Upper surface heat dissipation type power semiconductor module

Abstract

This upper surface heat dissipation type power semiconductor module comprises, in the stated order, a printed circuit board, one or more power semiconductor packages, a heat dissipation laminate, and a heat sink, wherein: the one or more power semiconductor packages each include a power semiconductor chip provided on the printed circuit board and a heat dissipation plate provided on a surface of the power semiconductor chip on the opposite side to the printed circuit board; the heat dissipation laminate has a layer including a compressive deformation member and a layer including a thermally conductive member; the layer including the compressive deformation member has a compressibility of 1% or more and 90% or less when 0.7 MPa is applied in the thickness direction at 25°C; and the layer including the thermally conductive member has a thermal conductivity of 10 W / m·K or more in the thickness direction at 25°C as measured in accordance with ASTM D5470, and a breakdown voltage of 4.0 kV or more as measured in accordance with JIS C2110-1.

Description

Top-mounted heat dissipation power semiconductor module

[0001] This disclosure relates to a top-surface heat dissipation type power semiconductor module. This application claims priority under Japanese Patent Application No. 2024-156778, filed in Japan on September 10, 2024, the contents of which are incorporated herein by reference.

[0002] Electric vehicles (EVs) and electric trains that use electricity supplied from batteries as a power source are equipped with top-surface heat-dissipating power semiconductor modules such as on-board chargers. In top-surface heat-dissipating power semiconductor modules, a power semiconductor package called a discrete device has been proposed that allows a heat sink, such as the one described in Non-Patent Document 1, to be installed on the opposite side of the printed circuit board. Such a power semiconductor package is expected to improve cooling capacity because it can dissipate heat directly to the heat sink without going through a printed circuit board. In such a top-surface heat-dissipating power semiconductor module, a thermal interface material (TIM) is required between the heat sink and the module to efficiently dissipate unwanted heat generated inside the electronic device. Non-Patent Document 1 proposes a liquid gap filler as the TIM material. Patent Document 1 also proposes a graphite sheet that can be used as a TIM material, which has good shape conformability and low contact resistance. Furthermore, Patent Document 2 proposes a thermosetting resin composition that contains epoxy resin as the main component resin and boron nitride aggregate particles as an inorganic filler, which can be suitably used as a TIM material in power semiconductor devices and the like.

[0003] Japanese Patent Publication No. 2020-152618, International Publication No. 2023 / 189030

[0004] Innovative top-side cooled package solution for high-voltage applications, Edition 2021-09-30, Published by Infineon Technologies AG

[0005] However, the Liquid gap filler described in Non-Patent Document 1 has low thermal conductivity, and when used in a top-surface heat-dissipating power semiconductor module, it may result in insufficient cooling capacity for the power semiconductor package and a decrease in power conversion efficiency. Furthermore, since the power semiconductor package and the heat sink need to be electrically insulated, the graphite sheet described in Patent Document 1 alone may reduce the insulation reliability of the top-surface heat-dissipating power semiconductor module. Moreover, when multiple power semiconductor packages are used, the height of each power semiconductor package will not be uniform, but the resin sheet obtained from the thermosetting resin composition described in Patent Document 2 alone may not be able to accommodate the tilt and height variations, potentially reducing heat dissipation and insulation performance. Therefore, in such a top-surface heat-dissipating power semiconductor module, it was considered necessary to have a TIM material in the layer between the heat sink and the package that has high dielectric strength to insulate them, high thermal conductivity to dissipate heat generated from the power semiconductor package to the outside, and compressive deformation capability that can accommodate the tilt and height variations of the power semiconductor package. Here, high dielectric strength refers to the function of preventing electrical short circuits between the electrodes of the power semiconductor package and the heat sink; high thermal conductivity refers to the function of efficiently dissipating heat generated from the power semiconductor package to the heat sink; and compressive deformation capability refers to a component that can adapt to variations in the distance between one or more power semiconductor packages and the heat sink, and that can be compressed and deformed at room temperature (25°C).

[0006] The object of this disclosure is to provide a top-surface heat-dissipating power semiconductor module equipped with a heat-dissipating laminate that can achieve high dielectric strength, high thermal conductivity, and compressive deformability.

[0007] The present disclosure has the following embodiments: [1] A top-surface heat-dissipating power semiconductor module comprising, in this order: a printed circuit board, one or more power semiconductor packages, a heat-dissipating laminate, and a heat sink, wherein the one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board, the heat-dissipating laminate has a layer including a compression deformation member and a layer including a thermally conductive member, the layer including the compression deformation member has a compressibility of 1% or more and 90% or less when 0.7 MPa is applied in the thickness direction at 25°C, the layer including the thermally conductive member has a thermal conductivity in the thickness direction at 25°C of 10 W / m·K or more as measured in accordance with ASTM D5470, and a dielectric breakdown voltage of 4.0 kV or more as measured in accordance with JIS C2110-1, a top-surface heat-dissipating power semiconductor module.[2] A top-heat-dissipating power semiconductor module that dissipates heat generated from one or more power semiconductor packages to the outside from the top surface, comprising in this order: a printed circuit board, one or more power semiconductor packages, a heat-dissipating laminate, and a heat sink, wherein the one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board for dissipating heat generated from the power semiconductor chip, the heat sink is a member for dissipating heat generated from the one or more power semiconductor packages to the outside, the heat-dissipating laminate is provided between the heat sink and the heat sink for transferring heat generated from the one or more power semiconductor packages to the heat sink, and the heat-dissipating laminate has a layer including a compression deformation member and a layer including a thermal conductive member. [3] The top-surface heat-dissipating power semiconductor module, wherein the layer including the compression deformation member is a member for following variations in the distance between the one or more power semiconductor packages and the heat sink, the layer including the compression deformation member has a compressibility of 1% or more and 90% or less when 0.7 MPa is applied in the thickness direction at 25°C, and the layer including the thermal conductive member is a member for transferring heat generated from the one or more power semiconductor packages to the heat sink and for electrically insulating the one or more power semiconductor packages and the heat sink. [4] The top-surface heat-dissipating power semiconductor module according to [1] or [2], wherein the compression deformation member is at least one selected from the group consisting of gap filler, graphite sheet, metal mesh, metal rubber (registered trademark), leaf spring, clay containing metal filler, and grease containing metal filler. [5] The top-surface heat-dissipating power semiconductor module according to any one of [1] to [3], wherein the thermal conductive member is a resin sheet obtained by curing a resin composition containing a matrix resin and a thermal conductive filler. [5] The top-surface heat-dissipating power semiconductor module according to any one of [1] to [4], wherein the heat-conducting member is a resin sheet obtained by curing a resin composition containing epoxy resin and boron nitride aggregate particles.[6] The top-surface heat-dissipating power semiconductor module according to any one of [1] to [5], wherein one or more power semiconductor packages are field-effect transistors. [7] The top-surface heat-dissipating power semiconductor module according to any one of [1] to [6], for use in electric vehicles. [8] A power generation system for electric vehicles equipped with the top-surface heat-dissipating power semiconductor module according to any one of [1] to [7]. [9] An electric vehicle equipped with the power generation system for electric vehicles according to [8].

[10] A heat-dissipating laminate for a top-surface heat-dissipating power semiconductor module according to any one of [1] to [7], having a layer including a compression deformation member and a layer including a thermally conductive member.

[11] A resin sheet for the thermally conductive member in the heat-dissipating laminate according to

[10] .

[0008] According to this disclosure, it is possible to provide a top-surface heat-dissipating power semiconductor module equipped with a heat-dissipating laminate that can achieve high dielectric strength, high thermal conductivity, and compressive deformability.

[0009] Figure 1 is an exploded perspective view showing an example of a top-dissipating power semiconductor module of the present disclosure. Figure 2 is a cross-sectional view showing an example of a power semiconductor package. Figure 3 is a cross-sectional view showing an example of a top-dissipating power semiconductor module of the present disclosure. Figure 4 is a cross-sectional view showing another example of a top-dissipating power semiconductor module of the present disclosure. Figure 5 is a cross-sectional view showing another example of a top-dissipating power semiconductor module of the present disclosure. Figure 6 is a cross-sectional view showing another example of a top-dissipating power semiconductor module of the present disclosure.

[0010] In this disclosure, when a numerical range is expressed using "~", the numbers on both sides of "~" are to be included in that numerical range. Embodiments of this disclosure will be described in detail below with reference to the drawings as appropriate, but this disclosure is not limited to the drawings or the embodiments described later, and various modifications are possible as long as they do not deviate from the gist of this disclosure.

[0011] <Top-Surface Heat Dissipation Power Semiconductor Module> A top-surface heat dissipation power semiconductor module according to a first embodiment of the present disclosure comprises, in this order, a printed circuit board, one or more power semiconductor packages, a heat dissipation laminate, and a heat sink, wherein the one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board. The heat dissipation laminate has a layer including a compression deformation member and a layer including a thermal conductive member, wherein the layer including the compression deformation member has a compressibility of 1% or more and 90% or less when 0.7 MPa is applied in the thickness direction at 25°C, the thermal conductivity in the thickness direction at 25°C measured in accordance with ASTM D5470 is 10 W / m·K or more, and the dielectric breakdown voltage measured in accordance with JIS C2110-1 is 4.0 kV or more.

[0012] A top-dissipating power semiconductor module according to a second aspect of the present disclosure is a top-dissipating power semiconductor module that dissipates heat generated from one or more power semiconductor packages to the outside from the top, and comprises, in this order, a printed circuit board, one or more power semiconductor packages, a heat-dissipating laminate, and a heat sink. The one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board, and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board for dissipating heat generated from the power semiconductor chip. The heat sink is a component for dissipating heat generated from the one or more power semiconductor packages to the outside. The heat-dissipating laminate is provided between the heat sink and the heat sink, and is a component for transferring heat generated from the one or more power semiconductor packages to the heat sink. The heat-dissipating laminate comprises a layer including a compression-deformable member and a layer including a thermally conductive member, wherein the layer including the compression-deformable member is a member for following variations in the distance between the one or more power semiconductor packages and the heat sink, the compression ratio of the layer including the compression-deformable member is 1% to 90% when 0.7 MPa is applied in the thickness direction at 25°C, and the layer including the thermally conductive member is a member for transferring heat generated from the one or more power semiconductor packages to the heat sink and for electrically insulating the one or more power semiconductor packages from the heat sink.

[0013] In this case, a top-dissipating power semiconductor module dissipates heat generated from one or more power semiconductor packages to the outside from the top. In a top-dissipating power semiconductor module, "top" refers to the side of the printed circuit board opposite the power semiconductor package.

[0014] FIG. 1 is an exploded perspective view showing an example of the top-surface heat-radiating type power semiconductor module of the present disclosure. In FIG. 1, the top-surface heat-radiating type power semiconductor module 100 of the present disclosure includes a printed circuit board 4, one or more power semiconductor packages 3, and a heat sink 1 in this order, and includes a heat-radiating laminate 2 for transferring heat generated from the power semiconductor package 3 to the heat sink 1 between the power semiconductor package 3 and the heat sink 1.

[0015] The heat sink 1 shown in FIG. 1 has a flat plate-shaped portion 12 and a plurality of fins 11 protruding from the plate surface of the flat plate-shaped portion 12 in a direction perpendicular to the plate surface. The flat plate-shaped portion 12 has a fin 11 side surface which is the surface on the side where the plurality of fins 11 are formed, and a flat surface which is the surface on the side where the fins 11 are not formed and is flat. The plurality of fins 11 are formed in a partial region near the center on the fin 11 side surface, and the outside of the region where the fins 11 are formed on the fin 11 side surface is a flat surface. The heat sink 1 shown in FIG. 1 is arranged with the flat surface which is the surface on the side where the fins 11 are not formed facing the heat-radiating laminate 2. The fin 11 side surface which is the surface on the side where the plurality of fins 11 are formed faces outward.

[0016] The power semiconductor package 3 shown in FIG. 1 includes a sealing material 32 enclosing a power semiconductor chip 35, a heat radiating plate 31 provided on the upper surface of the sealing material 32, and a plurality of outer leads 33 extending from the side surface of the sealing material 32, and is fixed to the printed circuit board 4 by the outer leads 33 and electrically connected.

