Method for producing thermosetting resin composition and method for producing electronic component device

Abstract

To provide a method for producing a thermosetting resin composition which allows an inorganic filler to be highly loaded.SOLUTION: In the method for producing a thermosetting resin composition, a mixture obtained by mixing a thermosetting resin, a curing agent, and a slurry containing an inorganic filler and a solvent is kneaded while removing the solvent. The proportion of a solvent having a boiling point of 50-180°C in all solvents contained in the mixture is 95 mass% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a thermosetting resin composition and a method for producing an electronic component device. [Background technology]

[0002] In recent years, in order to reduce the cost, size, thickness, and weight of electronic component devices and to improve their performance and functionality, progress has been made in increasing the density of packaging by miniaturizing the wiring of elements, increasing the number of layers, increasing the number of pins, and making packages smaller and thinner. Accordingly, electronic component devices that are roughly the same size as elements such as ICs (Integrated Circuits), i.e., CSPs (Chip Size Packages), have become widely used. Furthermore, SiPs (System in Packages), which incorporate multiple elements into a single package, have been developed.

[0003] Thermosetting resin compositions containing a thermosetting resin, a curing agent, and an inorganic filler are widely used as encapsulating materials for encapsulating elements in electronic component devices, due to their productivity and cost advantages. As the density and functionality of elements mounted on electronic component devices continue to increase, the distance between the bump and the chip in a CSP or the distance between elements in a SiP is becoming narrower. This has led to a trend toward smaller cut points for inorganic fillers. However, as the cut points become smaller, the specific surface area of the inorganic filler increases, making uniform dispersion difficult. As a result, achieving higher loadings of inorganic fillers has become a challenge.

[0004] As an example of a method for producing a thermosetting resin composition, there is disclosed a method for producing an epoxy resin molding material for semiconductor encapsulation, which is characterized by mixing all raw materials including an epoxy resin, a curing agent, and an inorganic filler in a solvent, dissolving them to form a mixed solution, and then removing the solvent (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-252041 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-252042 Summary of the Invention [Problem to be solved by the invention]

[0006] The manufacturing methods described in Patent Documents 1 and 2 involve converting raw materials into a mixed and molten state in order to remove metallic foreign matter from an epoxy resin molding material for semiconductor encapsulation. However, with the manufacturing methods described in Patent Documents 1 and 2, it is difficult to apply a strong shear force to the mixed and molten material, and it may be difficult to uniformly disperse an inorganic filler with a low cut point. One aspect of the present disclosure has been made in view of the above-described conventional circumstances, and aims to provide a method for producing a thermosetting resin composition that allows for high filling of an inorganic filler, and a method for producing an electronic component device using the thermosetting resin composition obtained by this production method. [Means for solving the problem]

[0007] Specific means for achieving the above object are as follows. <1> A mixture of a thermosetting resin, a curing agent, an inorganic filler, and a slurry containing a solvent is kneaded while removing the solvent, A method for producing a thermosetting resin composition, wherein the proportion of solvents having a boiling point of 50°C to 180°C in all solvents contained in the mixture is 95 mass % or more. <2> The slurry further comprises a coupling agent. <1> A method for producing the thermosetting resin composition according to claim 1. <3> The top cut diameter of the inorganic filler is 10 μm or less. <1> or <2> A method for producing the thermosetting resin composition according to claim 1. <4> The boiling point of the solvent contained in the slurry is 50°C to 180°C. <1> ~ <3> 10. A method for producing the thermosetting resin composition according to claim 9. <5> The solid content ratio of the inorganic filler in the slurry is 40% by mass to 90% by mass. <1> ~ <4> 10. A method for producing the thermosetting resin composition according to claim 9. <6> The solid content of the mixture is 35% by mass to 95% by mass. <1> ~ <5> 10. A method for producing the thermosetting resin composition according to claim 9. <7> <1> ~ <6> 10. A method for producing an electronic component device, comprising a step of encapsulating an element with a thermosetting resin composition obtained by the method for producing a thermosetting resin composition according to any one of claims 1 to 9. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, it is possible to provide a method for producing a thermosetting resin composition that allows for high loading of an inorganic filler, and a method for producing an electronic component device using the thermosetting resin composition obtained by this production method. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values and their ranges, and do not limit the present disclosure.

[0010] In the present disclosure, numerical ranges indicated using "to" include the numerical values before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple substances corresponding to the component. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, the particles corresponding to each component may contain multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, the term "solid content" refers to the remaining components after excluding volatile components such as solvents from a mixture, a slurry, or a thermosetting resin composition.

[0011] <Method for producing thermosetting resin composition> The method for producing a thermosetting resin composition of the present disclosure involves kneading a mixture of a thermosetting resin, a curing agent, and a slurry containing an inorganic filler and a solvent while removing the solvent, and the proportion of solvents having a boiling point of 50°C to 180°C (hereinafter sometimes referred to as specific solvents) in the total solvents contained in the mixture is 95 mass% or more. According to the method for producing a thermosetting resin composition of the present disclosure, it is possible to increase the loading of inorganic filler. The reason for this is not clear, but is presumed to be as follows. The solvent contained in the mixture acts as a dispersion medium, reducing the viscosity of the mixture and thereby suppressing the generation of shear heat when kneading the mixture. Conventional methods for producing thermosetting resin compositions that do not use a solvent as a dispersion medium have difficulty reducing the cohesive strength of the inorganic filler. Particularly when using an inorganic filler with a low cut point, significant shear heat can occur, resulting in gelation of the thermosetting resin composition. The method for producing a thermosetting resin composition of the present disclosure uses a solvent, which suppresses the temperature rise of the mixture compared to when a solvent is not used, making it possible to apply sufficient shear force to the mixture without worrying about gelation. Applying sufficient shear force to the mixture facilitates uniform dispersion of the inorganic filler in the thermosetting resin composition. Furthermore, since the solvent is removed during kneading the mixture, the shear force on the mixture increases as the viscosity of the mixture gradually increases with the progress of solvent removal, further improving the dispersibility of the inorganic filler and further suppressing re-agglomeration of the inorganic filler in the thermosetting resin composition. On the other hand, because the proportion of the specific solvent in the total solvents contained in the mixture is 95% by mass or more, the solvent contained in the mixture is easily removed, which is presumably why it becomes possible to highly load the inorganic filler into the thermosetting resin composition. Furthermore, because the solvent contained in the mixture can be removed at a lower temperature, it is possible to minimize the reaction between the thermosetting resin and the curing agent that may occur when the mixture is kneaded. This makes it possible to use a combination of a thermosetting resin and a curing agent that reacts easily when heated as components of the thermosetting resin composition, thereby increasing the degree of freedom in designing the thermosetting resin composition.

[0012] (Preparing the mixture) The method for producing a thermosetting resin composition according to the present disclosure uses a mixture of a thermosetting resin, a curing agent, and a slurry containing an inorganic filler and a solvent. The mixture may contain other components such as a curing accelerator, a stress relaxation agent, and an ion exchanger, as needed. The mixture is obtained by mixing a slurry containing a thermosetting resin, a curing agent, an inorganic filler, and a solvent, and other components such as a curing accelerator, a stress relaxation agent, an ion exchanger, etc., which are used as needed, using a mixer such as a stirrer or a planetary mixer, or a wet disperser such as an ultrasonic disperser or a jet mill, etc. The mixing conditions for preparing the mixture are set appropriately depending on the types of components contained in the mixture, the ratio of the components, etc.

[0013] From the viewpoint of liquid transportability during kneading, the solid content of the mixture is preferably 35% to 95% by mass, more preferably 60% to 90% by mass, and even more preferably 65% to 85% by mass.

