Epoxy resin composition for compression molding and electronic component device

Abstract

An epoxy resin composition for compression molding which comprises an epoxy resin including a polycyclic structure and / or two or more cyclic structures, a hardener, and an inorganic filler, the content of the inorganic filler being 87.0 mass% or higher with respect to the whole epoxy resin composition for compression molding, the epoxy resin composition having a maximum particle diameter of 2.0 mm or less.

Description

Epoxy resin composition for compression molding and electronic component device

[0001] The present disclosure relates to an epoxy resin composition for compression molding and an electronic component device.

[0002] Epoxy resin compositions have been widely used in the field of encapsulating electronic components such as transistors, integrated circuits (ICs), etc. This is because epoxy resins have a good balance of electrical properties, moisture resistance, heat resistance, mechanical properties, adhesiveness to insert products, etc.

[0003] Transfer molding is the most common method for encapsulating electronic components using epoxy resin compositions. However, in transfer molding, the molten epoxy resin composition is forced to flow within a mold by pressure, which can lead to wire sweep. To address this issue, methods for increasing the fluidity of epoxy resin compositions have been investigated, but there are still challenges in suppressing wire sweep. Compression molding is known as an alternative molding method to transfer molding. In compression molding, an epoxy resin composition is placed in a mold cavity and melted, and the mold is then closed and pressurized to encapsulate the device. Compression molding minimizes the flow of the epoxy resin composition, thereby suppressing wire sweep.

[0004] As an epoxy resin composition for encapsulating semiconductor elements by compression molding, for example, Patent Document 1 proposes a particulate epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a fatty acid having a melting point of 70°C or less, and a silane coupling agent having a boiling point of 200°C or more, and characterized in that the particle size distribution is such that 85% by mass or more falls within the range of 100 μm to 3 mm.

[0005] JP 2011-153173 A

[0006] When an epoxy resin composition is used as an encapsulant for electronic component devices such as semiconductor packages, the elimination of components such as heat sinks has been considered in order to reduce costs and size. However, when components such as heat sinks are not used in part, warping of the electronic component devices is likely to occur. Therefore, an epoxy resin composition that can suppress warping of electronic component devices is desirable.

[0007] For example, warpage of electronic component devices can be suppressed by increasing the content of inorganic filler in the epoxy resin composition, but increasing the content of inorganic filler makes wire sweep more likely to occur, making it difficult to simultaneously suppress warpage and wire sweep.

[0008] The present disclosure has been made in view of the above, and aims to provide an epoxy resin composition for compression molding that can suppress warpage and wire sweep in electronic component devices, and an electronic component device including an element encapsulated with this composition.

[0009] Specific means for achieving the above object are as follows. <1> An epoxy resin composition for compression molding, comprising: an epoxy resin containing at least one of a polycyclic structure and two or more types of cyclic structures; a curing agent; and an inorganic filler, wherein the content of the inorganic filler is 87.0 mass% or more based on the total amount of the epoxy resin composition for compression molding, and the maximum particle size of the epoxy resin composition for compression molding is 2.0 mm or less. <2> The epoxy resin composition for compression molding according to <1>, wherein the epoxy resin contains at least one epoxy resin selected from the group consisting of naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, and biphenylaralkyl-type epoxy resins. <3> The epoxy resin composition for compression molding according to <1> or <2>, wherein the epoxy equivalent of the epoxy resin is 200 g / eq to 1000 g / eq. <4> The epoxy resin composition for compression molding according to any one of <1> to <3>, wherein the inorganic filler contains alumina. <5> The epoxy resin composition for compression molding according to <4>, wherein the content of the alumina relative to the total amount of the inorganic filler is 40% by mass to 80% by mass. <6> The epoxy resin composition for compression molding according to any one of <1> to <5>, wherein the content of the epoxy resin containing at least one of a polycyclic structure and two or more ring structures relative to the total amount of the epoxy resin is 5% by mass to 50% by mass. <7> An electronic component device comprising an element and a cured product of the epoxy resin composition for compression molding according to any one of <1> to <6>, which encapsulates the element.

[0010] According to the present disclosure, it is possible to provide an epoxy resin composition for compression molding that can suppress warpage and wire sweep in electronic component devices, and an electronic component device including an element encapsulated with this composition.

