Resin composition, cured product thereof, laminate using same, electrostatic chuck, and plasma processing device

Abstract

The present invention addresses the problem of providing a thermally conductive sheet that has a high thermal conductivity, a low elastic modulus in a low temperature range of -30°C or lower, and excellent adhesive strength. The main objective of the present invention is to obtain a thermally conductive sheet by using a resin composition containing: (A) a polyimide resin comprising a siloxane skeleton; (B) an epoxy resin; (C) a siloxane diamine; and (D) a thermally conductive filler.

Description

Resin composition and cured product thereof, and laminate, electrostatic chuck, and plasma processing apparatus using the same

[0001] The present invention relates to a resin composition suitable for use in electronic components and electronic materials, and more particularly to an adhesive sheet that has high thermal conductivity and a low elastic modulus even at low temperatures and is used in heat dissipation materials and the like.

[0002] In semiconductor manufacturing equipment, a plasma processing system that performs plasma processing on semiconductor wafers has a wafer mounting stage installed inside a vacuum chamber. The mounting stage is primarily composed of an electrostatic chuck that attracts and holds the wafer and a cooler that controls the temperature of the electrostatic chuck. In recent years, the increasing density of semiconductor devices, such as 3D-NAND memory, has necessitated etching processes with large aspect ratios. In etching processes with large aspect ratios, the etching depth increases, resulting in longer etching times and higher costs. To address this issue, Patent Document 1 proposes a method of etching at extremely low temperatures of -30°C or below to increase the etching rate. This requires cooling the electrostatic chuck by keeping the cooler temperature below -30°C. Silicone-based or acrylic-based adhesive sheets have often been used to bond the cooler and electrostatic chuck. However, the adhesive sheet must be free of peeling or cracking at low temperatures below -30°C and have high thermal conductivity to lower the temperature of the electrostatic chuck.

[0003] As materials for use in such adhesive sheets, compositions have been proposed in which flexibility and thermal conductivity are improved by adding an inorganic filler with high heat dissipation properties to an acrylic resin or silicone resin (see, for example, Patent Document 2).

[0004] Patent No. 6621882 JP 2011-151280 A

[0005] However, in conventional compositions, when a large amount of inorganic filler is included, the thermal conductivity of the composition itself increases, but the elastic modulus increases in the low temperature range of −30° C. or below, resulting in increased thermal stress, which can lead to peeling from the substrate or cracks in the adhesive sheet.

[0006] Therefore, an object of the present invention is to provide a thermally conductive sheet that has high thermal conductivity by controlling the dispersibility of the thermally conductive filler, yet has a low elastic modulus in the low temperature range of −30° C. or less and excellent adhesive strength.

[0007] In order to solve these problems, the gist of the present invention is a resin composition containing (A) a polyimide resin containing a siloxane skeleton, (B) an epoxy resin, (C) a siloxane diamine, and (D) a thermally conductive filler.

[0008] According to the present invention, the dispersibility of the thermally conductive filler is controlled, and an adhesive sheet can be obtained which has high thermal conductivity, a low elastic modulus even in a temperature range of −30° C. or less, high adhesive strength and elongation at −30° C. or less, and which is less susceptible to peeling or cracking even in a low temperature range of −30° C. or less.

[0009] The resin composition of the present invention contains (A) a polyimide resin containing a siloxane skeleton, (B) an epoxy resin, (C) a siloxane diamine, and (D) a thermally conductive filler.

[0010] The polyimide resin (A) containing a siloxane skeleton used in the present invention preferably has a weight-average molecular weight of 5,000 or more. By making the weight-average molecular weight 5,000 or more, the toughness and flexibility of the thermally conductive sheet can be improved. Furthermore, the weight-average molecular weight is preferably 1,000,000 or less. By making the weight-average molecular weight 1,000,000 or less, the dispersibility of the thermally conductive filler (D) can be improved, and the particle utilization efficiency can be increased from the viewpoint of improving thermal conductivity.

[0011] The weight average molecular weight is measured by using a solution of a polyimide containing a siloxane skeleton and calculating the weight average molecular weight in terms of polystyrene using a GPC (gel permeation chromatograph) device.

[0012] Furthermore, it is desirable that the polyimide resin (A) containing a siloxane skeleton in the present invention is solvent-soluble. Solvent-solubility allows the viscosity to be kept low when preparing the resin composition, thereby improving the dispersibility of the thermally conductive filler. Solvent-soluble refers to the ability to dissolve 1 g or more of the resin at 25°C in 100 g of an organic solvent, such as an amide-based solvent such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, N-vinylpyrrolidone, or N,N-diethylformamide, or an ether-based solvent such as γ-butyrolactone, methyl monoglyme, methyl diglyme, methyl triglyme, ethyl monoglyme, ethyl diglyme, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, or ethylene glycol diethyl ether.

[0013] Furthermore, the polyimide resin (A) containing a siloxane skeleton in the present invention can be easily obtained primarily by reacting a tetracarboxylic dianhydride with a diamine, and contains tetracarboxylic dianhydride residues and diamine residues. Here, the polyimide containing a siloxane skeleton in the present invention preferably contains 20 mol % or more of residues corresponding to tetracarboxylic dianhydride having a structure represented by the following general formula (1), where the total amount of tetracarboxylic dianhydride residues is taken as 100 mol %. Introducing a siloxane skeleton into the tetracarboxylic dianhydride residues reduces the linearity and rigidity of the polyimide molecular chain, allowing the glass transition temperature to be lowered, particularly to −30° C. or lower. Lowering the glass transition temperature allows the elastic modulus at low temperatures to be lowered. From the perspective of lowering the glass transition temperature, the content of tetracarboxylic dianhydride residues having a structure represented by the following general formula (1) is more preferably 30 mol % or more, where the total amount of tetracarboxylic dianhydride residues is taken as 100 mol %. There is no particular upper limit, and it is preferable to set it at 100 mol % if possible, but from the viewpoint of improving the handling properties of the sheet, it is practical to set it at about 95 mol %.

[0014]

[0015] In the general formula (1), m represents an integer of 1 or more and 100 or less. 7 and R ８ R may be the same or different and represent an alkylene group or arylene group having 1 to 30 carbon atoms. The arylene group may have a substituent, and the substituent is not particularly limited, but examples thereof include an alkyl group having 1 to 24 carbon atoms. １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group. １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group. The alkyl group having 1 to 30 carbon atoms is not particularly limited, but a methyl group, an ethyl group, a propyl group, or a butyl group is preferred. The alkylene group having 1 to 30 carbon atoms is not particularly limited, but a methylene group, an ethylene group, a propylene group, or a butylene group is preferred. The alkyl group and the alkylene group do not need to have a linear structure. Y １ and Y ２ may be the same or different and each represents a trivalent hydrocarbon group having 1 to 20 carbon atoms.

[0016] Examples of products corresponding to the tetracarboxylic dianhydride represented by general formula (1) include, but are not limited to, X-22-168AS, X-22-168A, X-22-168B, and X-22-168-P5-B manufactured by Shin-Etsu Chemical Co., Ltd.

