Thermally conductive composition, method for manufacturing laminate, and laminate

Abstract

Provided is a thermally conductive composition containing a curing component, a curing agent, and a metal filler, the metal filler being at least one type selected from the group consisting of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles, and the volume filling rate of particles having a particle diameter of 1 [mu] m or less in the metal filler being 5 vol% or more. The volume filling rate of the metal filler is 30 vol% or more and 90 vol% or less.

Description

Technical Field

[0001] This invention relates to thermally conductive compositions, methods for manufacturing laminates, and laminates. Background Technology

[0002] Traditionally, in order to dissipate the heat generated by LED (light-emitting diode) chips or IC (integrated circuit) chips mounted on a heat-dissipating substrate to a heat sink, the heat-dissipating substrate and the heat sink have been joined together using a thermally conductive composition.

[0003] To achieve high thermal conductivity and low thermal resistance, such thermally conductive compositions require high filler content of metal fillers. In the case of liquid compositions, the fluidity will be reduced, and when made into sheets, there are problems such as sheet hardening, impaired conformability, and increased interfacial resistance.

[0004] To address the aforementioned problems, for example, a thermally conductive adhesive has been proposed. This thermally conductive adhesive comprises a thermosetting adhesive containing a curing component and a curing agent, and a metal filler dispersed in the thermosetting adhesive. The metal filler includes silver powder and solder powder, the solder powder exhibiting a melting temperature lower than the thermosetting temperature of the thermally conductive adhesive. Furthermore, the thermosetting adhesive reacts with the silver powder under thermosetting conditions to generate a high-melting-point solder alloy, representing a melting point higher than the melting temperature of the solder powder. The curing agent is a curing agent with fluxing activity relative to the metal filler, the curing component is a glycidyl ether type epoxy resin, and the curing agent is a tricarboxylic acid monoanhydride (for example, see Patent Document 1).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 5796242 Summary of the Invention The problem that the invention aims to solve However, in the prior art described in Patent Document 1, if solder powder with a large average particle size is used to bond small silver particles together to form a high-melting-point solder alloy network, the content of solder powder with low thermal conductivity by volume will be greater than the content of silver particles, failing to meet the requirements of high thermal conductivity and low thermal resistance. Furthermore, when using low-melting-point solder powder, the molten solder powder may form a resin layer on the surface of interface materials that are difficult to wet, resulting in a decrease in thermal conductivity.

[0006] The objective of this invention is to solve the aforementioned problems and achieve the following objective: that is, to provide a thermally conductive composition capable of achieving high thermal conductivity and low thermal resistance.

[0007] Methods for solving problems The method for solving the above-mentioned problem is as follows. That is, <1> A thermally conductive composition, characterized in that it contains a curing component, a curing agent, and a metal filler. The aforementioned metal filler is selected from at least one of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles. The volumetric filling rate of the aforementioned metal fillers containing particles smaller than 1 μm is 5% or more. The volumetric filling rate of the above-mentioned metal filler is above 30% and below 90% by volume.

[0008] <2> According to the thermally conductive composition described in <1> above, the volume filler of the metal filler is 50% to 80% by volume.

[0009] <3> In the thermally conductive composition according to any one of <1> to <2> above, the volume filling rate of particles with a particle size of 1 μm or less in the metal filler is 8% by volume or more.

[0010] <4> The thermally conductive composition according to any one of <1> to <3> above, wherein the curing component is at least one of an ethylene oxide cyclic compound and an oxobutane compound.

[0011] <5> The thermally conductive composition according to any one of <1> to <4> above, wherein the curing component is an ethylene oxide cyclic compound, The above-mentioned curing agent is an imidazole-based curing agent.

[0012] <6> The thermally conductive composition according to any one of <1> to <5> above further comprises a polymer having an intramolecular structure selected from at least one of a phenoxy structure, a polybutadiene structure, a polysiloxane structure, a poly(meth)acrylate structure, a polyalkylene structure, a polyalkyleneoxy structure, a polyisoprene structure, a polyisobutylene structure, a polyamide structure, and a polycarbonate structure.

[0013] <7> A method for manufacturing a laminate, characterized by comprising the following steps: The process of applying the thermally conductive composition described in any one of <1> to <6> to a substrate, and The process of heating the above-mentioned thermally conductive composition.

[0014] <8> The method for manufacturing the laminate according to <7> above further includes: a step of applying a second thermally conductive composition containing a second curing component, a second curing agent, a second metal filler, and low-melting-point metal particles to the above-mentioned thermally conductive composition. The heating process described above is a process of heating the above thermally conductive composition and the above second thermally conductive composition.

[0015] <9> In the method for manufacturing the laminate according to any one of <7> to <8> above, the substrate is a silicon substrate.

[0016] <10> A laminate, characterized in that it comprises: a substrate, A first thermally conductive layer containing curing components, a curing agent, and a sintered body is disposed on the aforementioned substrate. The sintered body described above is formed by sintering at least one type of metal filler selected from silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles, and is a sintered body that is connected in both the thickness direction and the planar direction of the first thermally conductive layer. The volume fill rate of the sintered body in the first thermally conductive layer is 30% to 90% by volume.

[0017] <11> The laminated body according to <10> above further comprises: A second thermally conductive layer containing a second curing component, a second curing agent, a second metal filler, and low-melting-point metal particles is disposed on the aforementioned thermally conductive layer.

[0018] <12> The laminate according to any one of <10> to <11> above, wherein the substrate is a silicon substrate.

[0019] <13> The laminate according to any one of <10> to <12> above has a thermal conductivity of 10 W / (m·K) or higher.

[0020] The effects of the invention According to the present invention, the aforementioned problems can be solved and the above-mentioned objectives can be achieved, and a thermally conductive composition capable of achieving high thermal conductivity and low thermal resistance can be provided. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating an example of the process of manufacturing a laminate according to the first embodiment.

[0022] Figure 2 This is a schematic diagram illustrating an example of a laminated body according to the first embodiment.

[0023] Figure 3 This is a schematic diagram illustrating an example of the process for manufacturing a laminate according to the second embodiment.

[0024] Figure 4 This is a schematic diagram illustrating an example of a laminated body according to the second embodiment.

[0025] Figure 5 This is a schematic cross-sectional view showing an example of a heat-dissipating structure having the laminate of this embodiment. Detailed Implementation

[0026] (Thermal conductive composition) The thermally conductive composition of the present invention contains a curing component, a curing agent, and a metal filler, and may further contain other components as needed.

[0027] The aforementioned metal filler is selected from at least one of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles. The volume filling rate of the aforementioned metal filler with particles smaller than 1 μm is 5% or more, and the volume filling rate of the aforementioned metal filler is 30% or more and 90% or less.

[0028] <Cureable Components> As the curing component, at least one of ethylene oxide cyclic compounds and oxobutane compounds is preferably used.

[0029] -Ethylene oxide cyclic compounds- The aforementioned ethylene oxide ring compounds are compounds having an ethylene oxide ring, such as epoxy resins.