[0017] The heat-radiating laminate 2 shown in FIG. 1 has a layer 22 including a compression deformation member and a layer 21 including a heat conductive member, is provided between the heat sink 1 and the heat radiating plate 31, and is arranged such that the layer 21 side including the heat conductive member faces the heat sink 1 side.

[0018] <Heat Sink>The heat sink 1 dissipates the heat generated from one or more power semiconductor packages 3 to the outside. The heat sink 1 can increase the surface area by having a plurality of fins 11, thereby enhancing the heat dissipation effect. The fins 11 may be columnar rising from the flat plate portion 12. And the shape of the fins 11 cut along the plane perpendicular to the protruding direction may be a quadrilateral such as a square, a rectangle, a rhombus, a circle, an ellipse, or a wave shape.

[0019] The heat sink 1 may be formed by forging. Also, the heat sink 1 is formed of at least one of a copper material or an aluminum material. The copper material may be pure copper or a copper alloy. The aluminum material may be pure aluminum or an aluminum alloy.

[0020] As shown in FIG. 1, the heat sink 1 may be fixed to the printed circuit board 4 with screws. (Method for manufacturing the heat sink) The method for manufacturing the heat sink is not particularly limited, and it can be manufactured by a known method.

[0021] <Power Semiconductor Package> The power semiconductor package 3 is a power semiconductor chip 35 having electrodes on its surface that is sealed with a sealing material 32 such as resin. Examples of field-effect transistors include IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), and FETs (Field Effect Transistors). Figure 2 is a cross-sectional view showing an example of a power semiconductor package 3. The power semiconductor package 3 shown in Figure 2 includes, for example, a power semiconductor chip 35 bonded to the inside of the sealing material 32 with a bonding material 34 such as solder, a die pad (not shown) for mounting the chip, an inner lead 36 for electrically connecting the power semiconductor chip 35 and the outer lead 33, and a wire 37 for electrically connecting the power semiconductor chip 35 and the inner lead 36. As shown in Figure 1, the printed circuit board 4 is on the bottom and the heat sink 1 is on the top, so the heat generated from the power semiconductor package 3 is dissipated to the outside from the heat sink 1, which is on the top surface. The power semiconductor package 3 is preferably a discrete device.

[0022] Examples of power semiconductor packages 3 include surface mount type. The power semiconductor package 3 in Figure 1 is approximately square in plan view, but it may also be approximately rectangular, and the shape is not particularly limited. In Figure 1, the multiple outer leads 33 extend from, for example, two paired sides of the power semiconductor package 3, but they may extend from only one side, or from all four sides. Note that a type of power semiconductor package 3 without outer leads 33 can also be used.

[0023] [Power Semiconductor Chip] The power semiconductor package 3 has a power semiconductor chip 35 and a heat sink 31. More specifically, the power semiconductor package 3 has a power semiconductor chip 35 provided on the printed circuit board 4, and a heat sink 31 provided on the side of the power semiconductor chip 35 opposite to the printed circuit board 4. The power semiconductor chip 35 is a semiconductor element used for power control and is electrically connected to the printed circuit board 4. The semiconductor element has n-type or p-type layers formed by impurities being injected into the semiconductor substrate. Conventional known semiconductor elements can be used to form the semiconductor element inside the semiconductor substrate, such as diodes, transistors, or thyristors. Examples of transistors include MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors).

[0024] The semiconductor substrate material can be any material that is conventionally known, such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), etc.

[0025] [Thermal pad] The thermal pad 31 is provided on the side of the power semiconductor chip 35 opposite to the printed circuit board 4 and dissipates the heat generated from the power semiconductor chip 35 to the outside. The material of the thermal pad 31 can be any material known to date, for example metal is preferred, and copper, aluminum, etc. are more preferred. (Method for manufacturing power semiconductor package) The method for manufacturing the power semiconductor package 3 is not particularly limited and can be manufactured by known methods.

[0026] <Printed Circuit Board> The printed circuit board 4 is made of a board made of an insulating material on which conductive wiring is provided, and is electrically connected to the power semiconductor module 3. As shown in Figure 1, the printed circuit board 4 is connected to the outer leads 33 of the power semiconductor module 3, for example, via solder or sintered material. (Manufacturing Method of Printed Circuit Board) The manufacturing method of the printed circuit board 4 is not particularly limited and can be manufactured by known methods.

[0027] <Heat Dissipation Laminate> The heat dissipation laminate 2 is provided between the heat sink 1 and the heat sink plate 31, and transfers heat generated from the one or more power semiconductor packages 3 to the heat sink 1. As shown in Figure 1, the heat dissipation laminate 2 has a layer 22 including a compression deformation member and a layer 21 including a thermal conductive member, and is provided on the side of the power semiconductor package 3 opposite to the printed circuit board 4. The layer 22 including the compression deformation member is a member that follows variations in the distance between the one or more power semiconductor packages 3 and the heat sink 1, and is a member that compresses and deforms at room temperature (25°C). The layer 21 including the thermal conductive member is a member that transfers heat generated from the one or more power semiconductor packages 3 to the heat sink 1, and is a member that electrically insulates the one or more power semiconductor packages 3 and the heat sink 1.

[0028] The layer 22 including the compression deformation member is a member for adjusting variations in the tilt and height of the power semiconductor package 3. The layer 22 including the compression deformation member has step-following properties for compression deformation. Because the layer 22 including the compression deformation member has step-following properties, the thermal resistance can be made uniform through contact between one or more power semiconductor packages 3 and the heat sink 1, thereby improving the power exchange efficiency of the device. The layer 22 including the compression deformation member may be an elastic deformation member that returns completely to its initial state after the external force is removed, or it may be a plastic deformation member that remains in a deformed state even after the external force is removed. By adjusting variations in the tilt and height of the power semiconductor package 3 with the layer 22 including the compression deformation member, the heat sink 1 and the printed circuit board 4 can be arranged substantially parallel to each other. The layer 22 including the compression deformation member only needs to have compressive deformation properties and does not need to have high dielectric strength like the layer 21 including the thermal conductive member described later, but it is preferable that it has thermal conductivity so that heat can be dissipated more easily from the heat sink 1.

[0029] The layer 21 including the thermal conductive member is a component that facilitates heat transfer from the power semiconductor package 3 to the heat sink 1 and heat dissipation from the heat sink 1. The layer 21 including the thermal conductive member only needs to have thermal conductivity and high dielectric strength, and does not need to have compressive deformability like the layer 22 including the compressive deformable member. The layer 21 including the thermal conductive member is a component that electrically insulates one or more power semiconductor packages 3 and the heat sink 1. Because the layer 21 including the thermal conductive member has insulating properties, it is possible to prevent short circuits between the power semiconductor package 3 and the heat sink 1, thereby improving the reliability of the device. The heat dissipation laminate 2 preferably has adhesive properties, and for example, as shown in Figure 1, it is preferable that it can adhere to at least one of the heat sink 1 and the power semiconductor package 3. This eliminates the need to use adhesive and reduces the number of parts. At least one of the layer 22 containing the compression deformation member and the layer 21 containing the thermal conductive member may be adhesive, or only the layer 21 containing the thermal conductive member may be adhesive.

[0030] The heat-dissipating laminate 2, by using a combination of a layer 22 containing a compression-deformable member and a layer 21 containing a thermally conductive member, can efficiently transfer heat generated from the power semiconductor package 3 to the heat sink 1 while maintaining insulation. This allows for an increase in the power input to a single power semiconductor package 3, thereby reducing the number of parallel power semiconductor packages 3 and reducing the number of components and occupied space in devices incorporating them (e.g., inverters, onboard chargers, etc.). Furthermore, by using a combination of a layer 22 containing a compression-deformable member and a layer 21 containing a thermally conductive member, thermal resistance can be reduced while ensuring sufficient space between the outer leads 33 of the power semiconductor package 3 and the heat sink 1, thereby suppressing discharge and improving the reliability of the module.

[0031] In the top-surface heat-dissipating power semiconductor module 100 of the present disclosure, the orientation of the heat-dissipating laminate 2 is not particularly limited. As shown in Figure 1, the side of the layer 21 containing the thermal conductive member may face the heat sink 1, or the side of the layer 22 containing the compression deformation member may face the heat sink 1.

[0032] In Figure 1, the layer 22 containing the compression deformation member and the layer 21 containing the thermal conductive member are the same size in plan view, but they only need to be laminated together, and their sizes in plan view may be the same or different, or the layer 21 containing the thermal conductive member made of a resin sheet may be laminated onto the layer 22 containing the mesh-like compression deformation member.

[0033] [Layer including compression deformation member] The layer 22 including the compression deformation member may be a layer consisting only of the compression deformation member. The layer 22 including the compression deformation member is a member for adjusting the tilt and height variations of the power semiconductor package 3, a member for following the distance variations between the power semiconductor package 3 and the heat sink 1, and has step-following properties that compress and deform at room temperature (25°C). For example, if there is only one power semiconductor package 3, it can absorb the height variations within the single power semiconductor package 3 due to warping and tilting when the power semiconductor package 3 is mounted, thereby ensuring uniform cooling performance. If there are multiple power semiconductor packages 3, it can absorb the height variations between the multiple power semiconductor packages 3 due to warping and tilting when the power semiconductor packages 3 are mounted, thereby ensuring uniform cooling performance. Furthermore, it is preferable that the layer 22 including the compression deformation member also has thermal conductivity to transfer heat generated from the power semiconductor package 3 to the heat sink 1.

[0034] The layer 22 containing the compression deformation member is a member for following variations in the distance between one or more power semiconductor packages 3 and heat sinks 1, and more specifically, it has step-following properties that compress and deform at room temperature (25°C). Furthermore, as mentioned above, the layer 22 containing the compression deformation member has step-following properties that compress and deform at room temperature (25°C), but more specifically, the compressibility ratio (an index of step-following properties) of the layer 22 containing the compression deformation member when 0.7 MPa is applied in the thickness direction at 25°C is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less. Furthermore, there are no particular limitations on the combination of upper and lower limit values, but it is preferably 1% or more and 90% or less, more preferably 3% or more and 85% or less, and even more preferably 5% or more and 80% or more. When the compressibility ratio when 0.7 MPa is applied at 25°C is within the above range, the step-following properties can be exhibited more fully. The compressibility when 0.7 MPa is applied at 25°C can be measured using a tensile-compression testing machine. Here, "compressibility" refers to the value obtained by dividing the decrease in the thickness of the layer 22 containing the compressively deformed member after applying 0.7 MPa by the thickness of the layer 22 containing the compressively deformed member before applying 0.7 MPa (initial value). The above compressibility can be adjusted to a desired range depending on the type and thickness of the compressively deformed member.

[0035] The layer 22 containing the compression deformation member may be conductive or insulating. Examples of materials for the compression deformation member include gap filler, graphite sheet, metal mesh, metal rubber (registered trademark), leaf spring, clay containing metal filler, and grease containing metal filler. Specifically, the compression deformation member is at least one selected from the group consisting of gap filler, graphite sheet, metal mesh, metal rubber (registered trademark), leaf spring, clay containing metal filler, and grease containing metal filler. Among these, materials such as graphite sheet, metal mesh, metal rubber, leaf spring, and clay containing metal filler are preferred due to their high thermal conductivity, and graphite sheet is more preferred among these. Using these materials can achieve higher heat dissipation. Furthermore, among these materials, gap filler, clay containing metal filler, and grease containing metal filler are preferred due to their high step-following ability, and gap filler is more preferred among these. Using these materials can achieve higher followability. Graphite sheet or gap filler is even more preferred as the compression deformation member.