[0014] The proportion of the specific solvent in the total solvent contained in the mixture is 95% by mass or more, preferably 97% by mass or more, more preferably 99% by mass or more, and even more preferably 99.9% by mass or more. By setting the proportion of the specific solvent to 95% by mass or more, the solvent contained in the mixture tends to be easily removed. Furthermore, by appropriately changing the kneading conditions of the mixture, the amount of residual solvent in the thermosetting resin composition tends to be easily adjusted to a desired range. The proportion of the specified solvent in the total solvents contained in the mixture can be determined by gas chromatography, etc. Furthermore, if the composition of the mixture is known, the proportion of the specified solvent can be determined from the composition of the mixture.

[0015] (Mixing the mixture and removing the solvent) In the method for producing a thermosetting resin composition according to the present disclosure, the mixture is kneaded while removing the solvent. The kneading device used to knead the mixture is not particularly limited. Examples of the kneading device include screw kneaders such as single-screw kneaders, twin-screw kneaders, and multi-screw kneaders with three or more screws, and roll mills such as two-roll mills and three-roll mills. The stirring blade of the screw mixer may be supported at both the base and the tip, or at the base only. From the viewpoint of improving mixing performance and productivity, it is preferable that the stirring blade be supported at the base only. Among these, a screw kneader, which is an example of a closed system kneading device that allows removal of the solvent by reducing pressure, is preferred, and a twin-screw kneader is more preferred from the viewpoint of being able to easily control the shear force. In addition, it is preferable to use a screw kneader as the kneading device, since it is easy to add a curing accelerator to a primary kneaded product obtained by kneading the mixture at a first kneading temperature, and then further knead the primary kneaded product to which the curing accelerator has been added at a second kneading temperature to obtain a secondary kneaded product.

[0016] The kneading temperature of the mixture is not particularly limited, but is preferably a temperature near the melting point or softening point of the thermosetting resin from the viewpoint of suppressing uneven distribution of the thermosetting resin. When two or more thermosetting resins are used in combination, the kneading temperature of the mixture is preferably a temperature near the melting point or softening point of the thermosetting resin with the highest melting point or softening point. The kneading temperature of the mixture is preferably in the range of 10°C lower to 70°C higher than the melting point or softening point of the thermosetting resin (when multiple types of thermosetting resins are used in combination, the thermosetting resin with the highest melting point or softening point), more preferably in the range of 8°C lower to 60°C higher, and even more preferably in the range of 6°C lower to 30°C higher. By kneading at such a temperature, the thermosetting resin can be melted and fluidity can be maintained, thereby enabling good stirring and mixing. In one embodiment, the kneading temperature of the mixture is preferably 30°C to 150°C, more preferably 50°C to 140°C, and even more preferably 60°C to 130°C. In the present disclosure, the "mixing temperature of the mixture" refers to the temperature of the heating section of the mixer when the mixture is mixed with the mixer.

[0017] The method for removing the solvent contained in the mixture when the mixture is kneaded is not particularly limited. When a screw kneader is used as the kneading device, it is preferable to remove the solvent by reducing the pressure inside the screw kneader. When a screw kneader is used as the kneading device, the pressure inside the screw kneader is preferably 0.001 MPa to 0.08 MPa, more preferably 0.003 MPa to 0.06 MPa, and even more preferably 0.005 MPa to 0.05 MPa, from the viewpoint of distilling off the solvent.

[0018] (Post-processing) In the method for producing a thermosetting resin composition according to the present disclosure, the thermosetting resin composition obtained through kneading may be cooled and pulverized to obtain a powdery thermosetting resin composition. The thermosetting resin composition obtained through kneading may also be molded into particles, tablets, pellets, or granules (e.g., cylindrical granules). The method for pulverizing or molding the thermosetting resin composition is not particularly limited, and conventionally known methods may be used.

[0019] Hereinafter, the various components contained in the mixture used in the method for producing a thermosetting resin composition will be described in detail.

[0020] (thermosetting resin) The mixture includes a thermosetting resin. The type of thermosetting resin is not particularly limited, and examples include epoxy resins, phenolic resins, thiol resins, urea resins, melamine resins, urethane resins, silicone resins, maleimide resins, and unsaturated polyester resins. In the present disclosure, "thermosetting resins" include those that exhibit both thermoplastic and thermosetting properties, such as acrylic resins containing epoxy groups. Thermosetting resins may be solid or liquid at room temperature and normal pressure (e.g., 25°C and atmospheric pressure), and are preferably solid. Thermosetting resins may be used alone or in combination of two or more.

[0021] The thermosetting resin preferably includes an epoxy resin. The type of epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule. Specifically, novolac epoxy resins (phenol novolac epoxy resins, orthocresol novolac epoxy resins, etc.) are obtained by epoxidizing novolac resins obtained by condensing or co-condensing, under an acid catalyst, at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc.; triphenylmethane epoxy resins are obtained by epoxidizing triphenylmethane phenolic resins obtained by condensing or co-condensing, under an acid catalyst, the above phenolic compounds with aromatic aldehyde compounds such as benzaldehyde, salicylaldehyde, etc.; and novolac resins obtained by co-condensing, under an acid catalyst, the above phenolic compounds and naphthol compounds with an aldehyde compound, etc., are epoxidized. diphenylmethane-type epoxy resins, which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl-type epoxy resins, which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene-type epoxy resins, which are diglycidyl ethers of stilbene-based phenolic compounds; sulfur-containing epoxy resins, which are diglycidyl ethers of bisphenol S, etc.; epoxy resins, which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester-type epoxy resins, which are glycidyl esters of polycarboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine-type epoxy resins, in which the active hydrogen bonded to the nitrogen atom of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is substituted with a glycidyl group; and dicyclopentadiene-type epoxy resins, which are epoxidized co-condensation resins of dicyclopentadiene and phenolic compounds.Alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, which are produced by epoxidizing the olefin bonds in the molecule; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenolic resins; and dicyclopentadiene-modified phenolic resins, which are glycidyl ethers of dicyclopentadiene-modified phenolic resins. Examples of suitable epoxy resins include pentadiene-modified epoxy resins, cyclopentadiene-modified epoxy resins, which are glycidyl ethers of cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified epoxy resins, which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins; naphthalene-type epoxy resins, which are glycidyl ethers of naphthalene ring-containing phenolic resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; and aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins. Further examples of suitable epoxy resins include epoxidized silicone resins and aminophenol-type epoxy resins, which are glycidyl ethers of aminophenols. These epoxy resins may be used alone or in combination of two or more.

[0022] Among the above epoxy resins, from the viewpoint of a balance between heat resistance and fluidity, epoxy resins selected from the group consisting of biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur-atom-containing epoxy resins, novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenylmethane-type epoxy resins, copolymer-type epoxy resins, and aralkyl-type epoxy resins (these are referred to as "specific epoxy resins"). The specific epoxy resins may be used alone or in combination of two or more.

[0023] When the epoxy resin contains a specific epoxy resin, the content of the specific epoxy resin is preferably 30% by mass or more, and more preferably 50% by mass or more, of the total epoxy resin, from the viewpoint of exhibiting the performance of the specific epoxy resin.

[0024] Among the specific epoxy resins, biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, and sulfur-atom-containing epoxy resins are more preferred from the viewpoint of fluidity, and dicyclopentadiene-type epoxy resins, triphenylmethane-type epoxy resins, and aralkyl-type epoxy resins are preferred from the viewpoint of heat resistance. Specific examples of preferred epoxy resins are shown below.

[0025] The biphenyl type epoxy resin is not particularly limited as long as it is an epoxy resin having a biphenyl skeleton. For example, an epoxy resin represented by the following general formula (II) is preferred. Among the epoxy resins represented by the following general formula (II), R 8 When the oxygen atom is substituted at the 4 and 4' positions, the 3, 3', 5, and 5' positions are methyl groups, and the other R 8 YX-4000H (Mitsubishi Chemical Corporation, product name) where R is a hydrogen atom, 8 4,4'-bis(2,3-epoxypropoxy)biphenyl, where R is a hydrogen atom, 8 When is a hydrogen atom and R 8 When the oxygen atom is substituted at the 4 and 4' positions, the 3, 3', 5, and 5' positions are methyl groups, and the other R 8is a hydrogen atom, YL-6121H (trade name, Mitsubishi Chemical Corporation) and the like are commercially available.

