Thermally conductive member

Abstract

Provided is a thermally conductive member having insulation properties and a low thermal resistance value for thermally conductive resin layers of the same thickness. This thermally conductive member (1) is provided with a substrate (2), a first thermally conductive resin layer (3) that is bonded to one surface of the substrate (2), and a second thermally conductive resin layer (4) that is bonded to the other surface of the substrate (2). The substrate (2) is a semiconductor or an insulator. The first thermally conductive resin layer (3) and the second thermally conductive resin layer (4) each include a binder resin (11) and a thermally conductive filler (12).

Description

Thermal Conductive Member

[0001] The present invention relates to a thermal conductive member.

[0002] In recent years, with the development of electronics, many heat-generating components have been used in electronic devices such as power devices. In controlling an electronic circuit, it is important to dissipate heat from these heat-generating components to cool the entire system. A thermal conductive sheet (heat dissipation sheet) is installed, for example, between a heat-generating component and a heat dissipation fin or a metal plate, and is closely adhered to the heat-generating component without gaps by pressure bonding, exhibits thermal conductivity, and transfers the heat generated from the heat-generating component to the heat dissipation fin or the like, thereby enabling heat extraction from the entire system.

[0003] For example, a thermal conductive resin layer composed of a thermal conductive inorganic filler and a resin is used for the above thermal conductive sheet. As the inorganic filler, aluminum hydroxide, aluminum oxide (alumina), silicon carbide, boron nitride, aluminum nitride, etc. are used.

[0004] Further, as a member for dissipating heat, a member having thermal conductive resin layers on both sides of a plastic film or a metal foil is known (see Patent Documents 1 to 3). Patent Documents 1 to 3 describe that by using a metal foil as a base material (substrate), excellent followability to an adherend can be achieved, crushing of the thermal conductive filler in the thermal conductive resin layer and tearing of the thermal conductive resin layer can be prevented, the strength can be increased, and a low thermal resistance can be realized. Further, Patent Document 4 discloses a member in which a plurality of different thermal conductive resin layers are laminated.

[0005] JP-A-2001-168246 JP-A-2020-006581 JP-A-2008-291220 JP-A-2019-114729

[0006] In recent years, semiconductors, substrates, and modules used in semiconductors have become smaller and more high-performance, resulting in increased heat generation from electronic components. Therefore, there is a demand for thermally conductive materials with higher thermal conductivity. While reducing the thickness of the thermally conductive resin layer is expected to improve thermal conductivity, there are limitations to how thin it can be, as this reduces adhesion to heat sources and increases the likelihood of tearing. For this reason, materials with superior thermal conductivity compared to a thermally conductive resin layer alone, at the same thickness, are useful.

[0007] Patent documents 1, 2, and 4 do not mention that a component having thermally conductive resin layers on both sides of a plastic film or metal foil has higher thermal conductivity than a thermally conductive resin layer alone. Patent document 3 discloses that low thermal resistance can be achieved by using metal foil as a base material. However, the component in patent document 3 uses highly conductive metal foil or graphite, which has the problem of poor insulation.

[0008] Therefore, the object of the present invention is to provide a thermally conductive member that has insulating properties and a lower thermal resistance value compared to a thermally conductive resin layer of the same thickness.

[0009] The present invention provides a thermal conductive member comprising a substrate, a first thermally conductive resin layer bonded to one side of the substrate, and a second thermally conductive resin layer bonded to the other side of the substrate, wherein the substrate is a semiconductor or an insulator, and the first thermally conductive resin layer and the second thermally conductive resin layer each contain a binder resin and a thermally conductive filler, respectively.

[0010] The material of the substrate is preferably one or more selected from the group consisting of alumina, aluminum nitride, silicon carbide, silicon nitride, and silicon.

[0011] The thermal conductive filler in the first thermal conductive resin layer and the second thermal conductive resin layer preferably contains one or more thermal conductive fillers selected from the group consisting of alumina and aluminum nitride.

[0012] The thermal conductive fillers in the first thermal conductive resin layer and the second thermal conductive resin layer preferably include one or more spherical and polyhedral thermal conductive fillers.

[0013] The binder resin in the first thermally conductive resin layer and the second thermally conductive resin layer is preferably a silicone resin.

[0014] The above thermal conductive material has a thermal resistance value in the thickness direction (calculated at a thickness of 1 mm) of 5.0 cm when compressed by 5%. ２ - Preferably, it is kW or less.

[0015] The thermal conductive member of the present invention has insulating properties and a low thermal resistance value compared to a thermal conductive resin layer of the same thickness. Therefore, it is possible to use the thermal conductive member of the present invention of the same thickness as a thermal conductive sheet consisting of a thermal conductive resin layer alone, while still exhibiting high thermal conductivity. Furthermore, because it has a specific base material, it has high strength even when thin, enabling a thinness that could not be achieved with a thermal conductive sheet consisting of a thermal conductive resin layer alone. In addition, since it can maintain a greater thickness than a single thermal conductive resin layer, it is possible to improve adhesion to the adherend, which is a heat source.