[0036] A gap filler is a thermally conductive material inserted between a power semiconductor package 3 and a heat sink 1 to efficiently dissipate heat from inside an electronic device. The gap filler may be formed from a resin composition containing a thermosetting resin, and the resin composition before curing may be in paste form. The gap filler may be formed, for example, by applying a paste to the heat sink 31 of the power semiconductor package 3, sandwiching it between a layer 21 containing a thermally conductive member or the heat sink 1, and curing it by heating, or by sandwiching the gap filler after it has been cured. Examples of resin components included in the gap filler include silicone resin, epoxy resin, and urethane resin. Examples of commercially available products include Shin-Etsu Chemical's "SDP-5040A / B", Henkel's "TGF-3600", and Laird's "Tflex® HD300". From the viewpoint of step-following, the compressibility of the gap filler after curing is preferably 1% or more, more preferably 5% or more, even more preferably 10% or more, and preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 1% to 90%, more preferably 5% to 85%, and even more preferably 10% to 80%. From the viewpoint of efficiently cooling the power semiconductor package 3, the thermal conductivity of the gap filler in the thickness direction is preferably 0.5 W / m·K or more, more preferably 1 W / m·K or more, even more preferably 1.5 W / m·K or more, and preferably 20 W / m·K or less, more preferably 18 W / m·K or less, and even more preferably 15 W / m·K or less. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 0.5 W / m·K or more and 20 W / m·K or less, more preferably 1 W / m·K or more and 18 W / m·K or less, and even more preferably 1.5 W / m·K or more and 15 W / m·K or less.The thickness of the gap filler is preferably 50 μm or more, more preferably 100 μm or more, even more preferably 150 μm or more, and also preferably 2,000 μm or less, more preferably 1,500 μm or less, and even more preferably 1,000 μm or less, from the viewpoint of absorbing the height tolerance after mounting the power semiconductor package 3 onto the printed circuit board 4. Furthermore, while there are no particular limitations on the combination of upper and lower limits, it is preferably 50 μm or more and 2,000 μm or less, more preferably 100 μm or more and 1,500 μm or less, and even more preferably 150 μm or more and 1,000 μm or less.

[0037] Examples of graphite sheets include natural graphite sheets obtained by forming natural graphite powder into sheets, and artificial graphite sheets obtained by heat-treating polymer films. Commercially available products include, for example, Panasonic's "PGS Graphite Sheet (GraphiteTIM)" and Showa Marutsutsu's "zebro". From the viewpoint of step-following, the compression ratio of the graphite sheet is preferably 1% or more, more preferably 2% or more, even more preferably 3% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 1% to 90%, more preferably 2% to 80%, and even more preferably 3% to 70%. The thermal conductivity of the graphite sheet in the thickness direction is preferably 1 W / m·K or higher, more preferably 3 W / m·K or higher, even more preferably 5 W / m·K or higher, and also preferably 1,000 W / m·K or lower, more preferably 900 W / m·K or lower, and even more preferably 800 W / m·K or lower, from the viewpoint of efficiently cooling the power semiconductor package 3. Furthermore, while the combination of upper and lower limit values ​​is not particularly limited, it is preferably 1 W / m·K or higher and 1,000 W / m·K or lower, more preferably 3 W / m·K or higher and 900 W / m·K or lower, and even more preferably 5 W / m·K or higher and 800 W / m·K or lower. The thickness of the graphite sheet is preferably 50 μm or more, more preferably 100 μm or more, even more preferably 150 μm or more, and also preferably 2,000 μm or less, more preferably 1,500 μm or less, and even more preferably 1,000 μm or less, from the viewpoint of absorbing the height tolerance after mounting the power semiconductor package 3 onto the printed circuit board 4. Furthermore, while there are no particular limitations on the combination of upper and lower limits, it is preferably 50 μm or more and 2,000 μm or less, more preferably 100 μm or more and 1,500 μm or less, and even more preferably 150 μm or more and 1,000 μm or less.

[0038] Examples of metal meshes include laminated nonwoven fabrics of metal fibers and sintered nonwoven fabrics thereof. For example, copper mesh or aluminum mesh are examples.

[0039] Metallic rubber is a material that possesses rubber properties such as flexibility and adhesion by applying microstructures to the surface of a metal. The surface modulus of metallic rubber, as measured in accordance with JIS K 6254:2016, may be between 0.5 GPa and 10 GPa. Metallic rubber has heat resistance comparable to that of the metal and may have a melting point of 600°C or higher. Examples of metals include iron, nickel, copper, and aluminum.

[0040] A leaf spring is a component made of a metal plate, formed into a shape suitable for its application, using a material that has achieved a certain level of spring properties. The leaf spring may be used by fixing it to the printed circuit board 4 with bolts or the like. Examples of metals include iron, nickel, copper, and aluminum.

[0041] In clay containing metal fillers, examples of metal fillers include silver fillers, copper fillers, and gold fillers. The clay is an aggregate of fine particles that exhibit viscosity and plasticity, and for example, mainly contains silica, alumina, and water, and may also contain metal components such as iron, magnesium, calcium, sodium, and potassium.

[0042] Examples of metal fillers in grease include silver fillers, copper fillers, and gold fillers. Grease is a semi-solid or solid product made by dispersing a thickener in a raw material base oil.

[0043] The thickness of the layer 22 containing the compression deformation member is not particularly limited, but is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 100 μm or more. When the thickness of the layer 22 containing the compression deformation member is above the lower limit, the compressive deformability can be more fully exhibited. The thickness of the layer 22 containing the compression deformation member is not particularly limited, but is preferably 1,000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. When the thickness of the layer 22 containing the compression deformation member is below the upper limit, the compressive deformability can be more fully exhibited. Furthermore, the combination of the upper and lower limit values ​​is not particularly limited, but is preferably 50 μm or more and 1,000 μm or less, more preferably 75 μm or more and 800 μm or less, and even more preferably 100 μm or more and 600 μm or less. When the thickness of the layer 22 containing the compression deformation member is within the above range, the compressive deformability can be more fully exhibited. In this disclosure, the thickness can be measured by conventionally known methods. Here, the thickness of the layer 22 containing the compression deformation member is the thickness of the layer 22 itself, which is located between the heat sink 1 and the power semiconductor package 3. For example, the thickness of the layer 22 containing the compression deformation member can be determined by measuring the thickness at five randomly selected locations using a micrometer in the portion in contact with the layer 21 containing the thermal conductive member, and averaging the result.

[0044] The layer 22 including the compression deformation member preferably also has thermal conductivity to transfer heat generated from the power semiconductor package 3 to the heat sink 1, as described above. Specifically, the thermal conductivity in the thickness direction of the layer 22 including the compression deformation member at 25°C is preferably 5 W / m·K or more, more preferably 10 W / m·K or more, even more preferably 15 W / m·K or more, and particularly preferably 20 W / m·K or more. If the thermal conductivity in the thickness direction of the layer 22 including the compression deformation member at 25°C is above the above lower limit, sufficient high heat dissipation performance for use in an upper-surface heat dissipation type power semiconductor module can be achieved. The upper limit of the thermal conductivity in the thickness direction of the layer 22 including the compression deformation member at 25°C is not particularly limited, but may be, for example, 1,000 W / m·K or less, or 800 W / m·K or less. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 5 W / m·K or more and 1,000 W / m·K or less, more preferably 10 W / m·K or more and 1,000 W / m·K or less, even more preferably 15 W / m·K or more and 800 W / m·K or less, and particularly preferably 20 W / m·K or more and 800 W / m·K or less. In this disclosure, the thermal conductivity in the thickness direction at 25°C can be measured in accordance with ASTM D5470. The above thermal conductivity can be adjusted to a desired range depending on the type of compression deformation member, etc.

[0045] [Layer containing a thermally conductive member] The layer containing the thermally conductive member 21 may be a layer consisting only of a thermally conductive member. The layer containing the thermally conductive member 21 has thermal conductivity to transfer heat generated from the power semiconductor package 3 to the heat sink 1. The layer containing the thermally conductive member 21 also has insulating properties to electrically insulate the power semiconductor package 3 from the heat sink 1.

[0046] The layer 21 containing the thermally conductive member is a component for transferring heat generated from one or more power semiconductor packages 3 to the heat sink 1. Specifically, it is preferable that the thermal conductivity in the thickness direction at 25°C be 10 W / m·K or more, more preferably 11 W / m·K or more, even more preferably 12 W / m·K or more, even more preferably 13 W / m·K or more, particularly preferably 14 W / m·K or more, and most preferably 15 W / m·K or more. By having a thermal conductivity in the thickness direction at 25°C that is above the lower limit of the above, a higher level of heat dissipation sufficient for use in an upper-surface heat-dissipating power semiconductor module can be achieved. In this disclosure, the thermal conductivity in the thickness direction at 25°C of the layer 21 containing the thermally conductive member can be measured in accordance with ASTM D5470. The above thermal conductivity can be adjusted to a desired range depending on the type of thermally conductive member, in particular the type and amount ratio of the thermally conductive filler and matrix resin described later, and manufacturing conditions such as low-temperature aging and curing processes.

[0047] The layer 21 containing the thermally conductive member is a member for electrically insulating one or more power semiconductor packages 3 from the heat sink 1. Specifically, it is preferable that the dielectric breakdown voltage is 4.0 kV or higher, more preferably 5.0 kV or higher, and even more preferably 6.0 kV or higher. The higher the dielectric breakdown voltage, the better, and there is no particular upper limit. By having a dielectric breakdown voltage above the lower limit, a sufficiently high dielectric breakdown voltage can be achieved to prevent electrical short circuits between the electrodes of the power semiconductor package 3 and the heat sink 1. In this disclosure, the dielectric breakdown voltage of the layer 21 containing the thermally conductive member can be measured in accordance with JIS C2110-1. When measuring in a module state, the voltage is measured between the short-circuited lead frame of the power semiconductor package 3 and the heat sink 1. The dielectric breakdown voltage can be adjusted to a desired range depending on the type of thermally conductive member, in particular the type and quantity ratio of the thermally conductive filler and matrix resin described later, and manufacturing conditions such as low-temperature aging and curing processes.

[0048] As described above, the layer 21 containing the thermal conductive member does not need to have compressive deformability like the layer 22 containing the compressive deformability member, as long as it has thermal conductivity and high dielectric strength. Preferably, the compressibility (an index of step-following ability) when 0.7 MPa is applied in the thickness direction at 25°C is less than 1%. The compressibility when 0.7 MPa is applied at 25°C can be measured with a tensile-compression testing machine. The "compressibility" referred to here is the value obtained by dividing the decrease in thickness of the layer 21 containing the thermal conductive member after applying 0.7 MPa by the thickness of the layer 21 containing the thermal conductive member before applying 0.7 MPa (initial value).

[0049] In this embodiment, the thermal conductive member having insulating properties and preferably thermal conductivity is preferably a resin sheet containing a matrix resin and a thermal conductive filler, more preferably a resin sheet obtained by curing a resin composition containing a matrix resin and a thermal conductive filler, even more preferably a resin sheet obtained by curing a resin composition containing a matrix resin and boron nitride particles, and most preferably a resin sheet obtained by curing a resin composition containing epoxy resin and boron nitride aggregate particles, as described later. The matrix resin can be any curable resin or thermoplastic resin without limitation. As the curable resin, thermosetting resins, photocurable resins, electron beam curable resins, etc. can be used, and thermosetting resins are preferred. The resin sheet is formed by curing a resin composition containing a matrix resin and a thermal conductive filler, etc. In addition to the matrix resin and thermal conductive filler, the resin composition may also contain a curing agent, a thermosetting catalyst, etc.

[0050] (Thermosetting resins) Any thermosetting resin can be a compound (including polymers) that has the property of hardening with heat, such as epoxy resins, cyanate resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, maleimide resins, and (meth)acrylic resins. Among these, epoxy resins are preferred from the viewpoint of viscosity, heat resistance, hygroscopicity, and ease of handling. As for epoxy resins, those exemplified in International Publication No. 2023 / 189030 are preferred.

[0051] Epoxy resins are a general term for compounds having one or more oxirane rings (epoxy groups) in their molecules. Furthermore, the oxirane rings (epoxy groups) contained in the epoxy resin are preferably alicyclic epoxy groups or glycidyl groups, and are more preferably glycidyl groups from the viewpoint of reaction rate or heat resistance.

[0052] Examples of epoxy resins include epoxy group-containing silicon compounds, aliphatic epoxy resins, bisphenol A or F type epoxy resins, novolac type epoxy resins, alicyclic epoxy resins, glycidyl ester type epoxy resins, polyfunctional epoxy resins, and polymeric epoxy resins.