[0026] [ka]

[0027] In formula (II), R 8 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 4 to 18 carbon atoms, and may all be the same or different. n is an average value and represents a number of 0 to 10.

[0028] The stilbene type epoxy resin is not particularly limited as long as it is an epoxy resin having a stilbene skeleton. For example, an epoxy resin represented by the following general formula (III) is preferred. Among the epoxy resins represented by the following general formula (III), R 9 When the oxygen atom is substituted at the 4 and 4' positions, the 3, 3', 5, and 5' positions are methyl groups, and the other R 9 is a hydrogen atom, and R 10 are all hydrogen atoms, and R 9 Three of the 3, 3', 5, and 5' positions are methyl groups, one is a t-butyl group, and the remaining R 9 is a hydrogen atom, and R 10 and mixtures of those in which all of the above are hydrogen atoms.

[0029] [ka]

[0030] In formula (III), R 9 and R 10 represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n is an average value and represents a number of 0 to 10.

[0031] The diphenylmethane type epoxy resin is not particularly limited as long as it is an epoxy resin having a diphenylmethane skeleton. For example, an epoxy resin represented by the following general formula (IV) is preferred. Among the epoxy resins represented by the following general formula (IV), R 11 are all hydrogen atoms, and R 12 When the oxygen atom is substituted at the 4 and 4' positions, the 3, 3', 5, and 5' positions are methyl groups, and the other R 12 YSLV-80XY (Nippon Steel Chemical & Material Co., Ltd., product name) in which is a hydrogen atom is commercially available.

[0032] [ka]

[0033] In formula (IV), R 11 and R 12 represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n is an average value and represents a number of 0 to 10.

[0034] The sulfur atom-containing epoxy resin is not particularly limited as long as it is an epoxy resin containing a sulfur atom. For example, an epoxy resin represented by the following general formula (V) can be mentioned. Among the epoxy resins represented by the following general formula (V), R 13 When the oxygen atom is substituted at the 4 and 4' positions, the 3 and 3' positions are t-butyl groups, and the 6 and 6' positions are methyl groups. 13 YSLV-120TE (Nippon Steel Chemical & Material Co., Ltd., product name) in which is a hydrogen atom is commercially available.

[0035] [ka]

[0036] In formula (V), R 13represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n is an average value and represents a number of 0 to 10.

[0037] The novolac epoxy resin is not particularly limited as long as it is an epoxy resin obtained by epoxidizing a novolac phenolic resin. For example, epoxy resins obtained by epoxidizing a novolac phenolic resin such as a phenol novolac resin, a cresol novolac resin, or a naphthol novolac resin using a method such as glycidyl etherification are preferred, and epoxy resins represented by the following general formula (VI) are more preferred. Among the epoxy resins represented by the following general formula (VI), R 14 are all hydrogen atoms, and R 15 is a methyl group, and i=1; ESCN-190 and ESCN-195 (product names, Sumitomo Chemical Co., Ltd.); 14 N-770 and N-775 (trade names, DIC Corporation) in which all of R are hydrogen atoms and i=0; 14 are all hydrogen atoms, and the part where i=0 and the part where i=1 are R 15 YDAN-1000-10C (Nippon Steel Chemical & Material Co., Ltd., product name), a styrene-modified phenolic novolac epoxy resin having a moiety where R is -CH(CH3)-Ph; 14 are all hydrogen atoms, i=1, and R 15 is a methyl group and i=2, R 15 Benzyl group-modified cresol novolac epoxy resins, which have one methyl group and one benzyl group, are commercially available.

[0038] [ka]

[0039] In formula (VI), R 14 R represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. 15represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

[0040] The dicyclopentadiene-type epoxy resin is not particularly limited as long as it is an epoxy resin obtained by epoxidizing a compound having a dicyclopentadiene skeleton as a raw material. For example, an epoxy resin represented by the following general formula (VII) is preferred. Among the epoxy resins represented by the following general formula (VII), HP-7200 (trade name, DIC Corporation), in which i = 0, is commercially available.

[0041] [ka]

[0042] In formula (VII), R 16 represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

[0043] The triphenylmethane epoxy resin is not particularly limited as long as it is an epoxy resin made from a compound having a triphenylmethane skeleton. For example, an epoxy resin obtained by glycidyl etherifying a triphenylmethane phenolic resin obtained from an aromatic aldehyde compound and a phenolic compound is preferred, and an epoxy resin represented by the following general formula (VIII) is more preferred. Among the epoxy resins represented by the following general formula (VIII), 1032H60 (Mitsubishi Chemical Corporation, trade name) and EPPN-502H (Nippon Kayaku Co., Ltd., trade name), in which i is 0 and k is 0, are commercially available.

[0044] [ka]

[0045] In formula (VIII), R 17 and R 18represents a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i independently represents an integer of 0 to 3, and each k independently represents an integer of 0 to 4. n is an average value and represents a number of 0 to 10.

[0046] The copolymerized epoxy resin obtained by epoxidizing a novolac resin obtained from a naphthol compound, a phenol compound, and an aldehyde compound is not particularly limited as long as it is an epoxy resin made from a compound having a naphthol skeleton and a compound having a phenol skeleton as raw materials. For example, an epoxy resin obtained by glycidyl etherifying a novolac phenolic resin using a compound having a naphthol skeleton and a compound having a phenol skeleton is preferred, and an epoxy resin represented by the following general formula (IX) is more preferred. Among the epoxy resins represented by the following general formula (IX), R 21 is a methyl group, i is 1, j is 0, and k is 0, and NC-7300 (trade name, Nippon Kayaku Co., Ltd.) is available as a commercially available product.

[0047] [ka]

[0048] In formula (IX), R 19 ~R 21 represents a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i independently represents an integer of 0 to 3, each j independently represents an integer of 0 to 2, and each k independently represents an integer of 0 to 4. Each l and m is an average value and a number of 0 to 10, and (l+m) represents a number of 0 to 10. The terminal of the epoxy resin represented by formula (IX) is either formula (IX-1) or (IX-2) below. In formulas (IX-1) and (IX-2), R 19 ~R 21 , i, j and k are defined as R 19 ~R 21 The definitions of i, j, and k are the same as those of i, j, and k. n is 1 (when the bond is formed via a methylene group) or 0 (when the bond is not formed via a methylene group).

[0049] [ka]

[0050] Examples of the epoxy resin represented by the general formula (IX) include random copolymers containing l structural units and m structural units randomly, alternating copolymers containing them alternately, copolymers containing them regularly, block copolymers containing them in blocks, etc. Any of these may be used alone or in combination of two or more.

[0051] Another preferred copolymer epoxy resin is Epiclon HP-5000 (trade name, DIC Corporation), a methoxynaphthalene-cresol-formaldehyde co-condensation epoxy resin containing the following two structural units in a random, alternating, or block order: In the following general formula, n and m each represent an average value and are numbers from 0 to 10, and (n+m) represents a number from 0 to 10, preferably n and m each represent an average value and are numbers from 1 to 9, and (n+m) represents a number from 2 to 10.

[0052] [ka]

[0053] The aralkyl epoxy resin is not particularly limited as long as it is an epoxy resin made from a phenolic resin synthesized from at least one selected from the group consisting of phenolic compounds such as phenol and cresol and naphthol compounds such as naphthol and dimethylnaphthol, and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or a derivative thereof. For example, epoxy resins obtained by glycidyl etherifying a phenolic resin synthesized from at least one selected from the group consisting of phenolic compounds such as phenol and cresol and naphthol compounds such as naphthol and dimethylnaphthol, and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or a derivative thereof are preferred, and epoxy resins represented by the following general formulas (X) and (XI) are more preferred.