[0030] There are no particular limitations on the epoxy resins mentioned above, and they can be appropriately selected according to the purpose. For example, glycidyl ether type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A type epoxy resin, triphenol type epoxy resin, tetraphenol type epoxy resin, phenol-phthalimide type epoxy resin, naphthol-phthalimide type epoxy resin, phenol-naphthol type epoxy resin, phenol-dicyclopentadiene type epoxy resin, alicyclic epoxy resin, and aliphatic epoxy resin are all examples.

[0031] They can be used individually or in combination with more than one type.

[0032] --Oxycyclic butane compounds-- The aforementioned oxetane compounds can be compounds containing oxetane groups, aliphatic compounds, alicyclic compounds, or aromatic compounds.

[0033] The aforementioned oxetane compounds can be monofunctional oxetane compounds having only one oxetane alkyl group, or polyfunctional oxetane compounds having two or more oxetane alkyl groups.

[0034] There are no particular limitations on the aforementioned oxetane compounds, and appropriate selection can be made according to the purpose. Examples include 3,7-bis(3-oxetane)-5-oxo-nonane, 1,4-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetane-butylmethyl) ether, triethylene glycol bis(3-ethyl-3-oxetane-butylmethyl) ether, tetraethylene glycol bis(3-ethyl-3-oxetane-butylmethyl) ether, 1,4-bis(3-ethyl-3-oxetane-butylmethoxy)butane, 1, 6-Bis(3-ethyl-3-oxetane)methoxy)hexane, 3-ethyl-3-(phenoxy)methyloxetane, 3-ethyl-3-(cyclohexyloxymethyl)oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-(chloromethyl)oxetane, 3-ethyl-3{[(3-ethyloxetane-3-yl)methoxy]methyl}oxetane, phenylenediamine dioxetane, 4,4'-bis[(3-ethyl-3-oxetane)methoxymethyl]biphenyl (OXBP), bis[(3-ethyl-3-oxetane)methyl]isophthalate (OXIPA), etc.

[0035] They can be used individually or in combination with more than one type.

[0036] As the aforementioned oxobutane compounds, commercially available products can be used. Examples of such commercially available products include the "ARONOXETANE (registered trademark)" series sold by Toa Synthetic Co., Ltd., and the "ETERNACOLL (registered trademark)" series sold by Ube Industries, Ltd.

[0037] Among the above-mentioned ethylene oxide cyclic compounds and oxetane compounds, the preferred types are glycidyl ether type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, phenol-dicyclopentadiene type epoxy resin, bisphenol A type epoxy resin, aliphatic epoxy resin, 4,4'-bis[(3-ethyl-3-oxetane)methoxymethyl]biphenyl (OXBP), and bis[(3-ethyl-3-oxetane)methyl]isophthalate (OXIPA).

[0038] The content of the aforementioned curing component is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.5% to 60% by volume relative to the total amount of the thermally conductive composition.

[0039] <Curing agent> As the curing agent mentioned above, the curing agent is the curing agent corresponding to the curing component mentioned above. For example, polyfunctional carboxylic acids, anhydride-based curing agents, aliphatic amine-based curing agents, aromatic amine-based curing agents (e.g., imidazole-based curing agents), phenol-based curing agents, thiol-based curing agents, and other addition-polymerization type curing agents, imidazole-based catalytic type curing agents, etc.

[0040] They can be used individually or in combination with more than one type.

[0041] Among these, aromatic amine curing agents are preferred, and imidazole curing agents are more preferred.

[0042] As the aforementioned imidazole-based curing agents, commercially available products can be used. Examples of such commercially available products include, for instance, 2P4MZ, 2PZ, and 2E4MZ-A from the "CUREZOL" series sold by Shikoku Kasei Corporation; and HX-3941HP, HXA3922HP, HXA3792, HXA3932HP, HXA3042HP, HXA9322HP, HXA9382HP, HXA5052HP, and HXA3542HP from the "NOVACURE (registered trademark)" series sold by Asahi Kasei Corporation.

[0043] When the curing component of the above-mentioned anhydride-based curing agent is epoxy resin, no gas is generated during heat curing, and a long shelf life can be achieved when mixed with epoxy resin. Furthermore, it is preferred from the perspective of achieving a good balance between the electrical, chemical and mechanical properties of the resulting cured product.

[0044] Examples of anhydride-based curing agents include cyclohexane-1,2-dicarboxylic acid anhydride and monocarboxylic acid anhydrides. Examples of monocarboxylic acid anhydrides include cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride.

[0045] The curing agent described above has flux activity and is preferred from the perspective of improving the wettability of low-melting-point metal particles relative to the melting of thermally conductive particles.

[0046] As a method to make the curing agent exhibit flux activity, for example, methods can be used to introduce protic acid groups such as carboxyl groups, sulfonyl groups, and phosphate groups into the curing agent using known methods. Among these, considering the reactivity with epoxy resins or oxobutane compounds that are curing components, introducing carboxyl groups is preferred; for example, polycarboxylic acids containing carboxyl groups such as glutaric acid and succinic acid can be used. Furthermore, the curing agent can be a compound modified with glutaric anhydride or succinic anhydride, or a metal salt of polycarboxylic acids such as silver glutarate.

[0047] The content of the curing agent is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.1% to 30% by volume relative to the total amount of the thermally conductive composition.

[0048] In one embodiment, the curing component is an ethylene oxide cyclic compound, and the curing agent is an imidazole-based curing agent, which is preferred from the perspective of achieving higher thermal conductivity.

[0049] The molar equivalent ratio (A / B) of the curing component A and the curing agent B varies depending on the type of curing component and curing agent used, and cannot be specified in general terms. It is preferably 5 or more and 15 or less, more preferably 7 or more and 13 or less, and even more preferably 9 or more and 11 or less.

[0050] If the above equivalent ratio (A / B) is 5 or more and 15 or less, when the thermally conductive composition is heated, a network of sintered body formed by sintering metal fillers can be formed, and the sintered body with a high volume filling rate of forming a network can be maintained.

[0051] <Metal Packing> The aforementioned metal filler is selected from at least one of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles.

[0052] The volume filling rate of particles with a diameter of less than 1 μm in the above-mentioned metal fillers is more than 5% by volume, and the volume filling rate of the above-mentioned metal fillers is more than 30% by volume and less than 90% by volume.

[0053] Examples of silver-coated particles include silver-coated copper particles, silver-coated nickel particles, and silver-coated aluminum particles.

[0054] There are no particular restrictions on the shape of the aforementioned metal fillers, and they can be appropriately selected according to the purpose. For example, spherical, flat, granular, and needle-shaped fillers are possible.

[0055] The volume average particle size (D) of the above-mentioned metal fillers 50 Preferably, the micrometer is 1μm or more and 10μm or less, and more preferably 1μm or more and 5μm or less.

[0056] If the volume average particle size of the metal filler is between 1 μm and 10 μm, then when the thermally conductive composition is heated, a network of sintered bodies formed by sintering the metal filler can be formed, which can achieve high thermal conductivity and low thermal resistance of the thermally conductive composition.

