Thermosetting resin composition and electronic component device

Abstract

To provide a thermosetting resin composition that does not contain carbon black or black titanium oxide, or contains only small amounts of these components, but yet maintains concealability, and has excellent flowability and insulation properties.SOLUTION: A thermosetting resin composition contains a thermosetting resin, a curing agent, and an inorganic filler. At least part of the inorganic filler is black silica particles.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, along with the trend toward smaller, lighter, and more powerful electronic devices, semiconductor packages have become smaller and thinner. The semiconductor packages described above are obtained by encapsulating semiconductor elements with a thermosetting resin composition, and as semiconductor packages become thinner, the encapsulating resin layer that encapsulates the semiconductor elements has also become thinner.

[0003] A thermosetting resin composition generally contains a thermosetting resin, a curing agent, an inorganic filler, and a colorant for ensuring the hiding property of the cured product. Carbon black, which has excellent hiding properties, is used as the colorant (see, for example, Patent Document 1). Furthermore, in resin-sealed semiconductor packages, various types of identification information such as manufacturing lot numbers and logos are sometimes printed on the surface of the encapsulating resin layer. Laser marking is known as one method for printing on the surface of the encapsulating resin layer. Examples of thermosetting resin compositions that take laser marking properties into consideration include compositions that use black titanium oxide as a colorant (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-275350 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-278959 Summary of the Invention [Problem to be solved by the invention]

[0005] Carbon black can exhibit excellent hiding power as a colorant for a thermosetting resin composition, but since it is also a material that exhibits electrical conductivity, it is desirable that the content of carbon black be as small as possible. Furthermore, black titanium oxide has a higher specific gravity than carbon black, and tends to be unevenly distributed in the thermosetting resin composition. Therefore, there has been a demand for the development of a thermosetting resin composition that does not contain carbon black and black titanium oxide or that contains these components in small amounts. The present disclosure has been made in consideration of the above-described conventional circumstances, and an object of one embodiment of the present disclosure is to provide a thermosetting resin composition that does not contain carbon black and black titanium oxide or has a small amount of these components, yet maintains hiding properties and has excellent fluidity and insulating properties, and an electronic component device using this thermosetting resin composition. [Means for solving the problem]

[0006] Specific means for achieving the above object are as follows. <1> Contains a thermosetting resin, a curing agent, and an inorganic filler, At least a part of the inorganic filler is black silica particles. <2> The black silica particles contain carbon. <1> The thermosetting resin composition according to claim 1. <3> The carbon content in the black silica particles is 0.1% by mass or more. <2> The thermosetting resin composition according to claim 1. <4> The particle size distribution of the inorganic filler has at least two peaks. <1> ~ <3> 10. The thermosetting resin composition according to claim 1 . <5> The particle size distribution of the inorganic filler has three peaks. <1> ~ <4> 10. The thermosetting resin composition according to claim 1 . <6> When the cured product has a thickness of 70 μm, the color difference ΔE0 between the coordinates (L*=0, a*=0, b*=0) in the CIE 1976 (L*, a*, b*) color space at the surface of the cured product is 50 or less. <1> ~ <5> 10. The thermosetting resin composition according to claim 1 . <7> an element and a device for sealing the element; <1> ~ <6> and a cured product of the thermosetting resin composition according to any one of claims 1 to 4. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, it is possible to provide a thermosetting resin composition that does not contain carbon black and black titanium oxide or has a small amount of these components but maintains hiding properties and has excellent fluidity and insulating properties, and an electronic component device using this thermosetting resin composition. [Brief explanation of the drawings]

[0008] [Figure 1] 1A is a schematic plan view showing the electrode structure on one surface of a test piece used in measuring the volume resistivity in this example, and FIG. 1B is a schematic plan view showing the electrode structure on the other surface of the test piece used in measuring the volume resistivity in this example. 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, the term "process" includes not only a process that is independent of other processes, but also a process that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. 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 "layer" includes cases where the layer is formed over the entire area when the area in which the layer exists is observed, as well as cases where the layer is formed over only a portion of the area.

[0011] <Thermosetting resin composition> The thermosetting resin composition of the present disclosure contains a thermosetting resin, a curing agent, and an inorganic filler, at least a portion of which is black silica particles. As a result of extensive investigations, the present inventors have adopted black silica particles as a suitable material for ensuring insulating properties while maintaining the hiding properties of an encapsulating resin layer. By using black silica particles as at least a part of the inorganic filler, a thermosetting resin composition can be obtained that maintains hiding properties and has excellent fluidity and insulating properties even though it does not contain carbon black or black titanium oxide or contains these components in small amounts, and this has led to the completion of the present invention.

[0012] The thermosetting resin composition of the present disclosure contains a thermosetting resin, a curing agent, and an inorganic filler, and may contain other components as needed. Each component contained in the thermosetting resin composition of the present disclosure will be described in detail below.