[0054] Among the epoxy resins represented by the following general formula (X), those in which i is 0 and R 38 is a hydrogen atom, i is 0, and R 38 is a hydrogen atom and all R 8 CER-3000 (trade name, Nippon Kayaku Co., Ltd.), which is a mixture of an epoxy resin in which l is a hydrogen atom and an epoxy resin in which k is a hydrogen atom at a mass ratio of 80:20, is commercially available. Furthermore, among the epoxy resins represented by the following general formula (XI), ESN-175 (trade name, Nippon Steel Chemical & Material Co., Ltd.), in which l is 0, j is 0, and k is 0, is commercially available.

[0055] [ka]

[0056] In formulas (X) and (XI), R 38 R represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. 37 , R 39 ~R 41 represents a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, each k is independently an integer of 0 to 4, and each l is independently an integer of 0 to 4. Each n is an average value and is independently a number of 0 to 10.

[0057] R in the above general formulas (II) to (XI) 8 ~R 21 and R 37 ~R 41 In the formula (II), "all of them may be the same or different" means, for example, that 8 to 88 R 8 This means that all of the R may be the same or different. 9 ~R 21 and R 37 ~R 41In addition, the numbers of R may all be the same or different. 8 ~R 21 and R 37 ~R 41 may be the same or different. For example, R 9 and R 10 may all be the same or different. Furthermore, the monovalent organic group having 1 to 18 carbon atoms in the general formulae (III) to (XI) is preferably an alkyl group or an aryl group.

[0058] In the general formulas (II) to (XI), n is an average value, and each independently is preferably in the range of 0 to 10. When n is 10 or less, the melt viscosity of the resin component does not become too high, and the viscosity of the thermosetting resin composition during melt molding tends to decrease, and the occurrence of filling defects, deformation of bonding wires (gold wires connecting elements to leads), etc. is more preferably set in the range of 0 to 4.

[0059] Specific examples of preferred epoxy resins that can be used in the thermosetting resin composition have been described above in accordance with the general formulas (II) to (XI). More specific preferred epoxy resins include 4,4'-bis(2,3-epoxypropoxy)-3,3',5,5'-tetramethylbiphenyl from the viewpoint of heat resistance, and 4,4'-bis(2,3-epoxypropoxy)-biphenyl from the viewpoint of moldability and heat resistance.

[0060] The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoint of a balance of various properties such as moldability, heat resistance, and electrical reliability, the epoxy equivalent of the epoxy resin is preferably 60 g / eq to 1000 g / eq, and more preferably 80 g / eq to 500 g / eq.

[0061] The epoxy resin may be liquid or solid. When the epoxy resin is solid, the softening point or melting point of the epoxy resin is not particularly limited. From the viewpoints of moldability and heat resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during preparation of the thermosetting resin composition, it is more preferably 50°C to 130°C. In the present disclosure, the softening point refers to a value measured by the ring and ball method of JIS K 7234:1986. In the present disclosure, the melting point refers to a value measured in accordance with the visual method of JIS K 0064:1992.

[0062] From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the content of the epoxy resin in the thermosetting resin composition is preferably 0.5 to 60% by mass, and more preferably 2 to 50% by mass.

[0063] (hardening agent) The mixture contains a curing agent. The type of curing agent is not particularly limited, as long as it is a compound that undergoes a curing reaction with the thermosetting resin used in combination. For example, curing agents that can be used in combination with an epoxy resin include phenol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, polymercaptan-based curing agents, polyaminoamide-based curing agents, isocyanate-based curing agents, and blocked isocyanate-based curing agents. One type of curing agent may be used alone, or two or more types may be used in combination. The curing agent may be solid or liquid at room temperature and normal pressure (e.g., 25°C, atmospheric pressure), and is preferably solid. When the thermosetting resin is an epoxy resin, the curing agent is preferably a phenol-based curing agent or an amine-based curing agent from the viewpoint of heat resistance. Examples of phenolic curing agents include phenolic resins and polyhydric phenolic compounds having two or more phenolic hydroxyl groups per molecule. Specific examples include polyhydric phenolic compounds such as resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; novolac phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aldehyde compound such as formaldehyde, acetaldehyde, or propionaldehyde, under an acidic catalyst; and phenolic resins synthesized from the above phenolic compounds and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or the like. Examples of suitable phenol curing agents include aralkyl phenolic resins such as aryl aralkyl resins and naphthol aralkyl resins; paraxylylene and / or metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above phenolic compounds with dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensing or co-condensing the above phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenolic curing agents may be used alone or in combination of two or more.

[0064] Among phenolic curing agents, from the viewpoint of heat resistance, at least one selected from the group consisting of aralkyl phenolic resins, dicyclopentadiene phenolic resins, triphenylmethane phenolic resins, copolymerized phenolic resins of triphenylmethane phenolic resins and aralkyl phenolic resins, and novolac phenolic resins (these are referred to as "specific phenolic curing agents"). The specific phenolic curing agents may be used alone or in combination of two or more.

[0065] When the phenolic curing agent contains a specific phenolic curing agent, the content of the specific phenolic curing agent is preferably 30% by mass or more, and more preferably 50% by mass or more, of the total phenolic curing agent, from the viewpoint of fully exhibiting its performance.

[0066] Examples of aralkyl phenolic resins include phenol aralkyl resins and naphthol aralkyl resins synthesized from a phenolic compound and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, etc. The aralkyl phenolic resin may be further copolymerized with other phenolic resins. Examples of copolymerized aralkyl phenolic resins include copolymerized phenolic resins of triphenylmethane phenolic resin and aralkyl phenolic resin, copolymerized phenolic resins of salicylaldehyde phenolic resin and aralkyl phenolic resin, and copolymerized phenolic resins of novolac phenolic resin and aralkyl phenolic resin.

[0067] The aralkyl phenolic resin is not particularly limited as long as it is a phenolic resin synthesized from at least one compound selected from the group consisting of phenol compounds and naphthol compounds, and dimethoxy-para-xylene, bis(methoxymethyl)biphenyl, or a derivative thereof. For example, phenolic resins represented by the following general formulas (XII) to (XIV) are preferred.

[0068] [ka]

[0069] In formulas (XII) to (XIV), R 23 R represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. 22 , R 24 , R 25 and R 28 R represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. 26 and R 27 represents a hydroxyl group or a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, each k is independently an integer of 0 to 4, and each p is independently an integer of 0 to 4. Each n is an average value and is independently a number of 0 to 10.

[0070] Among the phenolic resins represented by the general formula (XII), i is 0 and R 23 MEH-7851 (product name, Meiwa Kasei Co., Ltd.), in which all are hydrogen atoms, is commercially available.

[0071] Among the phenolic resins represented by the general formula (XIII) above, XL-225, XLC (Mitsui Chemicals, Inc., trade name), MEH-7800 (Meiwa Chemical Industry Co., Ltd., trade name), etc., in which i is 0 and k is 0, are commercially available.

[0072] Among the phenolic resins represented by the general formula (XIV), SN-170 (trade name, Nippon Steel Chemical & Material Co., Ltd.), in which j is 0, k is 0, and p is 0, and R 27 is a hydroxyl group and p is 0, and SN-395 (trade name, Nippon Steel Chemical & Material Co., Ltd.) is available as a commercially available product.

[0073] The dicyclopentadiene-type phenolic resin is not particularly limited as long as it is a phenolic resin obtained from a compound having a dicyclopentadiene skeleton as a raw material. For example, a phenolic resin represented by the following general formula (XV) is preferred. Among the phenolic resins represented by the following general formula (XV), phenolic resins in which i is 0 are commercially available.