[0016] This is a partial cross-sectional view showing one embodiment of the thermal conductive member of the present invention. This is a graph showing the relationship between the thermal resistance value evaluated in the example and the thickness (total film thickness) of the thermal conductive member.

[0017] [Thermal Conductive Member] A thermal conductive member (heat dissipation member) according to one embodiment of the present invention comprises a substrate and thermal conductive resin layers bonded to both sides of the substrate, that is, the thermal conductive member comprises at least a substrate, a first thermal conductive resin layer bonded to one side of the substrate, and a second thermal conductive resin layer bonded to the other side of the substrate.

[0018] The thermal conductive member of the present invention has insulating properties and a low thermal resistance value compared to a thermal conductive resin layer of the same thickness. Therefore, it is possible to use the thermal conductive member of the present invention of the same thickness as a thermal conductive sheet consisting of a thermal conductive resin layer alone, while still exhibiting high thermal conductivity. Furthermore, because it has a specific substrate, it has high strength even when thin, enabling a thinness that could not be achieved with a thermal conductive sheet consisting of a thermal conductive resin layer alone. Since the first thermal conductive resin layer and the second thermal conductive resin layer are bonded to the substrate, thermal resistance at the interface can be minimized, resulting in excellent thermal conductivity as a thermal conductive member. In addition, the thermal conductive resin layers on both sides of the substrate exhibit adhesion to the adherend, which is a heat source.

[0019] The first thermally conductive resin layer and the second thermally conductive resin layer each contain at least a binder resin and a thermally conductive filler. The first thermally conductive resin layer and the second thermally conductive resin layer may contain the same type of binder resin (e.g., silicone-based resin and silicone-based resin) or different types of binder resin. Furthermore, the first thermally conductive resin layer and the second thermally conductive resin layer may contain the same type of thermally conductive filler (e.g., alumina and alumina) or different types of thermally conductive filler. Therefore, the first thermally conductive resin layer and the second thermally conductive resin layer may have the same or different thicknesses, compositions (such as the type and proportion of binder resins and thermally conductive fillers), or physical properties.

[0020] The above-mentioned heat-conducting member may be provided with a release film. The release film may be provided on only one side of the heat-conducting member or on both sides. Examples of the release film include a film formed from a low-tack resin or a sheet comprising a release treatment layer provided on the surface of the film. The release film is peeled off and removed when the heat-conducting member is used.

[0021] Figure 1 is a schematic cross-sectional view showing one embodiment of the thermal conductive member of the present invention. As shown in Figure 1, the thermal conductive member 1 comprises a substrate 2, a first thermal conductive resin layer 3 bonded to one side of the substrate 2, and a second thermal conductive resin layer 4 bonded to the other side of the substrate 2. That is, the first thermal conductive resin layer 3 and the second thermal conductive resin layer 4 are directly laminated so as to be in contact with the substrate 2. The substrate 2 is a semiconductor or an insulator. The first thermal conductive resin layer 3 and the second thermal conductive resin layer 4 each contain a binder resin 11 which is a matrix component and a thermal conductive filler 12 dispersed in the binder resin 11. Release films 5 and 6 are provided on both sides of the thermal conductive member 1, and the thermal conductive member 1 is sandwiched between the two release films 5 and 6.

[0022] <Substrate> The substrate in the thermal conductive member of the present invention is a semiconductor or an insulator. The substrate may be a single layer or a multi-layer substrate. If the substrate is a multi-layer substrate, all layers are semiconductors or insulators. Furthermore, if the substrate is a multi-layer substrate, it is preferable that each layer is bonded together by a thermal conductive resin layer. The thermal conductive resin layer that can bond each layer constituting the substrate may have the same thickness, composition, or physical properties as the first thermal conductive resin layer or the second thermal conductive resin layer, or it may have different properties.

[0023] Examples of the substrate include known or conventional semiconductors or insulators. Examples of substrate materials include alumina, aluminum nitride, silicon carbide, silicon nitride, sapphire, and silicon. Among these, from the viewpoint of having superior thermal conductivity for the thermal conductive member, one or more selected from the group consisting of alumina, aluminum nitride, silicon carbide, silicon nitride, and silicon are preferred as substrate materials. The substrate may be composed of only one of the above materials, or it may be composed of two or more of them.

[0024] From the viewpoint of lowering the thermal resistance value, the material of the substrate described above preferably has a thermal conductivity of 10 W / m·K or higher, more preferably 20 W / m·K or higher, and may also be 30 W / m·K or higher. From the viewpoint that the higher the thermal conductivity, the lower the resistance value of the thermal conductive member, there is no particular upper limit to the thermal conductivity, and a higher value is preferable, but it may be, for example, 500 W / m·K or less.

