を表１及び表２に示す。 (Example 2)
In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating plate was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate prepared in this manner was used. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を用いたこと以外は、実施例１と同様にして、絶縁板を調製した。このように調製した絶縁板を用いたこと以外は、実施例１と同様にして放熱構造体を製造した。得られた絶縁板及び放熱構造体について、実施例１と同様に各種性状を評価した。結果を表１及び表２に示す。 (Example 2)
In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating plate was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate prepared in this manner was used. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
（実施例３）
絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を用いたこと以外は、実施例１と同様にして、絶縁板を調製した。このようにして調製した絶縁板を用い、締め付け圧力を２０ＭＰａとしたこと以外は実施例１と同様にして放熱構造体を製造した。得られた絶縁板及び放熱構造体について、実施例１と同様に各種性状を評価した。結果を表１及び表２に示す。 (Example 3)
In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating board was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate thus prepared was used and the tightening pressure was 20 MPa. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を用いたこと以外は、実施例１と同様にして、絶縁板を調製した。このようにして調製した絶縁板を用い、締め付け圧力を２０ＭＰａとしたこと以外は実施例１と同様にして放熱構造体を製造した。得られた絶縁板及び放熱構造体について、実施例１と同様に各種性状を評価した。結果を表１及び表２に示す。 (Example 3)
In the same manner as in Example 1, except that a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was used as the nitride sintered board when preparing the insulating board. An insulating board was prepared. A heat dissipation structure was manufactured in the same manner as in Example 1 except that the insulating plate thus prepared was used and the tightening pressure was 20 MPa. Regarding the obtained insulating plate and heat dissipation structure, various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
（比較例１）
［絶縁板の調製］
まず、絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を調製した。 (Comparative example 1)
[Preparation of insulation board]
First, as a nitride sintered board for preparing an insulating board, a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was prepared.
［絶縁板の調製］
まず、絶縁板を調製する際の窒化物焼結板として、表１に記載の平均気孔径、気孔率及びかさ密度を有する窒化ホウ素焼結板を調製した。 (Comparative example 1)
[Preparation of insulation board]
First, as a nitride sintered board for preparing an insulating board, a boron nitride sintered board having the average pore diameter, porosity, and bulk density listed in Table 1 was prepared.
次に、市販のエポキシ樹脂（三菱ケミカル株式会社製、商品名：エピコート８０７）１００質量部に対し、市販の硬化剤（日本合成化学工業株式会社製、商品名：アクメックスＨ－８を１０質量部配合して、熱硬化性樹脂組成物を調製した。調製した熱硬化性樹脂組成物を１２０℃で１５分間加熱した後、その温度を維持したままディスペンサーを用いて、上記窒化ホウ素焼結板の上側の主面上に滴下して熱硬化性樹脂組成物を含浸した。熱硬化性樹脂組成物の滴下量は、窒化ホウ素焼結板の気孔の総体積の１．５倍とした。滴下した熱硬化性樹脂組成物の一部は、窒化ホウ素焼結板に含浸せず、主面上に残存した。
Next, 10 parts by mass of a commercially available curing agent (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name: Akmex H-8) was added to 100 parts by mass of a commercially available epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: Epicote 807). After heating the prepared thermosetting resin composition at 120° C. for 15 minutes, the above-mentioned boron nitride sintered plate was heated using a dispenser while maintaining the temperature. The thermosetting resin composition was dripped onto the upper main surface to impregnate it.The amount of the thermosetting resin composition dropped was 1.5 times the total volume of the pores of the boron nitride sintered board. A part of the thermosetting resin composition did not impregnate the boron nitride sintered board and remained on the main surface.