[0017] The siloxane skeleton-containing polyimide resin (A) used in the present invention may naturally contain residues of other tetracarboxylic acid dianhydrides in addition to the residue of the siloxane skeleton-containing tetracarboxylic acid dianhydride. Examples of such tetracarboxylic acid dianhydrides include pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride (DSDA), 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA), 4,4'-hexafluoroisopropylidenediphthalic anhydride (6FDA), and 1,2-ethylenebis(anhydrotrimellitate) (TMEG). These may be used in combination. However, examples of the tetracarboxylic dianhydride that can be used in the present invention are not limited to these.

[0018] The polyimide resin (A) containing a siloxane skeleton used in the present invention preferably contains 50 mol% or more of residues corresponding to a diamine having a structure represented by the following general formula (2), when the total amount of diamine residues is taken as 100 mol%. Because siloxane skeletons are highly flexible, adhesive sheets obtained using polyimides having such a structure have a low elastic modulus and improved adhesion to substrates. From the viewpoint of reducing the elastic modulus, the content corresponding to the diamine residue having the structure represented by the following general formula (2), when the total amount of diamine residues is taken as 100 mol%, is more preferably 60 mol% or more. Furthermore, from the viewpoint of compatibility with the epoxy resin (B), the upper limit is preferably 99 mol% or less, and more preferably 95 mol% or less.

[0019]

[0020] In the general formula (2), n represents an integer of 1 or more and 100 or less. ７ and R ８R may be the same or different and represent an alkylene group or arylene group having 1 to 30 carbon atoms. The arylene group may have a substituent, and the substituent is not particularly limited, but examples thereof include an alkyl group having 1 to 24 carbon atoms. １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group. There are no particular restrictions on the alkyl group having 1 to 30 carbon atoms, but a methyl group, an ethyl group, a propyl group, or a butyl group is preferred. There are no particular restrictions on the alkylene group having 1 to 30 carbon atoms, but a methylene group, an ethylene group, a propylene group, or a butylene group is preferred. The alkyl group and alkylene group do not need to have a linear structure.

[0021] Examples of products corresponding to the diamine represented by general formula (2) include X-22-161A, X-22-161B, KF8012, KF8008, and X-22-1660B-3 manufactured by Shin-Etsu Chemical Co., Ltd.

[0022] The polyimide resin (A) having a siloxane skeleton used in the present invention preferably contains a diamine residue having a hydroxyl group or a carboxyl group. The presence of a diamine residue having a hydroxyl group or a carboxyl group promotes reaction with the epoxy resin (B), improving the toughness of the cured film after the curing reaction. Diamines having a carboxyl group are particularly preferred because they have stronger acidity, which can improve the dispersibility of thermally conductive fillers and thereby improve thermal conductivity. From the perspective of improving the toughness of the thermally conductive sheet, the content of the diamine residue having a hydroxyl group or a carboxyl group is preferably 1 mol% or more, where the total amount of diamine residues is 100 mol%. Furthermore, from the perspective of improving the flexibility of the adhesive sheet, the content is preferably 40 mol% or less, and more preferably 30 mol% or less. Examples of diamine residues having a hydroxyl group or a carboxyl group include the following:

[0023]

[0024]

[0025]

[0026] It is naturally acceptable for the polyimide resin (A) containing a siloxane skeleton used in the present invention to contain residues of other diamines in addition to the residue of the diamine containing a siloxane skeleton. Examples of such diamines include diamines containing one benzene ring such as 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, and 1,4-diamino-2,5-dihalogenobenzene; diamines containing two benzene rings such as bis(4-aminophenyl)ether, bis(3-aminophenyl)ether, bis(4-aminophenyl)sulfone, bis(3-aminophenyl)sulfone, bis(4-aminophenyl)methane, bis(3-aminophenyl)methane, bis(4-aminophenyl)sulfide, bis(3-aminophenyl)sulfide, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, o-dianisidine, o-tolidine, and tolidine sulfonic acids; Examples of diamines include diamines containing three benzene rings such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, and 5,10-bis(4-aminophenyl)anthracene. These may be used in combination. However, the other diamines that can be used in the present invention are not limited to these.

[0027] In (A) a polyimide resin containing a siloxane skeleton, the tetracarboxylic dianhydride residue and the diamine residue preferably satisfy one or more of the following: 1) a small number of benzene rings, 2) a large and bulky molecular weight, and 3) a large number of bending sites such as ether bonds. By having such a structure, the interaction between molecular chains is weakened, and the solubility of the polyimide in organic solvents is improved.

[0028] The polyimide resin (A) containing a siloxane skeleton in the present invention may be composed solely of polyimide structural units, or may be a copolymer containing other structures as copolymerization components in addition to the polyimide structural units. It may also contain a precursor of the polyimide structural unit (a polyamic acid structure). It may also be a mixture of these. Furthermore, any of these may be mixed with a polyimide represented by another structure. When other polyimides are mixed, it is preferable that the polyimide containing a siloxane skeleton account for 50 mol % or more. The type and amount of structures used for copolymerization or mixing are preferably selected within a range that does not impair the effects of the present invention.

[0029] The method for synthesizing the polyimide resin (A) containing a siloxane skeleton used in the present invention is not particularly limited, and it can be synthesized by a known method using a diamine and a tetracarboxylic dianhydride. For example, a polyimide precursor can be obtained by using a method such as reacting a tetracarboxylic dianhydride with a diamine compound (which may be partially substituted with an aniline derivative) at low temperature, a method of reacting a tetracarboxylic dianhydride with an alcohol to obtain a diester, and then reacting the diamine (which may be partially substituted with an aniline derivative) in the presence of a condensing agent, or a method of reacting a tetracarboxylic dianhydride with an alcohol to obtain a diester, and then converting the remaining two carboxyl groups into acid chlorides and reacting the diester with a diamine (which may be partially substituted with an aniline derivative), and then synthesizing the polyimide precursor by a known imidization method.

[0030] The resin composition of the present invention contains (B) an epoxy resin, which promotes the crosslinking reaction of (A) a polyimide resin containing a siloxane skeleton, thereby improving the toughness of the adhesive sheet and improving the adhesive strength.

[0031] The epoxy resin (B) used in the present invention is preferably an epoxy resin containing a siloxane skeleton, from the viewpoint of reducing the elastic modulus of the adhesive sheet after curing and improving its flexibility. Examples of such epoxy resins include X-40-2695B and X-22-2046 manufactured by Shin-Etsu Chemical Co., Ltd.

[0032] The epoxy resin (B) used in the present invention preferably has an epoxy equivalent of 400 g / eq or more, from the viewpoint of keeping the crosslink density of the epoxy resin low and lowering the glass transition temperature after curing of the adhesive sheet. Examples of such epoxy resins include YX7105, YX7110, YX7400, YX7400N, and JER871 manufactured by Mitsubishi Chemical Corporation, and EXA-4850-150 manufactured by DIC Corporation.