[0057] The above volume average particle size (D) 50 For example, it can be measured using a laser diffraction-scattering particle size distribution measuring device (product name: Microtrac MT3300EXII).

[0058] The volume filling rate (c / C) of particles c with a particle size of less than 1 μm in the above-mentioned metal filler C is 5% or more, preferably 8% or more.

[0059] If the volume filling rate (c / C) of particles c with a particle size of less than 1 μm in the above-mentioned metal filler C is 5% or more, then when the thermally conductive composition is heated, a network of sintered bodies formed by sintering the metal filler can be formed, and the high thermal conductivity and low thermal resistance of the thermally conductive composition can be achieved.

[0060] There is no particular limitation on the upper limit of the volume filling rate (c / C) of particles c with a particle size of less than 1 μm in the above-mentioned metal filler C. It can be appropriately selected according to the purpose, preferably 50% or less by volume, and more preferably 40% or less by volume.

[0061] The volumetric filling rate of the aforementioned metal filler is 30% to 90% and preferably 50% to 80%.

[0062] The lower limit of the volumetric filling rate of the aforementioned metal filler is 30% or more, preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 75% or more. The upper limit of the volumetric filling rate of the aforementioned metal filler is 90% or less, preferably 85% or less, and more preferably 80% or less.

[0063] If the volume filler ratio of the above-mentioned metal filler is 30% to 90% by volume, high thermal conductivity and low thermal resistance of the thermally conductive composition can be achieved.

[0064] <Specific polymers> In order to impart softness and sealing properties, the above-mentioned thermally conductive composition preferably contains a specific polymer.

[0065] As the specific polymer mentioned above, a polymer having at least one structure selected from the following in its molecule: phenoxy structure, polybutadiene structure, polysiloxane structure, poly(meth)acrylate structure, polyalkylene structure, polyalkyleneoxy structure, polyisoprene structure, polyisobutylene structure, polyamide structure, and polycarbonate structure is used.

[0066] As the specific polymers described above, for example, it is preferable to have a phenoxy structure selected from bisphenol A type, bisphenol F type, etc., a polybutadiene structure such as that of polybutadiene and hydrogenated polybutadiene, a polysiloxane structure such as that of silicone rubber, a poly(meth)acrylate structure, a polyalkylene structure (preferably a polyalkylene structure with 2 to 15 carbon atoms, more preferably a polyalkylene structure with 3 to 10 carbon atoms, and even more preferably a polyalkylene structure with 5 to 6 carbon atoms), or a polyalkylene oxide structure (preferably a polyalkylene oxide structure with 2 to 15 carbon atoms, more preferably...). The structure is selected as having a polyalkylene oxide structure with 3 to 10 carbon atoms, more preferably a polyalkylene oxide structure with 5 to 6 carbon atoms, a polyisoprene structure, a polyisobutylene structure, and a polycarbonate structure, preferably having a structure selected from at least one of a phenoxy structure, a polybutadiene structure, a polysiloxane structure, a poly(meth)acrylate structure, a polyisoprene structure, a polyisobutylene structure, and a polycarbonate structure, more preferably having a structure selected from at least one of a phenoxy structure, a polybutadiene structure, a polyisoprene structure, and a polycarbonate structure.

[0067] To exhibit flexibility, the aforementioned specific polymer is preferably of high molecular weight. The number average molecular weight (Mn) of the aforementioned specific polymer is preferably 1,000 or more but less than 1,000,000, more preferably 5,000 or more but less than 900,000.

[0068] The number-average molecular weight (Mn) mentioned above is the converted number-average molecular weight of polystyrene determined using GPC (gel permeation chromatography).

[0069] To exhibit flexibility, the aforementioned specific polymers are preferably selected from polymers with a glass transition temperature (Tg) below 25°C and polymers that are liquid at 25°C.

[0070] For polymers with a glass transition temperature (Tg) of 25°C or lower, the glass transition temperature is preferably 20°C or lower, more preferably 15°C or lower. There is no particular limitation on the lower limit of the glass transition temperature; it can be appropriately selected according to the purpose, but is preferably -15°C or higher.

[0071] The polymer is liquid at 25°C, preferably a polymer that is liquid at 20°C or below, and more preferably a polymer that is liquid at 15°C or below.

[0072] From the viewpoint of improving the mechanical strength of the cured product, it is preferable that the polymer has functional groups that can react with the cured components. Furthermore, functional groups that manifest upon heating are also included as functional groups that can react with the cured components.

[0073] The functional group capable of reacting with the aforementioned curing component is, for example, one or more functional groups selected from the group consisting of hydroxyl, carboxyl, anhydride, phenolic hydroxyl, epoxy, isocyanate, and urethane groups. Among these, hydroxyl, anhydride, phenolic hydroxyl, epoxy, isocyanate, and urethane groups are preferred as the aforementioned functional group, and hydroxyl, anhydride, phenolic hydroxyl, and epoxy groups are more preferred.

[0074] The content of the specific polymer mentioned above relative to the total amount of the thermally conductive composition is preferably 1% to 50% by volume, more preferably 1% to 30% by volume, even more preferably 1% to 20% by volume, and particularly preferably 1% to 10% by volume.

[0075] <Other Ingredients> The above-mentioned thermally conductive composition may contain other ingredients as long as it does not impair the effect of the present invention.

[0076] There are no particular restrictions on the other components mentioned above, and they can be appropriately selected according to the purpose. For example, thermally conductive particles other than metals (e.g., aluminum nitride, aluminum oxide, carbon fiber, etc.) and additives (e.g., antioxidants, UV absorbers, curing accelerators, silane coupling agents, leveling agents, flame retardants, etc.) can be mentioned.

[0077] The above-mentioned thermally conductive composition can be prepared by uniformly mixing the above-mentioned curing components, the above-mentioned curing agent and the above-mentioned metal filler, the above-mentioned specific polymer and other components as needed using conventional methods.

[0078] The above-mentioned thermally conductive composition can be either a sheet-like thermally conductive sheet or a paste-like thermally conductive paste (sometimes referred to as a thermally conductive adhesive or thermally conductive grease). Among these, the thermally conductive sheet is preferred from the perspective of ease of handling, while the thermally conductive paste is preferred from the perspective of cost.

[0079] (Manufacturing method of laminated bodies) The method for manufacturing the laminate of the present invention includes a first imparting step and a heating step, preferably including a second imparting step, and further including other steps as needed.

[0080] [Method for manufacturing the laminate according to the first embodiment] As one embodiment, the above-described method for manufacturing the laminate includes a first imparting step and a heating step, thereby enabling the manufacture of a laminate having a substrate and a first thermally conductive layer disposed on the substrate (the laminate of the first embodiment).

[0081] Thus, a thermally conductive layer of a sintered body containing the aforementioned curing components, curing agent, and metal filler is formed on the aforementioned substrate, and the sintered body is connected in the thickness direction and planar direction of the aforementioned thermally conductive layer, thereby enabling the manufacture of a laminate that achieves high thermal conductivity and low thermal resistance.

