JP6749262B2 - Heat sink - Google Patents

Description

The present invention relates to a heat sink.

Many electronic components such as IC chips and power chips are mounted on a semiconductor device. Therefore, a large amount of heat is generated from these electronic components when the semiconductor device is driven. Since this heat causes malfunction of the semiconductor device, it is necessary to efficiently dissipate the heat. As a material that radiates this heat, a heat dissipation plate including a metal layer and a resin layer is known.

By the way, a transfer molding method is known as one of methods for manufacturing a semiconductor device (for example, Patent Document 1). Specifically, the heat dissipation plate is placed in the resin sealing mold so that the metal layer of the heat dissipation plate including the metal layer and the resin layer and the resin sealing mold are in contact with each other. Next, a frame on which electronic components, wires, etc. are installed is placed at a predetermined position on the resin layer of the heat dissipation plate. After that, the resin sealing mold is heated, the sealing resin is filled, and the method for curing the sealing resin in a pressurized state, or the resin sealing mold is heated in advance, As described above, there is a method of placing each member on the resin layer of the heat dissipation plate, filling the sealing resin, and curing the sealing resin while applying pressure.

JP, 2005-109100, A

However, in the case of the method described above, since the resin sealing mold is heated, the curing reaction of the resin layer of the heat dissipation plate proceeds before the frame is placed, and the adhesion between the frame and the resin layer is unsatisfactory. Will be enough.

In view of the above circumstances, it is an object of the present invention to provide a heat radiating plate which is excellent in adhesion to an adherend such as a frame and withstand voltage characteristics in the transfer molding method.

In order to solve the above problems, in a first aspect of the present invention, a heat dissipation plate including a metal layer and a resin layer, having a void in the resin layer, the void ratio of the resin layer It is characterized by being 10 to 30%.

In a second aspect of the present invention, a heat sink including a metal layer and a resin layer, further comprising a second resin layer in addition to the resin layer, wherein the second resin layer is A heat dissipation plate formed between the metal layer and the resin layer and having substantially no voids.

INDUSTRIAL APPLICABILITY The present invention can provide a heat dissipation plate that is excellent in adhesion to an adherend such as a frame and withstand voltage characteristics in the transfer molding method.

Note that the above summary of the invention does not enumerate all necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

It is a schematic sectional drawing of the two-layer heat sink concerning embodiment. It is a schematic sectional drawing of the three-layer heat sink concerning embodiment.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Further, not all combinations of the features described in the embodiments are essential to the solving means of the invention. Note that, in the drawings, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratio of the drawings is not limited to the illustrated ratio. Further, in the drawings, duplicate description of common elements is omitted.

(2-layer heat sink)
FIG. 1 is a schematic cross-sectional view of a two-layer heat dissipation plate according to this embodiment. The heat dissipation plate 10 is a heat dissipation plate including a metal layer 11 and a resin layer 13.

The material of the metal layer 11 is not particularly limited, and various metals can be used. For example, copper, aluminum, stainless steel, etc. are mentioned. Among these, the metal layer 11 is preferably a copper foil layer from the viewpoint of thermal conductivity and workability. Copper foil is roughly classified into electrolytic copper foil and rolled copper foil, but electrolytic copper foil is preferred from the viewpoint of adhesion to the resin layer, and a resin layer is formed on the matte surface (rough surface) compared to the glossy surface. Preferably.

The thickness of the metal layer 11 is not particularly limited, and a suitable thickness can be appropriately selected. In the present embodiment, it is preferably 12 to 500 μm from the viewpoint of workability, and more preferably 35 to 105 μm from the viewpoint of workability and heat dissipation characteristics.

The resin layer 13 is made of a resin composition containing a main component, a curing agent, a curing accelerator, and a filler. As the main component, a thermoplastic polyimide resin (which may be in the thermoplastic polyimide precursor stage in this specification), an epoxy resin, an acrylic resin, a urethane resin, or a polyester resin can be appropriately selected. It should be noted that two or more kinds of resins may be selected or two or more kinds of resins may be selected and combined from the same kind of resin depending on the characteristics required for the heat sink. Among these, it is preferable to use a thermoplastic polyimide resin or an epoxy resin from the viewpoint of heat resistance and flame retardancy.

