Method for manufacturing a laminate, and a laminate

Abstract

To provide a method for manufacturing laminates that can relieve stress and produce laminates that are both reliable and have high thermal conductivity. [Solution] A method for manufacturing a laminate, comprising the steps of: sandwiching a metal layer and a heat-conducting sheet having a plurality of metal protrusions on at least a first surface of the metal layer between a substrate and an opposing substrate and heating it; and filling the spaces between the plurality of metal protrusions with a filler and curing it.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a laminate and to a laminate. [Background technology]

[0002] With the miniaturization of electronic devices such as power modules, image sensors, and high-performance computing (HPC), and the increase in information processing load, heat generation problems are becoming more pronounced, and the importance of heat dissipation from heat sources is increasing. In various electronic devices, LSIs and other components can malfunction or fail if they are exposed to high temperatures for extended periods due to heat generated by the elements used. For this reason, thermal conductive materials are widely used to prevent LSIs and other components from overheating. These thermal conductive materials can prevent the device from overheating by diffusing the heat generated by the elements or by transferring it to a heat dissipation component that releases it to the atmosphere or other external environment.

[0003] To date, sheet-like heat-bonding materials have been reported in which a support made of plate-shaped metal and a bonding agent containing metal nanoparticles and metal fine particles and a solvent are attached to both sides of the support, with the organic material mainly composed of an alcohol having 18 or fewer carbon atoms or a derivative thereof, or a compound containing a carboxyl group, or a mixture thereof. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-038748 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the conventional thermal conductive sheet described in Patent Document 1 has a problem in that, because the bonding agent adheres uniformly to the support, cracks occur in the bonding agent area during reliability tests, making practical application difficult. In addition, it requires a high-pressure press, which places a heavy load on the equipment, and it has a problem in that it cannot relieve stress in response to the applied pressure, resulting in poor reliability.

[0006] The present invention aims to solve the aforementioned conventional problems and achieve the following objectives. Specifically, the present invention aims to provide a method for manufacturing a laminate that can relieve stress and produce a laminate that is both reliable and highly thermally conductive. [Means for solving the problem]

[0007] The means to solve the aforementioned problem are as follows: <1> A step of heating a metal layer and a heat conductive sheet having a plurality of metal protrusions on at least a first surface of the metal layer, sandwiched between a substrate and an opposing substrate, A method for manufacturing a laminate, characterized by including a step of filling a filler between at least one of the substrate and the opposing substrate and the plurality of metal protrusions and curing it. <2> The area ratio of the plurality of metal protrusions to the first surface of the heat conductive sheet is 20% or more and 80% or less. <1> This is a method for manufacturing the laminate described above. <3> The heat conductive sheet further has a plurality of metal protrusions on a second surface opposite to the first surface of the metal layer. <1> or <2> This is a method for manufacturing the laminate described above. <4> The average thickness of the metal layer is 50 μm or more and 200 μm or less. <1> from <3> This is a method for manufacturing a laminate as described in any of the above. <5> The thermal conductivity of the metal layer is 50 W / (m·K) or more. <1> from <4> This is a method for manufacturing a laminate as described in any of the above. <6> The metal layer comprises at least one of gold, silver, copper, and aluminum. <1> from <5> This is a method for manufacturing a laminate as described in any of the above. <7> The heating is carried out at a temperature of 350°C or lower. <1> from <6> This is a method for manufacturing a laminate as described in any of the above. <8> The heating is performed under a pressure of 20 MPa or less. <1> from <7> This is a method for manufacturing a laminate as described in any of the above. <9> The filler contains a curable material selected from the group consisting of curable silicone, curable epoxy resin, curable polyurethane resin, and curable polyester resin. <1> from <8> This is a method for manufacturing a laminate as described in any of the above. <10> A base material and a counter base material, A thermal conductive sheet sandwiched between the substrate and the opposing substrate, having a metal layer and a plurality of metal protrusions on at least a first surface of the metal layer, The laminate is characterized by having a hardened product of a filler that is filled between the plurality of metal protrusions. [Effects of the Invention]

[0008] According to the present invention, it is possible to solve the aforementioned problems in the conventional method, achieve the aforementioned objectives, relieve stress, and provide a method for manufacturing a laminate that can produce a laminate that is both reliable and highly thermally conductive. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the process for manufacturing the laminate according to this embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing an example of the laminate according to this embodiment. [Figure 3] Figure 3 is a plan view showing an example of a thermal conductive sheet in the manufacturing method of the laminate according to this embodiment. [Figure 4] Figure 4 is a cross-sectional view AA' of the thermal conductive sheet shown in Figure 1. [Figure 5] Figure 5 is a cross-sectional view AA' showing another example of a thermal conductive sheet in the manufacturing method of the laminate according to this embodiment. [Figure 6]FIG. 6 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the first embodiment (Part 1). [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the first embodiment (Part 2). [Figure 8] FIG. 8 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the first embodiment (Part 3). [Figure 9] FIG. 9 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the first embodiment (Part 4). [Figure 10] FIG. 10 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the second embodiment (Part 3). [Figure 11] FIG. 11 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the second embodiment (Part 4). [Figure 12] FIG. 12 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the third embodiment (Part 1). [Figure 13] FIG. 13 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the third embodiment (Part 2). [Figure 14] FIG. 14 is a schematic cross-sectional view showing an example of the manufacturing process of the heat conduction sheet according to the third embodiment (Part 3). [Figure 15] FIG. 15 is a schematic cross-sectional view showing an example of the heat dissipation structure of the present embodiment.

Embodiments for Carrying Out the Invention

[0010] (Method for Manufacturing a Laminate) The method for manufacturing a laminate according to the present embodiment includes a step of sandwiching a metal layer and a heat conduction sheet having a plurality of metal convex portions on at least a first surface of the metal layer between a base material and a counter base material and heating them, and a step of filling a filler between the plurality of metal convex portions and curing it. Further, if necessary, it includes other steps such as a heat conduction sheet manufacturing step.