[0074] [ka]

[0075] In formula (XV), R 29 represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

[0076] The triphenylmethane type phenolic resin is not particularly limited as long as it is a phenolic resin obtained from an aromatic aldehyde compound as a raw material. For example, a phenolic resin represented by the following general formula (XVI) is preferred.

[0077] Among the phenolic resins represented by the following general formula (XVI), MEH-7500 (trade name, Meiwa Kasei Co., Ltd.), in which i and k are 0, is commercially available.

[0078] [ka]

[0079] In formula (XVI), R 30 and R 31 represents a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i is independently an integer of 0 to 3, and each k is independently an integer of 0 to 4. n is an average value and is a number of 0 to 10.

[0080] The copolymerized phenolic resin of a triphenylmethane type phenolic resin and an aralkyl type phenolic resin is not particularly limited as long as it is a copolymerized phenolic resin of a phenolic resin obtained from a compound having a benzaldehyde skeleton as a raw material and an aralkyl type phenolic resin. For example, a phenolic resin represented by the following general formula (XVII) is preferred.

[0081] Among the phenolic resins represented by the following general formula (XVII), HE-510 (trade name, Air Water Chemical Co., Ltd.), in which i is 0, k is 0, and q is 0, is commercially available.

[0082] [ka]

[0083] In formula (XVII), R 32 ~R 34 represents a monovalent organic group having 1 to 18 carbon atoms, and may all be the same or different. Each i is independently an integer of 0 to 3, each k is independently an integer of 0 to 4, and each q is independently an integer of 0 to 5. Each l and m is an average value and independently a number of 0 to 11, provided that the sum of l and m is a number of 1 to 11.

[0084] The novolac phenolic resin is not particularly limited as long as it is a phenolic resin obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenol compounds and naphthol compounds with an aldehyde compound in the presence of an acid catalyst. For example, a phenolic resin represented by the following general formula (XVIII) is preferred.

[0085] Among the phenolic resins represented by the following general formula (XVIII), those in which i is 0 and R 35 are all hydrogen atoms, such as Tamanol 758 and 759 (trade names, Arakawa Chemical Industries, Ltd.) and H-4 (trade name, Meiwa Chemical Industry Co., Ltd.).

[0086] [ka]

[0087] In formula (XVIII), R 35 R represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. 36 represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

[0088] R in the above general formulas (XII) to (XVIII) 22 ~R 36 The expression "may be the same or different" means, for example, that i R 22 This means that all of the R may be the same or different from each other. 23 ~R 36 In addition, the numbers of R may be the same or different from each other. 22 ~R 36 may be the same or different. For example, R 22 and R 23 may be the same or different, and R 30 and R 31 may all be the same or different.

[0089] In the general formulas (XII) to (XVIII), n is preferably in the range of 0 to 10. If n is 10 or less, the melt viscosity of the resin component does not become too high, and the viscosity of the thermosetting resin composition during melt molding also becomes low, making it less likely that filling defects, deformation of bonding wires (gold wires connecting elements to leads), etc. will occur. The average n in one molecule is preferably set in the range of 0 to 4.

[0090] Specific examples of amine curing agents include aliphatic amine compounds such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diamino-dicyclohexylmethane, aromatic amine compounds such as diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, dimethylthiotoluenediamine, and 2-methylaniline, imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, and 2-isopropylimidazole, and imidazoline compounds such as imidazoline, 2-methylimidazoline, and 2-ethylimidazoline. Among these, aromatic amine compounds are preferred from the viewpoint of storage stability, and diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and dimethylthiotoluenediamine are more preferred.

[0091] The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenolic curing agent, active hydrogen equivalent in the case of an amine-based curing agent) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, it is preferably 10 g / eq to 1000 g / eq, and more preferably 30 g / eq to 500 g / eq. The hydroxyl equivalent weight for phenolic curing agents is a value calculated based on the hydroxyl value measured in accordance with JIS K0070:1992, and the active hydrogen equivalent weight for amine curing agents is a value calculated based on the amine value measured in accordance with JIS K7237:1995.

[0092] When the curing agent is solid, the softening point or melting point is not particularly limited, but from the viewpoints of moldability and heat resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during production of the thermosetting resin composition, it is more preferably 50°C to 130°C.

[0093] When the thermosetting resin is an epoxy resin, the equivalent ratio of the epoxy resin to the curing agent (molar number of epoxy groups in the resin / molar number of active hydrogens in the curing agent) is not particularly limited, but from the viewpoint of minimizing the amount of unreacted components, it is preferably, for example, 0.7 to 1.6, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.2.

[0094] (slurry) The mixture contains a slurry that includes an inorganic filler and a solvent. The slurry is obtained by mixing the inorganic filler, the solvent, and the coupling agent, dispersant, etc., which are used as needed, using a mixer such as a stirrer or a planetary mixer, or a wet disperser such as an ultrasonic disperser or a jet mill, etc. The mixing conditions for preparing the slurry are appropriately set depending on the types of components contained in the slurry, the ratio of the components, etc. The inorganic filler contained in the slurry may be subjected to a wet sieving process, which tends to make it easier to reduce the top cut diameter (described later) compared to dry sieving.

[0095] The solid content ratio of the inorganic filler in the slurry is preferably 40% by mass to 90% by mass, more preferably 50% by mass to 85% by mass, and even more preferably 60% by mass to 80% by mass, from the viewpoint of suppressing sedimentation.

[0096] -Inorganic filler- The slurry contains an inorganic filler. The type of inorganic filler is not particularly limited. Specific examples include inorganic materials such as spherical silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, aluminum nitride, boehmite, beryllia, magnesium oxide, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, mica, and titanates. Inorganic fillers with flame retardant properties may also be used. Examples of inorganic fillers with flame retardant properties include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium-zinc composite hydroxide, and zinc borate. Among these, spherical silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. One type of inorganic filler may be used alone, or two or more types may be used in combination. The inorganic filler may be in the form of a powder, beads formed by spheroidizing powder, or fibers.

[0097] The top cut diameter of the inorganic filler is not particularly limited. From the viewpoint of filling narrow gaps of 30 μm or less, the top cut diameter of the inorganic filler is preferably 10 μm or less, more preferably 7 μm or less, even more preferably 6 μm or less, and particularly preferably 5 μm or less. From the viewpoint of suppressing an increase in viscosity of the thermosetting resin composition, the top cut diameter of the inorganic filler may be 1 μm or more. In the present disclosure, the top cut diameter of an inorganic filler refers to the particle size value at which the volume cumulative distribution curve is drawn from the small diameter side using a laser diffraction scattering particle size distribution measuring device, and the volume integrated value is 90% by volume.

[0098] The average particle size of the inorganic filler is not particularly limited. For example, the volume average particle size is preferably 10 μm or less, more preferably 0.1 μm to 10 μm, even more preferably 0.1 μm to 8 μm, and particularly preferably 0.2 μm to 6 μm. When the volume average particle size is 10 μm or less, the ability to fill narrow gaps tends to be improved. Furthermore, when the volume average particle size is 0.1 μm or more, the increase in viscosity of the thermosetting resin composition tends to be further suppressed. The volume average particle size of the inorganic filler can be measured as the volume average particle size (D50) using a laser diffraction scattering particle size distribution measuring device.

[0099] From the viewpoint of the flowability of the thermosetting resin composition, the particle shape of the inorganic filler is preferably spherical rather than angular, and the particle size distribution of the inorganic filler is preferably wide.

[0100] The content of the inorganic filler in the thermosetting resin composition is not particularly limited. From the viewpoint of fluidity and strength, it is preferably 30 to 95% by volume, more preferably 35 to 90% by volume, and even more preferably 40 to 80% by volume of the entire thermosetting resin composition. When the content of the inorganic filler is 30% by volume or more of the entire thermosetting resin composition, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved. When the content of the inorganic filler is 95% by volume or less of the entire thermosetting resin composition, an increase in the viscosity of the thermosetting resin composition is suppressed, and the fluidity is further improved, tending to result in better moldability.