大気圧下、窒化ホウ素焼結板の上側の主面上に残存する熱硬化樹脂組成物を、ステンレス製のスクレーパー（株式会社ナルビー製）を用いて平滑化した。余剰分の熱硬化性樹脂組成物を除去し、主面が平滑である含浸体を得た。含浸体を、大気圧下、１２０℃で１８０分間加熱して熱硬化性樹脂組成物を半硬化させた。このようにして、四角柱状の樹脂含浸板（縦×横×厚さ＝５０ｍｍ×５０ｍｍ×０．３２ｍｍ）を作製した。樹脂含浸板の主面の一部には、窒化ホウ素焼結体が露出していた。得られた樹脂含浸板を更に、２００℃、２４時間加熱することによって、半硬化樹脂を硬化させることで、樹脂充填板を調製した。得られた樹脂充填板（絶縁板）について、実施例１の絶縁板に対してした評価と同様の評価を行った。結果を表１に示す。
Under atmospheric pressure, the thermosetting resin composition remaining on the upper main surface of the boron nitride sintered plate was smoothed using a stainless steel scraper (manufactured by Narubi Co., Ltd.). The excess thermosetting resin composition was removed to obtain an impregnated body with a smooth main surface. The impregnated body was heated at 120° C. for 180 minutes under atmospheric pressure to semi-cure the thermosetting resin composition. In this way, a rectangular prism-shaped resin-impregnated plate (length x width x thickness = 50 mm x 50 mm x 0.32 mm) was produced. The boron nitride sintered body was exposed on a part of the main surface of the resin-impregnated plate. The obtained resin-impregnated plate was further heated at 200° C. for 24 hours to cure the semi-cured resin, thereby preparing a resin-filled plate. The obtained resin-filled board (insulating board) was evaluated in the same manner as the insulating board of Example 1. The results are shown in Table 1.
［放熱構造体の製造］
上述のように調製した樹脂充填板を用い、樹脂充填板、電気回路装置、及び樹脂充填板をこの順に積層し、絶縁板、電気回路装置及び絶縁板をこの順に備える積層体を調製した。得られた積層体の両面に絶縁板と接するように冷却器を積層し、ボルト及びナットによって、アルミニウム板間に１０ＭＰａの締め付け圧力がかかるように調整して、図１に示すような構造を有する放熱構造体を製造した。 [Manufacture of heat dissipation structure]
Using the resin-filled board prepared as described above, the resin-filled board, the electric circuit device, and the resin-filled board were laminated in this order to prepare a laminate including the insulating board, the electric circuit device, and the insulating board in this order. Coolers were stacked on both sides of the obtained laminate so that they were in contact with insulating plates, and bolts and nuts were adjusted so that a tightening pressure of 10 MPa was applied between the aluminum plates, resulting in a structure as shown in Figure 1. A heat dissipation structure was manufactured.
上述のように調製した樹脂充填板を用い、樹脂充填板、電気回路装置、及び樹脂充填板をこの順に積層し、絶縁板、電気回路装置及び絶縁板をこの順に備える積層体を調製した。得られた積層体の両面に絶縁板と接するように冷却器を積層し、ボルト及びナットによって、アルミニウム板間に１０ＭＰａの締め付け圧力がかかるように調整して、図１に示すような構造を有する放熱構造体を製造した。 [Manufacture of heat dissipation structure]
Using the resin-filled board prepared as described above, the resin-filled board, the electric circuit device, and the resin-filled board were laminated in this order to prepare a laminate including the insulating board, the electric circuit device, and the insulating board in this order. Coolers were stacked on both sides of the obtained laminate so that they were in contact with insulating plates, and bolts and nuts were adjusted so that a tightening pressure of 10 MPa was applied between the aluminum plates, resulting in a structure as shown in Figure 1. A heat dissipation structure was manufactured.
得られた放熱構造体について、実施例１と同様に各種性状を評価した。結果を表２に示す。
Various properties of the obtained heat dissipation structure were evaluated in the same manner as in Example 1. The results are shown in Table 2.
