JP6487829B2 - Thermally conductive thermosetting adhesive composition and thermally conductive thermosetting adhesive sheet - Google Patents

Description

  The present invention relates to a heat conductive thermosetting adhesive composition and a heat conductive thermosetting adhesive sheet.

Heat is generated during the operation of the semiconductor element. Particularly in a power semiconductor element that performs power conversion and control, the generated heat is large. In recent years, with the increase in capacity and miniaturization of semiconductor elements, the heat density has increased, and in order to prevent the semiconductor elements and peripheral members from being damaged by the generated heat, heat from the semiconductor elements and peripheral members is efficiently It is important to escape well.
Metal heat sinks are used to release heat from semiconductor elements and peripheral members. For example, by attaching a heat sink to a circuit board on which a semiconductor element is mounted, heat generated in the semiconductor element can be transferred to the heat sink through the circuit board and can be dissipated from the heat sink to the atmosphere.

In the case of using a heat sink, in order to prevent current leakage from the semiconductor element and peripheral members, it is common to arrange a thermal conductive material (Thermal Interface Material (TIM)) having an insulating property between them and the heat sink.
It has been proposed to use a thermally conductive adhesive as the TIM. The heat conductive adhesive can directly bond the semiconductor element and the heat sink. As a heat conductive adhesive, what contains a resin component and a heat conductive filler is common. Properties required for the heat conductive adhesive include thermal conductivity (heat dissipation), adhesion, insulation, heat resistance, and the like.
Until now, various heat conductive adhesives have been proposed (for example, Patent Documents 1 and 2). However, a heat conductive adhesive that can maintain high insulation has not been proposed at high temperatures, for example, at about 150 ° C., which is the operating temperature region of silicon-based semiconductor elements.

JP 2013-91680 A JP 2013-249391 A

  The present invention has been made in view of the above circumstances, and is excellent in thermal conductivity and insulation, and a thermally conductive thermosetting adhesive composition and thermal conductivity that can maintain excellent insulation even at high temperatures. An object is to provide a thermosetting adhesive sheet.

The present invention provides a heat conductive thermosetting adhesive composition and a heat conductive thermosetting adhesive sheet having the following configurations (1) to (4).
(1) containing an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a thermally conductive filler (D),
A ratio of the storage elastic modulus at −30 ° C. to the storage elastic modulus at the glass transition temperature measured after thermosetting is 300% or less, and the glass relative to the storage elastic modulus at the glass transition temperature. A thermally conductive thermosetting adhesive composition having a storage elastic modulus ratio of 40% or more at a transition temperature + 30 ° C.
(2) The heat conductive thermosetting adhesive composition according to (1), wherein the amine value of the diamine compound (B) is 30 to 100 KOH mg / g.
(3) The heat conductive thermosetting adhesive composition according to (1) or (2), wherein the polyimide resin (C) has a silicone skeleton.
(4) A heat conductive thermosetting adhesive sheet comprising the heat conductive thermosetting adhesive composition according to any one of (1) to (3).

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in heat conductivity and insulation, The heat conductive thermosetting adhesive composition and heat conductive thermosetting adhesive sheet which can maintain the outstanding insulation at the time of high temperature can be provided.

It is a figure which shows an example of a semiconductor module provided with a semiconductor element and a heat sink.

≪Heat conductive thermosetting adhesive composition≫
The heat conductive thermosetting adhesive composition of the present invention (hereinafter also simply referred to as an adhesive composition) includes an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a heat conduction. Containing a conductive filler (D).
The adhesive composition of the present invention is an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a thermally conductive filler (D) as long as the effects of the present invention are not impaired. You may further contain other components other than.
The adhesive composition of the present invention may or may not contain a liquid medium. When laminating the adhesive composition of the present invention on a substrate by a coating method, it is preferable to contain a liquid medium.

<Epoxy resin (A)>
“Epoxy resin” is a compound having two or more epoxy groups in one molecule.
As the epoxy resin (A), known ones can be used. For example, a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, a novolak type epoxy resin having a biphenyl type skeleton, an epoxy resin having a naphthalene skeleton, triphenyl Methane type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, dicyclopentadiene type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, halogenated epoxy resin, etc. Can be mentioned. An epoxy resin (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

The epoxy resin (A) is preferably a trifunctional or higher polyfunctional epoxy resin in terms of heat resistance of the cured product. From the viewpoint of the fluidity of the adhesive composition and the flexibility of the cured product, a double-ended epoxy resin is preferred. A trifunctional or higher polyfunctional epoxy resin and a both-end type epoxy resin may be combined.
Specific examples of the polyfunctional epoxy resin include triphenylmethane epoxy resin (for example, trade name: EPPN (registered trademark) 502H manufactured by Nippon Kayaku Co., Ltd.), naphthalene type epoxy resin (for example, product name manufactured by DIC). : 4032D, HP4700), cresol novolac type epoxy resin (trade name: EOCN (registered trademark) 1022 manufactured by Nippon Kayaku Co., Ltd.), trade name: VG3101 manufactured by Printec, and the like.
Specific examples of the both-end type epoxy resin include a bisphenol A type epoxy resin (for example, trade name: jER (registered trademark) 828, 1001 manufactured by Mitsubishi Chemical Corporation), and a biphenyl type epoxy resin (for example, a product manufactured by Mitsubishi Chemical Corporation). Name: YX-4000), dicyclopentadiene type epoxy resin (for example, product name: HP7200 manufactured by DIC) and the like.

The epoxy resin (A) may have a silicone skeleton.
As an epoxy resin having a silicone skeleton, for example, trade name: X-22-163A manufactured by Shin-Etsu Silicone Co., an epoxy resin having a side chain phenyl type siloxane skeleton, an alicyclic epoxy resin (for example, trade name: Shin-Etsu Silicone Co., Ltd .: X-22-2046) and the like.