[0101] -solvent- The slurry contains a solvent. The type of solvent is not particularly limited, and is appropriately selected from those that can be easily removed from the mixture when the mixture is kneaded. The solvent contained in the mixture may or may not dissolve either the thermosetting resin or the curing agent.

[0102] The boiling point of the solvent at normal pressure is preferably 50°C to 180°C, more preferably 60°C to 170°C, even more preferably 70°C to 160°C, particularly preferably 70°C to 140°C, and extremely preferably 70°C to 120°C, since this allows the solvent to be easily removed from the mixture. The solvent may be used alone or in combination of two or more. When two or more solvents are used in combination, it is preferable that the boiling point at normal pressure of the solvent with the highest boiling point is within the above range. Furthermore, in the present disclosure, it is preferable that the proportion of solvents (specific solvents) having a boiling point of 50°C to 180°C is 95% by mass or more of all solvents contained in the mixture, the proportion of solvents having a boiling point of 60°C to 170°C is 95% by mass or more, the proportion of solvents having a boiling point of 70°C to 160°C is more preferably 95% by mass or more, the proportion of solvents having a boiling point of 70°C to 140°C is even more preferably 95% by mass or more, and the proportion of solvents having a boiling point of 70°C to 120°C is particularly preferably 95% by mass or more.

[0103] Specific examples of the solvent include methyl ethyl ketone, methyl isobutyl ketone, toluene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, etc. Among these, methyl isobutyl ketone or methyl ethyl ketone is preferred.

[0104] -Coupling agent- The slurry may further contain a coupling agent. The type of coupling agent is not particularly limited, and known coupling agents can be used. Examples of the coupling agent include silane coupling agents and titanium coupling agents. One type of coupling agent may be used alone, or two or more types may be used in combination.

[0105] Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, octenyltrimethoxysilane, glycidoxyoctyltrimethoxysilane, and methacryloxyoctyltrimethoxysilane.

[0106] Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecyl benzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate.

[0107] When the slurry contains a coupling agent, the content of the coupling agent is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 8 parts by mass, and even more preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the inorganic filler, from the viewpoint of adhesion at the interface between the thermosetting resin and the inorganic filler.

[0108] By including a coupling agent in the slurry, it is possible to perform a more uniform surface treatment of the inorganic filler with the coupling agent than in a dry treatment method, and therefore the flowability of the thermosetting resin composition produced by the method for producing a thermosetting resin composition of the present disclosure is further improved.

[0109] (curing accelerator) The thermosetting resin composition produced by the method for producing a thermosetting resin composition of the present disclosure may contain a curing accelerator. The type of curing accelerator is not particularly limited and can be selected depending on the type of thermosetting resin, the desired properties of the thermosetting resin composition, etc.

[0110] Specifically, diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole, derivatives of the cyclic amidine compounds, phenol novolac salts of the cyclic amidine compounds or their derivatives, and the combination of these compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone, diazofuran, compounds having intramolecular polarization obtained by adding a compound having a π bond, such as phenylmethane; cyclic amidinium compounds such as the tetraphenylborate salt of DBU, the tetraphenylborate salt of DBN, the tetraphenylborate salt of 2-ethyl-4-methylimidazole, and the tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide;organic phosphines such as primary phosphines such as ethylphosphine and phenylphosphine; secondary phosphines such as dimethylphosphine and diphenylphosphine; and tertiary phosphines such as triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, trinaphthylphosphine, and tris(benzyl)phosphine; phosphine compounds such as complexes of the above organic phosphines with organoborons; and complexes of the above organic phosphines or the above phosphine compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, compounds having intramolecular polarization obtained by adding a compound having a π bond, such as quinone compounds, such as 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, and anthraquinone, or diazophenylmethane; compounds having intramolecular polarization obtained by adding the above organic phosphines or the above phosphine compounds with 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, and 4-iodophenol; compounds with intramolecular polarization obtained by reacting halogenated phenol compounds such as phenol, 3-iodophenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-t-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, and 4-bromo-4'-hydroxybiphenyl, followed by a dehydrohalogenation step;Examples of the tetra-substituted phosphonium compounds include tetra-substituted phosphonium compounds such as tetraphenylphosphonium, tetraphenylborate salts of tetra-substituted phosphonium compounds such as tetraphenylphosphonium tetra-p-tolylborate, and salts of tetra-substituted phosphonium compounds with phenolic compounds; phosphobetaine compounds; and adducts of phosphonium compounds with silane compounds. For example, when an epoxy resin is used as the thermosetting resin, examples of particularly suitable curing accelerators include triphenylphosphine and an adduct of triphenylphosphine and a quinone compound. Furthermore, for example, when an epoxy resin is used as the thermosetting resin, examples of curing accelerators that enable low-temperature curing include an adduct of tributylphosphine and 1,4-benzoquinone, dimethylaminopyridine, 2-ethyl-4-methylimidazole, 2-methylimidazole, and 1-benzyl-2-methylimidazole. The curing accelerators may be used alone or in combination of two or more.

[0111] When the thermosetting resin composition contains a curing accelerator, the content thereof is preferably 0.1 mass % to 8 mass %, more preferably 0.3 mass % to 6 mass %, and even more preferably 0.5 mass % to 5 mass %, relative to the total amount of the thermosetting resin and the curing agent.

[0112] When the thermosetting resin composition contains a curing accelerator, the curing accelerator may be added to the mixture when producing the thermosetting resin composition. Alternatively, the mixture may be first kneaded while removing the solvent without adding the curing accelerator to obtain a primary kneaded product, and then the curing accelerator may be added to the primary kneaded product and the primary kneaded product may be secondarily kneaded. In this case, in order to suppress the curing reaction between the thermosetting resin and the curing agent during kneading, it is preferable that the second kneading temperature during the secondary kneading is lower than the first kneading temperature during the primary kneading.

[0113] (coloring agent) The thermosetting resin composition produced by the method for producing a thermosetting resin composition according to the present disclosure may contain a colorant. Examples of the colorant include known colorants such as carbon black, titanium black oxide, organic dyes, organic pigments, red lead, and red iron oxide. The content of the colorant can be appropriately selected according to the purpose and the like. The colorant may be used alone or in combination of two or more kinds.

[0114] When the thermosetting resin composition contains a colorant, the content rate is preferably 0.01% by mass to 5% by mass, and more preferably 0.05% by mass to 3% by mass. When the thermosetting resin composition contains a colorant, the colorant may be added to the mixture.

[0115] (Ion exchanger) The thermosetting resin composition produced by the production method of the thermosetting resin composition of the present disclosure may contain an ion exchanger. In particular, from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of the semiconductor device, it is preferable to contain an ion exchanger. The ion exchanger is not particularly limited, and conventionally known ones can be used. Specifically, for example, hydrotalcite compounds and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth can be mentioned. The ion exchanger may be used alone or in combination of two or more kinds. Among them, hydrotalcite represented by the following general formula (A) is preferable.

[0116] Mg (1-X) Al X (OH)2(CO3) X / 2 ·mH2O ……(A) (0 < X ≦ 0.5, m is a positive number)

[0117] When the thermosetting resin composition contains an ion exchanger, the content thereof is not particularly limited as long as it is an amount sufficient to capture ions such as halogen ions. For example, it is preferably 0.1 part by mass to 30 parts by mass, and more preferably 1 part by mass to 5 parts by mass with respect to 100 parts by mass of the thermosetting resin. When the thermosetting resin composition contains an ion exchanger, the ion exchanger may be added to the mixture.

[0118] (mold release agent) The thermosetting resin composition produced by the method for producing a thermosetting resin composition according to the present disclosure may contain a release agent in order to obtain good releasability from the mold during molding. The release agent is not particularly limited, and conventionally known ones can be used. Specific examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. One type of release agent may be used alone, or two or more types may be used in combination.