[0033] The epoxy resin (B) used in the present invention is preferably a crystalline epoxy resin from the viewpoint of improving the structural regularity of the adhesive sheet and improving its thermal conductivity. Crystalline epoxy resins are epoxy resins having a mesogen skeleton such as a biphenyl group, a naphthalene skeleton, an anthracene skeleton, a phenylbenzoate group, or a benzanilide group. Examples of products compatible with such epoxy resins include JERYX4000, JERYX4000H, JERYX8800, JERYL6121H, JERYL6640, JERYL6677, and JERYX7399 manufactured by Mitsubishi Chemical Corporation, NC3000, NC3000H, NC3000L, and CER-3000L manufactured by Nippon Kayaku Co., Ltd., YSLV-80XY and YDC1312 manufactured by Nippon Steel Chemical Co., Ltd., and HP4032, HP4032D, and HP4700 manufactured by DIC Corporation.

[0034] The epoxy resin (B) used in the present invention is preferably an epoxy resin having a fluorene skeleton, from the viewpoint of improving the dispersibility of the thermally conductive filler (D) and improving thermal conductivity. Examples of such epoxy resins include PG100, CG500, CG300-M2, EG200, and EG250 manufactured by Osaka Gas Chemicals Co., Ltd.

[0035] The epoxy resin (B) used in the present invention is preferably a liquid epoxy resin from the viewpoint of reducing the viscosity when dispersing the thermally conductive filler (D). ５ N / m ２ Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, alkylene oxide modified epoxy resins, and glycidylamine type epoxy resins. Examples of products compatible with such epoxy resins include JER827, JER828, JER806, JER807, JER801N, JER802, JER604, JER630, and JER630LSD manufactured by Mitsubishi Chemical Corporation, Epicron 840S, Epicron 850S, Epicron 830S, Epicron 705, and Epicron 707 manufactured by DIC Corporation, YD127, YD128, PG207N, and PG202 manufactured by Nippon Steel Chemical Co., Ltd., and TEPIC-PASB26L, TEPIC-PASB22, TEPIC-VL, TEPIC-FL, and TEPIC-UC manufactured by Nissan Chemical Industries, Ltd.

[0036] The epoxy resin (B) used in the present invention may be one type, or two or more types may be used in combination. The content of the epoxy resin (B) is preferably 0.1 parts by weight or more per 100 parts by weight of the polyimide resin (A) containing a siloxane skeleton from the viewpoint of improving the toughness and adhesive strength of the adhesive sheet, and is preferably 15 parts by weight or less from the viewpoint of improving the flexibility of the adhesive sheet and keeping the elastic modulus at low temperatures low.

[0037] The resin composition of the present invention also contains (C) a siloxane diamine. This siloxane diamine can act as a curing agent for the (B) epoxy resin. Combining the (B) epoxy resin with the (C) siloxane diamine accelerates the curing of the epoxy resin, allowing it to cure in a short period of time. The siloxane diamine has a highly flexible siloxane skeleton, which can reduce the elastic modulus, particularly at low temperatures after curing. Furthermore, the reaction of the (B) epoxy resin with the (C) siloxane diamine results in a low crosslink density and high flexibility, allowing for increased shear strain at low temperatures. The (C) siloxane diamine preferably has a structure represented by general formula (3). From the viewpoint of reducing the elastic modulus of the adhesive sheet after curing, N is more preferably 6 or more. From the viewpoint of improving the crosslink density and increasing the adhesive strength in the curing reaction with the (B) epoxy resin, N is preferably 30 or less, more preferably 25 or less. Examples of products corresponding to the diamine represented by general formula (3) include KF8010, X-22-161A, and X-22-9409 manufactured by Shin-Etsu Chemical Co., Ltd. The content of (C) siloxane diamine is preferably 5% by weight or more and 20% by weight or less, when the total of (A) polyimide resin containing a siloxane skeleton, (B) epoxy resin, and (C) siloxane diamine is taken as 100% by weight. From the viewpoint of accelerating the curing reaction of (B) epoxy resin, it is preferably 5% by weight or more, and more preferably 6% by weight or more. Furthermore, from the viewpoint of suppressing the crosslink density after the curing reaction and keeping the elastic modulus low, it is preferably 20% by weight or less, and more preferably 15% by weight or less.

[0038]

[0039] (In the general formula (3), N is an integer of 5 or more and 30 or less. R 7 and R ８ may be the same or different and represent an alkylene group or an arylene group having 1 to 30 carbon atoms. １ ~R ６may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group. Furthermore, the resin composition of the present invention may contain a curing accelerator as needed. By combining the (B) epoxy resin with a curing accelerator, the curing of the epoxy resin can be accelerated, resulting in curing in a short period of time. Examples of curing accelerators that can be used include imidazoles, polyhydric phenols, acid anhydrides, amines, hydrazides, polymercaptans, Lewis acid-amine complexes, and latent curing agents.

[0040] Examples of imidazoles include Curesol 2MZ, Curesol 2PZ, Curesol 2MZ-A, and Curesol 2MZ-OK (all trade names, manufactured by Shikoku Chemical Industry Co., Ltd.). Examples of polyhydric phenols include SUMILITE RESIN PR-HF3 and SUMILITE RESIN PR-HF6 (all trade names, manufactured by Sumitomo Bakelite Co., Ltd.), KAYAHARD KTG-105 and KAYAHARD NHN (all trade names, manufactured by Nippon Kayaku Co., Ltd.), PHENOLITE TD2131, PHENOLITE TD2090, PHENOLITE VH-4150, PHENOLITE KH-6021, PHENOLITE KA-1160, and PHENOLITE KA-1165 (all trade names, manufactured by DIC Corporation). Examples of the latent curing accelerator include dicyandiamide-type latent curing accelerators, amine adduct-type latent curing accelerators, organic acid hydrazide-type latent curing accelerators, aromatic sulfonium salt-type latent curing accelerators, microcapsule-type latent curing accelerators, and photocurable latent curing accelerators.

[0041] Examples of amine adduct type latent curing accelerators include Amicure PN-23, Amicure PN-40, Amicure MY-24, Amicure MY-H (all trade names, manufactured by Ajinomoto Fine-Techno Co., Ltd.), and Fujicure FXR-1030 (trade name, manufactured by Fuji Kasei Co., Ltd.). Examples of organic acid hydrazide type latent curing accelerators include Amicure VDH and Amicure UDH (all trade names, manufactured by Ajinomoto Fine-Techno Co., Ltd.). Examples of aromatic sulfonium salt type latent curing accelerators include San-Aid SI100, San-Aid SI150, and San-Aid SI180 (all trade names, manufactured by Sanshin Chemical Industry Co., Ltd.). Examples of microcapsule type latent curing accelerators include those obtained by encapsulating the above-mentioned curing agents with a vinyl compound, a urea compound, or a thermoplastic resin. Among these, examples of microcapsule-type latent curing accelerators in which an amine adduct-type latent curing accelerator is treated with isocyanate include Novacure HX-3941HP, Novacure HXA3922HP, Novacure HXA3932HP, and Novacure HXA3042HP (all trade names, manufactured by Asahi Kasei Chemicals Corp.). Examples of photocurable latent curing accelerators include Optomer SP and Optomer CP (all trade names, manufactured by ADEKA Corporation).

[0042] When the resin composition contains a curing accelerator, the content thereof is preferably 0.1 parts by weight or more and 35 parts by weight or less per 100 parts by weight of the epoxy resin (B).