[0011] The manufacturing method for the laminate of this embodiment, by including these steps, can relieve stress and produce a laminate that achieves both reliability and high thermal conductivity. This is because the thermal conductive sheet sandwiched between the substrate and the opposing substrate, which has a metal layer and a plurality of metal protrusions on at least the first surface of the metal layer, communicates in the thickness direction and the planar direction, so that the thermal conductive sheet has thermal conductivity not only in the thickness direction but also in the planar direction, resulting in excellent thermal conductivity. Furthermore, the thermal conductive sheet sandwiched between the substrate and the opposing substrate has a plurality of metal protrusions and gaps therebetween, which can relieve stress in the laminate. In addition, the cured product of the filler filled between the plurality of metal protrusions reduces lifting and peeling of the thermal conductive sheet from the substrate and the opposing substrate, resulting in excellent adhesion to the substrate and excellent reliability.

[0012] Figure 1 shows a schematic cross-sectional view of an example of the manufacturing process for the laminate according to this embodiment. In the heating step shown in Figure 1, the metal layer 11 and the heat-conducting sheet 10 having a plurality of metal protrusions 12 on at least the first surface of the metal layer 11 are sandwiched between the base material 15 and the opposing base material 16 and heated. This allows the heat-conducting sheet and the base material, and the heat-conducting sheet and the opposing base material to be joined in a state where the stress is relieved.

[0013] Next, in the filler curing step, a filler is filled between at least one of the base material 15 and the opposing base material 16 and the plurality of metal protrusions 12, and then the filler is cured. This makes it possible to further improve the adhesion between the heat conductive sheet and the base material, and / or between the heat conductive sheet and the opposing base material, which are joined in a state where stress has been relaxed in the heating step. Then, as shown in Figure 2, the laminate having a base material 15 and an opposing base material 16, a heat conductive sheet 10 sandwiched between the base material 15 and the opposing base material 16 and having a metal layer 11 and a plurality of metal protrusions 12 on at least the first surface of the metal layer 11, and a cured product 14 of the filler filled between the plurality of metal protrusions 12 can be suitably manufactured.

[0014] -Thermal conductive sheet- The thermal conductive sheet has a metal layer and a plurality of metal protrusions on at least a first surface of the metal layer. The area ratio of the plurality of metal protrusions to the first surface of the thermal conductive sheet is preferably 20% to 80%, and more preferably 30% to 70%, in terms of reducing lifting and peeling from the substrate, providing excellent adhesion to the substrate, and ensuring high reliability.

[0015] The thermal conductive sheet is preferably a thermal conductive sheet having a plurality of metal protrusions on a second surface opposite to the first surface of the metal layer. Here, the area ratio of the plurality of metal protrusions to the second surface is preferably 20% to 80%, and more preferably 30% to 70%, in order to reduce lifting and peeling from the substrate, to have excellent adhesion to the substrate, and to have excellent reliability.

[0016] Figures 3 and 4 are a plan view and a schematic cross-sectional view of the AA' section of an example of a thermal conductive sheet according to this embodiment. The thermal conductive sheet 10 shown in Figures 3 and 4 has a metal layer 11 and a plurality of metal protrusions 12 on a first surface and a second surface opposite to the first surface of the metal layer 11. As shown in the top view of Figure 3, a pattern of metal protrusions 12 is formed. Preferably, the area ratio of the plurality of metal protrusions 12 to the first surface of the thermal conductive sheet 10 is 20% or more and 80% or less, and preferably the area ratio of the plurality of metal protrusions 12 to the second surface of the thermal conductive sheet 10 is 20% or more and 80% or less.

[0017] As shown in Figure 5, which illustrates another example of the thermal conductive sheet of this embodiment, the thermal conductive sheet 10 may have a plurality of metal protrusions 12 on the first surface (only one side). The thermal conductive sheet 10 shown in Figure 5 has a metal layer 11 and a plurality of metal protrusions 12 on the first surface of the metal layer 11. The pattern of the metal protrusions 12 in the top view of the thermal conductive sheet 10 in Figure 5 is the same as in the top view of Figure 1. It is preferable that the area ratio of the plurality of metal protrusions 12 to the first surface of the thermal conductive sheet 10 is 20% or more and 80% or less.

[0018] --Metal layer-- The material of the metal layer preferably contains a metal with high thermal conductivity, and more preferably consists of such a metal. From the viewpoint of thermal conductivity and safety, aluminum, nickel, iron, gold, silver, copper, zinc, and tin are preferred as the aforementioned metals, and gold, silver, copper, and aluminum are more preferred.

[0019] There are no particular restrictions on the thermal conductivity of the metal layer, and it can be appropriately selected according to the purpose. However, from the viewpoint of thermal conductivity, a value of 50 W / (m·K) or higher is preferred, and 100 W / (m·K) or higher is more preferred. There are no particular restrictions on the thermal conductivity of the aforementioned metal, and it can be appropriately selected according to the purpose. However, from the viewpoint of thermal conductivity, a thermal conductivity of 50 W / (m·K) or higher is preferred, 100 W / (m·K) or higher is more preferred, and 200 W / (m·K) or higher is even more preferred.

[0020] --Metal protrusions-- There are no particular limitations on the aforementioned metal protrusions, and they can be appropriately selected according to the purpose. Examples include metal formed by plating such as electrolytic plating or non-electrolytic plating; a metal material filled with a filler material if necessary; or a metal layer made of the same material as the metal layer cut from a metal plate. Among these, metals formed by electroplating are preferred. There are no particular restrictions on the metal formed by the electroplating, and it can be appropriately selected from the metals mentioned above depending on the purpose.

[0021] The aforementioned metal protrusion may be filled with a metal material, or it may be filled with a mixture of a metal material and a filler material of any component. There are no particular restrictions on the type of metal material, and it can be appropriately selected according to the purpose. However, from the viewpoint of thermal conductivity and safety, aluminum, aluminum oxide, aluminum nitride, boron nitride, carbon resin, nickel, iron, gold, silver, copper, zinc, and tin are preferred, and gold, silver, copper, and nickel are more preferred. These may be used individually or in combination of two or more types.

[0022] There are no particular restrictions on the shape of the metal material, and it can be appropriately selected according to the purpose. Examples include particles, plates, rods, and wires.

[0023] As for the content of the metal material in the metal protrusions, from the viewpoint of thermal conductivity, 50% by mass or more is preferred, any of 60% by mass or more, 70% by mass or more, and 80% by mass or more is preferred, 90% by mass or more is even more preferred, 95% by mass or more is particularly preferred, and 99% by mass or more is most preferred.