[0025] The resistivity of the above substrate is set to 1 × 10 from the viewpoint of excellent insulation properties of the thermally conductive material. ３ A value of Ω·cm or higher is preferable.

[0026] The thickness of the above-mentioned substrate is preferably 100 to 5000 μm, more preferably 300 to 3000 μm, and even more preferably 500 to 2000 μm, from the viewpoint of exhibiting a resistance value lower than that of a thermal conductive member consisting of a thermal conductive resin layer of the same thickness. In a thermal conductive member consisting of a three-layer structure of [first thermal conductive resin layer / substrate / second thermal conductive resin layer], heat transfer is inhibited at the interface between the thermal conductive resin layer and the substrate. When the above-mentioned thickness is 100 μm or more (particularly 300 μm or more), the thickness of the substrate, which has higher thermal conductivity than the thermal conductive resin layer, is sufficiently large. Therefore, even considering the inhibition of heat transfer, the effect of providing a semiconductor or insulator substrate can be fully exhibited, and it tends to exhibit a resistance value lower than that of a thermal conductive member consisting of a thermal conductive resin layer alone. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more, B or less".

[0027] <Thermal Conductive Resin Layer> In this specification, the first thermal conductive resin layer and the second thermal conductive resin layer may be collectively referred to simply as the "thermal conductive resin layer." The thermal conductive resin layer comprises at least a binder resin and a thermal conductive filler.

[0028] (Binder Resin) The binder resin contained in the first thermal conductive resin layer and the second thermal conductive resin layer is a component that forms the matrix of the thermal conductive resin layer. The thermal conductive resin layer exhibits adhesion to the adherend, which is a heat source, by containing the binder resin. Examples of the binder resin include thermoplastic resins, thermosetting resins, active energy ray curing resins, etc. Only one type of binder resin may be used, or two or more types may be used.

[0029] Examples of the thermoplastic resins mentioned above include polystyrene resins, vinyl acetate resins, polyester resins, polyolefin resins (e.g., polyethylene resins, polypropylene resin compositions, etc.), polyimide resins, and acrylic resins. Only one type of thermoplastic resin may be used, or two or more types may be used.

[0030] The above-mentioned thermosetting resins include both thermosetting resins and resins obtained by curing the above-mentioned thermosetting resins. Examples of the above-mentioned thermosetting resins include silicone resins, phenolic resins, epoxy resins, urethane resins, urethane urea resins, melamine resins, alkyd resins, polyimide resins, and acrylic resins. Only one type of the above-mentioned thermosetting resin may be used, or two or more types may be used.

[0031] The above-mentioned active energy ray curable resin includes both a resin that can be cured by irradiation with active energy rays (active energy ray curable resin) and a resin obtained by curing the above-mentioned active energy ray curable resin. The above-mentioned active energy ray curable resin is not particularly limited, but for example, a polymer of a polymerizable compound having at least two (meth)acryloyloxy groups in its molecule can be used. The above-mentioned active energy ray curable resin may be used by one type only, or by two or more types.

[0032] Among the binder resins mentioned above, thermosetting resins are preferred. Furthermore, silicone resins are preferred as the binder resin from the viewpoint of excellent thermal conductivity, heat resistance, and insulation properties. As the silicone resin, known or conventional silicone resins used in thermally conductive resin layers can be used. As the silicone resin, a two-component curing type silicone resin is preferred from the viewpoint of being able to disperse the thermally conductive filler well without using a solvent. One type of silicone resin may be used, or two or more types may be used.

[0033] The content of the binder resin is preferably 2% by mass or more, and more preferably 4% by mass or more, based on 100% by mass of the total amount of the thermal conductive resin layer. When the content is 2% by mass or more, the thermal conductive resin layer is less likely to become brittle and the moldability of the thermal conductive resin layer is excellent. The content is preferably 30% by mass or less, and more preferably 25% by mass or less. When the content is 30% by mass or less, the thermal conductivity of the thermal conductive member is better. In this specification, all combinations of the above lower limit and upper limit are included. That is, the content may be, for example, 2 to 30% by mass or 4 to 25% by mass. In particular, it is preferable that the content of the silicone resin is within the above range.

[0034] (Thermally conductive filler) The thermally conductive filler is a filler (particle) that has thermal conductivity and is a component that exhibits thermal conductivity in the thermally conductive resin layer. Examples of the thermally conductive filler include inorganic fillers such as ceramic fillers and carbon fillers. Only one type of thermally conductive filler may be used, or two or more types may be used.

[0035] Examples of materials for the ceramic fillers mentioned above include metal oxides such as alumina (aluminum oxide), titania (titanium oxide), magnesia (magnesium oxide), zirconia (zirconium oxide), and zinc oxide; nitrides such as aluminum nitride, titanium nitride, and boron nitride; metal hydroxides such as aluminum hydroxide; carbides such as silicon carbide; silicon compounds such as glass, silica, silicon carbide, silicon nitride, and silicon; and minerals such as steatite, forsterite, sialon, perlite, mullite, and zeolite.