<Diamine compound (B)>
A “diamine compound” is a compound having two amino groups. The diamine compound (B) functions as a curing agent for the epoxy resin (A). By using the diamine compound (B) as a curing agent, compared with the case of using another epoxy curing agent (for example, a novolak phenol resin), storage before and after Tg measured for the cured product after thermal curing of the adhesive composition. The amount of change in elastic modulus is small.
Examples of the diamine compound (B) include 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenylmethane. 3,3′-dimethyl-5,5′-diethyl-4,4′-diaminodiphenylmethane, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2 ′, 3,3′-tetrachloro -4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,4'-diamino Diphenylsulfone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminopheno) A) Aromatic diamine compounds such as phenyl] sulfone; 1,3-trimethylenediamine, 1,4-tetramethylenediamine, 1,3-pentamethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylene Examples thereof include aliphatic diamines such as diamine, 1,2-propylenediamine, 2-methyl-1,5-pentamethylenediamine, and 3-methyl-1,5-pentamethylenediamine. Any one of these may be used alone, or two or more may be used in combination.
Among these, aromatic diamine compounds are preferable in terms of heat resistance, mechanical properties, electrical properties, and pot life.

The diamine compound (B) may have a silicone skeleton.
As the diamine compound having a silicone skeleton, a modified silicone compound having a dimethylsiloxane skeleton in the main chain and having an amino group in the side chain or both ends can be used. Examples of such modified silicone compounds include trade names: KF8010 and KF8012, manufactured by Shin-Etsu Silicone.

The amine value of the diamine compound (B) is preferably 30 to 100 KOH mg / g, more preferably 40 to 90 KOH mg / g, and further preferably 50 to 80 KOH mg / g. If the amine value is less than or equal to the upper limit of the above range, the amount of change in storage elastic modulus before and after the Tg measured after thermosetting of the adhesive composition will be smaller. When the amine value is at least the lower limit of the above range, the low temperature rapid curability is excellent. If the amine value is less than or equal to the upper limit, the storage stability is excellent.
The amine value is the number of mg of potassium hydroxide equivalent to the equivalent of hydrochloric acid required to neutralize the amino group contained in 1 g of resin, and is generally determined according to JIS K 7237.

<Polyimide resin (C)>
“Polyimide resin” is a general term for polymers having an acid imide bond in the main chain.
The polyimide resin (C) is preferably a solvent-soluble or meltable one.

As the polyimide resin (C), those having a silicone skeleton are preferable.
Generally, a polyimide resin is rigid, and a cured product of an adhesive composition containing the polyimide resin is difficult to process at a low temperature. In particular, when a large amount of the thermally conductive filler (D) is contained, the flexibility of the cured product of the adhesive composition becomes low, and problems such as cracking tend to occur. If the polyimide resin (C) has a silicone skeleton, the glass transition temperature (hereinafter also referred to as “Tg”) and the storage elastic modulus are lower than those without a silicone skeleton, and processing at a low temperature is possible. And flexibility are improved.

  The silicone skeleton is preferably a polysiloxane skeleton having an average degree of polymerization of 2 to 33 (with a molecular weight of about 250 to 3000) from the viewpoints of hardness, heat resistance, adhesiveness, and the like, and an average degree of polymerization of 4 to 24 ( A polysiloxane skeleton having a molecular weight of about 400 to 2000) is more preferable.

Examples of the polyimide resin having a silicone skeleton include those having at least a structural unit represented by the following formula (I).
This polyimide resin may further have one or both of a structural unit represented by the following formula (II) and a structural unit represented by the following formula (III). By having the structural unit represented by the formula (II), heat resistance and insulation are further increased. The structural unit represented by the formula (III) has a hydroxyl group or a carboxyl group that is an epoxy reactive group that reacts with an epoxy group, and the heat resistance is further increased by including this structural unit.

（式中、Ｗ^１は直接結合、炭素数１〜４のアルキレン基、−Ｏ−、−ＳＯ_２−又は−ＣＯ−を表し、Ｒ^１及びＲ^６はそれぞれ独立に、炭素数１〜４のアルキレン基または下記式（１）で示される基を表し、Ｒ^２〜Ｒ^５はそれぞれ独立に、炭素数１〜４のアルキル基を表し、ｎは２〜３３の整数を表し、Ａｒ^１は下記式（２）又は（３）で示される２価の芳香族基を表し、Ａｒ^２は１個又は２個の水酸基またはカルボキシル基を有する２価の芳香族基を表す。）

(Wherein W ¹ represents a direct bond, an alkylene group having 1 to 4 carbon atoms, —O—, —SO ₂ — or —CO—, and R ¹ and R ⁶ each independently represents ^one having 1 to 4 carbon atoms. Represents an alkylene group or a group represented by the following formula (1), R ^{2 to} R ⁵ each independently represents an alkyl group having 1 to 4 carbon atoms, n represents an integer of 2 to 33, and Ar ¹ represents The divalent aromatic group represented by the formula (2) or (3) is represented, and Ar ² represents a divalent aromatic group having one or two hydroxyl groups or carboxyl groups.

（式中、Ａｌｋは炭素数１〜４のアルキレン基を表す。）

(In the formula, Alk represents an alkylene group having 1 to 4 carbon atoms.)

（式中、Ｗ^２は直接結合、炭素数１〜４のアルキレン基、−Ｏ−、−ＳＯ_２−又は−ＣＯ−を表し、Ｗ^３は、炭素数１〜４のアルキレン基を表し、Ｚ^１及びＺ^２はそれぞれ独立に、水素原子、ハロゲン原子、炭素数１〜４のアルキル基又は炭素数１〜４のアルコキシ基を表す。）

(Wherein W ² represents a direct bond, an alkylene group having 1 to 4 carbon atoms, —O—, —SO ₂ — or —CO—, and W ³ represents an alkylene group having 1 to 4 carbon atoms; ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms.)