[0011] Modes for carrying out the present invention are described in detail below. However, the present invention is not limited to the following embodiments. In the following embodiments, components (including elementary steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present invention. In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. In this disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In 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 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 this disclosure, each component may contain multiple corresponding substances. When a composition contains multiple substances corresponding to each component, the content or amount of each component refers to the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, multiple types of particles corresponding to each component may be contained. When a composition contains multiple types of particles corresponding to each component, the particle size of each component refers to the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0012] <Epoxy Resin Composition for Compression Molding> The epoxy resin composition for compression molding of the present disclosure (hereinafter also referred to as "epoxy resin composition") comprises an epoxy resin containing at least one of a polycyclic structure and two or more types of cyclic structures (hereinafter also referred to as "specific epoxy resin"), a curing agent, and an inorganic filler, wherein the content of the inorganic filler is 87.0 mass% or more relative to the total amount of the epoxy resin composition for compression molding, and the maximum particle size of the epoxy resin composition for compression molding is 2.0 mm or less.

[0013] By using the epoxy resin composition of the present disclosure for encapsulating elements, it is possible to suppress warpage and wire sweep in electronic component devices in which elements are encapsulated. The reason for this is presumed to be as follows. The present disclosure is not limited to the following presumption.

[0014] The epoxy resin composition of the present disclosure contains a specific epoxy resin and has an inorganic filler content of 87.0 mass% or more based on the total amount of the epoxy resin composition for compression molding. The rigid skeleton, such as a polycyclic structure and two or more ring structures, contained in the specific epoxy resin contributes to low thermal expansion and low shrinkage in the cured product obtained when the epoxy resin composition is cured. The inorganic filler content of a predetermined amount or more contributes to low thermal expansion and low shrinkage in the cured product. It is presumed that these factors favorably suppress warpage in electronic component devices. Meanwhile, when the epoxy resin composition contains a specific epoxy resin and the inorganic filler content of a predetermined amount or more, wire sweep is more likely to occur.

[0015] However, by setting the maximum particle size of the epoxy resin composition to 2.0 mm or less, the solubility of the epoxy resin composition when heated is improved, which is presumably why the occurrence of the wire sweep described above is suppressed.

[0016] As described above, by using the epoxy resin composition of the present disclosure for encapsulating elements, it is possible to suppress warpage in electronic component devices in which elements are encapsulated. Even when members such as heat sinks are eliminated to reduce costs, size, etc., warpage of the electronic component device is suitably suppressed.

[0017] From the viewpoint of more suitably suppressing the occurrence of wire sweep, the maximum particle size of the epoxy resin composition is preferably 1.4 mm or less, more preferably 1.0 mm or less, and may be 0.5 mm or more.

[0018] Components that may be contained in the epoxy resin composition of the present disclosure will be described in detail below.

[0019] [Specific Epoxy Resin] The epoxy resin composition of the present disclosure contains an epoxy resin (specific epoxy resin) containing at least one of a polycyclic structure and two or more types of cyclic structures. The specific epoxy resin preferably has two or more epoxy groups in one molecule.

[0020] In the present disclosure, a polycyclic structure refers to a ring structure in which at least two ring structures within the polycyclic structure share one or more atoms. For example, the polycyclic structure may be a fused ring or a bridged fused ring such as a dicyclopentadiene structure. In the present disclosure, two or more ring structures refer to two or more structures selected from a monocyclic ring (e.g., one aliphatic ring, one aromatic ring, or one heterocyclic ring) and a ring assembly in which two or more rings are bonded by a single bond (e.g., a biphenyl group). The two or more ring structures may be two or more monocyclic rings, two or more ring assemblies, or a combination of a monocyclic ring such as a benzene ring and a ring assembly such as a biphenyl group. Note that an epoxy resin containing only one ring assembly such as a biphenyl group does not qualify as a specific epoxy resin.

[0021] From the viewpoint of more suitably suppressing warpage of electronic component devices, the specific epoxy resin preferably contains at least one epoxy resin selected from the group consisting of naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, and biphenylaralkyl-type epoxy resins, and more preferably at least one selected from the group consisting of naphthalene-type epoxy resins and dicyclopentadiene-type epoxy resins.