[0013] (thermosetting resin) The thermosetting resin composition of the present disclosure contains 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). Thermosetting resins may be used alone or in combination of two or more.

[0014] 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 type epoxy resins (phenol novolac type epoxy resins, etc.) are obtained by epoxidizing novolac 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, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc., under an acidic catalyst. orthocresol novolac type epoxy resins, etc.); triphenylmethane type epoxy resins obtained by epoxidizing 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; copolymerized epoxy resins obtained by epoxidizing novolac resins obtained by co-condensing the above phenolic compounds and naphthol compounds with aldehyde compounds under an acidic catalyst; 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 atom-containing epoxy resins which are diglycidyl ethers of bisphenol S, etc.; glycidyl ester type epoxy resins which are glycidyl esters of polycarboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; dicyclopentadiene type epoxy resins obtained by epoxidizing co-condensation resins of dicyclopentadiene and phenolic compounds. Ene-type epoxy resins; 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 obtained by epoxidizing the olefin bonds in the molecule; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenolic resins; and metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenolic resins.Examples of suitable epoxy resins include terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenolic resins; dicyclopentadiene-modified epoxy resins, which are glycidyl ethers of dicyclopentadiene-modified phenolic 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. Epoxidized silicone resins are also suitable epoxy resins. Examples of epoxy resins include alkylene glycol diglycidyl ethers such as ethylene glycol diglycidyl ether and propylene glycol diglycidyl ether, poly(alkylene glycol) diglycidyl ethers such as polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, and bifunctional aliphatic epoxy compounds having two epoxy groups in the molecule, such as alkenylene glycol diglycidyl ether. Further, the epoxy resin may be a glycidylamine type epoxy resin. The glycidylamine type epoxy resin may be bifunctional or trifunctional or higher. From the viewpoint of improving heat resistance after curing, a trifunctional or higher glycidylamine type epoxy resin (having three or more epoxy groups in one molecule) is preferred. Examples of bifunctional glycidylamine type epoxy resins include N,N-diglycidylaniline and N,N-diglycidyl-o-toluidine. Examples of trifunctional or higher glycidylamine type epoxy resins include triglycidyl-p-aminophenol and 4,4'-methylenebis[N,N-bis(oxiranylmethyl)aniline]. These epoxy resins may be used alone or in combination of two or more.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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 8When 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 is a hydrogen atom, YL-6121H (trade name, Mitsubishi Chemical Corporation) and the like are commercially available.

[0019] [ka]

[0020] In formula (II), R 8 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 6 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.

[0021] 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.

[0022] [ka]

[0023] 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.

[0024] 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.

[0025] [ka]

[0026] 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.

[0027] 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.

[0028] [ka]

[0029] 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.

[0030] 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 and 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 and R 15 A benzyl group-modified cresol novolac epoxy resin having one methyl group and one benzyl group is commercially available.

[0031] [ka]

[0032] 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 all 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.

[0033] 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.

[0034] [ka]

[0035] In formula (VII), R 16 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. n is an average value and represents a number of 0 to 10.

[0036] 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.

[0037] [ka]

[0038] 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.

[0039] 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.

[0040] [ka]

[0041] 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).

[0042] [ka]

[0043] 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.

[0044] 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 1 to 10, and (n+m) represents a number from 2 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.

[0045] [ka]

[0046] 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.

[0047] 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.

[0048] [ka]

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] (hardening agent) The thermosetting resin composition of the present disclosure 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 epoxy resins 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, blocked isocyanate-based curing agents, and active ester compounds. 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). 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. Furthermore, the curing agent is preferably an acid anhydride-based curing agent from the viewpoint of preparing a liquid sealing material such as an underfill material. Furthermore, the curing agent is preferably an active ester compound from the viewpoint of obtaining a high-frequency compatible material with excellent water absorption resistance and reduced influence on electrical properties such as a low dielectric constant and a low dielectric loss tangent. 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; novolak-type 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 compounds synthesized from the above-mentioned phenolic compounds and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or the like. Examples of suitable curing agents include aralkyl-type phenolic resins such as aryl aralkyl resins and naphthol aralkyl resins; paraxylylene-modified phenolic resins; 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-mentioned phenolic compounds with dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensation or co-condensation of the above-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst; and phenolic resins obtained by copolymerization of two or more of these. These phenolic curing agents may be used alone or in combination of two or more.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] [ka]

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] [ka]

[0067] In formula (XV), R 29 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. n is an average value and represents a number of 0 to 10.

[0068] 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.

[0069] 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.

[0070] [ka]

[0071] 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.

[0072] 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.

[0073] 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.

[0074] [ka]

[0075] 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.

[0076] 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.

[0077] 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.).

[0078] [ka]

[0079] 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 all 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.

[0080] 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.