In the polyimide resin (C), the molar ratio of the structural unit represented by the above formula (I) and the sum of the structural unit represented by the above formula (II) and the structural unit represented by the formula (III) is 5:95. ~ 50: 50 is preferred.
The molar ratio of the structural unit represented by the formula (II) and the structural unit represented by the formula (III) is preferably 0: 100 to 99: 1, more preferably 80:20 to 95: 5, and 50: 50 to 95: 5 is more preferable.

Although it does not specifically limit as Tg of a polyimide resin (C), About 35-180 degreeC is preferable.
The molecular weight of the polyimide resin (C) is preferably about 15000 to 70000 in consideration of meltability. When the molecular weight of the polyimide resin (C) is less than the above lower limit value, the toughness and ductility of the film may be impaired, and the film may become brittle. It is inferior, the meltability as an adhesive is lowered, the processing temperature is increased, and it is difficult to put it to practical use.
The molecular weight of the polyimide resin (C) is a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as an eluent.

As the polyimide resin (C), a commercially available product may be used, or a product produced by a known production method may be used.
The polyimide resin (C) can be synthesized by cyclization polycondensation of a tetracarboxylic acid anhydride and a diamine compound.
For example, the polyimide resin having the structural unit represented by the formula (I) includes a tetracarboxylic dianhydride represented by the following formula (IV), a diaminosiloxane compound represented by the following formula (V), and as necessary. Either polycondensation of one or both of a diamine compound represented by the following formula (VI) and a diamine compound represented by the following formula (VII) in an organic solvent and imidation of the resulting polyamic acid by ring closure Can be obtained by:

（式中、Ｗ^１、Ｒ^１〜Ｒ^６、ｎ、Ａｒ^１、Ａｒ^２はそれぞれ前記した定義と同一のものを表す。）

(W ¹ , R ^{1 to} R ⁶ , n, Ar ¹ , and Ar ² each have the same definition as described above.)

  Examples of the tetracarboxylic dianhydride represented by the formula (IV) include 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic Acid dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ether Anhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,3 ′, 4′-benzophenonetetracarboxylic An acid dianhydride, 4 ', 4'-biphthalic acid dianhydride etc. are mentioned.

Examples of the diaminosiloxane compound represented by the formula (V) include 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-aminopropyl). Polydimethylsiloxane (for example, aminopropyl-terminated dimethylsiloxane tetramer to octamer), 1,3-bis (3-aminophenoxymethyl) -1,1,3,3-tetramethyldisiloxane, α , Ω-bis (3-aminophenoxymethyl) polydimethylsiloxane, 1,3-bis (2- (3-aminophenoxy) ethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (2- (3-Aminophenoxy) ethyl) polydimethylsiloxane, 1,3-bis (3- (3-aminophenoxy) propyl) -1,1,3,3-tetramethyldisi Hexane, alpha, .omega.-bis (3- (3-aminophenoxy) propyl) polydimethylsiloxane and the like.
In the above diaminosiloxane compound, in the case of polysiloxane, the average degree of polymerization is preferably 2 to 33 (molecular weight is about 250 to 3000), and the average degree of polymerization is 4 to 24 (molecular weight is about 400 to 2000). ) Is preferable.

  Examples of the diamine compound represented by the formula (VI) include 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, and 3,3'-diamino. Diphenyl ether, 4,4′-diaminobenzophenone, 3,3′-dimethyl-4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,3′-dimethoxy-4,4′-diaminodiphenylmethane, 2, 2′-bis (3-aminophenyl) propane, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, benzidine, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 3, 3′-diaminobiphenyl, 1,3-bis (3-aminophenoxy) Zen, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- Chloro-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] propane, 1,1′-bis [4- (4- Aminophenoxy) phenyl] ethane, 1,1′-bis [3-chloro-4- (4-aminophenoxy) phenyl] ethane, bis [4- (4-aminophenoxy) phenyl] methane, bis [3-methyl- 4- (4-aminophenoxy) phenyl] methane, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4 ′-[1,3-phenylenebis (1-methyl) Ruechiriden)] bisaniline, 4,4 '- [1,4-phenylene bis (1-methylethylidene)] bis (2,6-dimethyl-bis aniline), and the like. Two or more of these diamine compounds may be used in combination.

  Examples of the diamine compound represented by the formula (VII) include 2,5-dihydroxy-p-phenylenediamine, 3,3′-dihydroxy-4,4′-diaminodiphenyl ether, 4,3′-dihydroxy-3,4 ′. -Diaminodiphenyl ether, 3,3'-dihydroxy-4,4'-diaminobenzophenone, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 3,3'-dihydroxy-4,4'-diaminodiphenylsulfone, 4,4′-dihydroxy-3,3′-diaminodiphenylsulfone, 2,2′-bis [3-hydroxy-4- (4-aminophenoxy) phenyl] propane, bis [3-hydroxy-4- (4- Aminophenoxy) phenyl] methane, 3,3′-dicarboxy-4,4′-diaminodiphenylamine 4,3′-dicarboxy-3,4′-diaminodiphenyl ether, 3,3′-dicarboxy-4,4′-diaminobenzophenone, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 3,3′-dicarboxy-4,4′-diaminodiphenylsulfone, 4,4′-dicarboxy-3,3′-diaminodiphenylsulfone, 3,3′-dicarboxybenzidine, 2,2′-bis [ 3-carboxy-4- (4-aminophenoxy) phenyl] propane, bis [3-carboxy-4- (4-aminophenoxy) phenyl] methane and the like. Two or more of these diamine compounds may be used in combination.

  Examples of the organic solvent include amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, and N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, and the like. Examples thereof include sulfur-containing solvents, phenol solvents such as phenol, cresol, and xylenol, acetone, tetrahydrofuran, pyridine, and tetramethylurea.