[0024] The aforementioned filler material is not particularly limited and can be appropriately selected according to the purpose, and examples include dispersants, surfactants, and binder resins.

[0025] [pattern] There are no particular restrictions on the pattern of the metal protrusions 12, and they can be appropriately selected according to the purpose. For example, a pattern in which multiple shapes are arranged can be used. Among these, a pattern in which multiple geometric shapes are arranged regularly is preferred from the viewpoint of uniformity of thermal conductivity. Examples of the aforementioned patterns include 45° staggered (see Figure 1), 60° staggered, parallel squares, 60° staggered regular hexagons, equilateral triangle arrangement, and alternating rectangles.

[0026] There are no particular restrictions on the size of the metal protrusions 12 in the pattern, and they can be appropriately selected according to the purpose. However, the length of the longest side of the shape is preferably 10 μm or more and 1,000 μm or less, and more preferably 50 μm or more and 500 μm or less.

[0027] There are no particular restrictions on the thermal conductivity of the thermal conductive sheet, and it can be appropriately selected according to the purpose. However, from the viewpoint of thermal conductivity, a thermal conductivity of 50 W / (m·K) or higher is preferred, 60 W / (m·K) or higher is more preferred, 70 W / (m·K) or higher is even more preferred, and 80 W / (m·K) or higher is particularly preferred.

[0028] The average thickness of the heat conduction sheet is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 10 μm or more and 200 μm or less, and more preferably 30 μm or more and 150 μm or less.

[0029] The average thickness of the metal layer is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 10 μm or more and 100 μm or less, and more preferably 15 μm or more and 50 μm or less.

[0030] The ratio (T M ) of the average thickness (T m ) of the metal protrusions to the average thickness (T m ) of the metal layer (T M ) is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of further improving thermal conductivity and reliability, it is preferably 0.2 or more and 4 or less, and more preferably 0.5 or more and 2 or less.

[0031] In the case of the aspect having metal protrusions on both the first surface and the second surface of the heat conduction sheet, for the metal protrusions on each surface, the ratio (T m / T M ) can be set independently. The ratio (T m / T M ) of the first surface and the ratio (T m / T M ) of the second surface may be different or the same.

[0032] - Substrate - There are no particular limitations on the shape, structure, size, material, etc. of the substrate, and they can be appropriately selected according to the purpose. Examples of the shape of the substrate include plate shape and sheet shape. Examples of the structure of the substrate include single - layer structure and laminated structure. The size of the substrate can be appropriately selected according to applications and the like.

[0033] Suitable materials for the substrate include, for example, silicon, aluminum, tungsten, molybdenum, glass, molded resin, stainless steel, and ceramics. Examples of the aforementioned ceramics include aluminum nitride, silicon carbide, alumina, and gallium nitride. Examples of the aforementioned molding resins include epoxy resin, silicone resin, urethane resin, and acrylic resin. The substrate is preferably a silicon substrate.

[0034] The average thickness of the aforementioned substrate is not particularly limited and can be appropriately selected depending on the purpose. The aforementioned substrate may be the heat-generating element (electronic component) itself in the heat dissipation structure.

[0035] -Opposite substrate- The opposing substrate is positioned opposite the substrate, and there are no particular restrictions on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose. Examples of the shape of the opposing substrate include plate-like and sheet-like shapes. Examples of the structure of the opposing substrate include single-layer and laminated structures. The size of the opposing substrate can be appropriately selected depending on the application. The material of the opposing substrate is a material that is easily wetted by solder and includes at least one selected from copper, gold, platinum, palladium, silver, zinc, iron, tin, nickel, magnesium, indium, and alloys thereof. The average thickness of the opposing substrate is not particularly limited and can be appropriately selected depending on the purpose. The opposing substrate may be the heat spreader itself in the heat dissipation structure.

[0036] <Heating process> The heating step involves sandwiching a metal layer and a heat-conducting sheet having a plurality of metal protrusions on at least a first surface of the metal layer between a substrate and an opposing substrate and heating them. This allows for bonding while relieving stress between the heat-conducting sheet and the substrate, and between the heat-conducting sheet and the opposing substrate.

[0037] The method of heating by sandwiching a thermal conductive sheet between a substrate and an opposing substrate is not particularly limited as long as the substrate and the opposing substrate can be joined via the thermal conductive sheet to form a thermal conductive network, and can be appropriately selected according to the purpose. However, it is preferable to carry out the process at 350°C or below and under a pressure of 20 MPa or below.

[0038] <Filler curing process> The filler curing step involves filling the space between at least one of the substrate and the opposing substrate and the plurality of metal protrusions with a filler and curing it. This makes it possible to further improve the adhesion between the thermal conductive sheet and the substrate, and / or between the thermal conductive sheet and the opposing substrate, which are joined in a state where stress has been relieved during the heating step.

[0039] -Filler- The aforementioned filler is not particularly limited as long as it has curability and adhesive properties, and can be appropriately selected according to the purpose, but it is preferable that it contains a curable material, and further, if necessary, it may contain a curing agent, filler, or other components.

[0040] --Curable material-- The curable material is not particularly limited and can be appropriately selected depending on the purpose, but curable silicone, curable epoxy resin, curable polyurethane resin, and curable polyester resin are preferred examples. These may be used individually or in combination of two or more.

[0041] Examples of curable silicones include silicones having epoxy groups (glycidoxy groups), silicones having acryloyl groups (methacryloyl groups), and silicones having hydrosilyl groups and vinyl groups. Examples of curable epoxy resins include glycidyl ether type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, trisphenol type epoxy resins, tetraphenol type epoxy resins, phenol-xylylene type epoxy resins, naphthol-xylylene type epoxy resins, phenol-naphthol type epoxy resins, phenol-dicyclopentadiene type epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. Examples of curable polyurethane resins include polyurethanes having acryloyl groups, polyurethanes having methacryloyl groups, urethane prepolymers containing terminal isocyanate groups, and epoxy-modified polyurethanes. Examples of curable polyester resins include polyesters having acryloyl groups, polyesters having methacryloyl groups, and epoxy-modified polyesters.

[0042] --Hardening agent-- The curing agent is a curing agent corresponding to the curable material, and examples include polyaddition curing agents such as polyfunctional carboxylic acids, acid anhydride curing agents, aliphatic amine curing agents, aromatic amine curing agents (e.g., imidazole curing agents), phenol curing agents, and mercaptan curing agents, as well as catalytic curing agents such as imidazole. These can be used individually or in combination of two or more.