[0082] [Method for manufacturing the laminate according to the second embodiment] As another embodiment, the above-described method for manufacturing the laminate includes a first application step, a second application step, and a heating step, thereby enabling the manufacture of a laminate having a substrate, a first thermally conductive layer disposed on the substrate, and a second thermally conductive layer disposed on the first thermally conductive layer (the laminate of the second embodiment).

[0083] Therefore, by further having a second thermally conductive layer of a low-melting-point metal in the laminate of the first embodiment, it is possible to manufacture a laminate that can achieve a higher heat dissipation effect (high thermal conductivity).

[0084] <First Imparting Process> The first imparting step described above is the step of imparting the thermally conductive composition of the present invention (sometimes referred to as the "first thermally conductive composition") onto the substrate described above.

[0085] The curing components, curing agents, metal fillers, and other components contained in the above-described thermally conductive composition can be appropriately selected from the items described in the thermally conductive composition of this embodiment.

[0086] Methods for imparting the first thermally conductive composition to the substrate include, for example, inkjet printing, blade coating, gravure coating, gravure coating layering, bar coating, roller coating, knife coating, air knife coating, comma coating, U-comma coating, AKKU coating, smooth coating, micro-gravure coating, reverse roller coating, 4-roller coating, 5-roller coating, dip coating, curtain coating, sliding coating, and mold coating.

[0087] Furthermore, the sheet-like first thermally conductive composition described above can be applied to the substrate by means of transfer printing or the like.

[0088] -Substrate- There are no particular restrictions on the shape, structure, size, material, etc. of the aforementioned substrates, and appropriate selection can be made according to the purpose.

[0089] Examples of the shape of the substrate include, for example, a plate or sheet. Examples of the structure of the substrate include a single-layer structure or a laminated structure. Examples of the size of the substrate can be appropriately selected according to the application.

[0090] As the material of the aforementioned substrate, the first thermally conductive layer that is in contact with the aforementioned substrate does not contain low-melting-point metals, so materials that are not easily wetted by solder can be selected, such as silicon, aluminum, tungsten, molybdenum, glass, modeling resin, stainless steel, ceramics, etc.

[0091] Examples of ceramics mentioned above include aluminum nitride, silicon carbide, aluminum oxide, and gallium nitride.

[0092] Examples of the model resins mentioned above include epoxy resins, silicone resins, urethane resins, and acrylic resins.

[0093] The substrate is preferably a silicon substrate.

[0094] Furthermore, the first thermally conductive layer is formed by sintering the metal filler, and the sintered body, which is connected in the thickness direction and the planar direction of the thermally conductive layer, is in contact with the substrate. Therefore, it can be appropriately used as a substrate without a metal coating, and a laminate that can achieve high thermal conductivity and low thermal resistance can be manufactured.

[0095] Furthermore, in the first thermally conductive composition, the metal filler is not in a fully fluid state, thus generally eliminating the need for the pre-sintering of the substrate with metal required for sintering microparticles of silver. Compared to conventional silver powder used in the production of existing silver sintered bodies, the metal filler is not entirely melted and flowing. The sintered body formed by the metal filler maintains some particle shape while the metal fillers are connected to each other, becoming a sintered body capable of efficiently conducting heat along the thickness and planar directions of the thermally conductive layer. Therefore, conventional silver powder and silver sintered bodies that are fused to a substrate with a metal coating have different characteristics from the metal filler and sintered body of this embodiment.

[0096] There are no particular limitations on the average thickness of the aforementioned substrates, and they can be appropriately selected according to the purpose.

[0097] The aforementioned substrate can be the heat-generating element (electronic component) itself in the heat-generating structure.

[0098] <Heating Process> The heating process described above is a process of heating the thermally conductive composition, thereby forming a first thermally conductive layer on the substrate.

[0099] Furthermore, in the case of a second heating step described later, the heating step is a step of heating the first thermally conductive composition and the second thermally conductive composition, thereby forming the first thermally conductive layer and the second thermally conductive layer on the substrate.

[0100] As the heating conditions described above, the metal filler contained in the thermally conductive composition can be sintered to form the sintered body. If the conditions are for curing components and curing agents to react and be cured, there are no particular limitations, and they can be appropriately selected according to the purpose. For example, it is preferred to be 120°C to 190°C for 1 minute to 30 minutes, and more preferably 140°C to 170°C for 1 minute to 10 minutes.

[0101] <Second application process> The second application step described above is a step of applying the second thermally conductive composition to the thermally conductive composition (the first thermally conductive composition) applied to the substrate.

[0102] Methods for imparting the second thermally conductive composition to the substrate include, for example, inkjet printing, blade coating, gravure coating, gravure coating layering, bar coating, roller coating, knife coating, air knife coating, comma coating, U-comma coating, AKKU coating, smooth coating, micro-gravure coating, reverse roller coating, 4-roller coating, 5-roller coating, dip coating, curtain coating, sliding coating, and mold coating.

[0103] Furthermore, the sheet-like second thermally conductive composition described above can be applied to the substrate by means of transfer printing or the like.

[0104] A second thermally conductive composition can be applied to a first thermally conductive composition in a liquid phase, followed by a heating process, thereby improving the adhesion between the resulting first and second thermally conductive layers. Furthermore, the flux activity of the curing agent during the heating process enhances the wettability of the dissolved low-melting-point metal with the second thermally conductive particles.

[0105] -Second thermally conductive composition- The aforementioned second thermally conductive composition contains a second curing component, a second curing agent, second thermally conductive particles, and low-melting-point metal particles, and may further contain other components as needed.

[0106] -Second Curing Component- The second curing component preferably includes at least one of an oxetane compound and an epoxy resin, more preferably an oxetane compound and an epoxy resin.

[0107] As the second curing component, the oxetine compound, and the epoxy resin, the items described in the above-described curing components of the thermoplastic resin of the present invention can be appropriately selected.

[0108] The content of the second curing component in the second thermally conductive composition is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.5% to 20% by volume and more preferably 1% to 15% by volume relative to the total amount of the second thermally conductive composition.

[0109] -Second Curing Agent- As the curing agent mentioned above, the curing agent corresponding to the curing component mentioned above can be, for example, polyfunctional carboxylic acids, anhydride-based curing agents, aliphatic amine-based curing agents, aromatic amine-based curing agents, phenol-based curing agents, thiol-based curing agents and other addition-polymerization type curing agents, imidazole and other catalytic type curing agents.

[0110] They can be used individually or in combination with more than one type.

[0111] Among these, polyfunctional carboxylic acids are preferred, and glutaric acid is preferred.

[0112] As the second curing agent, the curing agents described above in the thermoplastic resin of the present invention can be appropriately selected.

[0113] The content of the second curing agent in the second thermally conductive composition is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.5% to 20% by volume and more preferably 1% to 15% by volume relative to the total amount of the second thermally conductive composition.

[0114] -Second thermally conductive particle- The second thermally conductive particle is preferably any one of copper particles, silver-coated particles, and silver particles, and more preferably silver-coated particles.