[0036] Examples of the carbon fillers mentioned above include carbon fibers, carbon nanotubes, and carbon material-containing particles such as diamond.

[0037] The above-mentioned thermally conductive filler plays a role in mediating between the substrate and the heat source, and from the viewpoint of ensuring insulation, it is preferable that the material includes a ceramic filler, and more preferably one or more selected from the group consisting of alumina and aluminum nitride.

[0038] The shape of the above-mentioned thermally conductive filler is not particularly limited and may include spherical (including perfect spheres and ellipsoids), flake-like (scaly), dendritic, massive, flattened, needle-like, polyhedral, fibrous, and irregular shapes.

[0039] The above-mentioned thermally conductive filler may or may not be surface-treated. Examples of surface treatment agents include silane coupling agents. When the surface is treated with a silane coupling agent, the thermally conductive filler disperses well in the binder resin (especially silicone resin) which is the matrix of the thermally conductive resin layer, resulting in superior filling and moldability. One type of silane coupling agent may be used, or two or more types may be used.

[0040] As the above silane coupling agent, for example, silane coupling agents having functional groups other than alkoxy groups (functional group-containing silane coupling agents) such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, etc.; silane coupling agents having no functional groups other than alkoxy groups (functional group-free silane coupling agents) such as n-octyltriethoxysilane, n-decyltrimethoxysilane, etc. can be mentioned. Among them, from the viewpoint that the wettability with metal oxides is good and an improvement in the bulk strength and flexibility of the thermal conductive resin layer is expected, a functional group-free silane coupling agent is preferred, and more preferably a silane coupling agent having an alkyl group at the terminal other than the alkoxy group (terminal alkyl group-containing silane coupling agent), particularly preferably n-octyltriethoxysilane.

[0041] As the above thermal conductive filler, among others, from the viewpoint of easily realizing a high thermal conductivity of the thermal conductive resin layer, it is preferable to include a thermal conductive filler containing one or more of aluminum nitride and alumina as the material. Further, from the viewpoint of easily realizing a high thermal conductivity of the thermal conductive resin layer while ensuring appropriate hardness, it is preferable to include one or more of spherical and polyhedral thermal conductive fillers.

[0042] The above thermal conductive filler preferably includes a spherical thermal conductive filler (sometimes referred to as "thermal conductive filler (A)") having a median diameter (D50) of 30 to 65 μm from the viewpoint of excellent thermal conductivity of the thermal conductive resin layer and being easily made to have appropriate hardness. The thermal conductive filler (A) is a particle group. The median diameter of the thermal conductive filler (A) is preferably 30 to 50 μm, more preferably 40 to 50 μm. The above thermal conductive filler (A) may be used alone or in two or more kinds (that is, two or more particle groups having different median diameters).

[0043] In this specification, the particle size of the thermal conductive filler is measured by the laser diffraction / scattering method. The median diameter (μm) of the thermal conductive filler can be measured, for example, by the following method. First, the particle size distribution of the particle group is measured by a laser diffraction particle size distribution analyzer to obtain a volume-based cumulative particle size distribution curve. In the obtained cumulative particle size distribution curve, the value of the particle diameter at 50% cumulative from the side of the fine particles is D50. As the laser diffraction particle size distribution analyzer, for example, a particle size distribution measuring device such as the product name "MT3300EXII" (manufactured by Microtrac Co., Ltd.) can be used.

[0044] The content ratio of the thermal conductive filler (A) is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, and still more preferably 45 to 60% by mass with respect to 100% by mass of the total amount of the thermal conductive resin layer. When the content ratio is within the above range, it is easy to realize a high thermal conductivity of the thermal conductive resin layer while ensuring appropriate hardness.

[0045] The content ratio of the thermal conductive filler (A) is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, and still more preferably 45 to 60% by mass with respect to 100% by mass of the total amount of the thermal conductive filler in the thermal conductive resin layer. When the content ratio is within the above range, it is easy to realize a high thermal conductivity of the thermal conductive resin layer while ensuring appropriate hardness.

[0046] From the viewpoint of easily realizing a particularly high thermal conductivity of the thermal conductive resin layer, the thermal conductive filler preferably includes a spherical thermal conductive filler (which may be referred to as "thermal conductive filler (B)") having a median diameter of 1 to 20 μm. The thermal conductive filler (B) is a particle group. The median diameter of the thermal conductive filler (B) is preferably 1 to 10 μm, more preferably 2 to 8 μm. Only one kind of the thermal conductive filler (B) may be used, or two or more kinds (that is, two or more particle groups having different median diameters) may be used.