[0043] --Filler-- The filler may further contain a filler. Examples of the fillers include metal powder, alloy powder, metal oxide, ceramic powder, and carbon powder. These may be used individually or in combination of two or more. There are no particular restrictions on the shape of the filler, and it can be appropriately selected depending on the purpose. Examples include spherical, flattened, granular, and needle-shaped fillers.

[0044] When the filler contains the filler, there are no particular restrictions on the filler content in the filler, and it can be appropriately selected according to the purpose. However, from the viewpoint of improving mechanical strength, heat resistance, and thermal conductivity without impairing the adhesiveness of the filler, it is preferable that the content is greater than 0 vol% and 90 vol% or less, more preferably 40 vol% to 80 vol% or less, and even more preferably 50 vol% to 70 vol% or less.

[0045] The volume-average particle size of the filler is preferably 0.3 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 10 μm or less. The aforementioned volume-average particle size can be measured, for example, by a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300EXII).

[0046] --Other ingredients-- Other ingredients are not particularly limited and can be selected as appropriate depending on the purpose, such as antioxidants.

[0047] <Manufacturing process for thermal conductive sheets> There are no particular limitations on the method for manufacturing the thermal conductive sheet, and a suitable method can be selected depending on the purpose. Examples include a method of forming protrusions containing a metal material on a metal layer (first embodiment); a method of forming protrusions on a metal layer by plating (second embodiment); and a method of cutting out a metal part in which the metal layer and protrusions are integrated by etching a metal plate (third embodiment).

[0048] [First Embodiment] The method for manufacturing a heat conductive sheet in the first embodiment includes a protrusion forming step of forming a protrusion containing a metal material, and further includes, if necessary, other steps such as a protective part application step, a protective part removal step, a sintering step, and a polishing step. The heat conductive sheet manufacturing method of the first embodiment can suitably manufacture the heat conductive sheet used in the manufacturing method of the laminate of this embodiment described above.

[0049] Figures 6-9 show schematic cross-sectional views illustrating an example of the process for manufacturing a heat conductive sheet according to the first embodiment. This embodiment involves forming protrusions on the first and second surfaces (both sides) of the metal layer. First, a metal layer 11 is prepared (Figure 6), and protective portions 13 are formed on the first surface and optionally on the second surface of the metal layer 11 (Figure 7, protective portion application process). Next, a composition containing a metal material is applied to the exposed surface of the metal layer 11 where the protective portions 13 are not applied to form a plurality of metal protrusions 12 (Figure 8, protrusion formation process). Then, the protective portions 13 are removed (Figure 9, protective portion removal process), and a heat conductive sheet 10 having a metal layer 11 and a plurality of metal protrusions 12 on the first and second surfaces of the metal layer 11 can be manufactured.

[0050] <<Protective coating process>> The protective portion application step is a step of applying a protective portion to at least a first surface of the metal layer, and can be suitably carried out by protective portion application means. When manufacturing a heat-conducting sheet having protrusions on both sides, the protective portion application step is a step of applying protective portions to the first surface and the second surface of the metal layer.

[0051] The pattern of the protective portion applied in the protective portion application step can be an inverse pattern of the convex portion pattern on the target heat conductive sheet. The protective portion can be suitably selected according to the desired embodiment, and examples include resist materials.

[0052] There are no particular restrictions on the method of applying the protective layer, and it can be appropriately selected according to the purpose. Examples include applying a protective layer with a desired pattern by imprinting; applying a protective layer with a desired pattern by inkjet, screen printing, etc.; and forming a protective layer with a desired pattern using resist. A method for forming a protective portion having a desired pattern using the resist includes, for example, applying the resist to at least a first surface of a metal layer, exposing and developing it to the desired pattern, and, if necessary, heating it after exposure or development to form the protective portion. The resist may be a negative type in which exposed areas remain after development, or a positive type in which unexposed areas remain after development.

[0053] <<Protrusion Formation Process>> The protrusion formation step is a step of forming the plurality of protrusions by applying a composition containing the metal material to at least a first surface of the metal layer, wherein the metal material is preferably the sinterable metal nanoparticles.

[0054] When the protective portion application step is performed, the convex portion formation step is a step of applying a composition containing the metal material to the exposed surface of the metal layer to which the protective portion has not been applied to form the plurality of convex portions, and can be suitably performed by a convex portion forming means.

[0055] The plurality of protrusions may be formed by applying the composition containing the metal material in a patterned manner without performing the protective portion application step. Methods for applying the composition in a pattern include, for example, applying the composition having a desired pattern by imprinting; or applying the composition having a desired pattern by inkjet printing, screen printing, etc.

[0056] The composition containing the metal material further comprises the metal material and, if necessary, a filler and a solvent. The content of the metal material in the composition is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, and 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the solid content of the composition.

[0057] The solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples include terpineol, butyl carbitol, butyl carbitol acetate, and texanol.

[0058] The above composition can be prepared by mixing and dispersing the metal material, and optionally a filler material and a solvent. The aforementioned composition may be a commercially available product, for example, a metal paste containing metal particles such as H 9890-6A (manufactured by Namics Corporation, a thermosetting conductive adhesive, silver paste).

[0059] <<Protective part removal process>> The protective part removal step is a step of removing the protective part, which can be suitably carried out by a protective part removal means. There are no particular restrictions on the method for removing the protective layer, and it can be appropriately selected depending on the purpose. For example, methods such as high-temperature heating, strong alkali, or organic solvent treatment can be used to remove the protective layer.

[0060] <<Sintering Process>> The sintering step is a step of sintering the sinterable metal nanoparticles by heating, when the protrusions contain sinterable metal nanoparticles. The heating step may be performed simultaneously with the protective part removal step, or it may be performed when joining the heat conductive sheet to the substrate and the opposing substrate.

[0061] <<Polishing process>> The polishing step is a step of polishing the surfaces of the multiple protrusions formed on the metal layer. There are no particular restrictions on the method of polishing the surface of the metal layer, and known methods can be appropriately selected depending on the purpose. There are no particular restrictions on the timing of the polishing step, and it can be appropriately performed depending on the purpose, for example, after the convex part formation step, before the protective part removal step, after the protective part removal step, after the heating step, etc.