The thermoplastic polyimide resin is obtained from at least one kind of tetracarboxylic dianhydride and one or more kinds of diamine as raw materials. Here, the thermoplasticity means that it has a glass transition temperature in the range of 100° C. to 400° C., and is melted and fluidized by heating at the glass transition temperature or higher so that it can be molded.

The tetracarboxylic dianhydride and diamine used as the raw materials are not particularly limited as long as they have thermoplasticity, and known raw materials can be used.

Examples of the tetracarboxylic dianhydride as a raw material include 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,3′,4,4′-biphenyltetracarboxylic dianhydride, and 2,3′,4,4′-biphenyltetracarboxylic dianhydride. 3,6,7-Naphthalenetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyl Ether tetracarboxylic dianhydride, p-phenylene bis (trimellitic acid monoester acid anhydride), m-phenylene bis (trimellitic acid monoester acid anhydride), o-phenylene bis (trimellitic acid monoester acid anhydride) ), TABP, p-methylphenylene bis (trimellitic acid monoester acid anhydride), 3,3′,4,4′-biphenyl sulfone tetracarboxylic acid dianhydride, 2,2-bis(3,4- Dicarboxyphenyl)hexafluoropropanoic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propanoic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, bicyclo[ 2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5-(dioxotetrahydrofuryl-3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride Anhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-tetralin-1,2-dicarboxylic acid dianhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic acid dianhydride, 1, 2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, etc. Also, two or more of these may be selected and used in combination. ..

Similarly, as the diamine, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4,4'-diamino. Diphenylmethane, 4,4'-methylenebis(2-methylaniline), 4,4'-methylenebis(2-ethylaniline), 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-methylenebis( 2,6-diethylaniline), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3 ,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzanilide, benzidine, 3,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine , O-tolidine, m-tolidine, 2,2′-bis(trifluoromethyl)benzidine, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1, 3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(3-aminophenoxy)phenyl)sulfone, bis(4-(4-aminophenoxy)phenyl ) Sulfone, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-amino) (Phenyl)hexafluoropropane, p-terphenylenediamine, 4,4'-methylenebis(cyclohexylamine), isophoronediamine, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-cyclohexanebis (Methylamine), 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 3,8-bis(amino) Methyl)tricyclo[5.2.1.0]decane, 1,3-diaminoadamantane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-aminocyclohexyl)hexafluoropropane, 1 ,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pepylene Examples include dimethylene diamine, 1,6-hexamethylene diamine, 1,7-heptamethylene diamine, 1,8-octamethylene diamine, and 1,9-nonamethylene diamine. Also, two or more of these may be selected and used in combination.

A known method can be applied to the method of polymerizing the thermoplastic polyimide precursor and the imidization reaction of the precursor. The timing of imidizing the precursor is, for example, applying the thermoplastic polyimide precursor dissolved in a solvent to the metal layer 11 and drying the resin layer 13 to form a resin layer 13, and a resin such as a frame on the resin layer 13. When the adherend is placed, the precursor is imidized. Thus, the resin layer 13 containing the thermoplastic polyimide resin can be obtained.

In the above case, since the reaction temperature of the imidization reaction is high, there is an advantage that it is not easily affected by the preheating of the resin sealing mold in the transfer molding method. That is, the imidization reaction of the resin layer 13 is less likely to be affected by the preheating of the resin sealing mold.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin and other novolac type epoxy resin, biphenyl type epoxy resin. Examples thereof include resins and naphthalene ring-containing epoxy resins. From the viewpoint of adhesion, bisphenol type epoxy resin is preferable, and from the viewpoint of heat resistance, novolac type epoxy resin is preferable.

Examples of the acrylic resin include polymers obtained by polymerizing monomers such as (meth)acrylic acid alkyl ester and (meth)acrylic acid.

Examples of the urethane resin include those obtained by polymerizing polyester polyol and polyisocyanate.

Examples of the polyester resin include those obtained by polycondensing dicarboxylic acid and polyalcohol.

Examples of the curing agent include an epoxy compound, an isocyanate compound, an amide compound, an imidazole compound, an amine compound, and an acid anhydride compound, and a combination with an epoxy resin, an imidazole compound, an amide compound, Acid anhydride compounds are preferred, and amide compound dicyandiamide is more preferred from the viewpoint of adhesion and curability. The compounding amount of the curing agent is 0.5 to 50 parts by weight, and preferably 1 to 10 parts by weight from the viewpoint of adhesion, with respect to 100 parts by weight (based on solid content) of the main component constituting the resin layer. ..