[0047] The content of the thermally conductive filler (B) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass, based on 100% by mass of the total amount of the thermally conductive resin layer. When the content is within the above range, it is easier to achieve high thermal conductivity of the thermally conductive resin layer while ensuring appropriate hardness.

[0048] The content of the thermally conductive filler (B) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass, based on 100% by mass of the total amount of thermally conductive filler in the thermally conductive resin layer. When the content is within the above range, it is easier to achieve high thermal conductivity in the thermally conductive resin layer while ensuring appropriate hardness.

[0049] The above-mentioned thermal conductive filler preferably includes polyhedral thermal conductive fillers (sometimes referred to as "thermal conductive filler (C)") having a median diameter of 0.1 μm or more and less than 1 μm. Using thermal conductive filler (C) allows for improved thermal conductivity while maintaining a moderately soft hardness in the thermal conductive resin layer. The polyhedral shape of the thermal conductive filler (C) with a particle size within this range increases the contact area between the thermal conductive fillers, which can lead to improved thermal conductivity while maintaining a moderate hardness in the thermal conductive resin layer. Thermal conductive filler (C) is a group of particles. The median diameter of thermal conductive filler (C) is preferably 0.1 to 0.8 μm, more preferably 0.3 to 0.6 μm. When the median diameter is 0.1 μm or more, viscosity increase can be suppressed during kneading of the thermal conductive filler and binder resin. When the median diameter is less than 1 μm, it is easier to mix during kneading, and the hardness can be kept low. The thermally conductive filler (C) may be of one type only, or two or more types (i.e., two or more groups of particles with different median diameters) may be used.

[0050] A polyhedral shape refers to a shape formed by combining polygonal faces, for example. The polygonal faces may be flat or not necessarily equiplane with irregularities. Polyhedral particles may be polyhedral spherical particles or single crystal particles. A polyhedral shape is different from, for example, spherical (including perfect spheres and ellipsoids), flake-like (scaly), dendritic, massive, flattened, needle-like, fragmented, and amorphous shapes. In particular, fragmented and amorphous shapes are inconsistent in size and shape, while polyhedral shapes are uniform in size and shape. In a group of polyhedral particles with uniform size, the particle size distribution becomes sharper, leading to a high packing efficiency for the entire thermally conductive filler. The sharpness of the particle size distribution of a given group of particles can be determined, for example, by the value of (D90 - D10) / D50 in the particle size distribution of that group of particles. The smaller this value, the sharper the particle size distribution of that group of particles can be judged. The (D90-D10) / D50 in the particle size distribution of the thermally conductive filler (B3) is preferably 0.1 to 10, and more preferably 0.5 to 5. D10 and D90 can be obtained as the particle size values ​​at the cumulative time of 10% and 90% from the fine particle side, respectively, obtained in the D50 measurement method described above.

[0051] The content of the thermally conductive filler (C) is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass, based on 100% by mass of the total amount of the thermally conductive resin layer. When the content is within the above range, it is easy to achieve high thermal conductivity of the thermally conductive resin layer while ensuring appropriate hardness.

[0052] The content of the thermally conductive filler (C) is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass, based on 100% by mass of the total amount of thermally conductive filler in the thermally conductive resin layer. When the content is within the above range, it is easier to achieve high thermal conductivity in the thermally conductive resin layer while ensuring appropriate hardness.

[0053] The above-mentioned thermal conductive fillers (especially thermal conductive fillers (A) to (C)) can be appropriately selected from the materials exemplified and described above as thermal conductive fillers. When the materials of thermal conductive fillers (A) to (C) are alumina, a thermal conductive resin layer with inexpensive and stable heat dissipation characteristics can be obtained. When one or more of the materials of thermal conductive fillers (A) to (C) are aluminum nitride, a thermal conductive resin layer with relatively low hardness can be obtained. When the materials of thermal conductive fillers (B) and (C) are alumina, and the material of thermal conductive filler (A) is aluminum nitride, a thermal conductive resin layer with a better balance between heat dissipation characteristics and hardness can be obtained.

[0054] The total content ratio (total amount) of the thermal conductive fillers (A) to (C) in the thermal conductive resin layer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more, based on 100% by mass of the total amount of thermal conductive fillers contained in the thermal conductive resin layer.

[0055] The content ratio (filling rate) of the thermal conductive filler in the thermal conductive resin layer is preferably 70 to 98% by mass, and more preferably 75 to 96% by mass, based on 100% by mass of the total amount of the thermal conductive resin layer. When the content ratio is 70% by mass or more, the filling rate of the thermal conductive filler in the thermal conductive resin layer is high, making it easier to achieve high thermal conductivity. When the content ratio is 98% by mass or less, the thermal conductive resin layer is less likely to become brittle, and the moldability when manufacturing the thermal conductive resin layer is excellent.