[0119] When the thermosetting resin composition contains a release agent, the content thereof is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the thermosetting resin. When the amount of the release agent is 0.01 part by mass or more per 100 parts by mass of the thermosetting resin, sufficient release properties tend to be obtained. When the amount of the release agent is 15 parts by mass or less per 100 parts by mass of the thermosetting resin, better adhesion tends to be obtained. When the thermosetting resin composition contains a release agent, the release agent may be added to the mixture.

[0120] (Flame retardant) The thermosetting resin composition produced by the method for producing a thermosetting resin composition of the present disclosure may contain a flame retardant. The flame retardant is not particularly limited, and conventionally known flame retardants can be used. Specific examples include organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, and metal hydroxides. The flame retardants may be used alone or in combination of two or more.

[0121] When the thermosetting resin composition contains a flame retardant, the content is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, the content is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, per 100 parts by mass of the thermosetting resin. When the thermosetting resin composition contains a flame retardant, the flame retardant may be added to the mixture.

[0122] (Stress reliever) The thermosetting resin composition produced by the method for producing a thermosetting resin composition of the present disclosure may contain a stress relief agent such as silicone oil or silicone rubber particles. By including a stress relief agent in the thermosetting resin composition, package warpage and package cracking can be further reduced. Examples of stress relief agents include commonly used known stress relief agents (flexibilizers). Specific examples include thermoplastic elastomers such as silicone, styrene, olefin, urethane, polyester, polyether, polyamide, and polybutadiene; rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder; and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. The stress relief agents may be used alone or in combination of two or more. Among these, silicone-based stress relief agents are preferred. Examples of silicone-based stress relaxation agents include those having an epoxy group, those having an amino group, and those modified with polyether.

[0123] When the thermosetting resin composition contains a stress relaxation agent, the content thereof is preferably 0.1 to 30 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the thermosetting resin. When the thermosetting resin composition contains a stress relaxation agent, the stress relaxation agent may be added to the mixture.

[0124] (solvent) The thermosetting resin composition produced by the method for producing a thermosetting resin composition of the present disclosure may contain a solvent. The type of solvent contained in the thermosetting resin composition is not particularly limited, and may be the same as or different from the solvent contained in the slurry, and may be a specific solvent or may not be a specific solvent. When the thermosetting resin composition contains a solvent, the flowability during molding tends to be improved. When the thermosetting resin composition contains a solvent, the content of the solvent in the entire thermosetting resin composition is preferably 0.1% by mass to 2% by mass, and more preferably 0.1% by mass to 0.5% by mass. When the content of the solvent in the entire thermosetting resin composition is 2% by mass or less, blocking of the thermosetting resin composition is less likely to occur, and the thermosetting resin composition tends to be easier to supply to a molding machine such as a press. When the content of the solvent in the entire thermosetting resin composition is 0.1% by mass or more, the fluidity during molding tends to be further improved.

[0125] (Physical Properties of Thermosetting Resin Composition) The viscosity of the thermosetting resin composition is not particularly limited. It is preferable to adjust the viscosity to a desired value depending on the molding method, the composition of the thermosetting resin composition, etc. When the thermosetting resin composition is used for sealing material applications, it is preferable to adjust the viscosity of the thermosetting resin composition depending on the likelihood of wire sweep during molding. For example, when the thermosetting resin composition is used as an encapsulant, from the viewpoint of reducing wire sweep, the viscosity of the thermosetting resin composition is preferably 200 Pa·s or less at 175°C, more preferably 150 Pa·s or less, even more preferably 100 Pa·s or less, particularly preferably 70 Pa·s or less, and extremely preferably 50 Pa·s or less. The lower limit of the viscosity of the thermosetting resin composition is not particularly limited, and may be, for example, 2 Pa·s or more at 175°C. The viscosity of the thermosetting resin composition can be measured using a Koka type flow tester (for example, manufactured by Shimadzu Corporation).

[0126] (Uses of thermosetting resin compositions) The thermosetting resin composition produced by the method for producing a thermosetting resin composition according to the present disclosure can be used in various packaging techniques, for example, as a sealant for electronic component devices. The thermosetting resin composition according to the present disclosure can also be used in various applications where it is desirable for the resin composition to have good fluidity and curability, such as resin molded articles for various modules, resin molded articles for motors, resin molded articles for in-vehicle use, and sealants for protecting electronic circuits.

[0127] <Electronic component device manufacturing method> The method for producing an electronic component device according to the present disclosure includes a step of encapsulating an element with the thermosetting resin composition obtained by the method for producing a thermosetting resin composition according to the present disclosure described above.

[0128] Examples of electronic component devices include devices obtained by mounting elements (active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils) on a support member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, or an organic substrate, and then sealing the resulting element portion with a thermosetting resin composition. More specifically, typical resin-sealed ICs such as DIP (Dual Inline Package), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), SOJ (Small Outline J-lead package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package) have a structure in which an element is fixed on a lead frame, and terminal portions of the element such as bonding pads and lead portions are connected by wire bonding, bumps, or the like, and then sealed by transfer molding or the like using a thermosetting resin composition; TCP (Tape Carrier Package) has a structure in which an element connected to a tape carrier by bumps is sealed with a thermosetting resin composition; and COB (Chip On Board) has a structure in which an element is connected to wiring formed on a support member by wire bonding, flip chip bonding, solder, or the like, and then sealed with a thermosetting resin composition. and BGA (Ball Grid Array), CSP, MCP (Multi-Chip Package), SiP, etc., which have a structure in which elements are mounted on the surface of a support member having terminals for connecting a wiring board formed on the back surface thereof, the elements are connected to wiring formed on the support member by bump or wire bonding, and then the elements are sealed with a thermosetting resin composition. Thermosetting resin compositions can also be suitably used in printed wiring boards.

[0129] Examples of methods for encapsulating electronic component devices using a thermosetting resin composition include low-pressure transfer molding, injection molding, and compression molding.

[0130] <Thermosetting resin composition> The thermosetting resin composition of the present disclosure can be obtained by the above-described method for producing a thermosetting resin composition of the present disclosure. The thermosetting resin composition may be solid or liquid at 25°C, and is preferably solid from the viewpoint of ease of handling. In the present disclosure, a thermosetting resin composition being "solid at 25°C" means that the thermosetting resin composition does not have flowability at 25°C. When the thermosetting resin composition is solid, the shape thereof is not particularly limited, and examples thereof include powder, granules, tablets, pellets, granules, etc. When the thermosetting resin composition is in tablet or pellet form, it is preferable that the dimensions and mass thereof are set to be suitable for the molding conditions of the package from the viewpoint of handleability. [Example]

[0131] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples.

[0132] <Preparation of Thermosetting Resin Composition> First, the following components were prepared.