[0081] In the general formulas (XII) to (XVIII), n is preferably in the range of 0 to 10. If it is 10 or less, the melt viscosity of the resin component will not be too high, and the viscosity of the thermosetting resin composition during melt molding will also be 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.

[0082] 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.

[0083] Acid anhydride curing agents include phthalic anhydride, maleic anhydride, methyl himic anhydride, himic anhydride, succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, chlorendic anhydride, methyltetrahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride maleic acid adduct, benzophenonetetracarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, hydrogenated methylnadic anhydride, and various cyclic acid anhydrides such as trialkyltetrahydrophthalic anhydrides having multiple alkyl groups obtained by Diels-Alder reaction from maleic anhydride and diene compounds, and dodecenyl succinic anhydride.

[0084] The type of active ester compound is not particularly limited as long as it is a compound having one or more ester groups in the molecule that react with an epoxy group.

[0085] Examples of the active ester compound include a phenol ester compound, a thiophenol ester compound, an N-hydroxyamine ester compound, and an ester of a heterocyclic hydroxy compound.

[0086] Examples of active ester compounds include ester compounds obtained from at least one of an aliphatic carboxylic acid and an aromatic carboxylic acid and at least one of an aliphatic hydroxy compound and an aromatic hydroxy compound. Ester compounds using an aliphatic compound as a polycondensation component tend to have excellent compatibility with epoxy resins due to the presence of an aliphatic chain. Ester compounds using an aromatic compound as a polycondensation component tend to have excellent heat resistance due to the presence of an aromatic ring.

[0087] Specific examples of active ester compounds include aromatic esters obtained by the condensation reaction between an aromatic carboxylic acid and a phenolic hydroxyl group. Among these, aromatic esters obtained by the condensation reaction between an aromatic carboxylic acid and a phenolic hydroxyl group using a mixture of raw materials: an aromatic carboxylic acid component in which 2 to 4 hydrogen atoms on the aromatic ring of benzene, naphthalene, biphenyl, diphenylpropane, diphenylmethane, diphenylether, diphenylsulfonic acid, etc. are substituted with carboxyl groups; a monohydric phenol in which one hydrogen atom on the aromatic ring is substituted with a hydroxyl group; and a polyhydric phenol in which 2 to 4 hydrogen atoms on the aromatic ring are substituted with hydroxyl groups. That is, aromatic esters having structural units derived from the aromatic carboxylic acid component, structural units derived from the monohydric phenol, and structural units derived from the polyhydric phenol are preferred.

[0088] Specific examples of the active ester compound include an active ester resin having a structure obtained by reacting a phenolic resin having a molecular structure in which phenolic compounds are linked via alicyclic hydrocarbon groups with an aromatic dicarboxylic acid or a halide thereof, and an aromatic monohydroxy compound, as described in JP 2012-246367 A. Another specific example of the active ester compound is the active ester resin described in JP-A-2014-114352. The active ester compounds may be used alone or in combination of two or more.

[0089] The functional group equivalent of the curing agent (hydroxyl group equivalent for phenolic curing agents, active hydrogen equivalent for amine curing agents, and acid anhydride equivalent for acid anhydride curing agents) 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 ester equivalent (molecular weight / number of active ester groups) of the active ester compound is not particularly limited, and from the viewpoint of a balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 150 g / eq to 400 g / eq, more preferably 170 g / eq to 300 g / eq, and even more preferably 200 g / eq to 250 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. The acid anhydride equivalent of an acid anhydride curing agent is a value calculated by determining the molecular weight by identifying the molecular structure of the acid anhydride curing agent using NMR, liquid chromatography, gas chromatography, etc., and dividing the molecular weight by the number of acid anhydride groups contained in the acid anhydride curing agent. The ester equivalent of an active ester compound refers to a value calculated based on the ester value measured in accordance with JIS K 0070:1992.

[0090] 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.

[0091] When the thermosetting resin is an epoxy resin, the ratio of the equivalent number of the functional group of the curing agent (for example, the active hydrogen contained in the amino group in the case of an amine-based curing agent, a phenolic hydroxyl group in the case of a phenol-based curing agent, an acid anhydride group in the case of an acid anhydride-based curing agent, or an active ester group in the case of an active ester compound) to the equivalent number of the epoxy resin (equivalent number of curing agent / equivalent number of epoxy resin) is preferably set in the range of 0.6 to 1.4, more preferably in the range of 0.7 to 1.3, and even more preferably in the range of 0.8 to 1.2.

[0092] (Inorganic filler) The thermosetting resin composition contains an inorganic filler. At least a portion of the inorganic filler is black silica particles. Hereinafter, inorganic fillers other than the black silica particles may be referred to as other inorganic fillers.