The reaction for polycondensation of the tetracarboxylic dianhydride with a diamine compound such as a diaminosiloxane compound to form a polyamic acid is, for example, -20 to 150 ° C, preferably several tens of degrees at a temperature of 0 to 60 ° C. It can be carried out under conditions of minutes to several days.
Examples of the imidization method of the polyamic acid include a method of dehydrating and ring-closing by heating, a method of chemically ring-closing using a dehydrating ring-closing catalyst, and the like. When dehydrating and ring-closing by heating, the reaction temperature is 150 to 400 ° C, preferably 180 to 350 ° C, and the reaction time is several tens of minutes to several days, preferably 2 to 12 hours. Examples of the dehydration ring closure catalyst in the case of chemical ring closure include acid anhydrides such as acetic acid, propionic acid, butyric acid, and benzoic acid, and it is preferable to use pyridine or the like that promotes the ring closure reaction. The amount of the catalyst used is preferably 200 mol% or more, more preferably 300 to 1000 mol%, based on the total amount of the diamine compound.

<Thermal conductive filler (D)>
As the thermally conductive filler (D), known materials can be used, for example, metal oxides such as silicon oxide (silica), aluminum oxide (alumina), magnesium oxide; silicon nitride, aluminum nitride, boron nitride. Metal carbides such as silicon carbide; metal hydroxides such as magnesium hydroxide; and the like. Any one of these may be used alone, or two or more may be used in combination.
As the thermally conductive filler (D), aluminum oxide (alumina), silicon nitride, aluminum nitride, boron nitride and the like are preferable from the viewpoint of insulation.

As the shape of the thermally conductive filler (D), irregular fine particles, spherical shape, plate shape, spherical shape and the like by crushing can be applied. In general, fine particles having an irregular shape are preferable because they have a high effect on heat conduction.
By using a plurality of fine particles having different particle sizes and shapes, the filling amount can be increased and the thermal conductivity can be further increased. By filling the gaps between the thermally conductive fillers with fillers having a small particle size or different shapes, the filling rate is improved and the thermal conductivity is increased. For example, in the case of spherical alumina particles, those having an average particle size of 10 μm and those having an average particle size of 3 μm are used in combination, and the ratio of the larger average particle size to the total amount of the thermally conductive filler (D) is 50 volumes. By making it more than%, higher thermal conductivity can be obtained. Spherical alumina particles and flake-form boron nitride particles can be used in combination.
Here, the average particle size is determined from the measured value of the particle size distribution by the laser diffraction / scattering method using a commercially available laser diffraction / scattering particle size distribution measuring device (for example, MT3000 series manufactured by Microtrac Bell Co., Ltd.). It can be obtained as a median diameter (d50, volume basis) by cumulative distribution.

The heat conductive filler (D) may be subjected to a surface treatment in order to improve wettability with the resin component, adhesion, and characteristics.
Examples of the surface treatment include oxide film treatment, surface treatment with a silane coupling agent, and surface treatment with a titanate coupling agent.
For example, when the heat conductive filler is aluminum nitride, ammonia is generated when exposed to the conditions of a pressure cooker test (for example, 121 ° C. and 100% RH 2.1 atm). Ammonia is an unfavorable substance in semiconductor packages and the like, and for example, the surface coating with silica suppresses the generation of ammonia.

As the surface treatment, a surface treatment with a silane coupling agent is preferable. By being surface-treated with the silane coupling agent, the thermally conductive filler (D) is more uniformly dispersed in the adhesive composition. Moreover, the adhesiveness of the interface with the resin component is improved, and the strength is improved. In addition, the solder heat resistance in mounting electronic components is improved.
A well-known thing can be used as a sila coupling agent, For example, an epoxy silane, an aminosilane, a vinyl silane, an acrylic silane etc. are mentioned. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3 -Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyl Trimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3- Dimethyl-butylidene) propylamine, N-pheny And ru-3-aminopropyltrimethoxysilane.
The amount of the surface treatment with the silane coupling agent is preferably 0.2 to 1 part by mass with respect to 100 parts by mass of the heat conductive filler (D).

<Other ingredients>
As other components, for example, imidazoles, diamines, triphenylphosphine curing accelerators and catalysts can be contained for the purpose of controlling the curing rate.
The sila coupling agent may be contained in the adhesive composition as it is without being used for the surface treatment of the heat conductive filler (D). In that case, the content of the silane coupling agent is preferably about 0.15 to 0.8% by mass with respect to the total amount of the adhesive composition.

<Liquid medium>
The liquid medium is preferably one that dissolves or disperses the above-described components, and can be appropriately selected from known liquid media. Specific examples of the liquid medium include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidone. Hexane, benzene, toluene, xylene, methyl ethyl ketone, acetone, diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, methyl cellosolve, cellosolve acetate, methanol, ethanol, propanol, isopropanol, methyl acetate, ethyl acetate, Examples include acetonitrile, methylene chloride, chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzene, dichloroethane, and trichloroethane.

<Content of each component>
In the adhesive composition, the content of the epoxy resin (A) is preferably from 30 to 55 mass%, more preferably from 35 to 45 mass%, based on the resin content (100 mass%) of the adhesive composition. Adhesiveness will be favorable if content of an epoxy resin (A) is more than the lower limit of the said range. If it is below the said upper limit, the film property at the time of film forming will be favorable.
The resin content in the adhesive composition is obtained by removing the heat conductive filler (D) from the solid content in the adhesive composition.
The solid content in the adhesive composition is the total of the epoxy resin (A), the diamine compound (B), the polyimide resin (C), the thermally conductive filler (D), and other components.

  The content of the diamine compound (B) is preferably such that the amino group of the diamine compound (B) is 0.92 to 1.03 mol with respect to 1 mol of the epoxy group of the epoxy resin (A). An amount of ˜1.00 mol is more preferred. If the content of the diamine compound (B) is not less than the lower limit of the above range, the thermosetting speed is improved, the thermosetting process can be simplified, and if it is not more than the above upper limit, the adhesiveness is good. .