[0056] The above-mentioned thermally conductive resin layer may contain a coloring agent. Including a coloring agent can impart opacity to the thermally conductive member. The above-mentioned coloring agent can be appropriately selected depending on the purpose, and examples include black coloring agents, cyan coloring agents, magenta coloring agents, yellow coloring agents, etc. For example, as the above-mentioned black coloring agent, black pigments or mixed pigments that have been blackened by color-reducing and mixing of multiple pigments can be used. Examples of the above-mentioned black pigments include carbon black, Ketjen black, perylene black, titanium black, iron black, and aniline black. The above-mentioned coloring agent may be used by one or two or more types.

[0057] The total amount of the coloring agent in the thermally conductive resin layer is, for example, 0.2 to 10% by mass, preferably 0.3 to 8% by mass, based on 100% by mass of the total amount of the thermally conductive resin layer.

[0058] The above-mentioned thermally conductive resin layer may contain other components in addition to the various components described above. Examples of these other components include thixotropy-imparting agents, dispersants, curing agents, curing accelerators, curing retarders, tackifiers, plasticizers, flame retardants, antioxidants, and stabilizers. Only one of these other components may be used, or two or more may be used.

[0059] The thickness of the above-mentioned thermally conductive resin layer is, for example, 100 to 3000 μm, and preferably 150 to 1000 μm.

[0060] The above-mentioned thermally conductive resin layer preferably has a thermal conductivity in the thickness direction of 3.0 W / m·K or higher when compressed by 10%, more preferably 4.0 W / m·K or higher, and even more preferably 5.0 W / m·K or higher. When the above-mentioned thermal conductivity is 3.0 W / m·K or higher, the thermal conductivity and heat dissipation in the thickness direction are excellent. The specific method for measuring the above-mentioned thermal conductivity is as described in the examples below.

[0061] The above-mentioned thermally conductive resin layer preferably has an Asker C hardness of 40 or higher, and more preferably 45 or higher. A hardness of 40 or higher provides appropriate hardness and excellent handling properties. From the viewpoint of excellent conformability to the adherend, which is a heat source, the above-mentioned thermally conductive resin layer preferably has an Asker C hardness of 70 or lower. The above hardness can be measured, for example, by an Asker C hardness tester.

[0062] (Method for manufacturing a thermally conductive resin layer) The method for molding the thermally conductive resin layer described above is not particularly limited, and known or conventional molding methods for molded bodies can be used. Among these, molding by roll to sheet is preferred from the viewpoint of continuous molding and excellent productivity.

[0063] The above-mentioned thermally conductive resin layer can be manufactured, for example, by placing a composition containing the various components described above between the release surfaces of two release films with flat bases or release surfaces, and molding it by heating or pressurizing.

[0064] The above composition includes, for example, the binder resin and the thermally conductive filler. If multiple types of thermally conductive fillers are used, they may be mixed beforehand and then mixed with the binder resin, or multiple types of thermally conductive fillers and the binder resin may be mixed simultaneously. The above composition is preferably in the form of a paste that does not contain organic solvents.

[0065] The apparatus for producing the above composition sheets is not particularly limited, and known molding equipment such as a roll laminator, roll press, hot press molding machine, or extruder can be used by placing the material between release films.

[0066] <Thermal Conductive Member> The thickness (total film thickness) of the thermal conductive member described above is preferably 300 to 5000 μm, more preferably 500 to 3000 μm, and even more preferably 1000 to 2500 μm, from the viewpoint of exhibiting a resistance value lower than that of a thermal conductive member consisting of a thermal conductive resin layer of the same thickness. In a thermal conductive member consisting of a three-layer structure of [first thermal conductive resin layer / substrate / second thermal conductive resin layer], heat transfer is inhibited at the interface between the thermal conductive resin layer and the substrate. When the thickness is 500 μm or more, the thickness of the substrate, which has higher thermal conductivity than the thermal conductive resin layer, is sufficiently thick. Therefore, even considering the inhibition of heat transfer, the effect of providing a semiconductor or insulator substrate can be fully exhibited, and it tends to exhibit a resistance value lower than that of a thermal conductive member consisting of a thermal conductive resin layer alone.

[0067] The thermal conductive member of the present invention has a thermal resistance value in the thickness direction (calculated at a thickness of 1 mm) of 5.0 cm when compressed by 5%. ２ - Preferably less than kW, and more preferably 4.0 cm ２ - K / W or less, more preferably 3.0 cm ２ • It is less than kW. The above thermal resistance value is 5.0 cm². ２- When the thermal resistance is kW or less, it exhibits excellent thermal conductivity and heat dissipation in the thickness direction. The above thermal resistance values ​​are calculated from measured values ​​to a value per 1 mm thickness. The specific measurement method for the above thermal resistance values ​​is as described in the examples below.