[0093] -Black silica particles- The black silica particles are not particularly limited as long as they are silica particles that exhibit a black color. The black silica particles may contain carbon. When the black silica particles contain carbon, the carbon content is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more. The carbon content may be 25% by mass or less, 22% by mass or less, or 20% by mass or less. The carbon content in the black silica particles can be measured using a carbon-sulfur analyzer.

[0094] The volume average particle size of the black silica particles is preferably from 0.1 μm to 75 μm, more preferably from 0.2 μm to 55 μm, and even more preferably from 0.3 μm to 45 μm.

[0095] The black silica particles may be produced by any method. A method for producing black silica particles may be, for example, a method in which silica particles, an alkali metal, and an organic substance are mixed together, and then heated to sinter the silica particles, and further to carbonize the organic substance in the silica particles to obtain black silica particles. Alternatively, black silica particles may be obtained by contacting silica particles with a fluoride compound such as hydrofluoric acid, hydrosilicic acid, or hydrofluoroboric acid and an organic solvent such as a monohydric alcohol such as methanol or ethanol, or a dihydric alcohol such as ethylene glycol or diethylene glycol, followed by heating. Alternatively, black silica particles may be obtained by adding a metal alkoxide to a water-alcohol dispersion containing a metal oxide or metal hydroxide maintained at an alkaline temperature, and then heat-treating the resulting particles. Alternatively, particles containing a condensate of trialkoxysilane substituted with an alkyl group, an acryloyloxy group, or the like may be mixed with a vinyl monomer such as acrylonitrile, and the vinyl monomer may then be polymerized to obtain composite particles, which may then be heated in a nitrogen atmosphere to obtain black silica particles.

[0096] -Other inorganic fillers- The type of other inorganic filler is not particularly limited. Specific examples include silica, such as spherical silica and 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 materials with flame retardant properties may also be used as the other inorganic filler. Examples of other inorganic fillers with flame retardant properties include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides, such as composite hydroxides of magnesium and zinc, 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. The other inorganic fillers may be used alone or in combination of two or more. Examples of the inorganic filler include powder, beads, and fibers formed by spheroidizing powder. In the present disclosure, the carbon content of the silica contained in the other inorganic filler is less than 0.1% by mass.

[0097] The top cut diameter of the other inorganic fillers is not particularly limited. In one embodiment, the top cut diameter of the other inorganic filler is preferably 1 μm to 100 μm, more preferably 5 μm to 90 μm, and even more preferably 10 μm to 80 μm. In one embodiment, from the viewpoint of filling narrow gaps of 30 μm or less, the top cut diameter of the other 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 other inorganic filler may be 1 μm or more. In the present disclosure, the top cut diameter of other inorganic fillers 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 other inorganic fillers is not particularly limited. For example, the volume average particle size is preferably 30 μm or less, more preferably 0.1 μm to 30 μm, even more preferably 1 μm to 25 μm, and particularly preferably 2 μm to 20 μm. When the volume average particle size is 30 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 fluidity 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 as a whole, including the black silica particles, is preferably distributed over a wide range.

[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. From the viewpoint of coloring properties, the content of black silica particles in the inorganic filler is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. In one embodiment, the entire inorganic filler may be black silica particles. In other words, the content of black silica particles in the inorganic filler may be 100% by mass. The particle size distribution of the inorganic filler may have at least two peaks. When the particle size distribution of the inorganic filler has at least two peaks, the combination of the inorganic filler may include a combination of black silica particles and other inorganic fillers. When these inorganic fillers are combined, a peak derived from the black silica particles and a peak derived from the other inorganic fillers are observed in the particle size distribution of the entire inorganic filler. The particle size distribution of the inorganic filler may have three peaks. In this case, three types of black silica particles with different average particle diameters may be used. When three types of black silica particles are used, the average particle diameter of the black silica particles with the largest average particle diameter is defined as particle diameter A, the average particle diameter of the black silica particles with the second largest average particle diameter is defined as particle diameter B, and the average particle diameter of the black silica particles with the smallest average particle diameter is defined as particle diameter C. Particle diameter A may be 20 μm to 40 μm, particle diameter B may be 1 / 2 to 1 / 4 of particle diameter A, and particle diameter C may be 1 / 2 to 1 / 4 of particle diameter B.

[0101] (curing accelerator) The 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, and the like.

[0102] 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.

[0103] 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.

[0104] (coloring agent) The thermosetting resin composition of the present disclosure may contain a colorant. Examples of colorants include known colorants such as carbon black, black titanium oxide, organic dyes, organic pigments, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose, etc. One type of colorant may be used alone, or two or more types may be used in combination.

[0105] When the thermosetting resin composition contains a colorant, the content thereof is preferably 0.01 to 5% by mass, and more preferably 0.05 to 3% by mass, of the entire thermosetting resin composition. The carbon black content in the thermosetting resin composition of the present disclosure is preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less of the total thermosetting resin composition. The carbon black content in the thermosetting resin composition of the present disclosure may be 0% by mass of the total thermosetting resin composition.