（比較例２）
絶縁板に変えて、ポリオルガノシロキサンベースポリマー（東レ・ダウコーニング・シリコーン社製、商品名：ＣＦ３１１０）１００質量部、架橋剤（東レ・ダウコーニング・シリコーン社製、商品名：ＲＣ－４）１質量部、及びアグリゲート状窒化ホウ素粉末（デンカ株式会社、ＳＧＰＳグレード）４８質量部を混合し、成形して調製された放熱シート（厚さ：０．２ｍｍ、かさ密度：１．６ｇ／ｃｍ３、熱伝導率：８Ｗ／ｍＫ）を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 2)
Instead of the insulating plate, 100 parts by mass of polyorganosiloxane base polymer (manufactured by Toray Dow Corning Silicone Company, trade name: CF3110), 1 part of crosslinking agent (manufactured by Toray Dow Corning Silicone Company, trade name: RC-4) A heat dissipation sheet (thickness: 0.2 mm, bulk density: 1.6 g/cm 3 A heat dissipation structure was prepared in the same manner as in Example 1, except that a heat dissipation structure (thermal conductivity: 8 W/mK) was used.
絶縁板に変えて、ポリオルガノシロキサンベースポリマー（東レ・ダウコーニング・シリコーン社製、商品名：ＣＦ３１１０）１００質量部、架橋剤（東レ・ダウコーニング・シリコーン社製、商品名：ＲＣ－４）１質量部、及びアグリゲート状窒化ホウ素粉末（デンカ株式会社、ＳＧＰＳグレード）４８質量部を混合し、成形して調製された放熱シート（厚さ：０．２ｍｍ、かさ密度：１．６ｇ／ｃｍ３、熱伝導率：８Ｗ／ｍＫ）を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 2)
Instead of the insulating plate, 100 parts by mass of polyorganosiloxane base polymer (manufactured by Toray Dow Corning Silicone Company, trade name: CF3110), 1 part of crosslinking agent (manufactured by Toray Dow Corning Silicone Company, trade name: RC-4) A heat dissipation sheet (thickness: 0.2 mm, bulk density: 1.6 g/cm 3 A heat dissipation structure was prepared in the same manner as in Example 1, except that a heat dissipation structure (thermal conductivity: 8 W/mK) was used.
（比較例３）
絶縁板に変えて、窒化ケイ素焼結板（厚さ：０．３２ｍｍ、かさ密度：３．２ｇ／ｃｍ３、熱伝導率：８０Ｗ／ｍＫ）を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 3)
The procedure was the same as in Example 1, except that a sintered silicon nitride plate (thickness: 0.32 mm, bulk density: 3.2 g/cm 3 , thermal conductivity: 80 W/mK) was used instead of the insulating plate. A heat dissipation structure was prepared.
絶縁板に変えて、窒化ケイ素焼結板（厚さ：０．３２ｍｍ、かさ密度：３．２ｇ／ｃｍ３、熱伝導率：８０Ｗ／ｍＫ）を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 3)
The procedure was the same as in Example 1, except that a sintered silicon nitride plate (thickness: 0.32 mm, bulk density: 3.2 g/cm 3 , thermal conductivity: 80 W/mK) was used instead of the insulating plate. A heat dissipation structure was prepared.
（比較例４）
絶縁板に変えて、窒化ケイ素焼結板（厚さ：０．３２ｍｍ、かさ密度：３．２ｇ／ｃｍ３、熱伝導率：８０Ｗ／ｍＫ）の両主面上に放熱グリース（信越化学工業株式会社製、商品名：Ｇ－７４７）からなるグリース層を設けた部材を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 4)
Instead of an insulating plate, heat dissipation grease (Shin-Etsu Chemical Co. , Ltd. A heat dissipation structure was prepared in the same manner as in Example 1, except that a member provided with a grease layer made of G-747 (trade name: G-747) manufactured by the company was used.