[0043] The resin composition of the present invention contains (D) a thermally conductive filler. In the present invention, the term "thermally conductive filler" refers to inorganic particles having a thermal conductivity of 2 W / m·K or more at 25°C. The thermal conductivity can be determined by measuring a sintered body having a thickness of approximately 1 mm and a porosity of 10% by volume or less in accordance with JIS R1611 (2010). While "7.2 Measurement Method" of JIS R1611 (2010) states that "c) Bulk Density: Thermal diffusivity is measured according to JIS R1634, etc." in the present invention, the "c) Bulk Density" refers to a value determined according to JIS R1634 (1998). Examples of (D) thermally conductive fillers include inorganic fillers such as carbon black, silica, magnesium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, silicon carbide, and silicon nitride, and metal fillers such as copper, aluminum, magnesium, silver, zinc, iron, and lead. These fillers may be used alone or in combination. The shape of the filler is not particularly limited, and examples thereof include spherical, globular, scale-like, flake-like, foil-like, fibrous, and needle-like shapes. From the viewpoint of incorporating the thermally conductive filler at high density, it is preferable to use a spherical filler.

[0044] In the present invention, the thermally conductive filler (D) is preferably spherical. Use of a spherical filler reduces the viscosity of the resin composition, thereby improving adhesion to the substrate. In the present invention, "spherical" refers to a shape obtained by observing primary particles of the thermally conductive filler with a scanning electron microscope (e.g., Hitachi, Ltd., product name: FE-SEM S4700) and calculating the average maximum length and average minimum length for 50 randomly selected primary particles, where the value of (average maximum length) / (average minimum length) is 1.0 or more and 1.9 or less. Here, "length" is determined as the distance between two parallel lines tangent to the outer edge of the image of the particle being measured at different points.

[0045] In the present invention, the content of the thermally conductive filler (D) preferably accounts for 50% by volume or more when the cured film is formed. By having a content of 50% by volume or more, the thermal conductivity of the cured film is increased. A content of 60% by volume or more is more preferred. Furthermore, from the viewpoint of improving adhesive strength, the content of the thermally conductive filler (D) is preferably 90% by volume or less, and more preferably 80% by volume or less.

[0046] The filler volume content can be calculated from the cured film by the following method using thermogravimetric analysis, or by an equivalent method. First, a cured product formed into a sheet is heated to 600-900°C to decompose and volatilize the resin, the weight of the filler contained is measured, and the weight of the resin is then calculated. This is then divided by the specific gravity of the filler and resin to calculate the volume, and the calculation can be performed using this method.

[0047] The thermally conductive filler (D) preferably contains two or more fillers with different average particle sizes. The two or more fillers may have the same composition but different average particle sizes, but they may also have different compositions. Furthermore, when the particle size distribution curve is split, at least two peaks are observed, and the average particle size of the thermally conductive particles constituting one of the peaks is 2 μm or more, preferably 2.5 μm or more, and more preferably 25 μm or more from the viewpoint of increasing thermal conductivity. The average particle size of the thermally conductive particles constituting the other peak is preferably 1 μm or less, preferably 0.8 μm or less. The particle size distribution of the thermally conductive filler (D) is measured by a laser diffraction / scattering method using a measuring instrument such as an SLD3100 manufactured by Shimadzu Corporation or an LA920 manufactured by Horiba, Ltd., or an equivalent. By including two or more fillers with different average particle sizes, the thermally conductive filler (D) can be packed at a high density, resulting in higher thermal conductivity. On the other hand, from the viewpoint of improving the dispersibility of the filler, the average particle size at the peak with the smallest average particle size is preferably 0.001 μm or more, and from the viewpoint of smoothing the surface of the film when formed into a cured film, the average particle size at the peak with the largest average particle size is preferably 100 μm or less.

[0048] Thus, there are no particular limitations on the method for making the particle size distribution curve show two or more peaks when peak division is performed. For example, a method can be used in which a thermally conductive filler having an average particle size of 1.0 μm or less is blended as a filler having a frequency peak of 1.0 μm or less, and a thermally conductive filler having an average particle size of 2 μm or more is blended as a filler having a frequency peak of 2 μm or more, and these are mixed to form a resin composition.

[0049] In addition, the content of the thermally conductive filler having a peak at 2 μm or more when peak division is performed on the particle size distribution curve is preferably 40% by volume or more, and more preferably 50% by volume or more, when the volume of the entire thermally conductive filler (D) is taken as 100% by volume, from the viewpoint of obtaining high thermal conductivity. Furthermore, in order to obtain high thermal conductivity by packing the thermally conductive filler at a high density, the content is preferably 80% by volume or less, and more preferably 70% by volume or less.

[0050] Furthermore, it is preferable to use alumina, boron nitride, aluminum nitride, zinc oxide, magnesium oxide, or silica as the thermally conductive filler. This is because the filler has high thermal conductivity and is highly effective in increasing the thermal conductivity of the resin composition. Aluminum nitride is particularly preferable. As an insulating thermally conductive filler, aluminum nitride has a high thermal conductivity of approximately 170 W / m·K, thereby achieving higher thermal conductivity. Examples of such aluminum nitride particles include FAN-f10, FAN-f30, FAN-f50, and FAN-f80 manufactured by Furukawa Denshi Co., Ltd., and M30, M50, and M80 manufactured by Maruwa Corporation.

[0051] (D) In ​​the thermally conductive filler, the specific surface area of ​​particles having an average particle diameter of 2 μm or more is 0.2 m ２ / g or more. ２ / g or more, the interaction with the resin can be strengthened, and the shear strain of the resin composition after curing can be increased. ２ / g or more, and more preferably 0.25m ２ / g or more. The specific surface area can be calculated by measuring the BET specific surface area by gas adsorption method based on JIS R 1626. The mass of the thermally conductive filler is measured, and then gas molecules of an inert gas such as nitrogen gas or helium gas are adsorbed, and the BET specific surface area is calculated from the monomolecular adsorption amount. The specific surface area is greatly influenced by the primary particle size, shape, and agglomeration state of the thermally conductive filler. One method for increasing the specific surface area is to crush the agglomerated particles of the thermally conductive filler using a dry jet mill or crusher.

[0052] The resin composition of the present invention may optionally contain a surfactant, which can improve the surface smoothness of the cured film and the adhesion to the substrate. Furthermore, the resin composition may contain 0.5 to 10 wt % of a silane coupling agent such as methylmethacryloxydimethoxysilane or 3-aminopropyltrimethoxysilane, or a titanium chelating agent.

[0053] Next, a method for applying the resin composition of the present invention to a support to form a laminate will be described. To process the resin composition of the present invention into a laminate, for example, the resin composition can be mixed in a solvent to form a varnish on a support, which can then be coated and dried to form a sheet.

[0054] The solvent used here may be appropriately selected from those that dissolve the above components, and examples thereof include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone, ether solvents such as 1,4-dioxane, tetrahydrofuran, and diglyme, glycol ether solvents such as methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and diethylene glycol methyl ethyl ether, as well as benzyl alcohol, propanol, N-methylpyrrolidone, γ-butyrolactone, ethyl acetate, and N,N-dimethylformamide. In particular, if the solvent contains a solvent having a boiling point of 120° C. or less at atmospheric pressure, the solvent can be removed at a low temperature in a short time, making it easy to form the solvent into a sheet.