[0053] The epoxy resin may be a compound containing an aromatic oxirane ring (epoxy group). Specific examples include bisphenol-type epoxy resins obtained by glycidly fermenting bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, and tetrafluorobisphenol A; biphenyl-type epoxy resins; epoxy resins obtained by glycidly fermenting divalent phenols such as dihydroxynaphthalene and 9,9-bis(4-hydroxyphenyl)fluorene; epoxy resins obtained by glycidly fermenting trisphenols such as 1,1,1-tris(4-hydroxyphenyl)methane; epoxy resins obtained by glycidly fermenting tetrakisphenols such as 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; and novolac-type epoxy resins obtained by glycidly fermenting novolacs such as phenol novolac, cresol novolac, bisphenol A novolac, and brominated bisphenol A novolac.

[0054] The density of the epoxy resin is set to 0.8 g / cm³ from the standpoint of its compatibility with thermally conductive fillers. ３ 1.5g / cm or more ３ Preferably, it is 0.9 g / cm³. ３ 1.4g / cm or more ３It is more preferable that the following is the case: 1.0 g / cm³ ３ 1.3g / cm or more ３ The following is even more preferable:

[0055] The molecular weight of the epoxy resin is not particularly limited. The epoxy resin may be a relatively low molecular weight epoxy resin with a molecular weight of 100 to 630, especially 200 to 600, or a high molecular weight epoxy resin with a mass average molecular weight of 10,000 or more, especially 20,000 or more, especially 30,000 or more, for example, 30,000 to 80,000. In particular, it is preferable to contain one or more of the "high molecular weight epoxy resin" and "polyfunctional epoxy resin" described later.

[0056] In addition, epoxy resins other than high molecular weight epoxy resins and polyfunctional epoxy resins included in the resin composition may include, for example, one or more combinations of the following: various bisphenol-type epoxy resins obtained by glycidly modifying bisphenols such as bisphenol A-type epoxy resin and bisphenol F-type epoxy resin; various biphenyl-type epoxy resins obtained by glycidly modifying biphenyls; epoxy resins obtained by glycidly modifying aromatic compounds having two hydroxyl groups such as dihydroxynaphthalene and 9,9-bis(4-hydroxyphenyl)fluorene; epoxy resins obtained by glycidly modifying trisphenols such as 1,1,1-tris(4-hydroxyphenyl)methane; epoxy resins obtained by glycidly modifying tetrakisphenols such as 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; novolac-type epoxy resins obtained by glycidly modifying novolacs such as phenol novolac, cresol novolac, bisphenol A novolac, and brominated bisphenol A novolac; and silicone-containing epoxy resins. However, the composition is not limited to these.

[0057] Among the thermosetting resins contained in the resin composition, the content of the epoxy resin is preferably 30% by mass or more and 100% by mass or less. Regarding such a lower limit value, it is more preferably 40% by mass or more, further preferably 50% by mass or more, particularly preferably 60% by mass or more, and most preferably 70% by mass or more. In addition, the epoxy resin at this time includes the high molecular weight epoxy resin described later.

[0058] ・・High molecular weight epoxy resinThe high molecular weight epoxy resin can be used as the epoxy resin which is the main component resin, and can also be used together with the low molecular weight epoxy resin as described above. Further, it can also be used as a preferable example of a polymer having a mass average molecular weight of 10,000 or more described later.

[0059] Examples of the high molecular weight epoxy resin include a phenoxy resin having at least one skeleton selected from the group consisting of a bisphenol A type skeleton, a bisphenol F type skeleton, a bisphenol A / F mixed type skeleton, a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a xanthene skeleton, an adamantane skeleton, and a dicyclopentadiene skeleton.

[0060] Examples of the high molecular weight epoxy resin include an epoxy resin having at least one structure selected from the structure represented by the following formula (1) (hereinafter, may be referred to as "structure (1)") and the structure represented by the following formula (2) (hereinafter, may be referred to as "structure (2)").

[0061]

[0062] In formula (1), R １ and R ２ each represent an organic group, and at least one of them is an organic group having a molecular weight of 16 or more. In formula (2), R ３ represents a divalent cyclic organic group.

[0063] Furthermore, the term "organic group" includes any group containing a carbon atom, such as alkyl groups, alkenyl groups, and aryl groups, which may be substituted with halogen atoms, heteroatoms, or other hydrocarbon groups. The same applies below.

[0064] Furthermore, as an example of a high molecular weight epoxy resin, an epoxy resin having a structure represented by the following formula (3) (hereinafter sometimes referred to as "structure (3)") can be given.

[0065]

[0066] In formula (3), R ４ , R ５ , R ６ , R ７ Each of these represents an organic group with a molecular weight of 15 or more.

[0067] In the above formula (1), R １ and R ２ At least one of these represents an organic group with a molecular weight of 16 or more, preferably 16 to 1,000, such as alkyl groups like ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups, or aryl groups like phenyl, tolyl, xylyl, naphthyl, and fluorenyl groups. １ and R ２ Both may be organic groups with a molecular weight of 16 or more, or one may be an organic group with a molecular weight of 16 or more and the other may be an organic group or hydrogen atom with a molecular weight of 15 or less. Preferably, one is an organic group with a molecular weight of 16 or more and the other is an organic group with a molecular weight of 15 or less, and in particular, it is preferable that one is a methyl group and the other is a phenyl group, as this makes it easier to control handling properties such as resin viscosity and is preferable from the viewpoint of the strength of the resin sheet.

[0068] In the above equation (2), R ３The group is a divalent cyclic organic group, and may be an aromatic ring structure such as a benzene ring structure, a naphthalene ring structure, or a fluorene ring structure, or an aliphatic ring structure such as cyclobutane, cyclopentane, or cyclohexane. Furthermore, these may independently have substituents such as hydrocarbon groups or halogen atoms. The divalent bond may be a divalent group located on a single carbon atom or on different carbon atoms. Preferably, examples include divalent aromatic groups having 6 to 100 carbon atoms, and groups derived from cycloalkanes having 2 to 100 carbon atoms, such as cyclopropane and cyclohexane. In particular, the 3,3,5-trimethyl-1,1-cyclohexylene group represented by the following formula (4) (hereinafter sometimes referred to as "structure (4)") is preferred from the viewpoint of controlling handling properties such as resin viscosity and the strength of the resin sheet.

[0069]

[0070] In the above formula (3), R ４ , R ５ , R ６ , R ７ Each of these is an organic group with a molecular weight of 15 or more. Preferably, it is an alkyl group with a molecular weight of 15 to 1,000, and especially R ４ , R ５ , R ６ , R ７ It is preferable that all of them be methyl groups from the viewpoint of controlling handling properties such as resin viscosity and the strength of the resin sheet.

[0071] The high molecular weight epoxy resin is preferably an epoxy resin that includes either structure (1) or structure (2) and structure (3) from the viewpoint of achieving both reduced hygroscopicity and strength retention of the resulting resin sheet.

[0072] Such epoxy resins may be used individually, in combination of two or more types, or in combination with other epoxy resins that do not have a high molecular weight.

[0073] Such high molecular weight epoxy resins contain more hydrophobic hydrocarbons and aromatic structures compared to typical epoxy resins with bisphenol A and bisphenol F skeletons. Therefore, by incorporating high molecular weight epoxy resins, the moisture absorption of the resulting resin sheet can be reduced.

[0074] Furthermore, from the viewpoint of reducing moisture absorption, it is preferable that the high molecular weight epoxy resin contains a large amount of hydrophobic structures (1), (2), and (3). The mass average molecular weight of the epoxy resin is preferably 10,000 or more, more preferably 20,000 or more, even more preferably 30,000 or more, and particularly preferably 30,000 to 40,000.

[0075] Furthermore, high molecular weight epoxy resins are preferably more hydrophobic, and from this viewpoint, a larger epoxy equivalent of the epoxy component is preferable. Specifically, it is preferable that it be 5,000 g / equivalent or more, more preferably 7,000 g / equivalent or more, and even more preferably 8,000 g / equivalent or more and 15,000 g / equivalent or less.

[0076] Here, the mass-average molecular weight of the epoxy resin is the polystyrene-equivalent value measured by gel permeation chromatography. Furthermore, epoxy equivalent is defined as "the mass of epoxy resin containing one equivalent of epoxy groups" and can be measured in accordance with JIS K7236.

[0077] Such high molecular weight epoxy resins may be used individually or in combination of two or more types.

[0078] The content of high molecular weight epoxy resin is preferably 10% by mass or more and less than 30% by mass, based on 100% by mass of the total solids content of the resin composition excluding the thermal conductive filler. A content of 10% by mass or more of high molecular weight epoxy resin is preferable because it maintains the retention capacity and film-forming properties of the thermal conductive filler, and a content of less than 30% by mass is preferable because it maintains the strength during curing. From this viewpoint, the content of high molecular weight epoxy resin is preferably 10% by mass or more, more preferably 13% by mass or more, even more preferably 15% by mass or more, and also preferably less than 30% by mass, more preferably 29% by mass or less, and even more preferably 28% by mass or less, based on 100% by mass of the total solids content of the resin composition excluding the thermal conductive filler. Furthermore, the combination of upper and lower limits is not particularly limited, but it is preferably 10% by mass or more and less than 30% by mass, more preferably 13% by mass or more and 29% by mass or less, and even more preferably 15% by mass or more and 28% by mass or less.

[0079] ...By incorporating a polyfunctional epoxy resin into the resin composition, the viscosity before curing can be reduced, and the elastic modulus after curing can be improved, thereby improving heat resistance.

[0080] As for the polyfunctional epoxy resin, from the viewpoint of increasing the storage modulus of the resin sheet, particularly the storage modulus at high temperatures which is important when generating a lot of heat such as in power semiconductors, an epoxy resin having three or more oxirane rings (epoxy groups) in the molecule is preferred, and an epoxy resin having four or more glycidyl groups in the molecule is even more preferred. Having multiple oxirane rings (epoxy groups), especially glycidyl groups, in the molecule improves the crosslinking density of the resin sheet, resulting in a higher strength resin sheet. As a result, when internal stress is generated in the resin sheet during a moisture absorption reflow test, the resin sheet does not deform or break, but maintains its shape, thereby suppressing the generation of voids and other air pockets within the resin sheet.

[0081] Furthermore, from the viewpoint of increasing the storage modulus of the resin sheet, the molecular weight of the polyfunctional epoxy resin is preferably 100 or more, more preferably 200 or more, preferably 650 or less, more preferably 630 or less, even more preferably 600 or less, and particularly preferably 550 or less. In addition, the combination of upper and lower limits is not particularly limited, but it is preferably 100 to 650, more preferably 100 to 630, even more preferably 200 to 600, and particularly preferably 200 to 550.

[0082] By adding a polyfunctional epoxy resin, it is possible to introduce highly polar oxirane rings (epoxy groups) at high density, thereby increasing the effects of physical interactions such as van der Waals forces and hydrogen bonds, and improving the adhesion between the resin composition or resin sheet formed from the resin composition and the conductor. Furthermore, by adding a polyfunctional epoxy resin, the storage modulus of the resin composition or resin sheet can be increased, so that after the resin sheet penetrates the irregularities on the surface of the conductor adherend, it exhibits a strong anchoring effect, improving the adhesion between the resin composition or resin sheet and the conductor. On the other hand, while the introduction of a polyfunctional epoxy resin tends to increase the hygroscopicity of the resin composition or resin sheet, by improving the reactivity of the oxirane rings (epoxy groups), the amount of hydroxyl groups during the reaction can be reduced, and the increase in hygroscopicity can be suppressed. In addition, by manufacturing a resin composition by combining the aforementioned high molecular weight epoxy resin and polyfunctional epoxy resin, it is possible to achieve both high elasticity and low hygroscopicity of the resin composition or resin sheet.

[0083] Specific examples of polyfunctional epoxy resins include, for example, polyfunctional epoxy resins having three or more epoxy groups per molecule and a molecular weight of 650 or less. For example, EX321L, DLC301, DLC402, etc., manufactured by Nagase ChemteX, can be used. These polyfunctional epoxy resins may be used individually or in combination of two or more.