[0115] Examples of silver-coated particles include silver-coated copper particles, silver-coated nickel particles, and silver-coated aluminum particles.

[0116] The shape of the aforementioned second thermally conductive particle is not particularly limited and can be appropriately selected according to the purpose. For example, spherical, flat, granular, and needle-shaped particles can be used.

[0117] The volume average particle size of the second thermally conductive particle is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, and even more preferably 5 μm or more and 50 μm or less. If the volume average particle size of the second thermally conductive particle is 1 μm or more and 100 μm or less, excellent thermal conductivity can be achieved.

[0118] The volume average particle size of the second thermally conductive particle can be measured in the same manner as the volume average particle size of the metal filler.

[0119] -Low melting point metal- The aforementioned low-melting-point metals refer to the aforementioned low-melting-point metal particles and the low-melting-point metals formed by the melting and solidification of the aforementioned low-melting-point metal particles.

[0120] As the aforementioned low-melting-point metal particles, solder particles as specified in JIS Z3282-1999 should be used appropriately.

[0121] Examples of solder particles mentioned above include Sn-Pb-based solder particles, Pb-Sn-Sb-based solder particles, Sn-Sb-based solder particles, Sn-Pb-Bi-based solder particles, Sn-Bi-Ag-based solder particles, Sn-Cu-based solder particles, Sn-Pb-Cu-based solder particles, Sn-In-based solder particles, Sn-Ag-based solder particles, Sn-Pb-Ag-based solder particles, Pb-Ag-based solder particles, and Sn-Ag-Cu-based solder particles. One type can be used alone, or two or more types can be used together.

[0122] Among these, solder particles containing Sn and at least one selected from Bi, Ag, Cu and In are preferred, Sn-Bi-based solder particles, Sn-Bi-Ag-based solder particles, Sn-Ag-Cu-based solder particles, Sn-In-based solder particles are more preferred, and Sn-Bi-based solder particles containing Sn and Bi are even more preferred.

[0123] There are no particular restrictions on the shape of the aforementioned low-melting-point metal particles, and they can be appropriately selected according to the purpose. For example, spherical, flat, granular, and needle-shaped particles can be used.

[0124] The melting point of the aforementioned low-melting-point metal particles is preferably 100°C to 250°C, and more preferably 120°C to 200°C.

[0125] The melting point of the aforementioned low-melting-point metal particles is preferably lower than the heating temperature of the aforementioned heating process.

[0126] Therefore, during the curing of the second thermally conductive composition, a second thermally conductive layer with a network (a continuous phase of metal) can be formed by molten low-melting-point metal and second thermally conductive particles. Thus, a laminate with excellent heat resistance, thermal conductivity, and adhesion can be achieved.

[0127] The volume average particle size of the aforementioned low-melting-point metal particles is preferably 10 μm or less, and more preferably 1 μm or more but less than 7 μm. If the volume average particle size of the low-melting-point metal particles is 10 μm or less, the volume ratio of the low-melting-point metal particles to the second thermally conductive particles can be reduced, thereby achieving high thermal conductivity and low thermal resistance of the second thermally conductive layer.

[0128] The volume average particle size of the aforementioned low-melting-point metal particles can be measured in the same manner as the volume average particle size of the aforementioned metal fillers.

[0129] The volume average particle size of the second thermally conductive particle is larger than that of the low-melting-point metal particle, and the volume average particle size ratio (α / β) of the second thermally conductive particle α to the low-melting-point metal particle β is preferably 1.5 or more. The upper limit of the volume average particle size ratio (α / β) is preferably 10 or less.

[0130] By using low-melting-point metal particles with a smaller volume average particle size compared to the second thermally conductive particles, the second thermally conductive particles become the main component in the second thermally conductive composition. The low-melting-point metal particles that exist between the second thermally conductive particles melt due to heating and alloy with the second thermally conductive particles to form a network, thereby achieving high thermal conductivity and low thermal resistance.

[0131] In the second thermally conductive composition used to form the second thermally conductive layer, the volume ratio (α / β) of the second thermally conductive particle α to the low-melting-point metal particle β is preferably 1 or more, more preferably 1.5 or more, and even more preferably 1.8 or more. The upper limit of the volume ratio (α / β) is preferably 4 or less, more preferably 3 or less.

[0132] <Other Processes> As for other processes, there are no particular restrictions, and they can be appropriately selected according to the purpose. For example, the protective layer formation process and the substrate lamination process can be cited.

[0133] (Layered structure) The laminate of the present invention has a substrate and a first thermally conductive layer, preferably further having a second thermally conductive layer, and further having an opposing substrate and other components as needed.

[0134] [Laminated body of the first embodiment] In one embodiment, the laminate has a substrate and a first thermally conductive layer disposed on the substrate. The first thermally conductive layer contains a curing component, a curing agent, and a sintered body.

[0135] The sintered body is formed by sintering the metal filler and is a sintered body that is connected in the thickness direction and the planar direction of the first heat-conducting layer.

[0136] The volume fill rate of the sintered body in the above-mentioned heat-conducting layer is more than 30% and less than 90% by volume.

[0137] The laminate of the first embodiment can be appropriately manufactured by the manufacturing method of the laminate of the first embodiment.

[0138] According to the laminate of the first embodiment, a thermally conductive layer containing the sintered body is formed on the substrate, and the sintered body is interconnected along the thickness direction and the planar direction of the thermally conductive layer, thereby achieving high thermal conductivity and low thermal resistance. Specifically, due to the high heat dissipation effect brought about by the interconnected sintered body, a thermal conductivity of 10 W / (m·K) or more can be achieved, preferably 15 W / (m·K) or more. Furthermore, even for substrates without a metal coating, zero contact thermal resistance can be achieved.

[0139] [Laminated body of the second embodiment] In another embodiment, the laminate has a substrate, a first thermally conductive layer disposed on the substrate, and a second thermally conductive layer disposed on the first thermally conductive layer.

[0140] The aforementioned second thermally conductive layer contains a second curing component, a second curing agent, a second metal filler, and low-melting-point metal particles, and may further contain other components as needed.

[0141] The laminate of the second embodiment can be appropriately manufactured by the manufacturing method of the laminate of the second embodiment.

[0142] According to the laminate of the second embodiment, by further providing a second thermally conductive layer having a low-melting-point metal compared to the laminate of the first embodiment, a further high heat dissipation effect (high thermal conductivity) can be achieved. A thermal conductivity of 15 W / (m·K) or higher can be achieved, preferably 20 W / (m·K) or higher.

[0143] <Substrate> As the aforementioned substrate, the items described in the manufacturing method of the laminate of the present invention can be appropriately selected.

[0144] <First thermal conductive layer> The first thermally conductive layer is preferably formed on the substrate and is in contact with the substrate.

[0145] The first thermally conductive layer mentioned above contains curing components, curing agents, and sintered bodies.

[0146] As curing components and curing agents, the items described in the above-described thermally conductive compositions of the present invention can be appropriately selected.