[0055] The method for converting the resin composition of the present invention into a varnish is not particularly limited, but it is preferable to mix (A) a polyimide resin containing a siloxane skeleton, (B) an epoxy resin, (C) a siloxane diamine, (D) a thermally conductive filler, and other components that may be added as needed in the above-mentioned solvent using a propeller stirrer, homogenizer, kneader, or the like, and then, from the viewpoint of improving the dispersibility of (D) the thermally conductive filler, to mix them using a bead mill, ball mill, three-roll mill, or the like.

[0056] Methods for applying the varnish to the support include spin coating using a spinner, spray coating, roll coating, screen printing, or coating methods using a blade coater, die coater, calendar coater, meniscus coater, bar coater, roll coater, comma roll coater, gravure coater, screen coater, slit die coater, etc.

[0057] As the coating machine, a roll coater, comma roll coater, gravure coater, screen coater, slit die coater, etc. can be used, but a slit die coater is preferably used because there is little solvent evaporation during coating and the coating properties are stable. The thickness of the sheeted resin composition (adhesive sheet) is not particularly limited, but from the viewpoints of adhesion to the substrate, handleability of the adhesive sheet, and heat dissipation, a range of 100 to 500 μm or less is preferred.

[0058] Drying can be performed using an oven, a hot plate, infrared rays, or the like. The drying temperature and drying time may be within a range that allows the organic solvent to volatilize, and are preferably set appropriately within a range that allows the adhesive sheet to reach an uncured or semi-cured state (B-stage state). Specifically, it is preferable to maintain the temperature in the range of 40°C to 120°C for 1 minute to several tens of minutes. Alternatively, the temperature may be increased stepwise by combining these temperatures, for example, by heat treatment at 70°C, 80°C, and 90°C for 1 minute each.

[0059] The support is not particularly limited, and various commercially available films such as polyethylene terephthalate (PET) film, polyphenylene sulfide film, and polyimide film can be used.

[0060] The surface of the support to be bonded to the resin composition may be subjected to a surface treatment with silicone, a silane coupling agent, an aluminum chelating agent, polyurea, etc., in order to improve adhesion and releasability. The thickness of the support is not particularly limited, but is preferably in the range of 10 to 200 μm from the viewpoint of workability.

[0061] Furthermore, the laminate processed into a sheet may have a protective film to protect its surface, thereby protecting the sheet surface from pollutants such as dust and dirt in the atmosphere.

[0062] Examples of the protective film include a polyethylene film, a polypropylene (PP) film, a polyester film, etc. It is preferable that the protective film has a small adhesive strength with the laminate processed into a sheet.

[0063] Next, an example of a method for bonding other components using the adhesive composition of the present invention or a laminate processed into a sheet form will be described. The resin composition is preferably used in the form of a varnish as described above. First, a resin composition film is formed on one side of the substrate or component to be bonded using the resin composition varnish. Examples of other components include thin metal sheets such as copper and SUS (stainless steel), and semiconductor devices (such as their lead frame portions) to be bonded thereto. Methods for applying the varnish-like resin composition include spin coating using a spinner, spray coating, roll coating, and screen printing. The coating thickness varies depending on the coating method, the solids concentration, and viscosity of the resin composition, but it is generally preferable to apply the coating so that the film thickness after drying is 50 μm to 400 μm. Next, the substrate coated with the adhesive composition varnish is dried to obtain an adhesive composition coating. Drying can be performed using an oven, a hot plate, infrared rays, or the like. The drying temperature and drying time may be within a range that allows the organic solvent to volatilize, and are preferably set within a range that leaves the adhesive resin composition coating in an uncured or semi-cured state. Specifically, it is preferable to carry out the treatment at a temperature in the range of 50 to 150° C. for one minute to several hours.

[0064] On the other hand, when a laminate processed into a sheet shape is used, if any, a protective film is peeled off, and the laminate and another member are placed face to face and bonded together by pressure bonding. Pressure bonding may be performed by applying heat, or by a heat press treatment, a heat lamination treatment, a thermal vacuum lamination treatment, or the like. When applying heat, the bonding temperature is preferably 40°C or higher in terms of adhesion to the substrate and embeddability. Furthermore, if the temperature is high during bonding, the curing time of the resin composition will be shortened and workability will decrease, so the bonding temperature is preferably 250°C or lower. When the laminate processed into a sheet shape has a support, the support may be peeled off before bonding, or may be peeled off at any point in the thermocompression bonding process or after thermocompression bonding.

[0065] The substrate thus obtained, on which the resin composition film is formed, is thermocompression bonded to a substrate or other member. The thermocompression temperature is preferably in the range of 100 to 400°C. The pressure during compression is preferably in the range of 0.01 to 10 MPa. The time is preferably 1 second to several hours. The thermocompression bond is preferably a cured product; for example, heat treatment is performed at 100°C and a pressure of 0.5 MPa for 24 hours.

[0066] Alternatively, after thermocompression bonding, a temperature of 120°C to 400°C may be applied to form a cured product. This heat treatment is carried out by selecting a temperature and gradually increasing the temperature, or by selecting a temperature range and continuously increasing the temperature for 5 minutes to 24 hours. One example is heat treatment at 130°C and 200°C for 30 minutes each. Another example is a method in which the temperature is linearly increased from room temperature to 250°C over 1 hour. In this case, the heating temperature is preferably 100°C or higher and 300°C or lower, and more preferably 120°C or higher and 200°C or lower.

[0067] The thus obtained sheet-like resin composition or cured film can reduce the contact thermal resistance at the interface with the substrate, and can be cooled to a lower temperature.

[0068] In this case, in order to reduce the thermal resistance of the sheet, the thermal conductivity of the adhesive sheet at -70°C is preferably 0.8 W / m·K or more, and more preferably 1.0 W / m·K or more.

[0069] The elastic modulus of the sheet-like resin composition or cured film at -50°C is preferably 1 MPa or more and 100 MPa or less, and the elastic modulus at -70°C is also preferably 1 MPa or more and 100 MPa or less. From the viewpoint of improving the adhesive strength at -50°C, these are preferably 1 MPa or more, and more preferably 2 MPa or more. From the viewpoint of reducing the thermal stress of the laminate at low temperatures and preventing peeling or cracking of the sheet-like resin composition or cured film, the elastic modulus is preferably 100 MPa or less, and more preferably 50 MPa or less. The elastic modulus of the cured film can be determined by the method shown in the Examples section.

[0070] Furthermore, the shear strain of the sheet-like resin composition or cured film at -50 ° C is preferably 2 or more and 10 or less. The shear strain is the value obtained by dividing the amount of strain until breakage by the thickness of the adhesive sheet when tested in accordance with JIS K 6850 (Test method for tensile shear adhesive strength of rigid adherends). From the viewpoint of suppressing peeling and cracking by following dimensional changes due to temperature changes of the adhered substrate, it is preferably 2 or more, more preferably 3 or more. From the viewpoint of suppressing dimensional changes of the sheet-like resin composition or cured film, it is preferably 10 or less, more preferably 8 or less. The above shear strain can be determined by the method shown in the Examples section.

[0071] The thickness of the cured film can be set arbitrarily, but is preferably 100 μm or more and 500 μm or less.