Examples of the isocyanate curing agent include isocyanate compounds such as TDI-TMP (tolylene diisocyanate-trimethylpropane adduct) and HMDI-TMP (hexamethylene diisocyanate-trimethylpropane adduct).

As the imidazole-based curing agent, 2-methylimidazole, 2-undecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2- Examples include imidazole compounds such as methyl-4-methylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, and epoxy-imidazole adduct.

As the curing accelerator, triphenyl phosphate, an amine compound such as boron trifluoride monoethylamine, 2-heptadecylimidazole, 2-methylimidazole, 2-undecylimidazole, 1,2-dimethylimidazole, 2-ethyl. -4-Methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-methyl-4-methylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2,3-dihydro-1H-pyrrolo[1, 2-a] Imidazole compounds such as benzimidazole and epoxy-imidazole adduct are mentioned, and 2-undecylimidazole is preferable from the viewpoint of adhesion. The compounding amount of the curing accelerator is 0.1 to 5 parts by weight with respect to 100 parts by weight of the main component (in terms of solid content) constituting the resin layer, and 0.2 to 1 part by weight from the viewpoint of adhesion and curability. It is preferably part.

Examples of the filler include boron nitride, aluminum nitride, silicon nitride, gallium nitride, aluminum oxide, silicon carbide, and silicon dioxide, and boron nitride is preferable from the viewpoint of thermal conductivity. The shape of the filler may be a scaly shape, a spherical shape, or the like of the primary particles, and the scaly shape is preferable from the viewpoint of void-forming property. Further, a shape (crushed shape) obtained by physically crushing the crystalline substance can also be preferably used as the shape of the primary particles from the viewpoint of void forming property. Agglomerated particles obtained by aggregating the above primary particles can also be used from the same viewpoint. Moreover, you may use these 2 or more types together. The blending amount of the filler is 30 to 70% by volume based on the total solid content of the resin composition constituting the resin layer, and preferably 45 to 60% by volume from the viewpoint of void forming property and adhesiveness.

Examples of the rubber include rubber-based resins such as polyisoprene rubber, styrene butadiene rubber, polybutadiene rubber, ethylene propylene rubber, ethylene propylene diene rubber, acrylonitrile butadiene rubber, and acrylic rubber. From the viewpoints of workability and adhesion, acrylonitrile butadiene rubber and styrene butadiene rubber are preferable. The amount of the rubber compounded (in terms of solid content) is 5 to 100 parts by weight with respect to 100 parts by weight of the main resin constituting the resin layer (in terms of solid content). From the viewpoint, it is preferably 10 to 50 parts by weight.

Regarding the thickness of the resin layer 13, the thickness of the resin composition in the B-stage cured state is 30 to 300 μm. The thickness is preferably 40 to 160 μm from the viewpoints of void forming property, adhesiveness, and heat dissipation property. When the thickness of the resin layer 13 becomes thick, for example, a plurality of sheets of the resin composition having a small thickness are produced, and these are laminated and thermocompression bonded to obtain the resin layer 13 having a desired thickness. Here, the degree of cure of the resin layer in the present invention refers to the degree of cure calculated from the amount of heat generated when measured using a differential scanning calorimeter DSC-60 (manufactured by Shimadzu Corporation, hereinafter also referred to as DSC). The B-stage cured state means a case where the value of the degree of curing is in the range of 0 to 64%, and is also called a semi-cured state. A specific measuring method will be described later. In the case of a curing agent whose degree of curing cannot be measured by DSC, the degree of curing is judged from the resin flow measuring method of the resin composition based on JPCA-BM02.

The method of forming the resin layer 13 on the surface of the metal layer 11 is not particularly limited, and various methods can be adopted. For example, a method in which a resin composition diluted with a solvent is applied to the metal layer 11 with a die coater, the solvent in the composition is dried and then heated, or a resin composition diluted with the solvent is applied to a separator film with a die coater. There is a method in which after coating and drying the solvent in the above composition, the metal layer 11 is laminated on the resin surface, and heat lamination or hot pressing is performed. The cured state of the resin layer 13 is adjusted by the amount of heat during processing in consideration of the composition of the resin composition of the resin layer 13. Examples of the coating means include a die coater, a comma coater, a gravure coater, and a bar coater.