[0062] As a result of the polishing process, the surfaces of the multiple metal protrusions 12 on the obtained thermal conductive sheet become smooth and coplanar, resulting in excellent adhesion between the substrate and the opposing substrate, as well as superior reliability and conductivity of the resulting laminate.

[0063] [Second Embodiment] The method for manufacturing a heat conductive sheet in the second embodiment includes a protective portion application step, a protrusion formation step in which protrusions are formed by plating, and a protective portion removal step, and further includes other steps such as a heating step and a polishing step as necessary. The method for manufacturing a thermal conductive sheet according to the second embodiment allows for the suitability of manufacturing a thermal conductive sheet used in the method for manufacturing the laminate of this embodiment described above.

[0064] Figures 6-7 and 10-11 show schematic cross-sectional views illustrating an example of the process for manufacturing a heat conductive sheet according to the second embodiment. In this embodiment, protrusions are formed on the first and second surfaces (both sides) of the metal layer. First, a metal layer 11 is prepared (Figure 6), and protective portions 13 are formed on the first surface and optionally on the second surface of the metal layer 11 (Figure 7, protective portion application process). Next, a plurality of metal protrusions 12 are formed by plating on the exposed surface of the metal layer 11 where the protective portions 13 are not applied (Figure 10, plating process). Then, the protective portions 13 are removed (Figure 11, protective portion removal process), and a heat conductive sheet 10 having a metal layer 11 and a plurality of metal protrusions 12 on the first and second surfaces of the metal layer 11 can be manufactured. For the protective part application step, protective part removal step, and other steps such as polishing step in the second embodiment, the items described in the first embodiment can be appropriately selected.

[0065] <<Plating Process>> The plating process is a process of forming the plurality of protrusions by plating the exposed surface of the metal layer that is not covered by the protective portion. There are no particular limitations on the method for forming multiple protrusions by plating, and it can be appropriately selected depending on the purpose. Examples include electroplating and electroless plating (chemical plating). Among these, electroplating is preferred from the viewpoint of throughput. There are no particular restrictions on the metal used for filling by the aforementioned plating, and it can be appropriately selected depending on the purpose. However, it is preferable that it contains at least one of nickel, gold, silver, and copper, and more preferably at least one of nickel, gold, silver, and copper.

[0066] [Third Embodiment] The method for manufacturing a thermal conductive sheet in the third embodiment includes a protective part formation step, an etching step, and a protective part removal step, and further includes other steps such as the polishing step as necessary.

[0067] Figures 12-14 show schematic cross-sectional views illustrating an example of the process for manufacturing a heat conductive sheet according to the third embodiment. In this embodiment, protrusions are formed on the first and second surfaces (both sides) of the metal layer. First, a metal plate 11' that will serve as a precursor to the metal layer 11 is prepared (Figure 12), and protective portions 13 are formed on the first surface and optionally on the second surface of the metal layer 11 (Figure 13, protective portion application process). Next, by removing the exposed surface of the metal plate 11' that does not have the protective portion 13 applied by etching, a metal layer 11 is obtained that integrally has the metal layer 11 and a plurality of metal protrusions 12 on the first and second surfaces of the metal layer 11 (etching process). Then, the protective portion 13 is removed (Figure 14, protective portion removal process), and a heat conductive sheet 10 having the metal layer 11 and a plurality of metal protrusions 12 on the first and second surfaces of the metal layer 11 can be manufactured.

[0068] The pattern of the protective portion applied in the aforementioned protective portion application step can be the same as the pattern of the protrusions on the target heat conductive sheet. The protective portion can be suitably selected according to the desired embodiment, and examples include resist materials.

[0069] (Laminated structure) The laminate of this embodiment comprises a base material and an opposing base material, a thermal conductive sheet sandwiched between the base material and the opposing base material and having a metal layer and a plurality of metal protrusions on at least a first surface of the metal layer, and a cured product of a filler filled between the plurality of metal protrusions.

[0070] -Heat dissipation structure- The laminate in this embodiment is preferably a heat dissipation structure. The heat dissipation structure comprises a heating element as a base material and a heat dissipation member as an opposing base material, a heat conductive sheet sandwiched between the base material and the opposing base material and having a metal layer and a plurality of metal protrusions on at least a first surface of the metal layer, and a cured product of a filler filled between the plurality of metal protrusions, and further comprises other members as necessary. The heat dissipation structure has the heat conductive sheet between the heat-generating element and the heat dissipation member. The heat dissipation structure may further have adhesive layers between its constituent members, if necessary.

[0071] There are no particular restrictions on the heat-generating element, and it can be appropriately selected according to the purpose. Examples include electronic components such as CPUs (Central Processing Units), MPUs (Micro Processing Units), and GPUs (Graphics Processing Units).

[0072] The heat dissipation member is not particularly limited as long as it is a structure that dissipates the heat generated by electronic components (heat-generating elements), and can be appropriately selected according to the purpose. Examples include heat spreaders, heat sinks, vapor chambers, and heat pipes. The heat spreader is a component for efficiently transferring heat from the electronic component to other components. There are no particular restrictions on the material of the heat spreader, and it can be appropriately selected according to the purpose, for example, copper, aluminum, etc. The heat spreader is usually in the shape of a flat plate. The heat sink is a component for releasing heat from the electronic component into the air. There are no particular restrictions on the material of the heat sink, and it can be appropriately selected depending on the purpose, for example, copper, aluminum, etc. The heat sink has, for example, a plurality of fins. The heat sink has, for example, a base portion and a plurality of fins provided so as to extend in a direction non-parallel to one surface of the base portion (for example, in a direction perpendicular to it). The heat spreader and the heat sink generally have a solid structure with no internal space. The vapor chamber is a hollow structure. A volatile liquid is sealed inside the hollow structure. Examples of the vapor chamber include a hollow heat spreader, a hollow heat sink, or a plate-shaped hollow structure. The heat pipe is a hollow structure that is cylindrical, substantially cylindrical, or flattened. A volatile liquid is sealed inside the hollow structure.