[0072] Next, an example of the uses of the resin composition of the present invention and the laminate processed into a sheet will be described, but the uses of the resin composition of the present invention and the laminate processed into a sheet are not limited to the following.

[0073] The resin composition and sheet-shaped laminate of the present invention can be widely used as adhesive sheets for semiconductor devices, but are particularly suitable for use in plasma processing equipment used in semiconductor manufacturing processes. In plasma processing equipment used in semiconductor manufacturing processes, a substrate to be processed, such as a semiconductor wafer, is placed on an electrostatic chuck installed in a processing chamber. A high-frequency voltage is applied to the processing chamber in a vacuum environment to generate plasma and perform etching and other processes. The electrostatic chuck is a laminate consisting of a ceramic plate incorporating a heater electrode and an electrostatic electrode and a cooling plate with an internal refrigerant flow path, joined together with an adhesive sheet. In recent years, semiconductor processing precision has increased, and etching processes to form high-aspect-ratio vias are performed at low temperatures below -30°C. This process requires cooling the ceramic plate to a temperature below -30°C using a cooling plate. The adhesive sheet of the present invention reduces the thermal resistance at the interface, enabling efficient cooling. An adhesive layer is formed by attaching an adhesive sheet to a cooling plate or by applying and drying a varnish of the resin composition. Then, by compressing or hot-compressing a ceramic plate, an electrostatic chuck is obtained that does not peel or crack even at low temperatures.

[0074] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. Details of the raw materials indicated by abbreviations in each example are shown below.

[0075] <Raw materials for polyimide> ODPA: 4,4'-oxydiphthalic dianhydride (manufactured by Manac Corporation) X-22-168AS: polysiloxane modified at both ends with maleic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd.) X-22-168A: polysiloxane modified at both ends with maleic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd.) BAHF: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (manufactured by AZ Electronic Materials Co., Ltd.) X-22-161A: polysiloxane modified at both ends with amine (manufactured by Shin-Etsu Chemical Co., Ltd.) X-22-161B: polysiloxane modified at both ends with amine (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0076] <Epoxy resin> YX7400N: rubber elastic liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation) <Curing agent> LP7100: bis(3-aminopropyl)tetramethyldisiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) KF8010: diaminopolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) X-22-161A: diaminopolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) X-22-161B: diaminopolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 3,3'-DDS: 3,3'-diaminodiphenylsulfone (manufactured by Wakayama Seika Kogyo Co., Ltd.).

[0077] <Spherical thermally conductive filler> DAW45: alumina particles (average particle diameter: 45 μm, specific surface area: 0.21 m) ２ / g, thermal conductivity: 26 W / m·K) (manufactured by Denki Kagaku Kogyo Co., Ltd.) AA3: alumina particles (average particle diameter: 3 μm, specific surface area: 0.60 m ２ / g, thermal conductivity: 20 W / m·K) (Sumitomo Chemical Co., Ltd.) AA04: alumina particles (average particle diameter: 0.4 μm, specific surface area: 4.10 m ２ / g, thermal conductivity: 20 W / m·K) (Sumitomo Chemical Co., Ltd.) FAN-30: aluminum nitride particles (average particle diameter: 30 μm, specific surface area: 0.15 m ２ / g, thermal conductivity: 170 W / m·K) (manufactured by Furukawa Denshi Co., Ltd.) The spherical thermally conductive fillers were confirmed to be spherical by observing the primary particles with a scanning electron microscope.

[0078] <Scaly thermally conductive filler> UHP-2: boron nitride particles (average particle size: 10 μm, specific surface area: 3.8 m) ２ / g, thermal conductivity: 80 W / m·K) (manufactured by Showa Denko K.K.).

[0079] <Curing accelerator> 2P4MZ: 2-phenyl-4-methylimidazole.

[0080] <Solvent> Triglyme: Triethylene glycol dimethyl ether.

[0081] The evaluation methods used in each of the examples and comparative examples are as follows.

[0082] <Weight-average molecular weight of polyimide> Using a solution of polyimide dissolved in N-methyl-2-pyrrolidone (hereinafter referred to as NMP) with a solids concentration of 0.1 wt%, the weight-average molecular weight in terms of polystyrene was calculated using a GPC apparatus Waters 2690 (manufactured by Waters Corporation) configured as shown below. The GPC measurement conditions were as follows: the mobile phase was NMP in which LiCl and phosphoric acid were dissolved at concentrations of 0.05 mol / l, and the development rate was 0.4 ml / min. Detector: Waters 996 System controller: Waters 2690 Column oven: Waters HTR-B Thermocontroller: Waters TCM Column: TOSOH Grad Common Column: THSOH TSK-GEL α-4000 Column: TOSOH TSK-GEL α-2500.

[0083] <Imidization rate of polyimide> First, the infrared absorption spectrum of the polymer was measured, and the absorption peak of the imide structure due to polyimide (1780 cm －１ Near 1377 cm －１ Next, the polymer was heat-treated at 350°C for 1 hour, and then the infrared absorption spectrum was measured again. －１ The imidization rate of the polymer before the heat treatment was calculated by setting the imidization rate of the polymer after the heat treatment at 100%.

[0084] <Average particle size of thermally conductive filler> The filler was dispersed in methanol, and the particle size distribution was measured by a laser diffraction / scattering method using an LA920 manufactured by Horiba, Ltd. The particle size D50 at which the cumulative particle size distribution from the small particle size side based on volume becomes 50% was defined as the average particle size.

[0085] <Specific Surface Area of ​​Thermally Conductive Filler> The specific surface area was measured by the single-point method using a fully automatic specific surface area measuring device Macsorb manufactured by Mountech Co., Ltd., according to the BET flow method.

[0086] <Thermal Conductive Filler Content> The weight of each component was divided by its specific gravity to calculate the volume, and the thermal conductive filler content was calculated relative to 100 parts by volume of the total of the polyimide resin, epoxy resin, siloxane diamine, and thermal conductive filler.

[0087] <Thermal Conductivity> The resin composition was applied to a 38 μm thick PET film using a comma roll coater so that the film thickness of the cured film was 250 μm, and the resin composition was dried at 100° C. for 30 minutes, and then thermally cured at 180° C. for 4 hours to obtain a sheet-like laminate. The PET film was then peeled off, and the thermal diffusivity of the cured film was measured using a laser flash thermal diffusivity measuring device LFA447 manufactured by Netsch Corporation. In addition, the specific gravity of the cured film was measured by the Archimedes method, and the specific heat of the adhesive sheet was measured by the DSC method. From the obtained measured values, the thermal diffusivity (m ２ / s) x specific gravity (kg / m ３ The thermal conductivity was calculated using the formula: ) × specific heat (J / kg·K).

[0088] <Elastic Modulus> The PET film was peeled off from the sheet-like laminate obtained by the above method, and the sheet was cut into a shape of 30 mm x 5 mm, and the elastic modulus of the film was measured using a dynamic viscoelasticity measuring device DVA-200 manufactured by IT Measurement Control Co., Ltd. The measurement conditions were a temperature rise rate of 5°C / min and a measurement frequency of 1 Hz, and the storage modulus was measured at each temperature in the range of -100°C to 300°C, and the elastic modulus at -50°C was determined.