[0106] (coupling agent) The thermosetting resin composition of the present disclosure may contain a coupling agent, such as a known coupling agent including a silane-based compound (e.g., epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, or vinylsilane), a titanium-based compound, an aluminum chelate compound, or an aluminum / zirconium-based compound.

[0107] When the thermosetting resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 2.5 parts by mass, per 100 parts by mass of the inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more per 100 parts by mass of the inorganic filler, adhesion to the frame tends to be further improved. When the amount of the coupling agent is 5 parts by mass or less per 100 parts by mass of the inorganic filler, moldability of the package tends to be further improved.

[0108] (ion exchanger) The thermosetting resin composition of the present disclosure may contain an ion exchanger (ion trapping agent). In particular, it is preferable to contain an ion exchanger from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of the semiconductor device. There are no particular limitations on the ion exchanger, and conventionally known ion exchangers can be used. Specific examples include hydrotalcite compounds and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchanger may be used alone or in combination of two or more. Among these, hydrotalcites represented by the following general formula (A) are preferred:

[0109] Mg (1-X) Al X (OH)2(CO3) X / 2 ·mH2O ……(A) (0 < X ≤ 0.5, m is a positive number)

[0110] When the thermosetting resin composition contains an ion exchanger, its content is not particularly limited as long as it is sufficient to capture ions such as halogen ions. For example, it is preferably 0.1 part by mass to 30 parts by mass, more preferably 1 part by mass to 5 parts by mass, based on 100 parts by mass of the thermosetting resin.

[0111] (Release agent) The thermosetting resin composition of the present disclosure may contain a release agent from the viewpoint of obtaining good mold release properties with the mold during molding. The release agent is not particularly limited, and conventionally known ones can be used. Specifically, higher fatty acids such as carnauba wax, montanic acid, stearic acid, metal salts of higher fatty acids, ester waxes such as montanic acid esters, polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene, etc. can be mentioned. The release agent may be used alone or in combination of two or more kinds.

[0112] When the thermosetting resin composition contains a release agent, its content is preferably 0.01 part by mass to 15 parts by mass, more preferably 0.1 part by mass to 10 parts by mass, based on 100 parts by mass of the thermosetting resin. When the amount of the release agent is 0.01 part by mass or more based on 100 parts by mass of the thermosetting resin, mold release properties tend to be sufficiently obtained. When the amount of the release agent is 15 parts by mass or less based on 100 parts by mass of the thermosetting resin, better adhesion properties tend to be obtained.

[0113] (Flame retardant) The thermosetting resin composition of the present disclosure may contain a flame retardant. The flame retardant is not particularly limited, and conventionally known ones can be used. Specifically, organic or inorganic compounds containing a halogen atom, antimony atom, nitrogen atom or phosphorus atom, metal hydroxides, etc. can be mentioned. The flame retardant may be used alone or in combination of two or more kinds.

[0114] 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.

[0115] (Stress reliever) The 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. One type of stress relief agent may be used alone, or two or more types may be used in combination. Among these, silicone-based stress relief agents are preferred. Examples of silicone-based stress relief agents include those having epoxy groups, those having amino groups, and polyether-modified versions of these.

[0116] 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.

[0117] (organic solvent) The thermosetting resin composition of the present disclosure may contain an organic solvent as needed to reduce viscosity. In particular, when a solid epoxy resin and curing agent are used to make the thermosetting resin composition liquid at 25°C, it is preferable to contain an organic solvent to obtain the thermosetting resin composition. The organic solvent is not particularly limited, and examples thereof include alcohol-based solvents such as methanol, ethanol, propanol, and butanol, ketone-based solvents such as acetone and methyl ethyl ketone, glycol ether-based solvents such as ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol methyl ether acetate, lactone-based solvents such as γ-butyrolactone, δ-valerolactone, and ε-caprolactone, amide-based solvents such as dimethylacetamide and dimethylformamide, and aromatic solvents such as toluene and xylene. One type may be used alone, or two or more types may be used in combination. Among these, organic solvents having a boiling point of 170°C or higher are preferred from the viewpoint of avoiding bubble formation due to sudden evaporation when curing the thermosetting resin composition.

[0118] The content of volatile components including organic solvents and the like is not particularly limited as long as it is to an extent that bubbles are not formed when the thermosetting resin composition is cured, and is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.1% by mass or less, of the entire thermosetting resin composition. In the present disclosure, the volatile content of a thermosetting resin composition is calculated by heating the thermosetting resin composition at 180°C for 30 minutes, based on the difference in weight before and after heating.