  30-60 mass% is preferable with respect to the resin part (100 mass%) of an adhesive composition, and, as for content of a polyimide resin (C), 40-50 mass% is more preferable. If the content of the polyimide resin (C) is not less than the lower limit of the above range, more excellent insulation and flexibility can be obtained, and if it is not more than the above upper limit, the meltability of the adhesive composition is sufficiently high. It can be secured, the processing temperature does not increase, and the wettability to the adherend during melting is good.

  The content of the heat conductive filler (D) is preferably 200 to 1000 parts by mass, and more preferably 350 to 700 parts by mass with respect to 100 parts by mass of the resin content in the adhesive composition. If the content of the thermally conductive filler (D) is not less than the lower limit of the above range, the thermal conductivity is more excellent, and if it is not more than the above upper limit, the adhesiveness, heat meltability, and insulation are more excellent.

<Characteristics of adhesive composition>
In the adhesive composition of the present invention, the ratio of the storage elastic modulus at Tg-30 ° C. to the storage elastic modulus at Tg, measured after heat curing, is 300% or less, and Tg + 30 with respect to the storage elastic modulus at Tg. The storage modulus ratio at 40 ° C. is 40% or more.
The ratio of the storage elastic modulus at Tg-30 ° C. to the storage elastic modulus at Tg is a value obtained by storage elastic modulus at Tg-30 ° C. (Pa) / storage elastic modulus at Tg (Pa) × 100. Hereinafter, it is also referred to as “storage elastic modulus ratio (Tg−30 ° C./Tg)”.
The ratio of the storage elastic modulus at Tg + 30 ° C. to the storage elastic modulus at Tg is a value determined by the storage elastic modulus at Tg + 30 ° C. (Pa) / the storage elastic modulus at Tg (Pa) × 100. Also referred to as “storage modulus ratio (Tg + 30 ° C./Tg)”.
“After heat curing” indicates a state in which the adhesive composition is completely cured by heating. Whether the adhesive composition is completely cured can be confirmed by differential scanning calorimetry (DSC) or the like.
In general, the storage elastic modulus at Tg−30 ° C.> the storage elastic modulus at Tg> Tg + the storage elastic modulus at 30 ° C.

The storage modulus ratio (Tg-30 ° C / Tg) is 300% or less and the storage modulus ratio (Tg + 30 ° C / Tg) is 40% or more. Compared to the agent, the change in storage elastic modulus before and after Tg is small. If the change in storage modulus before and after Tg is small, excellent insulation can be maintained even at high temperatures. For example, the breakdown voltage at about 150 ° C., which is the operating temperature region of a silicon-based semiconductor, is sufficiently maintained as compared with the breakdown voltage in a non-operating temperature region (for example, 25 ° C.).
That is, since the change in the storage elastic modulus before and after the Tg of the cured product of the adhesive composition is small, when the temperature changes from a low temperature (for example, a temperature range when the semiconductor is not operating) to a high temperature (for example, a semiconductor operating temperature range). The change in the hardness of the substrate is gradual, and distortion (stress) hardly occurs between the substrate and the adherend. Therefore, when the temperature change from low temperature to high temperature, or when the temperature change from low temperature to high temperature or from high temperature to low temperature is repeated, the layer formed from the adhesive composition is less likely to break, and excellent insulation Can be maintained. Moreover, since distortion hardly occurs between the adherend and the cured product, the cured product is difficult to peel off from the adherend, and the adhesion reliability is excellent. Furthermore, since the cured product is difficult to peel off from the adherend, voids (air gaps) are unlikely to occur at the interface between the cured product and the adherend, and thermal conductivity is unlikely to be impaired.
The storage elastic modulus ratio (Tg-30 ° C / Tg) is preferably 250% or less, and more preferably 200% or less.
The storage elastic modulus ratio (Tg + 30 ° C./Tg) is preferably 40% or more, and more preferably 50% or more.

The storage elastic modulus is measured by a dynamic viscoelasticity test on the adhesive composition after heat curing. Tg is measured as the temperature at which the loss tangent obtained as a ratio of the storage elastic modulus and the loss elastic modulus peaks.
The storage elastic modulus ratio (Tg−30 ° C./Tg) and the storage elastic modulus ratio (Tg + 30 ° C./Tg) can be adjusted depending on the type and content of each component contained in the adhesive composition. For example, if the amine value of the diamine compound (B) is not more than the preferable upper limit value, the change in storage elastic modulus before and after Tg tends to be small.

Although the storage elastic modulus in Tg measured after the said thermosetting is not specifically limited, 5.00 * 10 < ⁷ > -5.00 * 10 < ⁸ > Pa is preferable and 8.00 * 10 < ⁷ > -3.00 * 10 ⁸ Pa is more preferable. If the storage elastic modulus at Tg is less than or equal to the above upper limit, the resistance to strain and thermal expansion that occur when the temperature changes is excellent. If the storage elastic modulus at Tg is not less than the above lower limit, the resistance to shear stress is good.

  Although Tg measured after the said thermosetting is not specifically limited, 130-250 degreeC is preferable and 160-220 degreeC is more preferable. When Tg is high, heat resistance is generally good, but the elastic modulus tends to be high in a low temperature region, and there is a problem that workability and stress relaxation properties are poor.