Examples of the solvent include alcohols (eg, methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, cellosolve), ketones (eg, acetone, methyl ethyl ketone, cyclohexanone), aromatic hydrocarbons (eg, toluene, xylene), aliphatics Hydrocarbons (eg, hexane, octane, decane, dodencan), esters (eg, ethyl acetate, methyl propionate), ethers (eg, tetrahydrofuran, ethyl butyl ether, propylene glycol monoethyl ether) and the like can be mentioned. These may be used alone or in combination of two or more.

(3-layer heat sink)
FIG. 2 is a schematic cross-sectional view of the three-layer heat dissipation plate according to this embodiment. The heat dissipation plate 20 is a heat dissipation plate including a metal layer 11, a resin layer 22 that is a second resin layer, and a resin layer 13. Descriptions of the metal layer 11 and the resin layer 13 are omitted because they have overlapping contents. Further, only the portion of the resin layer 22 which is the second resin layer different from the resin layer 13 will be described.

Regarding the thickness of the resin layer 22, the thickness of the resin composition in the C-stage cured state is 30 to 300 μm. From the viewpoint of workability, withstand voltage characteristics, and heat dissipation characteristics, it is preferably 40 to 160 μm. Here, the C-stage cured state refers to the case where the value of the degree of curing calculated from the DSC measurement is in the range of 65 to 100%, and is also referred to as a gelled state.

The resin layer 22 can be formed on the metal layer 11 by a method similar to the method of forming the resin layer 13 described above. For example, a method in which a resin composition for the resin layer 22 diluted with a solvent is applied to the metal layer 11 with a die coater, the solvent in the composition is dried and then heated, or the resin layer 22 diluted with the solvent is used. It can be formed by a method of applying the resin composition to a separator film with a die coater, laminating the metal layer 11 on the resin surface obtained by drying the solvent in the above composition, and hot laminating or hot pressing. After that, a predetermined amount of heat is applied to the resin layer 22 to bring it into a C stage cured state. Next, a resin composition for the resin layer 13 diluted with a solvent is applied to a separator film with a die coater, and the resin layer 22 is laminated on the resin surface obtained by drying the solvent in the composition, followed by thermal lamination or heat treatment. Pressing is performed to obtain a three-layer heat sink.

In the present embodiment, the resin layer 13 has voids and can be represented by the void ratio. The porosity is preferably 10 to 30% from the viewpoint of adhesion, and is preferably 10 to 20% from the viewpoint of withstand voltage characteristics.
Here, in the field of heat dissipation plates, a large amount of filler having excellent thermal conductivity is added to the resin composition in order to improve heat dissipation properties. At this time, voids are likely to occur due to the shape of the filler, the resin may not sufficiently reach the voids, and voids may remain in the resin layer. It has been known that when the heat dissipation plate is incorporated in the semiconductor device with the voids existing in the resin, the withstand voltage characteristic is adversely affected.
For this reason, it has been common knowledge in the past to remove the voids as much as possible when manufacturing the heat sink.
However, in a closed molding method such as a transfer molding method, when the heat dissipation plate is used, there is a problem that the adhesion to the adherend is not sufficient, and the present invention is based on an idea different from the above common sense. The above problems were solved.

That is, the heat sink according to the present invention has a certain amount of voids in the resin layer so as to suppress the deterioration of withstand voltage characteristics and to be adhered even if it is a closed molding method such as a transfer molding method. It has excellent adhesion to the body. It is assumed that the mechanism of the adhesive force in the closed molding method such as the transfer molding method is as follows.

The resin layer 13 of the heat dissipation plate according to the present invention contains a filler of primary particles having a scaly shape, a spherical shape, or the like in which voids are easily formed, and a heat dissipation plate having a certain proportion of voids is formed by transfer molding. When used in a closed molding method such as a molding method, the voids present in the heat dissipation plate receive the resin component of the resin layer 13 softened by heating and pressurization, and resin flow occurs. Further, even if the curing reaction of the resin layer on the heat sink progresses when the heat sink is placed while the mold for resin encapsulation is heated, the resin flow described above causes the conventional heat sink It is more likely to occur than a heat sink that does not have. As a result, it is considered that the adhesion between the metal layer 11 and the adherend such as a frame is increased via the resin layer 13. Further, after the adhesion, the voids in the resin layer are almost eliminated, so that the withstand voltage characteristic is also improved.