[0119] (Method for preparing thermosetting resin composition) The method for preparing the thermosetting resin composition is not particularly limited. When the thermosetting resin composition is solid at 25°C, a common method includes thoroughly mixing predetermined amounts of components using a mixer or the like, melt-kneading the mixture using a mixing roll, extruder, or the like, cooling, and pulverizing the mixture. More specifically, a method includes uniformly stirring and mixing predetermined amounts of the components described above, kneading the mixture using a kneader, roll, extruder, or the like that has been preheated to 70°C to 140°C, cooling, and pulverizing the mixture.

[0120] When the thermosetting resin composition is solid at 25° C., 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.

[0121] When the thermosetting resin composition is liquid at 25° C., any method can be used to prepare the thermosetting resin composition as long as it can uniformly disperse and mix the various components. For example, the thermosetting resin composition can be obtained by weighing the components, mixing and kneading them using a three-roll mill, a mixing roll mill, a planetary mixer, or the like, and degassing as necessary.

[0122] (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 as an encapsulant, it is preferable that the thermosetting resin composition is solid at 25°C. It is also 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 at 175° C. can be measured using a Koka type flow tester (for example, manufactured by Shimadzu Corporation).

[0123] When the thermosetting resin composition is used for applications such as underfill materials, the thermosetting resin composition is preferably a liquid at 25°C. When the thermosetting resin composition is a liquid, there are no particular restrictions on the viscosity of the thermosetting resin composition. In particular, from the viewpoint of high fluidity, the viscosity is preferably 0.1 Pa·s to 50.0 Pa·s at 25°C, more preferably 1.0 Pa·s to 50.0 Pa·s, and even more preferably 10.0 Pa·s to 50.0 Pa·s. The viscosity of the thermosetting resin composition is measured at 25°C using an E-type viscometer (cone angle 3°, rotation speed 10 rpm).

[0124] Furthermore, when the thermosetting resin composition is used as an underfill material or the like, the viscosity at 110°C is preferably 0.20 Pa·s or less, and more preferably 0.15 Pa·s or less, as an indicator of the ease of filling a narrow gap of several tens to several hundreds of micrometers at around 100°C to 120°C. The viscosity of the thermosetting resin composition at 110°C is measured using a rheometer AR2000 (manufactured by TA Instruments, aluminum cone 40 mm, shear rate 32.5 / sec).

[0125] Furthermore, when the thermosetting resin composition is liquid at 25°C, the thixotropy index [(viscosity at 2.5 rpm) / (viscosity at 10 rpm)], which is the ratio of the viscosity at a rotation speed of 2.5 rpm to the viscosity at a rotation speed of 10 rpm measured using an E-type viscometer at 25°C, is preferably 0.3 to 1.5, more preferably 0.5 to 1.2. When the thixotropy index is within the above range, the filling ability tends to be further improved. The viscosity and thixotropy index of the thermosetting resin composition can be adjusted to a desired range by appropriately selecting the composition of the thermosetting resin composition, the content of the inorganic filler, etc.

[0126] When the thermosetting resin composition of the present disclosure is cured to a thickness of 70 μm, the surface of the cured product has a CIE 1976 (L * , a * , b * ) color space coordinates (L * =0, a * =0, b * =0), is preferably 50 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 1 or less. In the present disclosure, the lower limit of the color difference ΔE0 is not particularly limited, and may be 0.01 or more. When a cured product having a thickness of 70 μm is produced, by controlling the color difference ΔE0 on the surface of the cured product to 50 or less, hiding power and visibility of printing by laser marking tend to be further improved.

[0127] In the present disclosure, the color difference ΔE0 is measured as follows. The thermosetting resin composition of the present disclosure is heat-cured to obtain a cured product having a thickness of 70 μm. Note that the cured product having a thickness of 70 μm may have a region having a thickness of 70 μm, and the cured product does not necessarily have to be a sheet-like cured product having a thickness of 70 μm throughout. A cured product with a thickness of 70 μm can be produced by methods such as compression molding or transfer molding. For example, a compression molding machine PMC1040-S (TOWA Corporation) is used, and an amount of thermosetting resin composition corresponding to the volume of the molded product is placed between upper and lower molds, and the mixture is cured by automatic heating and pressing to obtain a cured product. The molding conditions are appropriately set depending on the composition of the thermosetting resin composition. The color difference ΔE0 of the resulting cured product having a thickness of 70 μm is determined by the following method. Using CM-3600A (Konica Minolta, Inc.) * a * b * Color space coordinates (L1 * , a1 * , b1 * ) is measured. The measured value L1 * , a1 * and b1 * Using the following formula, the coordinates (L * =0, a * =0, b * = 0) and calculate the color difference ΔE0. ΔE0=[(L1 * -0) 2 +(a1 * -0) 2 +(b1 * -0) 2 ] 1 / 2 The thickness of the cured product at a measurement point can be measured by observing the cross section of the measurement target using an electron microscope.