<Effect>
The adhesive composition of the present invention described above contains an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a heat conductive filler (D), and heat The storage elastic modulus ratio (Tg−30 ° C./Tg) measured after curing is 300% or less, and the storage elastic modulus ratio (Tg + 30 ° C./Tg) is 40% or more. The change in characteristics before and after Tg is small. That is, since the state such as the molecular bonding state of the adhesive composition is easily maintained in the high temperature region near Tg, excellent insulation and thermal conductivity can be maintained even at high temperatures. In addition, the adhesive reliability is excellent.
That is, the adhesive composition of the present invention is melted by heating before being cured, and can be pressure-bonded to an adherend (heat sink, circuit board, etc.), and is not melted even when heated after being cured by heat.
Although there are fine irregularities on the surface of the adherend such as copper foil, when the adhesive composition is placed on the surface of the adherend and heated, the adhesive composition melts and fills the irregularities. Therefore, a space is hardly generated between the adhesive composition and the adherend, and since the heat conductive filler (D) is included, the heat conductive effect is excellent.
Moreover, since a polyimide resin (C) is included, an adhesive composition and its hardened | cured material have high insulation. When used for applications that require insulation, the insulation can be ensured with a thinner film, so that the thermal resistance can be reduced and the heat dissipation effect is enhanced. Moreover, flexibility is provided by the polyimide resin (C), and insulation and adhesiveness are not easily impaired. Flexibility can be imparted by using other thermoplastic resins such as acrylonitrile butadiene rubber and acrylic rubber in place of the polyimide resin (C), but these other thermoplastic resins are added to the polyimide resin (C). In comparison, the thermal decomposition temperature tends to be low, it tends to deteriorate when left at high temperatures, and the temperature dependence of dielectric breakdown voltage and adhesive strength tends to be large. Such a problem can be avoided by using a polyimide resin (C).
The diamine compound (B) is used as a curing agent for the epoxy resin (A), the storage modulus ratio (Tg-30 ° C / Tg) measured after thermosetting is 300% or less, and the storage modulus ratio (Tg + 30). (° C./Tg) is 40% or more, and as described above, excellent insulation and thermal conductivity can be maintained even at high temperatures, and adhesion reliability is also excellent.

<Application>
Although it does not specifically limit as a use of the adhesive composition of this invention, From the point which has said effect, it uses suitably for the assembly of a semiconductor module provided with a semiconductor element and a heat sink as TIM which has insulation.
FIG. 1 shows an example of a semiconductor module including a semiconductor element and a heat sink.
The semiconductor module 10 of this example includes a semiconductor element 1, a circuit board 3 on which the semiconductor element 1 is mounted, a metal heat sink 5, and a TIM layer 7 that bonds the circuit board 3 and the heat sink 5.
The TIM layer 7 is made of a heat-cured product of the adhesive composition of the present invention. The circuit board 3 and the heat sink 5 are bonded and insulated by the TIM layer 7.
During operation of the semiconductor module 10, heat is generated in the semiconductor element 1. The heat generated in the semiconductor element 1 is transferred to the heat sink 5 through the circuit board 3 and the TIM layer 7 and is released from the heat sink 5 into the atmosphere.

  In the semiconductor module 10, for example, a heat conductive thermosetting adhesive sheet made of the adhesive composition of the present invention is disposed between the circuit board 3 on which the semiconductor element 1 is mounted and the heat sink 5 and heated. It can be produced by curing the adhesive sheet. The heat conductive thermosetting adhesive sheet will be described in detail later. Alternatively, the adhesive composition of the present invention is prepared in the form of a liquid containing a liquid medium (coating described later), and this coating is applied to the heat sink 5 (or the circuit board 3 on which the semiconductor element 1 is mounted) and dried. Then, an adhesive layer is formed, and the circuit board 3 (or the heat sink 5) on which the semiconductor element 1 is mounted is placed on the adhesive layer, and the adhesive layer is cured by heating.

≪Heat conductive thermosetting adhesive sheet≫
The heat conductive thermosetting adhesive sheet of the present invention (hereinafter also simply referred to as an adhesive sheet) is composed of the adhesive composition of the present invention. That is, the storage elastic modulus ratio (Tg−), which contains an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a thermally conductive filler (D) and is measured after thermosetting. 30 ° C./Tg) is 300% or less, and the storage elastic modulus ratio (Tg + 30 ° C./Tg) is 40% or more.

  In the adhesive sheet, the maximum particle size of the heat conductive filler (D) is preferably 1/2 or less of the thickness of the adhesive sheet. That is, the thickness of the adhesive sheet is preferably at least twice the maximum particle size of the thermally conductive filler (D). The thermally conductive filler (D) has a low dielectric breakdown voltage, and dielectric breakdown occurs locally at the weakest point. Therefore, the portion of the thermally conductive filler (D) is half the thickness in the adhesive sheet. When the above is occupied, the dielectric breakdown voltage may be extremely lowered. If the maximum particle size of the thermally conductive filler (D) is ½ or less of the thickness of the adhesive sheet, there is an insulating resin between the particles of the thermally conductive filler (D). Even if the individual particles are broken, they are blocked by the resin, thereby suppressing an extreme decrease in the dielectric breakdown voltage.

  50-300 micrometers is preferable and, as for the thickness of the adhesive sheet of this invention, 80-200 micrometers is more preferable. If the thickness of an adhesive sheet is below the said upper limit, thermal conductivity will be more excellent. In terms of heat conduction, the thickness is preferably as thin as possible as long as it can absorb the unevenness of the surface of the adherend. On the other hand, in the case of an adherend having a rough surface such as copper foil, the unevenness The effective thickness of the adhesive is reduced and the dielectric breakdown characteristics are degraded. When the thickness is small, it is necessary to select a heat conductive filler suitable for the thickness. For this reason, the thickness is preferably equal to or greater than the lower limit.

The adhesive sheet of the present invention may be a single layer or a multilayer.
For example, when the thickness of the adhesive sheet is thick, a plurality of layers made of the adhesive composition of the present invention may be laminated to form the adhesive sheet of the present invention.