The resin layer 22 preferably has substantially no voids from the viewpoint of withstand voltage characteristics. “Substantially free of voids” means that voids do not exist within a range that does not affect the withstand voltage characteristics, and the void ratio is 5% or less, preferably 3% or less.

The resin layer 22 has a higher degree of curing than the resin layer 13 and has few voids. This results in a heat dissipation plate having excellent withstand voltage characteristics. Further, the resin layer 13 and the resin layer 22 of the heat dissipation plate according to the present invention are made of the same resin composition, and the porosity is adjusted by pressing or the like, but the resin layers 13 and 22 are made of different resin compositions. Alternatively, the porosity may be adjusted by changing the kind of the filler in the resin composition constituting the resin or the other resin.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In Examples and Comparative Examples, measurement and evaluation of each physical property were performed by the following methods.

(1) Porosity For the porosity, first, the density of the sample was calculated using a balance for specific gravity measurement AUX220 (manufactured by Shimadzu Corporation), and the porosity was calculated from the following mathematical formula 1 based on the density.
[Formula 1]
Porosity [%]={1-(density of sample having voids [g/cm ³ ]/density of sample having substantially no voids [g/cm ³ ])}×100
The sample having voids was obtained by removing the copper foil layer of the two-layer heat sink having voids described below by etching, washing with water, drying at 100° C. for 1 hour, and then cooling in an atmosphere of 23° C. and 50% RH. As the sample having substantially no void, a two-layer heat dissipation plate having substantially no void, which will be described later, was treated in the same manner as in the above method, and was used as a sample for measuring voidage. The sample size was 2×2 cm. Here, it was confirmed that the density of the sample having substantially no void is equal to the theoretical density that can be obtained from the blending ratio of the resin composition.

(2) Adhesion Adhesion is the adhesion between the adherend and the resin layer on the heat sink, and was evaluated by an ultrasonic imaging device FineSAT FS300 II (manufactured by Hitachi Power Solutions). The degree of adhesion was judged by the grayscale of the observed image of the interface between the adherend and the resin layer. When the observation area is uniform, the adhesion is high, and when the observation area is nonuniform, the adhesion is low.
For the sample, a resin surface obtained by peeling off the release PET from the heat dissipation plate and a copper plate having a thickness of 300 μm as an adherend are combined, and in that state, MVLP-500 (manufactured by Meiki Seisakusho) is used and the temperature is 180° C. under vacuum. , 30 seconds, in a non-pressurized state, and then pressure-bonded under vacuum at 180° C., 1 MPa, 30 seconds, and further heated at 180° C. for 1 hour using a circulating drying oven, What was cooled in an atmosphere of 23° C. and 50% RH was used as a sample for measuring adhesion.
The evaluation of the adhesive strength was performed based on the observed image according to the following criteria.
◎・・・The entire observation area is uniform (no shade area).
○: There is a non-uniform area in part of the observation area.
X: The entire observation area is non-uniform.

(3) Withstand voltage The withstand voltage was measured according to JIS C2110.
The sample was prepared by the following procedure. First, the resin surface from which the release PET was peeled off from each heat sink and the glossy surface of the electrolytic copper foil with a thickness of 35 μm (manufactured by Fukuda Metal Foil & Powder Co., Ltd.) were combined, and in that state, MVLP-500 Was used in a non-pressurized state under vacuum at 180° C. for 30 seconds, and then pressure-bonded under vacuum at 180° C., 1 MPa for 30 seconds. Next, it was heated at 180° C. for 1 hour using a circulation type drying furnace and then cooled in an atmosphere of 23° C. and 50% RH. Further, the electrolytic copper foil was removed by etching, washed with water, dried at 100° C. for 1 hour, and then cooled in an atmosphere of 23° C. and 50% RH to obtain a withstand voltage sample.
The measurement conditions were such that the electrodes were sandwiched in oil with a diameter of 6 mm, the pressure was increased at a rate of 0.5 kV/min, and the voltage when short-circuited was measured.
The withstand voltage was evaluated according to the following criteria.
◎・・・7kV or more
◯... 4 kV or more and less than 7 kV Δ... 2 kV or more and less than 4 kV ×... less than 2 kV