絶縁板に変えて、窒化ケイ素焼結板（厚さ：０．３２ｍｍ、かさ密度：３．２ｇ／ｃｍ３、熱伝導率：８０Ｗ／ｍＫ）の両主面上に放熱グリース（信越化学工業株式会社製、商品名：Ｇ－７４７）からなるグリース層を設けた部材を用いたこと以外は、実施例１と同様にして、放熱構造体を調製した。 (Comparative example 4)
Instead of an insulating plate, heat dissipation grease (Shin-Etsu Chemical Co. , Ltd. A heat dissipation structure was prepared in the same manner as in Example 1, except that a member provided with a grease layer made of G-747 (trade name: G-747) manufactured by the company was used.
本開示によれば、ヒートサイクル特性に優れる放熱構造体を提供できる。
According to the present disclosure, a heat dissipation structure with excellent heat cycle characteristics can be provided.
２…発熱素子、４…放熱板、６…封止材、１０…電気回路装置、２０…絶縁板、３０…冷却器、４０…締め付け具、１００…放熱構造体。
2... Heat generating element, 4... Heat dissipation plate, 6... Sealing material, 10... Electric circuit device, 20... Insulating board, 30... Cooler, 40... Fastener, 100... Heat dissipation structure.
2... Heat generating element, 4... Heat dissipation plate, 6... Sealing material, 10... Electric circuit device, 20... Insulating board, 30... Cooler, 40... Fastener, 100... Heat dissipation structure.
Claims (6)
- 発熱素子及び前記発熱素子の両主面上に設けられた放熱板を含む電気回路装置と、
絶縁板を介して前記放熱板上に積層された一対の冷却器と、
前記電気回路装置、前記絶縁板及び前記冷却器を積層方向に加圧した状態に保持する締め付け具と、を有する放熱構造体であって、
前記絶縁板は、多孔質の窒化物焼結板と、前記窒化物焼結板の気孔に充填された樹脂と、を含み、
積層方向における熱抵抗が０．３０℃／Ｗ以下である、放熱構造体。 an electric circuit device including a heating element and a heat sink provided on both main surfaces of the heating element;
a pair of coolers stacked on the heat sink with an insulating plate interposed therebetween;
A heat dissipation structure comprising a fastener that holds the electric circuit device, the insulating plate, and the cooler in a pressurized state in a stacking direction,
The insulating plate includes a porous sintered nitride plate and a resin filled in the pores of the sintered nitride plate,
A heat dissipation structure having a thermal resistance in the lamination direction of 0.30° C./W or less. - 前記窒化物焼結板の気孔率は２５～６５体積％である、請求項１に記載の放熱構造体。 The heat dissipation structure according to claim 1, wherein the sintered nitride plate has a porosity of 25 to 65% by volume.
- 前記気孔に対する前記樹脂の充填率は９０体積％以上である、請求項１又は２に記載の放熱構造体。 The heat dissipation structure according to claim 1 or 2, wherein the filling rate of the resin with respect to the pores is 90% by volume or more.
- 前記絶縁板の厚さが０．３５ｍｍ以下である、請求項１又は２に記載の放熱構造体。 The heat dissipation structure according to claim 1 or 2, wherein the thickness of the insulating plate is 0.35 mm or less.
- 前記締め付け具による積層方向の圧力が１０ＭＰａ以上である、請求項１又は２に記載の放熱構造体。 The heat dissipation structure according to claim 1 or 2, wherein the pressure in the stacking direction by the fastener is 10 MPa or more.
- 前記樹脂が、シリコーン樹脂、及び、軟化点が８０℃以上である熱可塑性樹脂からなる群より選択される少なくとも一種を含む、請求項１又は２に記載の放熱構造体。
The heat dissipation structure according to claim 1 or 2, wherein the resin includes at least one selected from the group consisting of a silicone resin and a thermoplastic resin having a softening point of 80° C. or higher.
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| WO2021200967A1 (en) * | 2020-03-31 | 2021-10-07 | デンカ株式会社 | Composite and heat dissipation member |
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