[0068] The thermal conductive member of the present invention is not particularly limited and can be manufactured by bonding a first thermal conductive resin layer and a second thermal conductive resin layer to both sides of a substrate using known or conventional methods. Known or conventional methods can be used for the bonding, for example, by inserting a substrate between a first thermal conductive resin layer formed on a release film and a second thermal conductive resin layer formed on a release film, and using known molding equipment such as a roll laminator, roll press, hot press molding machine, or sheet-fed laminating machine.

[0069] The thermal conductive member of the present invention has insulating properties and a low thermal resistance value compared to a thermal conductive resin layer of the same thickness. Therefore, it is possible to use the thermal conductive member of the present invention of the same thickness as a thermal conductive sheet consisting of a thermal conductive resin layer alone, while still exhibiting high thermal conductivity. Furthermore, because it has a specific base material, it has high strength even when thin, enabling a thinness that could not be achieved with a thermal conductive sheet consisting of a thermal conductive resin layer alone. In addition, since it can maintain a greater thickness than a single thermal conductive resin layer, it is possible to improve adhesion to the adherend, which is a heat source.

[0070] Embodiments of the present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0071] Example 1 (Preparation of a thermally conductive resin layer) A particle composition was prepared by mixing 1503 g of alumina particles (A) (median diameter 42.8 μm, spherical), 907 g of alumina particles (B) (median diameter 6.8 μm, spherical), and 425 g of alumina particles (C) (median diameter 0.4 μm, polyhedral, (D90-D10) / D50 = 2.4) as a thermally conductive filler. Then, a resin paste was prepared by mixing the above particle composition with 165 g of a thermosetting silicone resin (a two-component addition reaction type silicone resin having a mechanism to crosslink a polymer having vinyl groups and a polymer having Si-H groups by hydrosilylation under a platinum catalyst). Subsequently, the above resin paste was placed between two release films (polymethylpentene films with a release treatment layer, thickness 50 μm), and a sheet-like resin paste layer was formed using a roll laminator. The above resin paste layer was placed in a heating furnace and heated at 120°C for 60 minutes to heat-cur it, thereby forming a sheet-like thermal conductive resin layer. In this way, a thermal conductive resin layer (thickness of the thermal conductive resin layer: approximately 0.25 mm) having a laminated structure of [release film / thermal conductive resin layer / release film] was produced.

[0072] (Fabrication of thermally conductive members) At room temperature, a roll press was used to bond the exposed surfaces of the thermally conductive resin layers, with one release film removed, to both sides of an alumina substrate (thickness: 0.55 mm) to produce a thermally conductive member having a laminated structure of [release film / thermally conductive resin layer / alumina substrate / thermally conductive resin layer / release film]. The thickness of the thermally conductive member excluding the release film is shown in Table 1.

[0073] Examples 2-4: Thermally conductive members were fabricated in the same manner as in Example 1, except that the thickness of the alumina substrate was changed as shown in Table 1.

[0074] Examples 5 and 6: Thermal conductive members were manufactured in the same manner as in Example 2, except that the thickness of the thermal conductive resin layer was changed as shown in Table 1.

[0075] Examples 7 and 8: Thermal conductive members were fabricated in the same manner as in Example 2, except that the substrate material was changed as shown in Table 1.

[0076] Comparative Examples 1-5 (Preparation of Thermally Conductive Members) A thermally conductive resin layer was prepared in the same manner as in Example 1, except that the thickness of the thermally conductive resin layer, excluding the release film, was changed so that the total thickness of the thermally conductive member was the value shown in Table 1. A thermally conductive member consisting of a thermally conductive resin layer alone, having a laminated structure of [release film / thermally conductive resin layer / release film], was then prepared.

[0077] <Evaluation> In the examples and comparative examples, each thermally conductive filler used, the resulting thermally conductive resin layer, and each thermally conductive component were evaluated as follows.

[0078] (1) Median diameter (D50), D10, and D90 The median diameter (D50) of the thermal conductive filler was measured using a particle size distribution analyzer (product name "MT3300EXII", manufactured by Microtrac Co., Ltd.). For D50, D10, and D90 of the thermal conductive filler (particles), if measurement was difficult, the values ​​listed in the product catalog of the thermal conductive filler (particles) were used as D50, D10, and D90 of the thermal conductive filler (particles).

[0079] (2) Thermal conductivity By adjusting the gap of the roll press machine, thermal conductive resin layers of four different thicknesses were fabricated: 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm. Then, the release film was peeled off the thermal conductive resin layers, and the thermal resistance was measured when the thermal conductive resin layers of the four thicknesses were compressed by 10% in the thickness direction (i.e., compressed to 90% of the original thickness) using a thermal property measuring device (product name "DynTIM", manufactured by Siemens K.K.). The thermal conductivity was calculated from the slope of the extrapolation line of the thermal resistance value obtained for each thermal conductive resin layer thickness. The evaluation results are shown in Table 1.

[0080] (3) The hardness of the Asker C hardness thermal conductive resin layer was measured using an Asker C hardness tester. The evaluation results are shown in Table 1.