[0147] -Sintered body- The sintered body is formed by sintering the metal filler and is a sintered body that is connected in the thickness direction and the planar direction of the first heat-conducting layer.

[0148] The sintered body is in contact with the substrate, thereby enabling zero contact thermal resistance even for substrates without metal coating, achieving high thermal conductivity and low thermal resistance.

[0149] The volume fill rate of the sintered body in the above-mentioned heat-conducting layer is 30% to 90% and preferably 50% to 80%.

[0150] The lower limit of the volume filling rate of the sintered body is 30% or more, preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 75% or more. The upper limit of the volume filling rate of the sintered body is 90% or less, preferably 85% or less, and more preferably 80% or less.

[0151] If the volume fill rate of the sintered body is above 30% and below 90% by volume, then high thermal conductivity and low thermal resistance of the laminate can be achieved.

[0152] The average thickness of the first thermally conductive layer is not particularly limited and can be appropriately selected according to the purpose. It is preferably 10 μm or more and 300 μm or less, and more preferably 20 μm or more and 200 μm or less.

[0153] <Second thermal conductive layer> The aforementioned second thermally conductive layer contains a second curing component, a second curing agent, a second metal filler, and low-melting-point metal particles, and may further contain other components as needed.

[0154] The second curing component, the second curing agent, the second metal filler, and the low-melting-point metal particles can be appropriately selected from the items described in the manufacturing method of the laminate of the present invention.

[0155] The average thickness of the second thermally conductive layer is not particularly limited and can be appropriately selected according to the purpose. It is preferably 20 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0156] <Opposite substrate> The aforementioned opposing substrates are arranged opposite each other, and there are no particular restrictions on their shape, structure, size, material, etc., and they can be appropriately selected according to the purpose.

[0157] Examples of the shape of the aforementioned opposing substrate include, for example, a plate or sheet. Examples of the structure of the aforementioned opposing substrate include a single-layer structure or a laminated structure. Examples of the size of the aforementioned opposing substrate can be appropriately selected according to the application, etc.

[0158] The aforementioned opposing substrate is made of a material that is easily wetted by solder, including at least one selected from copper, gold, platinum, palladium, silver, zinc, iron, tin, nickel, magnesium, indium, and alloys thereof.

[0159] There are no particular limitations on the average thickness of the aforementioned opposing substrates, and they can be appropriately selected according to the purpose.

[0160] The aforementioned opposing substrate can be the heat sink itself in the heat-dissipating structure.

[0161] <Other Components> As for other components, there are no particular restrictions, and they can be appropriately selected according to the purpose. For example, a protective layer can be mentioned.

[0162] Here, the manufacturing method of the laminate and the embodiments of the laminate of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in each drawing, the same reference numerals are used for the same constituent parts, and repeated descriptions are sometimes omitted. In addition, the number, position, shape, etc., of the constituent members described below are not limited to this embodiment; preferred numbers, positions, shapes, etc., can be adopted based on the implementation of the present invention.

[0163] Figure 1 This is a schematic diagram illustrating an example of the process of manufacturing a laminate according to the first embodiment.

[0164] Figure 1 The laminate 10a shown before curing is a laminate after the first imparting process and before the heating process. Specifically, it has a first thermally conductive composition 12a containing metal filler 12b on a substrate 11, and an opposing substrate 15 on the first thermally conductive composition 12a.

[0165] Figure 2 This is a schematic diagram illustrating an example of a laminated body according to the first embodiment.

[0166] Figure 2 The laminate 10 shown has a first thermally conductive layer 12 on a substrate 11, which is a sintered body 12c containing metal filler 12b sintered together, and an opposing substrate 15 on the first thermally conductive layer 12.

[0167] Figure 3 This is a schematic diagram illustrating an example of the process for manufacturing a laminate according to the second embodiment.

[0168] Figure 3 The laminate 20a shown before curing is a laminate before curing by humidification after the first application step and the second application step and before the heating step. Specifically, it has a first thermally conductive composition 12a containing metal filler 12b on the substrate 11, a second thermally conductive composition 14a containing second thermally conductive particles 14b and low melting point metal particles 14c on the first thermally conductive composition 12a, and an opposing substrate 15 on the second thermally conductive composition 14a.

[0169] Figure 4 This is a schematic diagram illustrating an example of a laminated body according to the second embodiment.

[0170] Figure 4The laminate 20 shown has a first thermally conductive layer 12 on a substrate 11, which is a sintered body 12c containing metal filler 12b sintered together. On the first thermally conductive layer 12, there is a second thermally conductive layer 14 containing second thermally conductive particles 14b and low-melting-point metal 14d. On the second thermally conductive layer 14, there is an opposing substrate 15.

[0171] The laminate of the present invention, for example, can be used to attach a heat-dissipating substrate, which is equipped with a thermal interface material (TIM) such that heat can flow smoothly between the heat source such as an LSI and a heat sink, to the heat sink by filling the tiny gap between them, and is suitable for use when constructing a power LED module or a power IC module.

[0172] Here, as a power LED module, there are modules with wire bonding implementation type and modules with flip chip implementation type; as a power IC module, there are modules with wire bonding implementation type.

[0173] (Exothermic structure) The heat-dissipating structure of this embodiment includes a heating element, the laminate of the present invention described above, and a heat-dissipating component, and may further include other components as needed.

[0174] There are no particular limitations on the heat source mentioned above, and it can be appropriately selected according to the purpose. For example, electronic components such as CPU (Central Processing Unit), MPU (Micro Processing Unit), and GPU (Graphics Processing Unit) can be cited.

[0175] As for the aforementioned heat-generating components, if they are structures that generate heat from heat-generating electronic components (heat-generating elements), there are no particular restrictions, and they can be appropriately selected according to the purpose. For example, heat sinks, heat fins, air chambers, heat pipes, etc. can be mentioned.

[0176] The aforementioned heat sink is a component used to efficiently transfer heat from the aforementioned electronic components to other components. There are no particular limitations on the material of the heat sink; it can be appropriately selected depending on the purpose. For example, copper and aluminum are suitable materials. The aforementioned heat sink is typically in the shape of a flat plate.

[0177] The aforementioned heat sink is a component used to dissipate heat from the aforementioned electronic components into the air. There are no particular limitations on the material of the heat sink; it can be appropriately selected depending on the purpose. For example, copper, aluminum, etc., can be used. The aforementioned heat sink, for example, has multiple fan blades. The aforementioned heat sink, for example, has a base, and multiple fan blades are arranged extending in a non-parallel direction (e.g., an orthogonal direction) relative to one surface of the base.

[0178] The aforementioned heat sinks and heat fins are generally solid structures without internal space.

[0179] The aforementioned air chamber is a hollow structure. A volatile liquid is sealed inside the hollow structure. Examples of such air chambers include hollow structures that make the radiator hollow, and plate-shaped hollow structures that make the heat sink fins hollow.

[0180] The aforementioned heat pipe is a cylindrical, roughly cylindrical, or flattened hollow structure. The internal space of this hollow structure is filled with a volatile liquid.