[0073] Here, Figure 15 is a schematic cross-sectional view showing an example of a semiconductor device as a heat dissipation structure. The thermal conductive sheet 7 of the present invention dissipates heat generated by electronic components 3 such as semiconductor elements, and as shown in Figure 15, it is fixed to the main surface 2a of the heat spreader 2 facing the electronic components 3 and sandwiched between the electronic components 3 and the heat spreader 2. The thermal conductive sheet 1 is sandwiched between the heat spreader 2 and the heat sink 5. The thermal conductive sheet 1 may be the thermal conductive sheet of the present invention, or it may be another thermal conductive sheet.

[0074] The heat spreader 2 is formed, for example, in the shape of a rectangular plate and has a main surface 2a facing the electronic component 3 and side walls 2b erected along the outer circumference of the main surface 2a. The heat spreader 2 has a thermal conductive sheet 1 provided on the main surface 2a surrounded by the side walls 2b, and a heat sink 5 is provided on the other surface 2c opposite to the main surface 2a via the thermal conductive sheet 1. The higher the thermal conductivity of the heat spreader 2, the lower the thermal resistance and the more efficiently it absorbs heat from electronic components 3 such as semiconductor elements. For example, it can be formed using copper or aluminum, which have good thermal conductivity.

[0075] The electronic component 3 is, for example, a semiconductor element such as a BGA, and is mounted on the wiring board 6. The heat spreader 2 also has the leading edge of its side wall 2b mounted on the wiring board 6, thereby surrounding the electronic component 3 at a predetermined distance by the side wall 2b. Furthermore, by providing the heat conductive sheet 7 of the present invention on the main surface 2a of the heat spreader 2, a heat dissipation member is formed that absorbs the heat emitted by the electronic component 3 and dissipates heat from the heat sink 5. [Examples]

[0076] The present invention will be described more specifically below based on examples, but the present invention is not limited to the following examples.

[0077] (Example 1) <Manufacturing of laminates> <<Manufacturing of thermal conductive sheets>> According to the manufacturing methods shown in Figures 6-7 and 10-11, a thermal conductive sheet of Example 1 having the pattern of metal protrusions shown in Figures 3-4 was manufactured by following the procedure below. On both sides of a copper plate (size: 20 mm x 20 mm, average thickness 100 μm, Figure 6), etching resist X-87 (manufactured by Taiyo Ink Manufacturing Co., Ltd.) was screen printed to an average thickness of 9 μm as a coating liquid for forming a protective layer in the area corresponding to the negative pattern of the metal protrusions shown in Figure 3, and then heated at 100°C for 5 minutes to form the protective layer (Figure 7). In the metal protrusion pattern (45° staggered) shown in Figure 3, the metal protrusions were made up of multiple circles with a diameter of 100 μm, and by adjusting the pitch (distance between centers) of adjacent metal protrusions, the area ratio of the metal protrusions, i.e., the area ratio of multiple metal protrusions to each surface of the thermal conductive sheet, was set to 80%.

[0078] The metal plate with the protective layer formed was plated using a nickel sulfamate bath under the following conditions: 50°C, pH 4.5, 10 mA / cm². 2 Plating was performed to form metal protrusions with an average thickness of 30 μm (Figure 10). Next, the protective layer was removed by immersion in 3% NaOH at 40°C for 15 seconds to fabricate a thermal conductive sheet with metal protrusions on both sides of the metal layer (Figure 11).

[0079] <<Preparation of Filler 1>> Dimethyldimethoxysilane (500 g) and 3-glycidoxypropylmethyldimethoxysilane (100 g) were placed in a separable flask equipped with a 1000 mL thermometer and dropping funnel, and stirred at 50°C. An aqueous solution of potassium hydroxide (1.3 g) dissolved in water (165 g) was slowly added dropwise, and after the addition was complete, the mixture was stirred at 50°C for 6 hours. Acetic acid (1.4 g) was added, and volatile components were removed under reduced pressure. The potassium acetate was filtered to obtain the polymer. The obtained polymer was washed with hexane and water, and volatile components were removed under reduced pressure to obtain polymer A.

[0080] The polymer A (100g) obtained above, Ricasid MH-700G (acid anhydride, manufactured by Shin Nippon Rika Co., Ltd., 25g), U-CAT SA 102 (curing accelerator, manufactured by Sunapro Co., Ltd., 0.5g), HOSTANOX O16 (phenolic antioxidant, manufactured by Clariant, 0.5g), and Adeka Stab 3010 (phosphorus antioxidant, manufactured by ADEKA Corporation, 0.5g) were added, mixed, and degassed to obtain filler 1.

[0081] <<Heating process>> As the base material, a silicon chip (size: 20mm x 20mm, average thickness 0.6mm) with a copper layer on the contact surface with the thermal conductive sheet was used. The copper layer of the base material was pre-treated at 150°C for 10 minutes in an N2 atmosphere saturated with formic acid. As the opposing base material, a copper plate (size: 30mm x 30mm, average thickness 0.1mm) was used, which had also been treated at 150°C for 10 minutes in an N2 atmosphere saturated with formic acid. The fabricated thermal conductive sheet was sandwiched between the base material and the opposing base material, treated at 150°C for 10 minutes in an N2 atmosphere saturated with formic acid, and then lightly pressed with tweezers. The resulting laminate was placed in a vacuum high-pressure press (manufactured by Meisho Kiko Co., Ltd.), and a heating process was carried out at 350°C for 5 minutes under an N2 atmosphere saturated with formic acid and a pressure of 20 MPa. This resulted in a bonded structure in which the copper plate and silicon chip were joined by sintering via the thermal conductive sheet (see Figure 1).

[0082] <<Filler Filling Process>> The resulting bonded structure was fixed in a cup with a sample clip, and the filler 1 obtained above was poured in until the space formed between the base material and the metal protrusions of the thermal conductive sheet, and the space formed between the opposing base material and the metal protrusions of the thermal conductive sheet were filled. The structure was then left to stand in a vacuum desiccator and degassed for 1 minute to fill it with filler 1. After that, the degassed bonded structure was cured at 100°C for 3 hours, followed by curing at 130°C for 3 hours to produce the laminate of Example 1.

[0083] (Example 2) The laminate of Example 2 was manufactured in the same manner as in Example 1, except that filler 1 was replaced with filler 2, which was prepared by the following procedure.