A protective film may be laminated on one or both sides of the adhesive sheet of the present invention to form an adhesive sheet with a protective film.
As the protective film, for example, a peelable film can be used. Examples of the peelable film that can be used include a polypropylene film, a fluororesin film, a polyethylene film, a polyethylene terephthalate film, paper, and, in some cases, a film that has been made peelable with a silicone resin. 1-200 micrometers is preferable and, as for the thickness of a peelable film, 10-100 micrometers is more preferable.
The peelable film preferably has a 90 ° peel strength with respect to the adhesive sheet in the range of 0.01 to 10.0 g / cm. When the 90 ° peel strength is within the above range, the peelable film is not easily peeled off when the adhesive sheet with the protective film is processed, and the peelable film is peeled cleanly from the adhesive layer during the pasting process, and the workability is good. Become. The 90 ° peel strength is measured by a tensile tester.
When the peelable film is laminated on both surfaces of the adhesive sheet, it is preferable that the peel force of the peelable film laminated on one surface is different from the peel force of the peelable film laminated on the other surface.

The adhesive sheet of the present invention includes, for example, an epoxy resin (A), a diamine compound (B), a polyimide resin (C), a thermally conductive filler (D), a liquid medium, and other materials as necessary. It can be produced by preparing a paint containing the components, applying the paint on a substrate and drying.
At this time, the adhesive sheet may be in a semi-cured state. The method for controlling the semi-cured state is not limited, but is preferably controlled by aging or the like.

  A plurality of adhesive sheets may be produced and laminated to obtain a multilayer adhesive sheet. Moreover, it is good also as a multilayer adhesive sheet by performing the process of apply | coating a coating material further on the formed adhesive sheet, and drying once or more. When the thickness of the adhesive sheet is large, the residual solvent tends to increase when the adhesive sheet is formed at one time. is there. In particular, when used for bonding metals, the residual solvent that volatilizes cannot escape and tends to foam. Therefore, when manufacturing an adhesive sheet with a large thickness, it is preferable to make it a multilayer in order to reduce the residual solvent concentration. The residual solvent concentration in the adhesive sheet is desirably 100 ppm or less, and more desirably 50 ppm or less.

Examples of the epoxy resin (A), diamine compound (B), polyimide resin (C), thermally conductive filler (D), liquid medium, and other components in the coating are the same as those described above, and preferred embodiments are also the same. It is.
As a base material, the above-mentioned peelable film is mentioned, for example.
As a method for applying the paint, a normal coating method or printing method can be used. Specific coating methods include air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, dam Examples of the coating method include coating, dip coating, and die coating. Specific examples of the printing method include intaglio printing such as gravure printing, stencil printing such as screen printing, and the like.
The drying temperature for drying the applied paint is not particularly limited as long as the liquid medium can be removed, but is preferably a temperature at which the formed adhesive sheet is in a semi-cured state.
The thickness of the adhesive sheet can be adjusted by the solid content concentration of the paint, the coating thickness, the number of coatings, and the like.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following description.

<Synthesis Example 1>
1,3-bis (3-aminophenoxy) benzene 23.6 g (81 mmol), 3,3′-dihydroxy-4,4′-diaminodiphenylmethane 2.1 g (9 mmol), aminopropyl-terminated dimethylsiloxane octamer Using 8.1 g (10 mmol), 20.0 g (100 mmol) of bis (3,4-dicarboxyphenyl) ether dianhydride and 300 mL of N-methyl-2-pyrrolidone, JP2013-249391A In the same manner as in Synthesis Example 4, 45.6 g (yield 91%) of polyimide was obtained. The number average molecular weight of this polyimide was 16000, and Tg was 105 ° C.

<Synthesis Example 2>
2,2-bis [4- (4-aminophenoxy) phenyl] propane 32.0 g (78 mmol), aminopropyl-terminated dimethylsiloxane octamer 17.0 g (22 mmol), bis (3,4-dicarboxyphenyl) ) 78.7 g of polyimide (yield 97%) using 35.8 g (100 mmol) of sulfone dianhydride and 300 mL of N-methyl-2-pyrrolidone in the same manner as in Synthesis Example 2 of JP2013-249391A. ) The number average molecular weight of this polyimide was 22000, and Tg was 50 degreeC.

<Examples 1-6, Comparative Examples 1-8>
Based on the formulation described in Tables 1 and 2 below, an epoxy resin, a curing agent, a curing accelerator, a thermoplastic resin, a thermally conductive filler, and a solvent are mixed, and the filler is dispersed by a bead mill to form an adhesive composition. Was prepared.
In the formulations shown in Tables 1 and 2, the compounding amounts (equivalents) of the curing agents in Examples 1 to 6, Comparative Examples 2 to 3 and 6 to 8 are the amino groups of the curing agent per mole of epoxy groups of the epoxy resin. Indicates the number of moles. The compounding quantity (phr) of a heat conductive filler shows the mass part of the heat conductive filler per 100 mass parts of resin parts (solid content-heat conductive filler). The unit of the compounding amount of components other than these is part by mass. In Examples 1 to 6 and Comparative Examples 1 to 8, as the thermally conductive filler, the thermally conductive filler 1, the thermally conductive filler 2 and the thermally conductive filler 3 are 6: 3: 1. Used in volume ratio. Tables 1 and 2 show the total amount of the thermally conductive fillers 1 to 3. The coating solid content concentration indicates the ratio (mass%) of the solid content with respect to the total amount of the adhesive composition.

The materials shown in Tables 1 and 2 were as follows.
Epoxy resin 1: bisphenol A type epoxy resin.
Epoxy resin 2: Biphenyl type epoxy resin.
Epoxy resin 3: Dicyclopentadiene (DCPD) type epoxy resin.
Diamine 1: 4,4′-diaminodiphenyl sulfone (amine value: 62.1 KOH mg / g).
Diamine 2: 3,3′-diaminodiphenyl sulfone (amine value: 62.1 KOH mg / g).
Diamine 3: 2,2-bis [4- (4-aminophenoxy) phenyl] propane (amine value: 102.6 KOH mg / g).
Diamine 4: Bis [4- (4-aminophenoxy) phenyl] sulfone (amine value: 108.1 KOH mg / g).
Novolac type phenolic resin: trade name CKM-2400 manufactured by Showa Denko KK
Imidazole: trade name 2MA-OK (2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct) manufactured by Shikoku Kasei Co., Ltd.
Polyimide 1: Polyimide obtained in Synthesis Example 1.
Polyimide 2: The polyimide obtained in Synthesis Example 2.
NBR: acrylonitrile butadiene rubber (acrylonitrile unit content: 42.5% by mass).
Polyamide: Polyetheresteramide (Tg: -62 ° C).
Thermally conductive filler 1: Alumina (average particle size 20 μm).
Thermally conductive filler 2: Alumina (average particle size 3 μm).
Thermally conductive filler 3: Alumina (average particle size 0.5 μm).