[0084] As a polyfunctional epoxy resin, it is preferable that it does not contain amine-based or amide-based structures containing nitrogen atoms, from the viewpoint of achieving lower moisture absorption and higher crosslinking. Furthermore, from the viewpoint of controlling the viscosity, i.e., the coatability, of the resin composition and achieving low moisture absorption, it is preferable that it does not contain rigid, intermolecularly interacting structures such as aromatic rings.

[0085] The polyfunctional epoxy resin content is preferably 5% by mass or more and 80% by mass or less, based on 100% by mass of the total solids content of the resin composition excluding the thermal conductive filler. A polyfunctional epoxy resin content of 5% by mass or more is preferable because it can maintain the elastic modulus of the resin sheet, and a content of 80% by mass or less is preferable because it does not result in excessively high water absorption. From this viewpoint, the polyfunctional epoxy resin content is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and also preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 50% by mass or less, based on 100% by mass of the total solids content of the resin composition excluding the thermal conductive filler. Furthermore, the combination of upper and lower limits is not particularly limited, but is preferably 5% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 70% by mass or less, and even more preferably 15% by mass or more and 50% by mass or less.

[0086] When a high molecular weight epoxy resin and a polyfunctional epoxy resin are used in combination, from the viewpoint of the film-forming properties of the resin sheet and its elastic modulus, the content of the polyfunctional epoxy resin per 100 parts by mass of the high molecular weight epoxy resin is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 50 parts by mass or more, also preferably 1,000 parts by mass or less, more preferably 500 parts by mass or less, and even more preferably 200 parts by mass or less. Furthermore, the combination of upper and lower limits is not particularly limited, but it is preferably 15 parts by mass or more and 1,000 parts by mass or less, more preferably 30 parts by mass or more and 500 parts by mass or less, and even more preferably 50 parts by mass or more and 200 parts by mass or less.

[0087] In the resin composition, the matrix resin content is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total mass of the resin composition. In the resin composition, the matrix resin content is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 38% by mass or less, based on the total mass of the resin composition. Furthermore, while the combination of upper and lower limits is not particularly limited, 5% by mass or more and 45% by mass or less is preferred, 10% by mass or more and 40% by mass or less is more preferred, and 15% by mass or more and even more preferably 38% by mass or less. If the matrix resin content is above the lower limit, dielectric strength can be maintained. If the matrix resin content is below the upper limit, thermal conductivity can be maintained.

[0088] (Curing agent) These thermosetting resins can also be cured with a curing agent. The curing agent contained in the sheet is not particularly limited, but preferred curing agents are phenolic resins, compounds having a heterocyclic structure containing nitrogen atoms, or acid anhydrides having an aromatic or alicyclic skeleton, aqueous additives of the acid anhydrides, or modified products of the acid anhydrides, with phenolic resin being a particularly preferred curing agent. By using this preferred curing agent, a resin sheet with an excellent balance of heat resistance, moisture resistance, and electrical properties can be obtained. Only one type of curing agent may be used, or two or more types may be used in combination.

[0089] The phenolic resin described above is not particularly limited. Specific examples of the phenolic resin include phenol novolac, o-cresol novolac, p-cresol novolac, t-butylphenol novolac, dicyclopentadiene cresol, poly-p-vinylphenol, bisphenol A type novolac, xylylene-modified novolac, decalin-modified novolac, poly(di-o-hydroxyphenyl)methane, poly(di-m-hydroxyphenyl)methane, or poly(di-p-hydroxyphenyl)methane. In particular, to further enhance the flexibility and flame retardancy of the resin sheet and improve the mechanical properties and heat resistance of the resin sheet, novolac-type phenolic resins having a rigid main skeleton or phenolic resins having a triazine skeleton are preferred, or to improve the flexibility of the uncured sheet and the toughness of the resin sheet, phenolic resins having allyl groups are preferred.

[0090] When the resin composition according to this disclosure contains a curing agent, the content of the curing agent in the resin composition forming the resin sheet according to this disclosure is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on 100% by mass of the total solids content of the resin composition excluding the thermal conductive filler. Furthermore, the combination of the upper and lower limits is not particularly limited, but it is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less. When the curing agent content is above the lower limit, sufficient curing performance tends to be obtained. Furthermore, when it is below the upper limit, the reaction proceeds effectively, the crosslinking density can be improved, the strength can be increased, and the film-forming properties tend to be improved.

[0091] In the resin composition, the curing agent content is preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and even more preferably 3.0% by mass or more, based on the total mass of the resin composition. In the resin composition, the curing agent content is preferably 6.5% by mass or less, more preferably 6.0% by mass or less, and even more preferably 5.5% by mass or less, based on the total mass of the resin composition. Furthermore, the combination of upper and lower limits is not particularly limited, but 2.0% by mass or more and 6.5% by mass or less is preferred, 2.5% by mass or more and 6.0% by mass or less is more preferred, and 3.0% by mass or more and even more preferably 5.5% by mass or less. If the curing agent content is above the lower limit, the curing time can be reduced. If the curing agent content is below the upper limit, the mechanical properties at high temperatures can be maintained.

[0092] (Thermosetting catalyst) The resin composition may contain a thermosetting catalyst as a curing accelerator to adjust the curing speed, the physical properties of the resin sheet, etc., as needed.

[0093] The thermosetting catalyst is preferably selected appropriately depending on the type of thermosetting resin component and curing agent. Specific examples of thermosetting catalysts include linear or cyclic tertiary amines, organophosphorus compounds, diazabicycloalkenes such as quaternary phosphonium salts or organic acid salts, and imidazoles. Organometallic compounds, quaternary ammonium salts, or metal halides can also be used. Examples of the above organometallic compounds include zinc octoate, tin octoate, or aluminum acetylacetone complexes. These may be used individually or in combination of two or more.

[0094] In particular, compounds containing imidazole (hereinafter sometimes referred to as "imidazole compounds") are preferred from the viewpoint of storage stability, heat resistance, and curing speed. Preferred imidazole compounds include, for example, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2, Examples include 4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. From the viewpoint of obtaining a resin sheet with excellent storage stability and adhesion, the melting point of the imidazole compound is preferably 100°C or higher, and more preferably 200°C or higher. Furthermore, a compound containing nitrogen-containing heterocyclic compounds other than the imidazole ring mentioned above is even more preferable from the viewpoint of adhesion.

[0095] The thermosetting catalyst content is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, based on 100% by mass of the total solids content of the resin composition excluding the thermally conductive filler. The thermosetting catalyst content is preferably 10% by mass or less, and more preferably 5% by mass or less, based on 100% by mass of the total solids content of the resin composition excluding the thermally conductive filler. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. If the thermosetting catalyst content is above the lower limit, the curing reaction can be sufficiently promoted and cured well, and if it is below the upper limit, the curing speed will not be too fast, and therefore the storage stability of the resin composition can be improved.

[0096] In the resin composition, the content of the thermosetting catalyst is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, based on the total mass of the resin composition. In the resin composition, the content of the thermosetting catalyst is preferably 2.5% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less, based on the total mass of the resin composition. Furthermore, the combination of the upper and lower limits is not particularly limited, but is preferably 0.1% by mass or more and 2.5% by mass or less, more preferably 0.2% by mass or more and 2.0% by mass or less, and even more preferably 0.3% by mass or more and 1.5% by mass or less. If the content of the thermosetting catalyst is above the lower limit, proper curing can be achieved. If the content of the thermosetting catalyst is below the upper limit, the handling properties of the sheet can be improved.

[0097] (Thermal Conductive Filler) The thermal conductive filler included in the resin sheet can be any filler with thermal conductivity without restriction, but to maintain the insulation properties of the sheet, a highly insulating filler is used. In power semiconductor applications, insulation is required, so the thermal conductive filler has a volume resistivity of 1 × 10⁻⁶. １３ Ω·cm or larger, especially 1 × 10⁻⁶ １４It is preferable that the inorganic filler has excellent insulating properties of Ω·cm or more. Among these, oxides and nitrides are more preferable because the electrical insulation of the resin sheet is sufficient. More specifically, such a thermally conductive filler is alumina (Al ２ O ３ Volume resistivity 1 × 10 １４ Ω·cm), aluminum nitride (AlN, volume resistivity 1 × 10⁻⁶ １４ Ω·cm), Boron nitride (BN, volume resistivity 1 × 10⁻⁶ １４ Ω·cm), silicon nitride (Si ３ N ４ Volume resistivity 1 × 10 １４ Ω·cm), silica (SiO ２ Volume resistivity 1 × 10 １４ Examples include Ω·cm, among which alumina, aluminum nitride, and boron nitride are preferred, and alumina and boron nitride are more preferred.

[0098] When using an inorganic filler as a thermally conductive filler, the inorganic filler may be surface-treated with a surface treatment agent. Any known surface treatment agent can be used. The inorganic filler may be used alone, or two or more types may be mixed in any combination and ratio. From the viewpoint of high thermal conductivity and ease of handling, the thermally conductive filler preferably contains boron nitride particles, more preferably boron nitride aggregate particles, and even more preferably boron nitride aggregate particles having a cardhouse structure. The cardhouse structure is described, for example, in Ceramics 43 No. 2 (published by the Ceramics Society of Japan in 2008), and is a structure in which plate-like particles are not oriented and are intricately stacked. More specifically, boron nitride aggregate particles having a cardhouse structure are aggregates of primary boron nitride particles, and are boron nitride aggregate particles having a structure in which the planar portion and end face portion of the primary particles are in contact. The aggregation morphology of boron nitride aggregate particles can be confirmed by scanning electron microscopy (SEM).

[0099] Boron nitride aggregated particles are formed by the aggregation of primary BN particles, preferably h-BN (hexagonal boron nitride) primary particles. As described above, the boron nitride aggregated particles preferably have a cardhouse structure and, more preferably, satisfy the physical properties described later; however, the manufacturing method is not limited. Such boron nitride aggregated particles can be manufactured, for example, by the method described in International Publication No. 2015 / 119198.

[0100] Boron nitride aggregated particles have a maximum particle size D based on volume. ｍａｘ There are no particular restrictions on the particle size (hereinafter sometimes referred to as "maximum particle diameter"), but it is preferably 20 μm or more, more preferably 30 μm or more, even more preferably 40 μm or more, preferably 300 μm or less, more preferably 200 μm or less, even more preferably 100 μm or less, and particularly preferably 90 μm or less. Furthermore, there are no particular restrictions on the combination of upper and lower limits, but it is preferably 20 μm or more and 300 μm or less, more preferably 30 μm or more and 200 μm or less, even more preferably 40 μm or more and 100 μm or less, and particularly preferably 40 μm or more and 90 μm or less. Regarding the particle size of the boron nitride aggregated particles, by increasing the particle size, the heat transfer path between the thermally conductive filler via the thermosetting resin with low thermal conductivity can be reduced, and therefore the increase in thermal resistance in the heat transfer path in the thickness direction can be reduced. From this viewpoint, it is preferable that the maximum particle diameter of the boron nitride aggregated particles is within the above range.

[0101] Furthermore, the average particle diameter D of boron nitride aggregated particles is based on volume. ５０There are no particular restrictions on the average particle diameter (hereinafter sometimes referred to as "average particle size"), but it is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, preferably 100 μm or less, and even more preferably 90 μm or less. Furthermore, there are no particular restrictions on the combination of the upper and lower limits, but it is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 15 μm or more and 90 μm or less. When the average particle diameter is above the lower limit, the number of particles in the resin sheet is relatively small, so the number of interparticle interfaces is small, which reduces thermal resistance and can increase the thermal conductivity of the resin sheet. Also, when the average particle diameter is below the upper limit, the surface smoothness of the resin sheet can be improved.

[0102] The average particle size mentioned above refers to the particle size at which the cumulative volume reaches 50% when a cumulative curve is drawn with the volume of the boron nitride aggregated particles subjected to measurement set to 100%, and the maximum particle size mentioned above refers to the maximum particle size when such a cumulative curve is drawn. Specifically, one method is to measure the particle size distribution using a laser diffraction / scattering particle size analyzer on a sample in which boron nitride aggregated particles are dispersed in a pure water medium containing naphthalene sulfonate / formaldehyde condensate as a dispersion stabilizer.