[0084] <<Preparation of Filler 2>> 25% by mass of bisphenol F type liquid epoxy resin (EXA-830CRP, manufactured by DIC Corporation) was mixed with 10% by mass of imidazole type latent epoxy resin (NovaCure HP-3941HP, manufactured by Asahi Kasei Corporation) and 65% by mass of spherical silica fine particles (SeaHostar KE-S 250, manufactured by Nippon Shokubai Co., Ltd.). The mixture was then mixed and degassed at room temperature (approximately 25°C) to obtain filler 2.

[0085] (Example 3) The laminate of Example 2 was manufactured in the same manner as in Example 1, except that filler 1 was replaced with filler 3, which was prepared by the following procedure.

[0086] <<Preparation of Filler 3>> 76% by mass of polyurethane acrylate (UV-3000B, manufactured by Mitsubishi Chemical Corporation) was mixed with 20% by mass of isobornyl acrylate (IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and 4% by mass of a curing agent (Perloyl L, manufactured by NOF Corporation). The mixture was then mixed and degassed at room temperature (approximately 25°C) to obtain filler 3.

[0087] (Example 4) The laminate of Example 2 was manufactured in the same manner as in Example 1, except that filler 1 was replaced with filler 4, which was prepared by the following procedure.

[0088] <<Preparation of Filler 4>> In a 300 mL three-necked flask, 209 g (0.39 mol) of polycaprolactone diol (Praxel 205U, molecular weight: 530, manufactured by Daicel Corporation) was mixed with 100 g (0.71 mol) of 2-isocyanate ethyl acrylate (Kalenz AOI, manufactured by Showa Denko K.K.) in an amount equal to 0.9 equivalents relative to the hydroxyl value of polycaprolactone diol. The flask was then sealed and stirred at 60°C for 3 days to obtain a colorless liquid polyester-modified acrylate having a polycaprolactone skeleton.

[0089] To 100 parts by mass of the obtained polyester-modified acrylate having a polycaprolactone skeleton, 4 parts by mass of a curing agent (Perloyl L, manufactured by NOF Corporation) was added, and the mixture was mixed and degassed at room temperature (approximately 25°C) to obtain filler 4.

[0090] (Example 5) The laminate of Example 5 was obtained in the same manner as in Example 1, except that the average thickness of the metal layer was 20 μm and the average thickness of the metal protrusions was 15 μm.

[0091] (Example 6) In Example 1, the laminate of Example 6 was obtained in the same manner as in Example 1, except that the area ratio of the metal protrusions was changed to 50% by adjusting the pitch of the adjacent metal protrusions.

[0092] (Example 7) In Example 1, the laminate of Example 7 was obtained in the same manner as in Example 1, except that the area ratio of the metal protrusions was changed to 20% by adjusting the pitch of the adjacent metal protrusions.

[0093] (Comparative Example 1) In Example 1, no filler was used, and the bonded body obtained in the heating step of Example 1 was used as the laminate for Comparative Example 1.

[0094] (Comparative Example 2) A laminate of Comparative Example 2 was obtained in the same manner as in Example 1, except that the area ratio of the metal protrusions was changed to 10% by adjusting the pitch of the adjacent metal protrusions.

[0095] (Comparative Example 3) A laminate of Comparative Example 3 was obtained in the same manner as in Example 1, except that no metal protrusions were processed and formed on the metal plate, the metal plate was used as a heat conductive sheet, and the area ratio of the metal protrusions was changed to 100%.

[0096] (Comparative Example 4) A thermal conductive sheet of Comparative Example 4 was prepared by filling the spaces between multiple metal protrusions on each surface of the thermal conductive sheet of Example 1 with filler 5 using the following procedure. Next, the laminate of Comparative Example 4 was obtained by following the procedure below without filling with filler after lamination.

[0097] <Preparation of Filler 5> Filler 5, an epoxy resin composition, was prepared by mixing 25% by mass of bisphenol F type epoxy resin (EPICRON 830 (trademark registered), manufactured by DIC Corporation), 5% by mass of 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ-PW, manufactured by Shikoku Chemicals, Inc.), and 70% by mass of phenoxy resin (Phenotote YP-50 (trademark registered), manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0098] <Filling with filler 5> Comparative Example 4 was prepared by filling the spaces between multiple metal protrusions on each surface of the metal layer in the thermal conductive sheet of Example 1 with an epoxy resin composition to a thickness equivalent to that of the metal protrusions, using a comma knife bar coater (FJ-TADK104, manufactured by Fuji Seiki Co., Ltd.).

[0099] <Heating process> Next, the thermal conductive sheet of Comparative Example 4 was sandwiched between the base material and the opposing base material, and heated and pressed for 2 minutes using a mini press machine under the conditions of an upper plate temperature of 170°C on the copper plate (opposing base material) side, a lower plate temperature of 170°C on the silicon plate (base material) side, and a set air pressure of 0.11 MPa (equivalent to 40 psi). After natural cooling, the press was released to produce the laminate of Comparative Example 4.

[0100] (Comparative Example 5) In Comparative Example 5, a film-like heat-conducting composition prepared by the following procedure was used as the heat-conducting sheet instead of the heat-conducting sheet of Example 1. Next, the laminate of Comparative Example 5 was obtained by following the procedure below without filling with filler after lamination.

[0101] <Preparation of a film-like heat-conducting composition> 3.26 parts by mass of a base thermoplastic resin (M2513, random copolymer polyamide, manufactured by Arkema Corporation, melting point: 125°C~135°C) and 4.48 parts by mass of a rosin-based resin (hydrogenated acid-modified rosin, KE-604, manufactured by Arakawa Industries Co., Ltd.) were placed in a jacketed flask capable of heating, and stirred for 30 minutes while maintaining a temperature of 125°C under a nitrogen gas atmosphere. Next, 56.30 parts by mass of heat-conducting particles (Ag-coated Cu particles, manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd., volume-average particle size Dv: 40 μm) and low-melting-point metal particles (Sn 58 Bi 42 35.96 parts by mass of particles (manufactured by Mitsui Mining & Smelting Co., Ltd., volume average particle size Dv: 4 μm) were added and mixed uniformly. Next, a 38 μm release film (38GS, manufactured by Lintec Corporation) cut to a standard size was placed in a press machine (mini press, manufactured by Dexerials Corporation) with upper and lower heat tools (170 mm x 70 mm) heated to 125°C. A fixed amount of the mixture prepared above was potted onto this film, and then sandwiched between a thickness gauge of 100 μm. Next, the 38 μm release film was placed over the thickness gauge and heated and pressed at 3.3 MPa (air pressure of 0.6 MPa) for 5 minutes, and then cooled to room temperature to produce a thermal conductive sheet of Comparative Example 5, which is a film-like thermal conductive composition.