[0089] <Shear adhesive strength and shear strain> The resin composition was applied to a 38 μm thick PET film using a comma roll coater so that the thickness of the cured film was 250 μm, and then dried at 100 ° C. for 30 minutes to obtain a pre-cured laminate. This pre-cured laminate was cut to 12.5 × 25 mm and laminated on a 100 × 25 mm, 1.6 mm thick aluminum plate at 60 ° C. and 0.1 MPa. After peeling the PET film, a 100 × 25 mm, 1.6 mm thick aluminum plate was laminated and hot-pressed at 180 ° C. and 0.5 MPa for 1 hour. Thereafter, in accordance with JIS K 6850, a shear test was performed using a Shimadzu Corporation universal testing machine AGX-V at a tensile speed of 2 mm / min in an atmosphere of -50 ° C., and the stress at break, the shear adhesive strength, and the shear strain were measured.

[0090] <Cold-heat cycle reliability test> The resin composition was applied to a 38 μm thick PET film using a comma roll coater so that the thickness of the cured film was 250 μm, and the resin composition was dried at 100 ° C for 30 minutes to obtain a pre-cured laminate. This pre-cured laminate was cut to 150 mm and laminated on a φ100 mm, 3 mm thick aluminum plate at 60 ° C and 0.1 MPa. After peeling the PET film, a φ100 mm, 3 mm thick alumina substrate was laminated and hot-pressed at 120 ° C and 0.5 MPa for 24 hours. The laminate thus obtained was observed with an ultrasonic flaw detector FS300 manufactured by Hitachi Power Solutions Co., Ltd. to check for peeling. Thereafter, a thermal shock tester was used to check for cracks in the alumina substrate based on the peeling state and appearance after 250, 500, and 1000 cycles, with one cycle consisting of 30 minutes at -65°C and 30 minutes at 100°C. If peeling or cracking occurred immediately after the laminate was produced, the respective phenomena that occurred are recorded in the table. If peeling or cracking was observed during the cycle test, the number of cycles at which peeling or cracking was first observed is recorded.

[0091] Example 1: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 78.53 g of triglyme and 40.40 g of X-22-168AS were charged and stirred to dissolve at 60°C. Subsequently, 7.33 g of BAHF and 30.80 g of X-22-161A were added while stirring at 60°C, and the mixture was stirred for 1 hour. The temperature was then raised to 180°C, and the mixture was stirred for 3 hours. The mixture was then cooled to room temperature to obtain polyimide solution A (solids concentration: 50.0 wt%). The weight-average molecular weight of the polyimide was measured to be 28,600, and the imidization rate was measured to be 99%.

[0092] To 10.8 g of the polyimide solution A (5.4 g solids) obtained by the above method, 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added and stirred, and 18 g of AA3 and 12 g of AA04 were added and kneaded five times in a three-roll mill to obtain a viscous liquid resin composition. The obtained resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the above methods.

[0093] Example 2: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 87.92 g of triglyme and 40.40 g of X-22-168AS were charged and stirred to dissolve at 60 ° C. Subsequently, 4.40 g of BAHF and 43.12 g of X-22-161A were added while stirring at 60 ° C., and the mixture was stirred for 1 hour. The temperature was then raised to 180 ° C., and the mixture was stirred for 3 hours, after which it was cooled to room temperature to obtain polyimide solution B (solids concentration 50.0 wt%). The weight average molecular weight of the polyimide was measured to be 19,400, and the imidization rate was measured to be 99%. 10.8 g of the polyimide B (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0094] Example 3: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 72.98 g of triglyme and 30.30 g of X-22-168AS were charged and stirred to dissolve at 60 ° C. Then, 1.10 g of BAHF and 41.58 g of X-22-161A were added while stirring at 60 ° C., and the mixture was stirred for 1 hour. The temperature was then raised to 180 ° C. and the mixture was stirred for 3 hours, after which it was cooled to room temperature to obtain polyimide solution C (solids concentration 50.0 wt%). The weight average molecular weight of the polyimide was measured to be 18,800, and the imidization rate was measured to be 99%. 10.8 g of the polyimide C (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0095] Example 4: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 74.93 g of triglyme and 20.20 g of X-22-168AS were charged and stirred to dissolve at 60 ° C. Then, 0.73 g of BAHF and 54.00 g of X-22-161B were added while stirring at 60 ° C., and the mixture was stirred for 1 hour. The temperature was then raised to 180 ° C. and the mixture was stirred for 3 hours, after which it was cooled to room temperature to obtain polyimide solution D (solids concentration 50.0 wt%). The weight average molecular weight of the polyimide was measured to be 19,200, and the imidization rate was measured to be 99%. 10.8 g of the polyimide D (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0096] Example 5: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 68.45 g of triglyme and 40.00 g of X-22-168A were charged and stirred to dissolve at 60 ° C. Then, while stirring at 60 ° C, 0.73 g of BAHF and 27.72 g of X-22-161A were added and stirred for 1 hour. The temperature was then raised to 180 ° C. and stirred for 3 hours, after which the solution was cooled to room temperature to obtain polyimide solution E (solids concentration 50.0 wt%). The weight-average molecular weight of the polyimide was measured to be 16,520, and the imidization rate was measured to be 99%. 10.8 g of the polyimide E (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0097] Example 6: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 83.31 g of triglyme, 20.20 g of X-22-168A, and 6.20 g of ODPA were charged and stirred to dissolve at 60 ° C. Then, 1.47 g of BAHF and 55.44 g of X-22-161A were added while stirring at 60 ° C., and the mixture was stirred for 1 hour. The temperature was then raised to 180 ° C. and the mixture was stirred for 3 hours, after which it was cooled to room temperature to obtain polyimide solution F (solids concentration 50.0 wt%). The weight average molecular weight of the polyimide was measured to be 23,900, and the imidization rate was measured to be 99%. 10.8 g of the polyimide F (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0098] Example 7 A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 72.11 g of triglyme, 4.04 g of X-22-168A, and 11.17 g of ODPA were charged and stirred to dissolve at 60 ° C. Subsequently, 1.47 g of BAHF and 55.44 g of X-22-161A were added while stirring at 60 ° C., and the mixture was stirred for 1 hour. The temperature was then raised to 180 ° C. and the mixture was stirred for 3 hours, after which it was cooled to room temperature to obtain polyimide solution G (solids concentration 50.0 wt%). The weight average molecular weight of the polyimide was measured to be 30,100, and the imidization rate was measured to be 99%. 10.8 g of the polyimide G (solids content 5.4 g) obtained in this manner was mixed with the components listed in Table 2 in the same manner as in Example 1 to obtain a resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability by the methods described above.

[0099] Example 8: 0.5 g of YX7400N, 0.1 g of LP7100, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (5.4 g solids) obtained in Example 3, and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0100] Example 9: 0.25 g of YX7400N, 0.35 g of X-22-161A, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C obtained in Example 3 (solid content 5.4 g), and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were added to the mixture, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0101] Example 10: 0.2 g of YX7400N, 0.4 g of X-22-161B, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C obtained in Example 3 (solid content 5.4 g), and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were added to the mixture, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0102] Example 11: 0.9 g of YX7400N, 0.9 g of KF8010, and 0.02 g of 2P4MZ were added to 8.4 g of the polyimide solution C (4.2 g solids) obtained in Example 3, and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were then added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0103] Example 12: 1.5 g of YX7400N, 1.5 g of KF8010, and 0.02 g of 2P4MZ were added to 6.0 g of the polyimide solution C (3.0 g solids) obtained in Example 3, and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were then added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0104] Example 13 A viscous liquid resin composition was obtained in the same manner as in Example 3, except that 18 g of AA3 was changed to 18 g of DAW45. The obtained resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability test by the methods described above.