[0103] The content of boron nitride aggregated particles in the thermally conductive member (resin sheet) of this disclosure is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, per 100% by mass of the resin sheet. Furthermore, the combination of upper and lower limits is not particularly limited, but it is preferably 30% by mass or more and 99% by mass or less, more preferably 40% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less. Furthermore, the content of boron nitride aggregated particles in the resin composition forming the resin sheet of this disclosure is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, preferably 99% by mass or less, even more preferably 90% by mass or less, and even more preferably 80% by mass or less, per 100% by mass of the resin composition. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 30% by mass or more and 99% by mass or less, more preferably 40% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less. When the content of boron nitride aggregated particles is above the lower limit, it tends to be possible to sufficiently obtain the effect of improving thermal conductivity and controlling the coefficient of linear expansion due to the inclusion of boron nitride aggregated particles. Also, when it is below the upper limit, it tends to improve the moldability of the resin sheet and the interfacial adhesion in the laminated structure.

[0104] When other inorganic fillers are used in combination with boron nitride aggregates as a thermally conductive filler, the ratio of boron nitride aggregates to other inorganic fillers in the resin composition is not particularly limited, but is preferably 90:10 to 10:90 by mass, and more preferably 80:20 to 20:80. The other inorganic fillers preferably include alumina particles, and in particular spherical alumina particles.

[0105] In the resin composition, the content of the thermally conductive filler is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, based on the total mass of the resin composition. In the resin composition, the content of the thermally conductive filler is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, based on the total mass of the resin composition. Furthermore, the combination of the upper and lower limits is not particularly limited, but 50% by mass or more and 95% by mass or less is preferred, 55% by mass or more and 90% by mass or less is more preferred, and 60% by mass or more and even more preferably 80% by mass or less. If the content of the thermally conductive filler is above the lower limit, thermal conductivity can be maintained. If the content of the thermally conductive filler is below the upper limit, insulation resistance can be maintained.

[0106] (Organic Solvents) The resin composition according to this disclosure may contain an organic solvent, for example, to improve the coatability when forming a resin sheet through a coating process. Examples of organic solvents that the resin composition according to this disclosure may contain include methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether acetate, butyl acetate, isobutyl acetate, and propylene glycol monomethyl ether. These organic solvents may be used individually or in combination of two or more.

[0107] If the resin composition according to this disclosure contains an organic solvent, the amount thereof is appropriately determined according to the handling requirements during the production of the resin sheet. If the resin composition is in the form of a slurry to be used in the coating process, the organic solvent is used such that the solid content (total of components other than the solvent) concentration in the resin composition according to this disclosure is preferably 10% by mass or more, more preferably 40% by mass or more, preferably 90% by mass or less, and more preferably 80% by mass or less. Furthermore, the combination of upper and lower limits is not particularly limited, but it is preferably used so that it is 10% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 80% by mass or less.

[0108] (Other Components) The resin composition forming the resin sheet of this disclosure may contain other components not mentioned above, to the extent that they do not impair the effects of this disclosure. Examples of other components include additives such as silane coupling agents that improve the interfacial adhesion strength between the thermally conductive filler and the resin component, which may be used when manufacturing the resin sheet using the resin composition; insulating carbon components such as reducing agents; viscosity modifiers; dispersants; thixotropic agents; flame retardants; and colorants.

[0109] The thickness of the layer 21 containing the thermal conductive member is not particularly limited, but is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 100 μm or more. The thickness of the layer 21 containing the thermal conductive member is not particularly limited, but is preferably 1,000 μm or less, more preferably 800 μm or less, even more preferably 600 μm or less, and particularly preferably 400 μm or less. Furthermore, the combination of upper and lower limit values ​​is not particularly limited, but is preferably 50 μm or more and 1,000 μm or less, more preferably 75 μm or more and 800 μm or less, even more preferably 100 μm or more and 600 μm or less, and particularly preferably 100 μm or more and 400 μm or less. When the thickness of the layer 21 containing the thermal conductive member is within the above range, the heat dissipation performance can be more fully exhibited. The thickness of the layer 21 containing the thermal conductive member is determined by measuring the thickness at five randomly selected locations using a micrometer in the area in contact with the layer 22 containing the compression deformation member, and averaging the result. Here, the thickness of the layer 21 containing the thermal conductive member refers to the thickness of the layer 21 itself, which is located between the heat sink 1 and the power semiconductor package 3.

[0110] <Other Layers> In addition to the above-mentioned components, other layers consisting of grease, adhesive, etc., may be provided between each component. For example, these other layers may be present between layer 21 containing the thermal conductive component and layer 22 containing the compression deformation component, between layer 22 containing the compression deformation component and the power semiconductor package 3, or between layer 22 containing the compression deformation component and the heat sink 1. Note that this disclosure is not limited to the embodiment shown in Figure 1.

[0111] Figure 3 is a cross-sectional view showing an example of a top-surface heat-dissipating power semiconductor module of the present disclosure. In Figure 3, the heat-dissipating laminate 2 is arranged such that the layer 21 containing the thermal conductive member faces the heat sink 1, similar to Figure 1. In Figure 3, the layer 22 containing the compression deformation member is a layer consisting only of the compression deformation member, which is a gap filler, and is laminated on the top surface of the power semiconductor package 3 and arranged to cover the side surface of the power semiconductor package 3.

[0112] Figure 4 is a cross-sectional view showing another example of a top-surface heat-dissipating power semiconductor module of the present disclosure. In Figure 4, the heat-dissipating laminate 2 is arranged such that, contrary to Figure 3, the layer 22 containing the compression-deformable member faces the heat sink 1. In Figure 4, the layer 22 containing the compression-deformable member is a layer consisting only of the compression-deformable member, which is a gap filler, laminated on the upper surface of the layer 21 containing the thermal conductive member, and arranged to cover the side surface of the power semiconductor package 3.

[0113] In the cross-sectional views of Figures 3 and 4, the layer 22 including the compression deformation member covers the outer lead 33, but it does not have to cover the outer lead 33, as shown in Figures 5 and 6 later. In particular, when using multiple power semiconductor packages 3, it is preferable to use the layer 22 including the compression deformation member after insulating each power semiconductor package 3, as shown in Figure 6. Also, in the cross-sectional views of Figures 3 and 4, the layer 22 including the compression deformation member is arranged to cover the side surface of the power semiconductor package 3, but it does not have to be arranged to cover the side surface.

[0114] Figure 5 is a cross-sectional view showing an example of a top-surface heat-dissipating power semiconductor module of the present disclosure. In Figure 5, the heat-dissipating laminate 2 is arranged such that the layer 21 containing the thermal conductive member faces the heat sink 1, similar to Figure 3. In Figure 5, the layer 22 containing the compression deformation member is a layer consisting only of the compression deformation member, which is a graphite sheet. The heat-dissipating laminate 2 is formed by laminating a layer containing the plate-shaped thermal conductive member layer 21 and a layer containing the plate-shaped compression deformation member layer 22.

[0115] Figure 6 is a cross-sectional view showing another example of a top-surface heat-dissipating power semiconductor module of the present disclosure. In Figure 6, the heat-dissipating laminate 2 is arranged such that, contrary to Figure 3, the layer 22 containing the compression-deformable member faces the heat sink 1. In Figure 6, the layer 22 containing the compression-deformable member is a layer consisting only of the compression-deformable member, which is a graphite sheet. A layer containing a plate-shaped thermal conductive member (layer 21) and a layer containing a plate-shaped compression-deformable member (layer 22) are laminated to form the heat-dissipating laminate 2.

[0116] (Method for manufacturing a heat-dissipating laminate) The heat-dissipating laminate 2 can be manufactured by laminating a layer 22 containing a compressible member and a layer 21 containing a thermally conductive member. Alternatively, the layer 22 containing the compressible member and the layer 21 containing the thermally conductive member may be integrally molded. (Method for manufacturing a layer containing a compressible member) The method for manufacturing the layer 22 containing the compressible member is not particularly limited, and commercially available materials can be used as is. (Method for manufacturing a layer 21 containing a thermally conductive member) Next, as a representative example of the method for manufacturing a layer 21 containing a thermally conductive member according to this embodiment, a method for manufacturing a resin sheet that can be used as a thermally conductive member is shown, but the product is not limited to those manufactured by these methods as long as it has the configuration described above.

[0117] (Method for Manufacturing Resin Sheets) The method for manufacturing the thermally conductive member (resin sheet) of this disclosure is not particularly limited, but the resin composition according to this disclosure is formed into a sheet (hereinafter sometimes referred to as the "film forming step"), dried as necessary (hereinafter sometimes referred to as the "drying step"), and further pressurized as necessary (hereinafter sometimes referred to as the "pressurization step"). If necessary, low-temperature aging is performed after the drying step and pressurization step by placing the sheet in a temperature environment of 0°C or lower (hereinafter sometimes referred to as the "low-temperature aging step"). Then, the sheet-like resin composition obtained in this way is cured (hereinafter sometimes referred to as the "curing step") to produce a resin sheet.

[0118] In the film-forming process, for example, a slurry-like resin composition according to the present disclosure is formed into a sheet by a coating method such as the blade method, a solvent casting method, or an extrusion film formation method. When forming a sheet by the above coating method, first the slurry-like resin composition according to the present disclosure is applied to the surface of a substrate such as a PET film to form a coating film. That is, a coating film is formed on the substrate using the slurry-like resin composition according to the present disclosure by a dip method, spin coating method, spray coating method, blade method, or any other method. For applying the slurry-like resin composition according to the present disclosure, coating devices such as spin coaters, slit coaters, die coaters, and blade coaters can be used. With such coating devices, it is possible to uniformly form a coating film of a predetermined thickness on the substrate.

[0119] In the drying process, the resin composition according to the disclosure, which has been formed into a sheet-like film as described above, is preferably dried at a temperature of 10°C or higher, more preferably 25°C or higher, even more preferably 30°C or higher, and preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 110°C or lower, in order to remove solvents and low molecular weight components. Furthermore, while the combination of upper and lower limits is not particularly limited, it is preferably 10°C to 150°C, more preferably 25°C to 120°C, and even more preferably 30°C to 110°C. When the drying temperature is below the upper limit, the hardening of the resin in the resin composition according to the disclosure is suppressed, and in the subsequent pressurizing process, the resin in the sheet-like resin composition according to the disclosure tends to flow, making it easier to remove voids. When the drying temperature is above the lower limit, the solvent can be effectively removed, and productivity tends to improve. The drying time is not particularly limited and can be adjusted as appropriate depending on the state of the resin composition according to the disclosure, the drying environment, etc. The drying time is preferably 1 minute or more, more preferably 2 minutes or more, even more preferably 5 minutes or more, preferably 24 hours or less, more preferably 10 hours or less, even more preferably 4 hours or less, and particularly preferably 2 hours or less. The combination of upper and lower limits is not particularly limited, but it is preferably 1 minute or more and 24 hours or less, more preferably 2 minutes or more and 10 hours or less, even more preferably 5 minutes or more and 4 hours or less, and particularly preferably 5 minutes or more and 2 hours or less. When the drying time is above the lower limit, the solvent can be sufficiently removed and the formation of voids in the resin sheet by residual solvent tends to be suppressed. When the drying time is below the upper limit, productivity tends to be improved and manufacturing costs tend to be suppressed.