[0128] (Uses of thermosetting resin compositions) The use of the thermosetting resin composition of the present disclosure is not particularly limited, and it can be used in various mounting techniques, for example, as a sealant for electronic component devices, an underfill material, etc. Furthermore, the thermosetting resin composition of the present disclosure can 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.

[0129] <Electronic component equipment> An electronic component device according to one embodiment of the present disclosure includes an element and a cured product of the above-described thermosetting resin composition that encapsulates the element. 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. Examples of suitable thermosetting resin modules include BGA (Ball Grid Array), CSP (Chip Size Package), and MCP (Multi Chip Package), 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 the elements are then sealed with a thermosetting resin composition. The thermosetting resin composition of the present disclosure can also be suitably used in printed wiring boards.

[0130] Furthermore, when the thermosetting resin composition of the present disclosure is in liquid form, it is suitable as an underfill material for flip chips, exhibiting excellent reliability. The thermosetting resin composition of the present disclosure is particularly suitable for use in flip chip applications, not only when the bump material connecting a wiring board and a semiconductor element is a conventional lead-containing solder, but also when flip chip semiconductor components are made using lead-free solder, such as Sn-Ag-Cu solder. The thermosetting resin composition of the present disclosure tends to maintain good reliability even for flip chips bump-connected using lead-free solder, which is physically more brittle than conventional lead solder. Furthermore, when mounting chip-scale packages such as wafer-level CSPs (chip size packages) on substrates, application of the thermosetting resin composition of the present disclosure tends to improve reliability. [Example]

[0131] The above-described embodiment will be specifically described below using examples, but the scope of the above-described embodiment is not limited to these examples.

[0132] -Preparation of thermosetting resin composition- Thermosetting resin compositions of each Example and Reference Example were prepared by mixing the components shown in Table 1 in the amounts (parts by mass) shown in Table 1. Specifically, after mixing the materials, the mixture was kneaded in a twin-screw extruder with the internal temperature adjusted to 70°C to 100°C, cooled, and then pulverized to obtain thermosetting resin compositions. The details of each component are as follows:

[0133] Epoxy resin 1...Diphenylmethane type epoxy resin (epoxy equivalent: 192g / eq) Epoxy resin 2: Biphenyl type epoxy resin (epoxy equivalent: 186g / eq) Hardener 1: Triphenylmethane phenolic resin (hydroxyl equivalent: 102 g / eq) Curing agent 2: Aralkyl phenolic resin with a biphenyl skeleton (hydroxyl group equivalent: 205 g / eq) Curing accelerator: Phosphorus catalyst Coupling agent 1...3-glycidoxypropyltrimethoxysilane Coupling agent 2: N-phenyl-3-aminopropyltrimethoxysilane Release agent: Montan acid ester Pigment 1...Carbon black Pigment 2: Black titanium dioxide Additives: Hydrotalcite-based ion trapping agent Inorganic filler 1...Silica particles (volume average particle size: 15 μm, top cut diameter: 75 μm, other inorganic fillers) Inorganic filler 2...Silica particles (volume average particle size: 9 μm, top cut diameter: 20 μm, other inorganic fillers) Black silica 1...Volume average particle size: 4 μm Black silica 2...Volume average particle size: 30 μm Black silica 3...Volume average particle size: 11 μm

[0134] <Liquidity> (Spiral Flow (SF) Evaluation) Using a spiral flow measurement mold conforming to EMMI-1-66, the thermosetting resin composition was molded with 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 120 seconds, and the flow distance (inches) was measured. The results are shown in Table 1. (Disc flow (DF) evaluation) Using a flat mold for measuring disc flow, with an upper mold of 200mm (W) x 200mm (D) x 25mm (H) and a lower mold of 200mm (W) x 200mm (D) x 15mm (H), 5g of the thermosetting resin composition weighed on a balance was placed in the center of the lower mold heated to 180°C. After 5 seconds, the upper mold heated to 180°C was closed and compression molded under conditions of a load of 78N and a cure time of 120 seconds. The major and minor diameters (mm) of the molded product were measured with calipers, and the average value (mm) was taken as the disc flow. The results are shown in Table 1.

[0135] (Evaluation of hot hardness) The hot hardness of the thermosetting resin composition was evaluated as follows. The thermosetting resin composition was molded into test pieces (disks with a diameter of 50 mm and a thickness of 3 mm) for measuring hot hardness using a transfer molding machine under the following conditions: mold temperature 175°C to 180°C, molding pressure 6.9 MPa, and curing time 90 seconds. Immediately after molding, the hot hardness (Shore D) of the test pieces was measured using a Shore D hardness tester. The results are shown in Table 1.

[0136] (Melt viscosity at 175°C) The thermosetting resin composition was heated to melt, and the melt viscosity (ηFT) at 175° C. was measured using a Koka type flow tester. The results are shown in Table 1.