[0081] (4) Thermal Resistance Value The release film was peeled off the thermal conductive member, and the thermal resistance was measured using a thermophysical property measuring device (product name "DynTIM", manufactured by Siemens K.K.) when the thermal conductive member was compressed by 5% in the thickness direction (i.e., compressed to 95% of the original thickness). The evaluation results are shown in Table 1. A graph was then created by plotting the thickness of the thermal conductive member on the horizontal axis and the thermal resistance value on the vertical axis (Figure 2). The graph in Figure 2 shows the approximate linear function for Comparative Examples 1 to 5, and the high and low thermal resistance of the thermal conductive members can be compared by comparing them with the thermal conductive resin layer alone with the same total thickness in the above approximate linear function. Note that the thermal resistance values ​​shown in Table 1 and the graph are measured values, and the thermal resistance value per 1 mm thickness is, for example, 1.63 cm for the thermal conductive member of Example 1, which is the measured value for Example 1. ２ - The value will be slightly lower than kW.

[0082]

[0083] As can be seen from Figure 2, the thermal conductive member of the example was shown to have a significantly lower thermal resistance value than the thermal conductive member consisting of a thermal conductive resin layer of the same thickness as each example, as predicted from the approximate linear function of Comparative Examples 1 to 5. In particular, based on Figure 2, from the relationship between the total film thickness and the thermal resistance value of the thermal conductive member of the example, it was predicted that when the total film thickness is 500 μm or more, it will exhibit a lower thermal resistance value than the approximate linear function of Comparative Examples 1 to 5, which are thermal conductive members consisting of a thermal conductive resin layer alone. Furthermore, since the thermal conductive member of the example uses alumina, which has insulating properties, as the base material, it has higher insulating properties compared to thermal conductive members that use conductive materials such as metal foil as the base material.

[0084] The following describes variations of the invention according to the present invention. [Note 1] A thermal conductive member comprising a substrate, a first thermal conductive resin layer bonded to one side of the substrate, and a second thermal conductive resin layer bonded to the other side of the substrate, wherein the substrate is a semiconductor or an insulator, and the first thermal conductive resin layer and the second thermal conductive resin layer each contain a binder resin and a thermal conductive filler. [Note 2] The thermal conductive member according to Note 1, wherein the material of the substrate is one or more selected from the group consisting of alumina, aluminum nitride, silicon carbide, silicon nitride, and silicon. [Note 3] The thermal conductive member according to Note 1 or 2, wherein the thermal conductive filler in the first thermal conductive resin layer and the second thermal conductive resin layer contains a thermal conductive filler that includes one or more selected from the group consisting of alumina and aluminum nitride as its material. [Note 4] The thermal conductive member according to Note 3, wherein the thermal conductive filler in the first thermal conductive resin layer and the second thermal conductive resin layer includes one or more spherical and polyhedral thermal conductive fillers. [Note 5] The thermal conductive member according to any one of Notes 1 to 4, wherein the binder resin in the first thermal conductive resin layer and the second thermal conductive resin layer is a silicone resin. [Note 6] The thermal resistance value in the thickness direction (calculated at a thickness of 1 mm) at 5% compression is 5.0 cm. ２ A thermally conductive member described in any one of the appendices 1 to 5, having a power of kW or less.

[0085] 1. Thermally conductive component 2. Substrate 3. First thermally conductive resin layer 4. Second thermally conductive resin layer 5, 6. Release film 11. Binder resin 12. Thermally conductive filler

Claims

1. A thermal conductive member comprising a substrate, a first thermally conductive resin layer bonded to one side of the substrate, and a second thermally conductive resin layer bonded to the other side of the substrate, wherein the substrate is a semiconductor or an insulator, and the first thermally conductive resin layer and the second thermally conductive resin layer each contain a binder resin and a thermally conductive filler.

2. The thermal conductive member according to claim 1, wherein the material of the substrate is one or more selected from the group consisting of alumina, aluminum nitride, silicon carbide, silicon nitride, and silicon.

3. The thermal conductive member according to claim 1 or 2, wherein the thermal conductive filler in the first thermal conductive resin layer and the second thermal conductive resin layer includes a thermal conductive filler that includes one or more selected from the group consisting of alumina and aluminum nitride as a material.

4. The thermal conductive member according to claim 3, wherein the thermal conductive filler in the first thermal conductive resin layer and the second thermal conductive resin layer includes one or more spherical and polyhedral thermal conductive fillers.

5. The thermal conductive member according to claim 1 or 2, wherein the binder resin in the first thermal conductive resin layer and the second thermal conductive resin layer is a silicone resin.

6. The thermal resistance value in the thickness direction (calculated at a thickness of 1 mm) at 5% compression is 5.0 cm. ２ A thermally conductive member according to claim 1 or 2, wherein the power is less than or equal to kW.

Images