[0102] <Heating process> Next, the thermal conductive sheet of Comparative Example 4 was sandwiched between the base material and the opposing base material, and a mini press was used to heat and press for 2 minutes under the conditions of an upper plate temperature of 170°C on the copper plate (opposing base material) side, a lower plate temperature of 170°C on the silicon plate (base material) side, and a set air pressure of 0.11 MPa (equivalent to 40 psi). After natural cooling, the press was released to produce the laminate of Comparative Example 5.

[0103] <Rating> The obtained laminates were evaluated for "thermal conductivity," "warpage," and "reliability" as follows. The results are shown in Table 1.

[0104] <Thermal conductivity> In accordance with JIS R 1611, the thermal resistance of each laminate was measured using a Netsch flash method thermal diffusivity / thermal conductivity measuring device (LFA467, manufactured by Netsch-Gereitebau) under conditions of a pulse width of 20 μsec. Next, the thermal resistance of the heat conductive sheet filled with filler was calculated by subtracting the thermal resistance of the silicon chip with a copper layer (the base material) and the copper plate with titanium plating and nickel plating applied in that order (the opposing base material) from the measured values. Then, the thermal conductivity W / (m·K) of the heat conductive sheet filled with filler was calculated by dividing the average thickness of the heat conductive sheet measured in advance by the thermal resistance. Thermal conductivity was evaluated according to the following criteria. The results are shown in Table 1. [Evaluation Criteria] ◎: Thermal conductivity is 70 W / m·K or higher. ○: The thermal conductivity is 50 W / m·K or higher and less than 70 W / m·K. △: Thermal conductivity is 10 W / m·K or more and less than 50 W / m·K. ×: The thermal conductivity is less than 10 W / m·K.

[0105] <Amount of curvature> The amount of warping was measured using a shape measuring device (One-Shot 3D Shape Measuring Machine VR-5000, manufactured by Keyence Corporation). Specifically, the laminate was placed on a horizontal and flat experimental bench so that the opposing substrate side (size: 30 mm x 30 mm) of the laminate was in contact with the substrate side. The difference between the Max and Min shape measurements along two diagonal lines on the surface of the substrate (size: 20 mm x 20 mm) of the laminate was measured, and the amount of warping was calculated as the average value. [Evaluation Criteria] ◎: The amount of warping is 50 μm or less, and the stress during lamination is greatly reduced. ○: The amount of warpage is between 50 μm and 100 μm, indicating that the stress during lamination is sufficiently relieved. △: The amount of warping is between 100 μm and 300 μm, which is within the practical range. ×: The amount of warping is less than 300 μm, which is outside the practical range.

[0106] <Vitality> The resulting laminates were placed in a thermal shock test apparatus (device name: TSA-73EL-A, manufactured by ESPEC Corporation) and subjected to a temperature cycling test consisting of 1000 cycles of -55°C (30 min) and 125°C (30 min). After the temperature cycling test, the adhesion of each laminate was observed using an ultrasonic imaging device (SAT, device name: FS300IIIHR, manufactured by Hitachi Power Solutions, Ltd.), and reliability was evaluated based on the following evaluation criteria. A 50 MHz, 7 mm probe was used on the copper plate (opposing substrate) side, and a 25 MHz probe was used on the silicon plate (substrate) side. The results are shown in Table 1. [Evaluation Criteria] ◎: There is almost no lifting, peeling, or voids from the thermal conductive sheet to the substrate, and these are less than 5% of the observation field of view. ○: Lifting, delamination, or voids of the thermal conductive sheet from the substrate are less than 20% of the observation field. △: Lifting, delamination, or voids of the thermal conductive sheet from the substrate are present in 20% to less than 80% of the observation field, which is within the practical range. ×: Lifting, delamination, or voids of the thermal conductive sheet from the substrate are present in more than 80% of the observation field, which is outside the practical range.

[0107] [Table 1]

[0108] [Table 2] [Explanation of symbols]

[0109] 1. Thermal conductive sheet 2 Heat spreader 2a Main surface 3. Heat-generating element (electronic component) 3a Top side 5 Heatsink 6 Wiring board 7. Thermal conductive sheet 10 Thermal conductive sheets 11 Metal layer 11' Metal plate before etching 12 Convex part 13 Protection part 14. Cured filler 15 Base material 16 Opposing substrate

Claims

1. A step of heating a metal layer and a heat conductive sheet having a plurality of metal protrusions on at least a first surface of the metal layer, sandwiched between a substrate and an opposing substrate, A method for manufacturing a laminate, comprising the step of filling a filler between at least one of the substrate and the opposing substrate and the plurality of metal protrusions and curing it.

2. The method for manufacturing a laminate according to claim 1, wherein the area ratio of the plurality of metal protrusions to the first surface of the heat conductive sheet is 20% or more and 80% or less.

3. The method for manufacturing a laminate according to claim 1, wherein the heat conductive sheet further has a plurality of metal protrusions on a second surface opposite to the first surface of the metal layer.

4. The method for manufacturing a laminate according to claim 1, wherein the average thickness of the metal layer is 10 μm or more and 200 μm or less.

5. The method for manufacturing a laminate according to claim 1, wherein the thermal conductivity of the thermal conductive sheet is 50 W / (m·K) or more.

6. The method for manufacturing a laminate according to claim 1, wherein the metal layer comprises at least one of gold, silver, copper, and aluminum.

7. The method for manufacturing a laminate according to claim 1, wherein the heating is performed at 350°C or lower.

8. The method for manufacturing a laminate according to claim 1, wherein the heating is performed under a pressing pressure of 20 MPa or less.

9. The method for producing a laminate according to claim 1, wherein the filler contains a curable material selected from the group consisting of curable silicone, curable epoxy resin, curable polyurethane resin, and curable polyester resin.

10. A base material and a counter base material, A thermal conductive sheet sandwiched between the substrate and the opposing substrate, having a metal layer and a plurality of metal protrusions on at least a first surface of the metal layer, A laminate characterized by having a cured product of a filler filled between the plurality of metal protrusions.

Images