(4) Curing degree The curing degree was calculated from the following Equation 2 by measuring the calorific value using a differential scanning calorimeter DSC-60 (manufactured by Shimadzu Corporation).
[Formula 2]
Curing degree [%]={(H0-H1)/H0}×100
In Equation 2, H0 is the heat value [J/g] of the resin composition in the pre-cured state, and H1 is the heat value [J/g] of the resin composition in each cured state.
The sample was prepared by the following procedure. First, for the resin composition in a pre-cured state, a resin composition which is heated at 120° C. for 5 minutes to remove a solvent component contained in the resin composition described later and cooled in an atmosphere of 23° C. and 50% RH is used. I was there. The samples in the B-stage cured state and the C-stage cured state were obtained by separating the resin layer portion from each heat dissipation plate described later.
The measurement was performed from room temperature to 300° C. at a heating rate of 10° C./min. Next, each calorific value was obtained from the DSC curve obtained from the measurement, and the degree of curing was obtained from the above mathematical formula 2.

(Preparation of resin composition)
(Example 1)
The resin composition comprises a bisphenol A type epoxy resin having an epoxy equivalent of 875 to 975 g/eq (manufactured by Mitsubishi Chemical Corporation) in terms of solid content of 50 parts by weight, and an epoxy equivalent of 200 to 220 g/eq of a bisphenol A type epoxy resin (Mitsubishi. 50 parts by weight in terms of solid content, 5 parts by weight of dicyandiamide (manufactured by Alz Chem), 0.2 parts by weight of 2-undecylimidazole (manufactured by Shikoku Kasei), and acrylonitrile butadiene rubber (Nippon Zeon). 20 parts by weight in terms of solid content, 180 parts by weight of methyl ethyl ketone, and 220 parts by weight of propylene glycol monomethyl ether high-solve MP (manufactured by Toho Kagaku Kogyo Co., Ltd.) are added and well stirred, and then the total solid content in the resin composition is increased. Further, 60% by volume of scaly boron nitride SGP (manufactured by Denki Kagaku) was further added and sufficiently dispersed to obtain a resin composition.

(Examples 2 to 10, Comparative Examples 1 to 4)
A resin composition was prepared in the same manner as in Example 1 except that the type and addition amount of the filler component in Example 3 and Comparative Example 8 were changed.

(Production of two-layer heat sink)
(1) Production of void-unadjusted dry film A polyethylene terephthalate film (hereinafter also referred to as a release film) (manufactured by Lintec Co., Ltd.) having a 50 μm-sided release treatment on one surface thereof was applied to a bar coater. Was applied so that the film thickness after drying would be about 230 μm, and dried at 100 to 150° C. for about 5 minutes using a circulation type drying oven to obtain a void-unadjusted dry film.

(2) Preparation of Two-Layer Heat Sink Having Voids in Resin Layer In Examples 1 to 5, while considering the relationship with the void ratio of the void-unadjusted dry film obtained above, 2 having a void in the resin layer was used. The layer heat sink was produced as follows. The exposed resin surface of the void-unadjusted dry film and a copper plate of 105 μm (manufactured by Fukuda Metal Foil & Powder Co., Ltd.) are heated under vacuum at 80 to 150° C., 0.5 to 10 MPa, and 0.25 to 5 minutes. After pressure-pressing treatment and further baking treatment at 70 to 120° C. for 1 to 3 days, it was cooled to room temperature to obtain a two-layer heat sink having voids in the resin layer. The degree of cure in each example was adjusted to 25%.

(3) Production of two-layer heat dissipation plate having substantially no voids in resin layer In Comparative Examples 1 and 2, one release film of the void-unadjusted dry film was peeled off to expose the resin surface and a copper plate of 105 μm. (Manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.) and 140° C., 6 to 10 MPa, 4 to 6 minutes, and hot pressing was performed to make the thickness of the resin layer about 160 μm. After that, baking treatment was performed at 70 to 120° C. for 1 to 3 days and then cooled to room temperature to obtain a two-layer heat dissipation plate having substantially no voids in the resin layer. The curing degree of each comparative example was adjusted to 25%.