[0181] here, Figure 1 This is a schematic cross-sectional view showing an example of a semiconductor device as a heat-dissipating structure. The laminate 7 of the present invention dissipates the heat emitted by electronic components such as the heat-dissipating semiconductor assembly 3. Figure 1 As shown, the main surface 2a, which is fixed to the electronic component 3 opposite to the heat sink 2, is held between the electronic component 3 and the heat sink 2. Furthermore, the heat-conducting fin 1 is held between the heat sink 2 and the heat sink 5.

[0182] For example, the heat sink 2 has a main surface 2a formed in the shape of a square plate, facing the electronic component 3, and a side wall 2b erected along the outer periphery of the main surface 2a. A heat-conducting fin 1 is provided on the main surface 2a surrounded by the side wall 2b, and a heat sink 5 is provided on the opposite side 2c of the main surface 2a, separated by the heat-conducting fin 1. The higher the thermal conductivity of the heat sink 2, the lower the thermal resistance, and the more efficiently it absorbs heat from the electronic component 3, such as semiconductor components. For example, it can be formed using copper or aluminum, which have good thermal conductivity.

[0183] Electronic component 3, for example, is a semiconductor assembly such as a BGA, and is mounted on wiring board 6. Furthermore, in heat sink 2, the front end face of sidewall 2b is mounted on wiring board 6, thereby surrounding electronic component 3 at a predetermined distance through sidewall 2b.

[0184] Furthermore, by providing the laminate 7 of the present invention on the main surface 2a of the heat sink 2, the heat emitted by the electronic component 3 is absorbed, forming a heat-dissipating component that is heated by the heat sink 5.

[0185] Example The following describes embodiments of the present invention, but the present invention is not limited by these embodiments.

[0186] (Example 1-1) <Modulation of Thermally Conductive Compositions> The composition and content listed in Table 1 were uniformly mixed using a stirring device (Rentaro Bubble Mixer, Automatic Rotary Mixer, Thinky Co., Ltd.) to prepare the first thermally conductive composition.

[0187] In addition, the content of each component in Tables 1-7 is by volume.

[0188] <Manufacturing of Laminated Structures> Next, a first thermally conductive composition was applied to a 20mm×20mm×1mm substrate (silicon substrate), and a 20mm×20mm×1mm opposing substrate (copper) was laminated on the applied first thermally conductive composition. Using a micro press, the laminate was pressed for 5 minutes at a temperature of 150°C on the upper plate of the copper substrate side, a temperature of 150°C on the lower plate of the silicon substrate side, and an air pressure of 0.11MPa (40psi). The laminate was then cured to produce a laminate of Example 1-1 with a first thermally conductive layer having an average thickness of 101μm.

[0189] (Examples 1-2 to 1-9) In Example 1-1, the composition of the first thermally conductive composition was changed as shown in Tables 1-2. Otherwise, the same procedure as in Example 1-1 was followed to produce the laminates of Examples 1-2 to 1-9.

[0190] (Comparative Examples 1-1 to 1-4) In Example 1-1, the composition of the first thermally conductive composition was changed as shown in Table 3. Otherwise, the same procedure was followed as in Example 1-1 to produce the laminates of Comparative Examples 1-1 to 1-4.

[0191] Next, for each of the resulting laminates, the following procedures were followed to evaluate the "measurement of the average thickness of each layer" and the "thermal conductivity". The results are shown in Tables 1-3.

[0192] <Determination of the average thickness of each layer> Each layer of the laminate was cut, and the cut surfaces were ground. The ground surfaces were photographed using a scanning electron microscope (S-3000N, manufactured by Hitachi, Ltd.). The thickness of each layer was measured from the cut surfaces of the laminate, and the average thickness at any three points was calculated. The results are shown in Tables 1 to 3.

[0193] In each of the stacked bodies of the embodiments, with Figure 2 The cross-sectional view of the laminate shown confirms that a first thermally conductive layer and an opposing substrate are sequentially present on the substrate.

[0194] Thermal conductivity <<The Creation of Stacked Bodies After Pressing>> Each laminate is sandwiched between a 20mm×20mm square silicon plate (0.77mm thick) and a 20mm diameter copper plate (1.0mm thick). Using a micro press, the upper plate temperature on the copper substrate side is 150°C, the lower plate temperature on the silicon substrate side is 150°C, and the air pressure is set to 0.11MPa (40psi). The press is then pressed for 5 minutes.

[0195] <<Evaluation of thermal conductivity>> For the pressed laminate (interface Cu and silicon), the thermal resistance (°C·cm) was determined according to ASTM-D5470. 2 / W). Subtract the thermal resistance of the substrate (silicon substrate) and the opposing substrate (copper substrate) from the result, calculate the thermal resistance of the portion of the laminate excluding the substrate and the opposing substrate, and obtain the thermal conductivity (W / m·K) from the thermal resistance and the thickness (100μm) of the portion of the laminate excluding the substrate and the opposing substrate. Evaluate the thermal conductivity using the following criteria.

[0196] [Evaluation Criteria] ◎: Thermal conductivity is above 20 W / m·K.

[0197] 〇: Thermal conductivity is above 10 W / m·K and less than 20 W / m·K.

[0198] ×: Thermal conductivity is less than 10 W / m·K.

[0199] [Table 1] [Table 2] [Table 3] (Example 2-1) <Modulation of Thermally Conductive Compositions> The components and contents listed in Table 4 were uniformly mixed using a stirring device (Rentaro Bubble Mixer, Automatic Rotary Mixer, Thinky Co., Ltd.) to prepare the first thermally conductive composition and the second thermally conductive composition.

[0200] <Manufacturing of Laminated Structures> A first thermally conductive composition with an average thickness of 30 μm and a second thermally conductive composition with an average thickness of 70 μm were laminated at 75 °C to obtain a two-layer thermally conductive composition.

[0201] The surface of the first thermally conductive layer is applied to a 20mm×20mm×1mm substrate (silicon substrate). A 20mm×20mm×1mm opposing substrate (copper) is laminated on the second thermally conductive composition. Using a micro press, the upper plate temperature on the copper substrate side is 150°C, the lower plate temperature on the silicon substrate side is 150°C, and the air pressure is set to 0.11MPa (40psi). The press is then cured to form a laminate of Example 2-1 with the first and second thermally conductive layers having a combined average thickness of 99μm.

[0202] (Examples 2-2 to 2-9) In Example 2-1, the composition of the first thermally conductive composition was changed as shown in Tables 4-5. Otherwise, the same procedure as in Example 2-1 was followed to produce the laminates of Examples 2-2 to 2-9.

[0203] (Comparative Examples 2-1 to 2-3) In Example 2-1, the composition of the first thermally conductive composition was changed as shown in Table 6. Otherwise, the same procedure as in Example 1-1 was followed to produce the laminates of Comparative Examples 2-1 to 2-3.

[0204] Next, for each of the resulting laminates, the "measurement of the average thickness of each layer" and "thermal conductivity" were evaluated. The results are shown in Tables 4–6.