[0120] In the pressurization step, it is desirable to apply pressure to the sheet-like resin composition according to the present disclosure after the drying step for purposes such as bonding the thermally conductive fillers together to form thermal conduction paths, eliminating voids and air gaps within the resin sheet, and improving adhesion to the substrate. However, pressurization may be omitted depending on the purpose. In the pressurization step, it is desirable to apply a load of 2 MPa or more to the sheet-like resin composition according to the present disclosure on the substrate. The load is preferably 5 MPa or more, more preferably 7 MPa or more, and even more preferably 9 MPa or more. Furthermore, the load is preferably 1,500 MPa or less, more preferably 1,000 MPa or less, and even more preferably 800 MPa or less. Furthermore, the combination of upper and lower limits is not particularly limited, but the load is preferably 5 MPa or more and 1,500 MPa or less, more preferably 7 MPa or more and 1,000 MPa or less, and even more preferably 9 MPa or more and 800 MPa or less. By setting the load during pressurization to below the above upper limit, a sheet with high thermal conductivity can be obtained that is free of voids in the sheet-like resin composition according to this disclosure, without the secondary particles of the boron nitride aggregate particles being destroyed. By setting the load to above the above lower limit, contact between the thermally conductive fillers is improved, making it easier to form thermal conduction paths, thus enabling the acquisition of a resin sheet with high thermal conductivity. The heating temperature of the sheet-like resin composition according to this disclosure on the substrate during the pressurization process is not particularly limited. The heating temperature is preferably 10°C or higher, more preferably 20°C or higher, and even more preferably 30°C or higher. The heating temperature is preferably 300°C or lower, more preferably 250°C or lower, even more preferably 200°C or lower, and particularly preferably 100°C or lower. Furthermore, the combination of the upper and lower limits is not particularly limited, but the heating temperature is preferably 10°C to 300°C, more preferably 20°C to 250°C, even more preferably 30°C to 200°C, and particularly preferably 30°C to 100°C.By performing the pressurization process within the above temperature range, the melt viscosity of the resin in the sheet-like resin composition according to this disclosure can be reduced, thereby further reducing voids and air pockets in the resin sheet. Furthermore, heating below the above upper limit tends to suppress the decomposition of organic components in the resin sheet and the generation of voids due to residual solvents. The duration of the pressurization process is not particularly limited. Preferably, the pressurization process duration is 30 seconds or more, more preferably 1 minute or more, even more preferably 3 minutes or more, and particularly preferably 5 minutes or more. Preferably, the pressurization process duration is 1 hour or less, more preferably 30 minutes or less, and even more preferably 20 minutes or less. Furthermore, while the combination of upper and lower limits is not particularly limited, the pressurization process duration is preferably 30 seconds or more and 1 hour or less, more preferably 1 minute or more and 30 minutes or less, even more preferably 3 minutes or more and 20 minutes or less, and particularly preferably 5 minutes or more and 20 minutes or less. By keeping the pressurization time below the above upper limit, the manufacturing time of the resin sheet can be reduced, and production costs tend to be lowered. When the pressurization time is above the lower limit mentioned above, voids and air pockets within the resin sheet can be sufficiently removed, which tends to improve thermal conductivity and dielectric strength.

[0121] In the low-temperature aging process, the ambient temperature is preferably lower because a faster cooling rate results in the formation of finer ice crystals. From this viewpoint, it is preferable that the temperature be 0°C or lower, more preferably -5°C or lower, even more preferably -10°C or lower, and particularly preferably -15°C or lower. On the other hand, if the temperature is too low, it will fall below the glass transition temperature (Tg) of the uncured thermosetting sheet, making it prone to cracking. Therefore, it is preferable that the temperature be -50°C or higher, and if epoxy resin is included, more preferably -30°C or higher, and even more preferably -25°C or higher. Furthermore, there are no particular limitations on the combination of upper and lower limits, but it is preferable that the temperature be between -50°C and 0°C, more preferably -30°C and -5°C, even more preferably -25°C and -10°C, and particularly preferably -25°C and -15°C. The duration of the low-temperature aging is not particularly limited as long as the resin composition is frozen. Rapid freezing and holding for 10 minutes or more is sufficient, preferably 30 minutes or more, more preferably 1 hour or more, even more preferably 2 hours or more, most preferably 4 hours or more, most preferably 8 hours or more, most preferably 16 hours or more, and most preferably 24 hours or more. On the other hand, since epoxy resin reacts gradually even at low temperatures, from the viewpoint of avoiding leaving it for a long period of time, it is preferable to keep it for 365 days or less, more preferably 180 days or less, even more preferably 90 days or less, most preferably 30 days or less, and most preferably 7 days or less. Furthermore, there are no particular limitations on the combination of upper and lower limits, but rapid freezing and holding for 10 minutes to 365 days or less is sufficient, preferably 30 minutes to 180 days or less, more preferably 1 hour to 90 days or less, even more preferably 2 hours to 30 days or less, most preferably 4 hours to 7 days or less, most preferably 8 hours to 7 days or less, most preferably 16 hours to 7 days or less, and most preferably 24 hours to 7 days or less. While it is not necessary to apply pressure during the low-temperature aging process, applying a small pressure of 0.1 kPa or less is acceptable.

[0122] In the curing process, curing can be achieved by heating. The heating temperature is preferably 30°C or higher, more preferably 50°C or higher, even more preferably 90°C or higher, preferably 400°C or lower, more preferably 300°C or lower, and even more preferably 250°C or lower. While the combination of upper and lower limits is not particularly limited, it is preferably 30°C to 400°C, more preferably 50°C to 300°C, and even more preferably 90°C to 250°C. The curing process, which allows the resin composition according to this disclosure to undergo a complete curing reaction, may be carried out under pressure or without pressure. If pressure is applied, it is desirable to carry it out under the same conditions as the pressure application process for the same reasons as above. The pressure application and curing process may be carried out simultaneously. In particular, in the sheet formation process, which involves both the pressure application and the curing process, it is preferable to apply a load within the above range and then apply pressure and perform curing. During this process, the sheet may be bonded to other components besides the layer 21 containing the thermal conductive member. The load applied when the pressure application and curing process are carried out simultaneously is not particularly limited. In this case, the load applied to the sheet-like resin composition according to the present disclosure on the substrate is preferably 5 MPa or more, more preferably 7 MPa or more, even more preferably 9 MPa or more, and particularly preferably 20 MPa or more. Furthermore, the load is preferably 2,000 MPa or less, and more preferably 1,500 MPa or less. While the combination of upper and lower limits is not particularly limited, it is preferably 5 MPa to 2,000 MPa, more preferably 7 MPa to 2,000 MPa, even more preferably 9 MPa to 1,500 MPa, and particularly preferably 20 MPa to 1,500 MPa. By setting the load applied when the pressurizing process and curing process are performed simultaneously to be below the above upper limits, a resin sheet with high thermal conductivity can be obtained without voids in the sheet-like resin composition according to the present disclosure, without the secondary particles of boron nitride aggregate particles being destroyed. Furthermore, by setting the load above the lower limit mentioned above, contact between the thermally conductive fillers is improved, making it easier to form thermal conduction paths, thus enabling the production of a resin sheet with high thermal conductivity.The pressurizing time when the pressurizing and curing processes are performed simultaneously is not particularly limited. The pressurizing time is preferably 30 seconds or more, more preferably 1 minute or more, even more preferably 3 minutes or more, and particularly preferably 5 minutes or more. Furthermore, the pressurizing time is preferably 1 hour or less, more preferably 30 minutes or less, and even more preferably 20 minutes or less. Furthermore, the combination of the upper and lower limits is not particularly limited, but it is preferably 30 seconds or more and 1 hour or less, more preferably 1 minute or more and 30 hours or less, even more preferably 3 minutes or more and 20 minutes or less, and particularly preferably 5 minutes or more and 20 minutes or less. When the pressurizing time is below the above upper limit, the manufacturing time of the resin sheet can be suppressed and production costs tend to be reduced. When the pressurizing time is above the above lower limit, voids and air pockets in the resin sheet can be sufficiently removed, and thermal conductivity and dielectric strength tend to be improved.

[0123] ≪Manufacturing Method for Top-Surface Heat Dissipation Power Semiconductor Modules≫ The manufacturing method for top-surface heat dissipation power semiconductor modules of the present disclosure is not particularly limited and can be manufactured by known methods, for example, by stacking the components.

[0124] <<Applications of Top-Surface Heat Dissipation Power Semiconductor Modules>> The top-surface heat dissipation power semiconductor module disclosed herein can be used in electric vehicles, onboard chargers, EV chargers, solar power generation, power supply devices, data centers (storage systems), etc., and is preferably used in electric vehicles.

[0125] ≪Power Generation System for Electric Vehicles≫ The power generation system for electric vehicles of this disclosure is equipped with the top-surface heat-dissipating power semiconductor module of this disclosure.

[0126] ≪Electric Vehicles≫ The electric vehicles of this disclosure are equipped with the electric vehicle power generation system of this disclosure.

[0127] ≪Heat Dissipating Laminate≫ The heat dissipating laminate of the first embodiment of this disclosure is used as a heat dissipating laminate in the top-surface heat dissipating power semiconductor module of the first embodiment of this disclosure. The heat dissipating laminate 2 of the first embodiment of this disclosure has a layer 22 including a compression deformation member and a layer 21 including a thermal conductive member. In the heat dissipating laminate 2 of the first embodiment of this disclosure, the layer including the layer 22 including the compression deformation member may be a layer consisting only of the compression deformation member. Also, the layer including the layer 21 including the thermal conductive member may be a layer consisting only of the thermal conductive member.

[0128] A heat-dissipating laminate according to a second aspect of the present disclosure is used as a heat-dissipating laminate in a top-surface heat-dissipating power semiconductor module according to a second aspect of the present disclosure. The heat-dissipating laminate 2 according to a second aspect of the present disclosure has a layer 22 including a compression-deformable member and a layer 21 including a thermally conductive member. In the heat-dissipating laminate 2 according to a second aspect of the present disclosure, the layer 22 including the compression-deformable member may consist only of the compression-deformable member. Also, the layer 21 including the thermally conductive member may consist only of the thermally conductive member.

[0129] Examples of the heat-dissipating laminate 2 in this disclosure include those similar to those described above as the heat-dissipating laminate 2 in the top-surface heat-dissipating power semiconductor module of this disclosure. That is, the specific embodiments and preferred embodiments of the heat-dissipating laminate 2 in this disclosure are the same as the heat-dissipating laminate 2 in the top-surface heat-dissipating power semiconductor module of this disclosure, and all of these can be applied.

[0130] ≪Resin Sheet≫ The resin sheet of this disclosure is used as a thermal conductive member in the heat-dissipating laminate 2 of this disclosure. Examples of the resin sheet of this disclosure include those similar to those described above as a preferred embodiment of the thermal conductive member in the top-surface heat-dissipating power semiconductor module of this disclosure. That is, the specific embodiments and preferred embodiments of the resin sheet of this disclosure are the same as the resin sheet listed as a thermal conductive member in the top-surface heat-dissipating power semiconductor module of this disclosure, and all of these can be applied.

[0131] The present disclosure will be described in detail below by examples, but the present disclosure is not limited to the following statements.