[0105] Example 14: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C obtained in Example 3 (solid content 5.4 g), and the mixture was stirred. 22 g of AA3 and 15 g of AA04 were added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0106] Example 15: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C obtained in Example 3 (solid content 5.4 g), and the mixture was stirred. 16.5 g of FAN-30 and 10 g of AA04 were added to the mixture, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0107] Example 16: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (5.4 g solids) obtained in Example 3, and the mixture was stirred. 30 g of AA04 was added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0108] Example 17: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (5.4 g solids) obtained in Example 3, and the mixture was stirred. 30 g of AA3 was added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0109] Example 18: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (5.4 g solids) obtained in Example 3, and the mixture was stirred. 30 g of DAW45 was added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0110] Example 19: 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C obtained in Example 3 (solid content 5.4 g), and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0111] Example 20 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (solid content 5.4 g) obtained in Example 3, and the mixture was stirred. FAN-30 was ground and crushed in a mortar to reduce the specific surface area to 0.26 m ２ / g. 16.5 g of the crushed FAN-30 and 10 g of AA04 were added and kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0112] Example 21 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (solid content 5.4 g) obtained in Example 3, and the mixture was stirred. FAN-30 was ground and crushed in a mortar to reduce the specific surface area to 0.36 m ２ / g. 16.5 g of the crushed FAN-30 and 10 g of AA04 were added and kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0113] Example 22 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (solid content: 5.4 g) obtained in Example 3, and the mixture was stirred. FAN-30 was ground and crushed in a mortar to reduce the specific surface area to 0.51 m ２ / g. 16.5 g of the crushed FAN-30 and 10 g of AA04 were added and kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0114] Comparative Example 1: 0.35 g of YX7400N, 0.25 g of 3,3'-DDS, and 0.02 g of 2P4MZ were added to 10.8 g of the polyimide solution C (5.4 g solids) obtained in Example 3 and stirred. 18 g of AA3 and 12 g of AA04 were added to the mixture and kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0115] Comparative Example 2: 0.6 g of YX7400N and 0.02 g of 2P4MZ were added to 10.8 g (5.4 g solids) of the polyimide solution C obtained in Example 3, and the mixture was stirred. 18 g of AA3 and 12 g of AA04 were then added, and the mixture was kneaded five times using a three-roll mill to obtain a viscous liquid resin composition. The resulting resin composition was then measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the methods described above.

[0116] Comparative Example 3: A 300 ml four-neck flask was equipped with a stirrer, thermometer, nitrogen inlet tube, and dropping funnel. Under a nitrogen atmosphere, 135.3 g of triglyme and 62.40 g of ODPA were charged and stirred and dissolved at 60°C. Subsequently, 73.25 g of BAHF was added while stirring at 60°C, and the mixture was stirred for 1 hour. The temperature was then raised to 180°C, and the mixture was stirred for 3 hours. After cooling to room temperature, polyimide solution H (solids concentration: 50.0 wt%) was obtained. The weight-average molecular weight of the polyimide was measured to be 38,500, and the imidization rate was measured to be 99%.

[0117] To 10.8 g of the polyimide solution H (5.4 g solids) obtained by the above method, 0.3 g of YX7400N, 0.3 g of KF8010, and 0.02 g of 2P4MZ were added and stirred, and 18 g of AA3 and 12 g of AA04 were added and kneaded five times in a three-roll mill to obtain a viscous liquid resin composition. The obtained resin composition was measured for thermal conductivity, elastic modulus, shear adhesive strength, shear strain, and thermal cycle reliability using the above methods.

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Claims

1. A resin composition comprising (A) a polyimide resin containing a siloxane skeleton, (B) an epoxy resin, (C) a siloxane diamine, and (D) a thermally conductive filler, wherein the thermally conductive filler (D) exhibits at least two peaks when peak division is performed on a particle size distribution curve, and the thermally conductive filler constituting one of the peaks has an average particle diameter of 2 μm or more, and the thermally conductive filler constituting the other of the peaks has an average particle diameter of 1 μm or less.

2. The resin composition according to claim 1, wherein the thermally conductive filler (D) is spherical.

3. 3. The resin composition according to claim 1, wherein the polyimide resin (A) containing a siloxane skeleton contains residues of an acid anhydride represented by general formula (1) in an amount of 20 mol % or more when the total amount of tetracarboxylic dianhydride residues is taken as 100 mol %, and contains residues of a diamine represented by general formula (2) in an amount of 50 mol % or more when the total amount of diamine residues is taken as 100 mol %. 【Chemical 1】 (In the general formula (1), m represents an integer of 1 or more and 100 or less. R 7 and R ８ may be the same or different and represent an alkylene group or an arylene group having 1 to 30 carbon atoms. The arylene group may have a substituent. R １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group. １ and Y ２ may be the same or different and represent a trivalent hydrocarbon group having 1 to 20 carbon atoms. 【Chemistry 2】 (In the general formula (2), n represents an integer of 1 or more and 100 or less. R 7 and R ８ may be the same or different and represent an alkylene group or an arylene group having 1 to 30 carbon atoms. １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group.

4. 3. The resin composition according to claim 1, wherein the siloxane diamine (C) has a structure represented by general formula (3), and N is 5 or more and 30 or less. 【Chemistry 3】 (In general formula (3), R 7 and R ８ may be the same or different and represent an alkylene group or an arylene group having 1 to 30 carbon atoms. １ ~R ６ may be the same or different and represent an alkyl group having 1 to 30 carbon atoms, a phenyl group, or a phenoxy group.

5. The specific surface area of ​​the thermally conductive filler (D) having an average particle size of 2 μm or more is 0.2 m ２ The resin composition according to claim 1 or 2, characterized in that the resin composition has a viscosity of 1000 MPa or more.

6. 3. The resin composition according to claim 1, wherein the content of the siloxane diamine (C) is 5% by weight or more and 20% by weight or less, when the total of the polyimide resin (A) containing a siloxane skeleton, the epoxy resin (B), and the siloxane diamine (C) is taken as 100% by weight.

7. A laminate comprising a support and the resin composition according to claim 1 or 2 applied thereto, the sheet having a thickness of 50 μm or more and 400 μm or less.

8. A cured product obtained by curing the resin composition according to claim 1 or 2.

9. 9. The cured product according to claim 8, characterized in that the elastic modulus at -50°C is 1 MPa or more and 100 MPa or less, and the shear strain at -50°C is 2 or more and 10 or less.

10. An electrostatic chuck comprising a laminate having, in this order: a cooling plate; the cured product according to claim 8; and a ceramic plate.

11. A plasma processing apparatus comprising at least a plasma source and the electrostatic chuck of claim 10.

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