(Production of three-layer heat sink)
In Examples 6 to 10 and Comparative Examples 3 and 4, similarly to the two-layer heat dissipation plate, the void-unadjusted dry film obtained above was produced as follows while considering the relationship with the void ratio. First, the release film of the void-unadjusted dry film was peeled off, and the exposed resin surface and a 105 μm copper plate (manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.) were heated under conditions of 170° C., 6-10 MPa, and 4-6 minutes. By performing pressure pressing, a two-layer heat dissipation plate having a resin layer thickness of 160 μm and having substantially no voids in the resin layer was produced. Next, a void-unadjusted dry film is further laminated on the resin layer side, and hot-pressing treatment is performed under vacuum at 80 to 150° C., 0.5 to 10 MPa, and 0.25 to 5 minutes for each. A resin layer having a porosity was formed. After that, baking treatment was further performed at 70 to 120° C. for 1 to 3 days and then cooled to room temperature to obtain a three-layer heat sink.

Table 1 shows each composition of the resin layer having voids in the two-layer heat dissipation plate, and the results of the porosity, the curing degree, and the adhesive force of each of the examples and the comparative examples.

In Examples 1 to 5 of Table 1, the adhesion was good when the porosity was 10 to 30%. Furthermore, when the porosity of Examples 1 to 4 is 10 to 20%, the withstand voltage becomes 4 kV or more, and it can be seen that even the two-layer heat dissipation plate satisfies both characteristics of adhesion and withstand voltage characteristics. It was Note that when the porosity of Example 5 was 30%, the withstand voltage was 3 kV, but it can be sufficiently used practically as a heat dissipation plate, and it is possible to achieve both withstand voltage and adhesion. is there. Further, when the porosity of Comparative Examples 1 and 2 is 5% or less, the withstand voltage is 9 kV, but as shown in Table 1, both the withstand voltage and the adhesive force have not been realized.

Table 2 shows the results of the composition of the resin layer having substantially no voids in the three-layer heat dissipation plate, and the porosity, the degree of cure, the adhesion, and the withstand voltage characteristics in each Example and each Comparative Example. It is a thing. The composition, porosity, and degree of cure of the resin layer having voids are the same as those described in Table 1, and therefore omitted. The void-unadjusted dry films used in Examples 6-10 and Comparative Examples 3-4 have the void-unadjusted dry films of Examples 1-5 and Comparative Examples 1-2, respectively, so that the numbers of Examples correspond in ascending order. A film was used.

In Examples 6 to 10 in Table 2, it was found that the withstand voltage was 10 kV or more and the three-layer heat dissipation plate satisfied both the adhesiveness and withstand voltage characteristics.

Although the present invention has been described above using the embodiment, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operation, procedure, step, and step in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is "preceding" or "prior to". It should be noted that the output of the previous process can be realized in any order unless the output of the previous process is used in the subsequent process. The operation flow in the claims, the description, and the drawings is described by using “first,” “next,” and the like for the sake of convenience, but it is essential to carry out in this order. Not a thing.

10 2 layer heat sink, 11 metal layer, 13 resin layer, 20 3 layer heat sink, 22 resin layer.

Claims (6)

A heat dissipation plate including a metal layer and a resin layer,
Having a void in the resin layer,
The resin layer has a porosity of 10 to 30%,
The resin layer contains a filler,
A heat sink for a transfer molding method , wherein the amount of the filler to be blended is 45 to 60% by volume based on the total solid content of the resin composition constituting the resin layer. The heat dissipation plate for a transfer molding method according to claim 1, wherein the resin layer is in a B-stage cured state. The resin layer further contains a main component, a curing agent, a curing accelerator, and rubber,
The heat sink for a transfer molding method according to claim 1, wherein the shape of the primary particles of the filler is at least one shape selected from a scaly shape and a spherical shape. The heat sink for transfer molding according to claim 1, wherein the filler is aggregated particles obtained by aggregating primary particles. In addition to the resin layer, a second resin layer is further included,
The heat dissipation plate for transfer molding according to claim 1, wherein the second resin layer is formed between the metal layer and the resin layer and has substantially no void. The heat sink for transfer molding according to claim 5, wherein the second resin layer is in a C-stage cured state.

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