[0132] <<Thermal Conductive Components>> [Raw Materials] The raw materials used in the examples as thermal conductive components were as follows:

[0133] <Thermal Conductivity Filler> Thermal Conductivity Filler 1: Spherical boron nitride aggregate particles having a cardhouse structure, manufactured in accordance with the method for manufacturing boron nitride aggregate particles disclosed in the examples of International Publication No. 2015 / 119198, with a maximum particle diameter (D ｍａｘ ): 90 μm Average particle diameter (D ５０ ): 45 μm Maximum particle size of thermal conductive filler 1 (D ｍａｘ ) and average particle diameter (D ５０ ) is determined by dispersing a thermally conductive filler in a pure water medium containing sodium hexametaphosphate as a dispersion stabilizer, measuring the volume-based particle size distribution using a laser diffraction / scattering particle size distribution analyzer LA-300 (manufactured by Horiba, Ltd.), and determining the maximum particle diameter (D) from the obtained particle size distribution. ｍａｘ ) and cumulative volume 50% particle diameter (average particle diameter (D ５０ )) is. Thermally conductive filler 2: Boron nitride aggregated particles (Momentive PTX60, average particle size (D ５０ ): 55 μm or more and 65 μm or less) Thermally conductive filler 3: Boron nitride aggregated particles (Saint-Gobain CTS7M, average particle size (D ５０ ): 120 μm)

[0134] <Matrix Resins> Matrix Resin 1: Manufactured by Mitsubishi Chemical Corporation, a biphenyl-type solid epoxy compound, containing two glycidyl groups in one molecule, mass-average molecular weight (Mw): approximately 400, epoxy equivalent (WPE): 200 g / equivalent. Matrix Resin 2: Manufactured by Nagase ChemteX Corporation, a polyfunctional epoxy compound containing a structure with four or more glycidyl groups in one molecule, and does not contain amine-based or amide-based structures containing nitrogen atoms. Mass-average molecular weight (Mw): Approximately 400 Epoxy equivalent (WPE): 100 g / equivalent Matrix resin 3: Manufactured by Mitsubishi Chemical Corporation, 157S70 Epoxy equivalent (WPE): 200 g / equivalent or more and 220 g / equivalent or less Matrix resin 4: Manufactured by Mitsubishi Chemical Corporation, E828, bisphenol A type liquid epoxy compound, having two glycidyl groups in one molecule Matrix resin 5: Manufactured by Mitsubishi Chemical Corporation, a bifunctional epoxy polymer disclosed as resin component 1 in Japanese Patent Application Publication No. 2020-63438, having the above structure (2) and structure (3), and R in formula (2) ３ R in structure (4) and equation (3) ４ , R ５ , R ６ , R ７ All were methyl groups. Mass-average molecular weight (Mw) in polystyrene equivalent: 30,000 Epoxy equivalent (WPE): 9,000 g / equivalent Matrix resin 6: Manufactured by Mitsubishi Chemical Corporation, jER4275 Mass-average molecular weight (Mw) in polystyrene equivalent: 60,000 Epoxy equivalent (WPE): 9,000 g / equivalent

[0135] <Hardening Agents> Hardening agent 1: "H-4" manufactured by UBE Corporation, phenol resin-based hardening agent (phenol novolac) Hardening agent 2: "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd., phenol resin-based hardening agent (allylphenol novolac)

[0136] <Thermosetting Catalysts> Thermosetting catalyst 1: 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine; structure derived from imidazole; possesses both structures derived from triazine in a single molecule (manufactured by Shikoku Chemicals Co., Ltd., "Cureazole 2E4MZ-A") Thermosetting catalyst 2: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals Co., Ltd., "Cureazole 2PHZ-PW") Thermosetting catalyst 3: 1-cyanoethyl-2-undecylimidazole (manufactured by Shikoku Chemicals Co., Ltd., "Cureazole C11Z-CN")

[0137] [Sample Preparation] The method for preparing the sample used in the example as a thermally conductive member was as follows. A thermally conductive member (sheet-like cured material) was obtained by curing the following sheet-like resin composition.

[0138] <Examples 1-6> Each raw material was weighed to obtain the composition (parts by mass) shown in Table 1, and mixed using a rotation-and-revolution type stirrer to obtain a mixture. When preparing this mixture, a slurry-like resin composition was prepared using 20% ​​by mass each of methyl ethyl ketone and cyclohexanone so that the above mixture constituted 60% by mass (solid content concentration) of the coating slurry. The obtained slurry-like resin composition was applied to a PET substrate using the doctor blade method and heated and dried at 60°C (heating atmosphere temperature) for 120 minutes to obtain a sheet-like resin composition. The total content of methyl ethyl ketone and cyclohexanone in the sheet-like resin composition was 1% by mass or less. The obtained slurry-like resin composition was applied to a PET substrate using the doctor blade method and heated and dried at 60°C (heating atmosphere temperature) for 120 minutes to obtain a sheet-like resin composition. The total content of methyl ethyl ketone and cyclohexanone in the sheet-like resin composition was 1% by mass or less. Next, for Examples 1 to 3, the sheet-like resin composition was placed in a vacuum-sealed bag, the air inside the bag was removed, and the opening of the bag was heat-sealed to seal it. Then, the bag was stored in a freezer at -20°C for 72 hours to perform low-temperature aging.

[0139] [Measurement of Samples] The measurement method for the samples used in the examples as thermally conductive materials was as follows.

[0140] <Thermal Conductivity> The sheet-like resin compositions prepared in each example were cured by heating them at 175°C (product temperature) for 30 minutes, followed by heating them at 200°C (product temperature) for 30 minutes, while applying pressure at 10 MPa, to obtain sheet-like cured products. Furthermore, four types of sheet-like cured products with different thicknesses were obtained by stacking two, three, or four sheets of the sheet-like resin composition prepared in each example and applying pressure and heating them in the same manner as above. For these four types of sheet-like cured products with different thicknesses, the thermal conductivity at 25°C in the sheet thickness direction was measured using the steady-state method, based on the slope represented by the thermal resistance value with respect to the sheet thickness (according to ASTM D5470). (1) Thickness: Thickness (μm) when pressed at a press pressure of 3400 kPa using a Mentor Graphics T3Ster-DynTIM. (2) Measurement area: Area (cm²) of the heat-transferring portion when measured using a Mentor Graphics T3Ster-DynTIM. ２ (3) Thermal resistance: The thermal resistance (K / W) was measured when pressing with a press pressure of 3400 kPa using a T3Ster-DynTIM manufactured by Mentor Graphics. (4) Thermal conductivity: The thermal resistance of four types of sheet-like cured materials (samples) with different thicknesses was measured, and the thermal conductivity (W / m·K) was calculated from the following formula. Formula: Thermal conductivity (W / m·K) = 1 / ((Slope (thermal resistance / thickness): K / (W·μm)) × (Area: cm ２ )) × 10 －２

[0141] <Dielectric Breakdown Voltage> The sheet-like resin compositions prepared in each example were placed on a 2 mm thick copper plate and heated at 175°C (product temperature) for 30 minutes under pressure of 10 MPa, followed by heating at 200°C (product temperature) for 30 minutes to bond them by heat and pressure curing. A composite molded body (evaluation sample) was then prepared by laminating the cured sheet-like material onto the copper plate. The composite molded body (evaluation sample) was immersed in insulating oil (3M's "Fluorinert FC-40"), and using a super high voltage withstand voltage tester 7470 (manufactured by Keisoku Gijutsu Kenkyusho Co., Ltd.), electrodes were placed on a patterned φ25 mm copper plate, a voltage of 0.5 kV was applied, and the voltage was increased by 500 V every minute until the cured sheet-like material broke down (BDV: dielectric breakdown voltage).

[0142] <Film Thickness> The thickness was measured at five randomly selected locations using a micrometer, and the average value was used as the thickness.

[0143] [Evaluation Results of Samples] Table 1 shows the evaluation results of the samples used in the examples as thermally conductive members.

[0144]

[0145] <<Compression Deformation Member>> [Raw Materials] The following materials were used as compression deformation members in the example: Gap filler 1: Tflex manufactured by Laird ＴＭ HD300" Graphite Sheet 1: Panasonic's "PGS Graphite Sheet (GraphiteTIM) EYGR type"

[0146] [Measurement of the sample] The measurement method for the sample in the example, as a compression-deformed member, was as follows.

[0147] <Thermal conductivity> Measured in the same manner as above.

[0148] <Compression Ratio> Using a tensile-compression testing machine, the decrease in the thickness of the compressed member after applying 0.7 MPa at 25°C was divided by the thickness of the compressed member before applying 0.7 MPa (initial value) to determine the value.

[0149] <Film Thickness> Measured in the same manner as above.

[0150] <<Heat-dissipating laminate>> An example of a combination of a heat-conducting member and a compression-deformable member is as follows.

[0151]

[0152] The top-dissipating power semiconductor module of this disclosure achieves high dielectric strength and high thermal conductivity by comprising a heat-dissipating laminate combining a layer containing a thermally conductive member and a layer containing a compression-deformable member. Furthermore, by dividing the module into two components, a thermally conductive member and a compression-deformable member, it can accommodate variations in the tilt and height of the power semiconductor package, thereby suppressing a decrease in heat dissipation and insulation performance. As a result, the top-dissipating power semiconductor module of this disclosure can obtain sufficient cooling capacity for the power semiconductor package, suppress a decrease in power conversion efficiency, and suppress a decrease in insulation reliability. In other words, according to this disclosure, it is possible to provide a top-dissipating power semiconductor module comprising a heat-dissipating laminate that can achieve high dielectric strength, high thermal conductivity, and compression deformability.

[0153] According to this disclosure, it is possible to provide a top-surface heat-dissipating power semiconductor module equipped with a heat-dissipating laminate that can achieve high dielectric strength, high thermal conductivity, and compressive deformability.

[0154] 1 Heat sink 2 Heat dissipation laminate 3 Power semiconductor package 4 Printed circuit board 10, 20, 30, 40, 100 Top-surface heat dissipation type power semiconductor module 11 Fin 12 Flat plate portion 21 Layer containing thermal conductive material 22 Layer containing compression deformation material 31 Heat sink 32 Encapsulating material 33 Outer lead 34 Bonding material 35 Power semiconductor chip 36 Inner lead 37 Wire

Claims

1. A top-surface heat-dissipating power semiconductor module comprising, in this order: a printed circuit board, one or more power semiconductor packages, a heat-dissipating laminate, and a heat sink, wherein the one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board, the heat-dissipating laminate has a layer including a compression deformation member and a layer including a thermally conductive member, the layer including the compression deformation member has a compressibility of 1% or more and 90% or less when 0.7 MPa is applied in the thickness direction at 25°C, the layer including the thermally conductive member has a thermal conductivity in the thickness direction at 25°C of 10 W / m·K or more as measured in accordance with ASTM D5470, and a dielectric breakdown voltage of 4.0 kV or more as measured in accordance with JIS C2110-1.

2. An upper-surface heat-dissipating power semiconductor module that dissipates heat generated from one or more power semiconductor packages to the outside from the top surface, comprising in this order: a printed circuit board, one or more power semiconductor packages, a heat-dissipating laminate, and a heat sink, wherein the one or more power semiconductor packages have a power semiconductor chip provided on the printed circuit board and a heat sink provided on the side of the power semiconductor chip opposite to the printed circuit board for dissipating heat generated from the power semiconductor chip, the heat sink is a member for dissipating heat generated from the one or more power semiconductor packages to the outside, the heat-dissipating laminate is provided between the heat sink and the heat sink for transferring heat generated from the one or more power semiconductor packages to the heat sink, and the heat-dissipating laminate has a layer including a compression deformation member and a layer including a thermal conductive member. The layer including the compression deformation member is a member for following variations in the distance between the one or more power semiconductor packages and the heat sink, the layer including the compression deformation member has a compressibility of 1% to 90% when 0.7 MPa is applied in the thickness direction at 25°C, and the layer including the thermal conductive member is a member for transferring heat generated from the one or more power semiconductor packages to the heat sink and for electrically insulating the one or more power semiconductor packages from the heat sink, an over-surface heat dissipation type power semiconductor module.

3. The top-surface heat-dissipating power semiconductor module according to claim 1 or 2, wherein the compression deformation member is at least one selected from the group consisting of gap filler, graphite sheet, metal mesh, metal rubber (registered trademark), leaf spring, clay containing metal filler, and grease containing metal filler.

4. The top-surface heat-dissipating power semiconductor module according to claim 1 or 2, wherein the thermal conductive member is a resin sheet obtained by curing a resin composition containing a matrix resin and a thermal conductive filler.

5. The top-surface heat-dissipating power semiconductor module according to claim 1 or 2, wherein the thermal conductive member is a resin sheet obtained by curing a resin composition containing epoxy resin and boron nitride aggregate particles.

6. The top-heat-dissipating power semiconductor module according to claim 1 or 2, wherein one or more power semiconductor packages are field-effect transistors.

7. The top-surface heat-dissipating power semiconductor module according to claim 1 or 2, for use in electric vehicles.

8. A power generation system for electric vehicles equipped with the top-surface heat-dissipating power semiconductor module described in claim 1 or 2.

9. An electric vehicle equipped with the electric vehicle power generation system described in claim 8.

10. A heat-dissipating laminate for an upper-surface heat-dissipating power semiconductor module according to claim 1 or 2, comprising a layer including a compression deformation member and a layer including a thermal conductive member.

11. A resin sheet for a thermally conductive member in a heat-dissipating laminate according to claim 10.

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