Next, the obtained adhesive composition was applied to a release-treated polyester film so that the thickness after drying was 50 μm, and dried at 120 ° C. for about 3 minutes to prepare an adhesive sheet. Next, two adhesive sheets were laminated to obtain an adhesive sheet having a thickness of 100 μm.
Next, the following measurements and evaluations were performed. The results are shown in Tables 1-2.

[Tg after storage and storage modulus]
The prepared adhesive sheet was subjected to thermosetting treatment (temperature raised from room temperature to 175 ° C. over 1 hour and held at 175 ° C. for 5 hours) to obtain a measurement sample.
About a measurement sample, a dynamic viscoelasticity test (made by Orientec Co., Ltd.) was used, and dynamic viscoelasticity was measured on the conditions of temperature rising rate: 10 degreeC / 1 minute, frequency: 11 Hz, measurement temperature: 25 degreeC-300 degreeC. , Tg, storage elastic modulus at Tg, storage elastic modulus at Tg-30 ° C, and storage elastic modulus at Tg + 30 ° C.
From the above results, the storage elastic modulus ratio (Tg−30 ° C./Tg) and the storage elastic modulus ratio (Tg + 30 ° C./Tg) were calculated.

[Dielectric breakdown test]
The prepared adhesive sheet was subjected to thermosetting treatment (temperature raised from room temperature to 175 ° C. over 1 hour and held at 175 ° C. for 5 hours) to obtain a measurement sample.
The measurement sample was allowed to stand for 24 hours under environmental conditions of a temperature of 25 ° C. and a humidity of 60% RH, and then a DC voltage was applied at a boosting rate of 1 kV / sec, and a voltage (breakdown voltage) was applied until breakdown. As the breakdown strength, the breakdown voltage was divided by the thickness, and the breakdown voltage per 1 mm (kV / mm) was obtained. The dielectric breakdown voltage was obtained for 10 measurement samples, and the average value thereof was calculated.
From the obtained breakdown voltage (25 ° C.), the insulation was evaluated according to the following criteria.
○: Dielectric breakdown voltage (25 ° C.) is 110 kV / mm or more.
Δ: Dielectric breakdown voltage (25 ° C.) of 100 kV / mm or more and less than 110 kV / mm ×: Dielectric breakdown voltage (25 ° C.) of less than 100 kV / mm

Next, the dielectric breakdown voltage at 150 ° C. of the measurement sample was measured in the same manner as above except that the temperature was changed from 25 ° C. to 150 ° C., and the average value of 10 measurement samples was calculated.
From the above results, the dielectric breakdown voltage ratio was calculated by the following formula.
Dielectric breakdown voltage ratio = (dielectric breakdown voltage at 150 ° C.) / (Dielectric breakdown voltage at 25 ° C.) × 100 [%]
From the obtained breakdown voltage ratio, the maintainability of insulation at high temperatures was evaluated according to the following criteria.
○: Dielectric breakdown voltage ratio is 90% or more.
Δ: Dielectric breakdown voltage ratio is 80% or more and less than 90% ×: Dielectric breakdown voltage ratio is less than 80%.

[Thermal conductivity]
The prepared adhesive sheet was laminated to a thickness of 1 mm by heating, and subjected to a curing treatment (heating from room temperature to 175 ° C. over 1 hour and holding at 175 ° C. for 5 hours) to obtain a measurement sample.
About the measurement sample, the thermal diffusivity was measured with the thermal constant measuring apparatus by ULVAC-RIKO. The density of the measurement sample was measured by the Archimedes method, the specific heat was measured by the DSC method, and the thermal conductivity was calculated therefrom. If the normal organic resin is 0.1 to 0.22 W / (m · K) and the thermal conductivity is 0.6 W / (m · K) or more, it can be said to be a heat conductive adhesive.

  As described above, the adhesive sheets of Examples 1 to 6 had sufficiently high dielectric breakdown voltage and thermal conductivity, and had excellent insulating properties and thermal conductivity. Moreover, the adhesive sheet of Examples 1-6 had a high dielectric breakdown voltage ratio compared with the adhesive sheet of Comparative Examples 1-8, and was maintaining the outstanding insulation also at the time of high temperature.

DESCRIPTION OF SYMBOLS 1 Semiconductor element 3 Circuit board 5 Heat sink 7 TIM layer 10 Semiconductor module

Claims (4)

Containing an epoxy resin (A), a diamine compound (B), a polyimide resin (C), and a thermally conductive filler (D);
A ratio of the storage elastic modulus at −30 ° C. to the storage elastic modulus at the glass transition temperature measured after thermosetting is 300% or less, and the glass relative to the storage elastic modulus at the glass transition temperature. A thermally conductive thermosetting adhesive composition having a storage elastic modulus ratio of 40% or more at a transition temperature + 30 ° C.   The heat conductive thermosetting adhesive composition according to claim 1, wherein the amine value of the diamine compound (B) is 30 to 100 KOHmg / g.   The heat conductive thermosetting adhesive composition according to claim 1 or 2, wherein the polyimide resin (C) has a silicone skeleton.   The heat conductive thermosetting adhesive sheet which consists of a heat conductive thermosetting adhesive composition as described in any one of Claims 1-3.

Images