[0137] (Gel time measurement) The gel time (GT) of the thermosetting resin composition was measured using a Curastometer manufactured by JSR Trading Co., Ltd. Measurement was carried out at 180°C using 3 g of the thermosetting resin composition using a Curastometer manufactured by JSR Trading Co., Ltd. The time until the torque curve rose was taken as the gel time (seconds). The results are shown in Table 1.

[0138] (Measurement of color difference ΔE0) The color difference ΔE0 was measured as follows. A 10 mm x 10 mm x 400 μm silicon chip was mounted on a 240 mm x 70 mm glass epoxy substrate. Furthermore, a 30 μm thick polyimide tape was attached to the top surface of the silicon chip mounted on the substrate. The silicon chip was then sealed with a thermosetting resin composition so that the resin layer on the polyimide tape had a thickness of 70 μm, yielding a sealed molded product. The sealed molded product was obtained using a compression molding machine PMC1040-S (TOWA Corporation) by placing an amount of sealing resin composition corresponding to the volume of the molded product in a mold, sandwiching the substrate between the upper and lower molds, and automatically heating and pressing the molded product to harden it. In the obtained sealed molded product, the color difference ΔE0 was determined by the following method at a location where the resin layer on the polyimide tape had a thickness of 70 μm. Using CM-3600A (Konica Minolta, Inc.) * a * b *Color space coordinates (L1 * , a1 * , b1 * ) was measured. The measured value L1 * , a1 * and b1 * Using the following formula, the coordinates (L * =0, a * =0, b * The color difference ΔE0 from the original color (=0) was calculated. ΔE0=[(L1 * -0) 2 +(a1 * -0) 2 +(b1 * -0) 2 ] 1 / 2 The thickness of the cured product at the measurement point was measured by observing the cross section of the measurement target using an electron microscope. The results are shown in Table 1.

[0139] (high temperature volume resistivity) The thermosetting resin composition obtained above was molded into a mold capable of forming a 100 mm diameter x 3 mm thick disk-shaped test specimen using a transfer molding machine under conditions of a mold temperature of 175°C to 180°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds. The test specimen was then post-cured at 175°C for 5 hours to prepare a test specimen. A surface electrode consisting of an inner circular portion 2 and an outer circular portion 4 was formed on one side of the resulting test specimen 10 using a mask seal and conductive silver paint, as shown in Figure 1(A). Similarly, a back electrode 6 was formed on the other side of the test specimen 10, as shown in Figure 1(B). The test specimen 10 with the electrode formed was placed in an environment at 150°C, and the volume resistivity was read 1 minute after applying a voltage of 500 V. The high-temperature volume resistivity at 150°C was calculated using the following formula (2). The results are shown in Table 1.

[0140] Volume resistivity (Ω cm)=(πd 2 / 4t)×(Rv)...Equation (2) d: Outer diameter of the inner circle of the surface electrode = 5.0 (cm) t: thickness of test piece = 0.3 (cm) Rv: Volume resistance (MΩ) π: Pi=3.14

[0141] (Volume resistivity after moisture absorption) The same test specimens as those used to measure high-temperature volume resistivity were used, and these test specimens were treated for 20 hours under pressure cooker test conditions (2 atmospheres (0.2 MPa) / 121°C / 100% RH). After treatment, water droplets were wiped off the surface of the test specimen, and the specimen was placed in an environment at 25°C. A voltage of 500 V was applied and the value of the volume resistivity meter was read one minute later. The volume resistivity after moisture absorption was calculated using the above formula (2). The results are shown in Table 1.

[0142] [Table 1]

[0143] As is clear from Table 1, the thermosetting resin compositions of the Examples ensure the same hiding power, fluidity and insulating properties as the thermosetting resin compositions of the Reference Examples.

Claims

1. Contains a thermosetting resin, a curing agent, and an inorganic filler, At least a part of the inorganic filler is black silica particles.

2. The thermosetting resin composition for sealing material according to claim 1 , wherein the black silica particles contain carbon.

3. The thermosetting resin composition for encapsulation according to claim 2 , wherein the carbon content in the black silica particles is 0.1% by mass or more.

4. 4. The thermosetting resin composition for encapsulation according to claim 1, wherein the particle size distribution of the inorganic filler has at least two peaks.

5. 5. The thermosetting resin composition for encapsulation according to claim 1, wherein the particle size distribution of the inorganic filler has three peaks.

6. When the cured product has a thickness of 70 μm, the color difference ΔE between the coordinates (L*=0, a*=0, b*=0) in the CIE 1976 (L*, a*, b*) color space on the surface of the cured product is ０ The thermosetting resin composition for encapsulation according to any one of claims 1 to 5, wherein the tensile strength is 50 or less.

7. 10. An electronic component device comprising: an element; and a cured product of the thermosetting resin composition for encapsulation according to claim 1 that encapsulates the element.

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