[0133] (thermosetting resin) Epoxy resin 1: NC-3000 (trade name, Nippon Kayaku Co., Ltd., aralkyl epoxy resin with an epoxy equivalent of 265g / eq to 285g / eq and a softening point of 53°C to 63°C) Epoxy resin 2: jER YX-4000H (trade name, Mitsubishi Chemical Corporation, biphenyl-type epoxy resin with an epoxy equivalent of 180 g / eq to 192 g / eq and a melting point of 105°C) Epoxy resin 3: EPPN501HY (trade name, Nippon Kayaku Co., Ltd., triphenylmethane-type epoxy resin with an epoxy equivalent of 163 g / eq to 175 g / eq and a softening point of 57°C to 63°C)

[0134] (hardening agent) Curing agent 1: MEHC-7851 (product name, Meiwa Kasei Co., Ltd., aralkyl phenolic resin with a hydroxyl equivalent of 205 g / eq, softening point 60°C to 70°C) Curing agent 2: MEHC-7800 (product name, Meiwa Kasei Co., Ltd., aralkyl phenolic resin with a hydroxyl equivalent of 170 g / eq, softening point 60°C to 70°C)

[0135] (coupling agent) Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane

[0136] (Inorganic filler) Slurry 1: A methyl ethyl ketone solution of spherical silica with a volume average particle size of 1.5 μm (top cut diameter 5 μm), solid content 70% by mass (treated with N-phenyl-3-aminopropyltrimethoxysilane) Slurry 2: Methyl ethyl ketone solution of spherical silica with a volume average particle size of 0.3 μm (top cut diameter 5 μm), solid content 60% by mass (treated with N-phenyl-3-aminopropyltrimethoxysilane) Inorganic filler: Spherical silica (no surface treatment) with a volume average particle size of 1.5 μm (top cut diameter 5 μm)

[0137] (curing accelerator) -Curing accelerator: Phosphorus-based curing accelerator

[0138] (Other additives) Release agent: Hoechst wax (Hoechst) Colorant: Carbon black MEK: Methyl ethyl ketone (boiling point: 80°C) MIBK: Methyl isobutyl ketone (boiling point: 116°C) NMP: N-methyl-2-pyrrolidone (boiling point: 202°C)

[0139] The thermosetting resin compositions of Examples 1 to 7 and Comparative Example 1 were produced by the following method (referred to as "production method A"). The components shown in Table 1 were mixed in a container and stirred with a stirrer for 1 hour. Then, using a twin-screw kneader (twin-screw extruder), the mixture was melt-kneaded for approximately 7 minutes under a reduced pressure of 0.02 MPa and the kneading temperature conditions shown in Table 1. The molten material was then cooled with a press roll through which 10°C cold water was circulated, and the resulting sheet was pulverized to prepare a powdered thermosetting resin composition.

[0140] The thermosetting resin compositions of Comparative Examples 2 and 3 were produced by the following method (referred to as "production method B"). The components shown in Table 1 were mixed in a container and stirred with a stirrer for 1 hour. The solvent was then distilled off at 140°C under a reduced pressure of 0.02 MPa for 2 hours using a vacuum dryer. The solid was then pulverized to prepare a powdered thermosetting resin composition.

[0141] The thermosetting resin composition of Comparative Example 4 was produced by the following method (referred to as "production method C"). The components shown in Table 1 were mixed in a container. Then, using a twin-screw kneader (twin-screw extruder), the mixture was melt-kneaded at 100°C for about 7 minutes. The molten material was then cooled with a press roll through which cold water at 10°C was circulated, and the resulting sheet was pulverized to prepare a powdered thermosetting resin composition.

[0142] <Evaluation of Thermosetting Resin Composition> The prepared thermosetting resin compositions were evaluated by the following tests. The evaluation results are shown in Table 1. Unless otherwise specified, the thermosetting resin compositions were molded using a transfer molding machine under conditions of a mold temperature of 180°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds. If necessary, post-curing was performed at 175°C for 6 hours.

[0143] [Spiral Flow] Using a spiral flow measurement mold conforming to EMMI-1-66, the thermosetting resin composition was molded under the above conditions, and the flow distance (cm) was determined.

[0144] [Melt Viscosity] The minimum melt viscosity of the thermosetting resin composition at 175°C was measured using a Koka type flow tester (manufactured by Shimadzu Corporation).

[0145] [Filler aggregation] The appearance of the thermosetting resin composition molded using a transfer molding machine was visually observed and evaluated for the presence or absence of filler aggregation. Cases where filler aggregation was observed were rated "A," and cases where filler aggregation was not observed were rated "B."

[0146] [Gel time] Measurement was carried out on 3 g of the thermosetting resin composition at a temperature of 175° C. using a Curelastometer manufactured by JSR Trading Co., Ltd., and the time until the torque curve rose was taken as the gel time (GT, seconds).

[0147] [Solvent content] Five grams of the thermosetting resin composition was treated at 175°C for one hour using an explosion-proof dryer, and the solvent content was calculated using formula 1. From the viewpoint of void generation after molding, a solvent content of 0.5% by mass or less was rated as "A," a solvent content of more than 0.5% by mass but less than 2% by mass was rated as "B," and a solvent content of more than 2% by mass was rated as "C." Solvent content (mass%) = ((mass before heat treatment - mass after heat treatment) / mass before heat treatment) x 100

[0148] [Blocking property] The sheet-shaped thermosetting resin compositions obtained in the examples and comparative examples after press rolling were cut into approximately 50 mm x 50 mm pieces to prepare test pieces for evaluating blocking properties. A plurality of test pieces were stacked and allowed to stand at 5°C for 12 hours. After standing, the appearance and bonding state of the sheet-shaped thermosetting resin compositions were observed. A test piece with no sagging at the edges of the sheets and no adhesion between sheets was rated "A." A test piece with sagging at the edges of the sheets or adhesion between several sheets, but which could be easily separated by placing the sheet-shaped thermosetting resin composition in a container and shaking the container, was rated "B." A test piece with sheets that could not be separated from each other even by shaking the container was rated "C."

[0149] [Table 1]

[0150] In Table 1, "non-volatile components" refers to the mass content of non-volatile components when each component is added to a container, and corresponds to the solid content ratio of the mixture. In Table 1, "filler content" refers to the volume content of inorganic filler contained in the thermosetting resin composition, and "specific solvent ratio" refers to the ratio of the specific solvent to all solvents contained in the mixture.

[0151] As is clear from the evaluation results in Table 1, when the filler filling rate was 70% by volume or more, the properties of the thermosetting resin compositions obtained by the manufacturing methods of the Examples were superior to the properties of the thermosetting resin compositions obtained by the manufacturing methods of the Comparative Examples. This shows that the manufacturing methods of the Examples enable high loading of inorganic fillers without deteriorating the properties of the thermosetting resin compositions compared to the manufacturing methods of the Comparative Examples. The filler aggregation evaluation for Comparative Example 1, in which the proportion of the specific solvent was 90% by mass, was ranked A, indicating excellent dispersibility of the inorganic filler. However, the minimum melt viscosity and GT of the thermosetting resin composition obtained in Comparative Example 1 were inferior to those of the thermosetting resin composition of Example 1, which was obtained from a mixture of the same composition except for the content of the specific solvent. This is presumably because the kneading temperature in Comparative Example 1 was set to 150°C to remove NMP, which is not a specific solvent, from the mixture, resulting in the progress of the curing reaction between the epoxy resin and the curing agent during kneading. The minimum melt viscosity and GT are important properties when using a thermosetting resin composition as an encapsulant, and a thermosetting resin composition with poor minimum melt viscosity and GT may not be suitable for use as an encapsulant.

Claims

1. A mixture of a thermosetting resin, a curing agent, and a slurry containing an inorganic filler and a solvent is kneaded using a screw kneader while reducing the pressure inside the screw kneader to remove the solvent, the proportion of solvents having a boiling point of 50°C to 180°C in all solvents contained in the mixture is 95% by mass or more; The solid content ratio of the inorganic filler in the slurry is 40% by mass to 90% by mass, The method for producing a thermosetting resin composition, wherein the inorganic filler has a volume average particle size of 0.1 μm to 10 μm.

2. The method for producing a thermosetting resin composition according to claim 1 , wherein the slurry further comprises a coupling agent.

3. 3. The method for producing a thermosetting resin composition according to claim 1, wherein the inorganic filler has a top cut diameter of 10 μm or less.

4. 4. The method for producing a thermosetting resin composition according to claim 1, wherein the boiling point of the solvent contained in the slurry is 50°C to 180°C.

5. The method for producing a thermosetting resin composition according to any one of claims 1 to 4, wherein the solid content of the mixture is 35% by mass to 95% by mass.

6. A method for producing an electronic component device, comprising a step of encapsulating an element with a thermosetting resin composition obtained by the method for producing a thermosetting resin composition according to any one of claims 1 to 5.

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