[0205] [Table 4] [Table 5] [Table 6] (Examples 3-1 to 3-2) In Example 1-1, the combination of the substrate and the opposing substrate was changed as shown in Table 7. Otherwise, the same procedure was followed as in Example 1-1 to produce the laminates of Examples 3-1 to 3-2.

[0206] Regardless of the type of substrate and the opposing substrate, it can be confirmed that the thermal conductivity remains unchanged. This result indicates that the contact thermal resistance reaches zero.

[0207] (Example 3-3) In Example 1-1, the thickness of the first thermally conductive layer was changed as shown in Table 7. Otherwise, the same procedure was followed as in Example 1-1 to produce the laminates of Examples 3-1 to 3-3.

[0208] Regardless of the thickness of the first thermally conductive layer, it can be confirmed that the thermal conductivity remains unchanged. This result indicates that the contact thermal resistance reaches zero.

[0209] (Examples 3-4) In Example 2-1, the combination of the substrate and the opposing substrate was changed as shown in Table 7. Otherwise, the same operation was performed as in Example 2-1 to manufacture the laminates of Examples 3-4.

[0210] Regardless of the type of substrate and the opposing substrate, it can be confirmed that the thermal conductivity remains unchanged. This result indicates that the contact thermal resistance reaches zero.

[0211] [Table 7] The details of each component in Tables 1 to 7 are as follows.

[0212] -Cure Component A- • Epoxy resin: EPICLON (registered trademark) EXA-850CRP (manufactured by DIC Corporation) -Curing Agent B- • Epoxy resin curing agent: CUREZOL (registered trademark) 2P4MZ (manufactured by Shikoku Kasei Corporation) -Metal filler C- • Ag particles (D50: 1μm): Ag particles, manufactured by DOWA Electronics Co., Ltd., with a volume average particle size Dv: 1μm. • Ag particles (D50: 2μm): Ag particles, manufactured by DOWA Electronics Co., Ltd., with a volume average particle size Dv of 2μm. • Ag-coated Cu particles (D50: 5μm): Ag-coated Cu particles, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., with a volume average particle size Dv of 5μm. • Cu particles (D50: 5μm): Manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., with a volume average particle size Dv of 5μm. The volume average particle size Dv of the above-mentioned metal filler is the value measured by a laser diffraction-scattering particle size distribution measuring device (product name: Microtrac MT3300EXII).

[0213] -Polymer D- YP-50 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin. -Fixed components- • Curing component (oxetane compound): ETERNACOLL (registered trademark) OXBP (manufactured by Ube Industries, Ltd.), 4,4'-bis[(3-ethyl-3-oxetane)methoxymethyl]biphenyl -Curing agent- · Glutaric acid: Manufactured by Tokyo Chemical Co., Ltd., 1,3-propanedicarboxylic acid -Low melting point metal particles (solder particles)- ·Sn 58 Bi 42 Manufactured by Mitsui Metals & Minerals Co., Ltd., volume average particle size Dv: 6 μm, melting point 139℃ The volume average particle size Dv of the aforementioned low melting point metal particles was measured using a laser diffraction-scattering particle size distribution measuring device (product name: Microtrac MT3300EXII).

[0214] -thermally conductive particles- • Ag-coated Cu particles (Dv: 10μm): Ag-coated Cu particles, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., with a volume average particle size Dv of 10μm. Industry availability The laminate of the present invention, as a thermal interface material (TIM), can achieve excellent heat resistance, thermal conductivity and adhesion, and is therefore suitable for, for example, use in the peripherals of various electrical devices such as CPUs, MPUs, power transistors, LEDs, and laser diodes where temperature has an adverse effect on the efficiency and lifespan of component operation.

[0215] This international application claims priority based on Japanese Patent Application No. 2023-128350, filed on August 7, 2023, and incorporates the entire contents of Japanese Patent Application No. 2023-128350 into this international application.

[0216] Symbol Explanation 1 heat-conducting sheet 2 radiators 2a Main face 3. Heating element (electronic component) 3a above 5 heat sinks 6-wire substrate 7-layer stack 10-layer stack Laminates before 10a curing 11 substrates 12 First thermal conductive layer 12a First thermally conductive composition 12b metal packing 12C sintered body 14 Second thermal conductive layer 14a Second thermally conductive composition 14b Second thermally conductive particle 14c low melting point metal particles 14d low melting point metal 15 Opposite substrates

Claims

1. A thermally conductive composition, characterized by comprising: a curing component, a curing agent, and a metal filler, the metal filler being at least one selected from the group consisting of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles, a volume fraction of particles having a particle size of 1 μm or less in the metal filler being 5% or more, a volume fraction of the metal filler being 30% or more and 90% or less.

2. The thermally conductive composition according to claim 1, a volume fraction of the metal filler being 50% or more and 80% or less.

3. The thermally conductive composition according to claim 1 or 2, a volume fraction of particles having a particle size of 1 μm or less in the metal filler being 8% or more.

4. The thermally conductive composition according to any one of claims 1 to 3, the curing component being at least one of an oxirane ring compound and an oxetane compound.

5. The thermally conductive composition according to any one of claims 1 to 4, the curing component being an oxirane ring compound, the curing agent being an imidazole-based curing agent.

6. The thermally conductive composition according to any one of claims 1 to 5, further comprising a polymer having at least one structure selected from the group consisting of a phenoxy structure, a polybutadiene structure, a polysiloxane structure, a poly(meth)acrylate structure, a polyalkylene structure, a polyalkyleneoxy structure, a polyisoprene structure, a polyisobutylene structure, a polyamide structure, and a polycarbonate structure, in a molecule thereof. comprising:

7. A method for manufacturing a laminate, characterized by a step of imparting the thermally conductive composition according to any one of claims 1 to 6 on a substrate, and a step of heating the thermally conductive composition.

8. The method for producing a laminate according to claim 7, further comprising: a step of imparting a second thermally conductive composition containing a second curing component, a second curing agent, second thermally conductive particles, and low-melting-point metal particles on the thermally conductive composition, the step of heating being a step of heating the thermally conductive composition and the second thermally conductive composition.

9. The method for producing a laminate according to claim 7 or 8, the substrate being a silicon substrate. comprising:

10. A laminate characterized by comprising a substrate, and a first thermally conductive layer containing a curing component, a curing agent, and a sintered body provided on the substrate, the sintered body being a sintered body of a metal filler of at least one selected from the group consisting of silver particles, copper particles, silver-coated copper particles, and copper-coated silver particles, and communicating in a thickness direction and a planar direction of the first thermally conductive layer, a volume fraction of the sintered body in the first thermally conductive layer being 30% or more and 90% or less.

11. The laminate according to claim 10, further comprising: a second thermally conductive layer containing a second curing component, a second curing agent, a second metal filler, and low-melting-point metal particles provided on the first thermally conductive layer.

12. The laminate according to claim 10 or 11, the substrate being a silicon substrate.

13. The laminate according to any one of claims 10 to 12, a thermal conductivity being 10 W / (m-K) or more. ​

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