[0022] The naphthalene-type epoxy resin is not particularly limited as long as it has an epoxy group and a naphthalene ring structure. For example, it may be an epoxy resin in which two glycidyl ether groups are bonded to one naphthalene ring (e.g., 1,6-bis(glycidyloxy)naphthalene), an epoxy resin in which a plurality of naphthalene rings are bonded via linking groups (ether groups, methylene groups, etc.) and one glycidyl ether group is bonded to each of at least two naphthalene rings, or an epoxy resin in which naphthalene rings and benzene rings are bonded alternately or randomly via linking groups (ether groups, methylene groups, etc.) and one or more glycidyl ether groups are bonded to each of at least two naphthalene rings.

[0023] Examples of naphthalene-type epoxy resins include epoxy resins represented by the following general formulas (I) to (III).

[0024]

[0025]

[0026]

[0027] In general formulas (I) to (III), R １ ~R ３ Each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. p is an average value, and each p independently represents a number from 1 to 10. Each i independently represents an integer from 0 to 4, each j independently represents an integer from 0 to 2, and each k independently represents an integer from 0 to 2. R １ ~R ３ In general formula (I) or (III), examples of the substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms include an alkyl group. In general formula (I) or (III), the glycidyloxy groups bonded to the naphthalene ring may each be independently bonded to either one of the two benzene rings constituting the naphthalene ring.

[0028] The naphthalene-type epoxy resin may be a copolymer epoxy resin obtained by epoxidizing a novolac resin obtained from a naphthol compound, a phenol compound, and an aldehyde compound, or may be an epoxy resin obtained by glycidyl etherification of a novolac-type phenolic resin using a compound having a naphthol skeleton and a compound having a phenol skeleton. Examples of such copolymer epoxy resins include epoxy resins represented by the following general formula (IV):

[0029]

[0030] In general formula (IV), R １９ ~R ２１ Each of the i's independently represents an integer of 0 to 3, each of the j's independently represents an integer of 0 to 2, and each of the k's independently represents an integer of 0 to 4. Each of the l and m's is an average value and is a number of 1 to 10, and (l+m) is a number of 2 to 20. The terminal of the epoxy resin represented by general formula (IV) is either of the following formula (IV-1) or (IV-2). In formulas (IV-1) and (IV-2), R １９ ~R ２１ The definitions of i, j and k are R in formula (IV). １９ ~R ２１ is the same as the definition of i, j, and k. n is 1 (when bonding via a methylene group) or 0 (when bonding not via a methylene group). Among the epoxy resins represented by general formula (IV), R ２１ is a methyl group, i is 1, j is 0, and k is 0.

[0031]

[0032] Examples of the epoxy resin represented by the general formula (IV) 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 block form, etc. Any of these may be used alone or in combination of two or more.

[0033] The copolymerized epoxy resin may be a methoxynaphthalene-cresol-formaldehyde co-condensed epoxy resin represented by the following general formula (V), which contains the following two structural units in a random, alternating, or block order: In the following general formula (IV), 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.

[0034]

[0035] 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 (VI) is preferred.

[0036]

[0037] In general formula (VI), R １６ each independently represents a monovalent organic group having 1 to 18 carbon atoms. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

[0038] Examples of biphenylaralkyl epoxy resins include epoxy resins made from raw materials such as phenolic compounds such as phenol and cresol, and phenolic resins synthesized from bis(methoxymethyl)biphenyl or its derivatives. As such epoxy resins, for example, epoxy resins represented by general formula (VII) are preferred.

[0039]

[0040] In general formula (VII), R ３８ R each independently represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms. ３７ Each independently represents a monovalent organic group having 1 to 18 carbon atoms. Each 1 independently represents an integer of 0 to 3. n is an average value and is a number of 0 to 10. Among the epoxy resins represented by the following general formula (VII), those in which 1 is 0 and R ３８ is a hydrogen atom.

[0041] The total content of the naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, and biphenylaralkyl-type epoxy resin is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass, based on the total amount of the specific epoxy resin.

[0042] From the viewpoint of suitably reducing warpage of electronic component devices, the epoxy equivalent of the specific epoxy resin is preferably 200 g / eq to 1000 g / eq, and more preferably 200 g / eq to 500 g / eq. The epoxy equivalent of the specific epoxy resin is a value measured by a method in accordance with JIS K 7236:2009.

[0043] The epoxy resin composition of the present disclosure may or may not contain an epoxy resin other than the above-mentioned specific epoxy resin (hereinafter also referred to as "other epoxy resin").

[0044] Other epoxy resins include, specifically, novolac epoxy resins (phenol novolac epoxy resins, orthocresol novolac epoxy resins, etc.) which are obtained by epoxidizing novolac resins obtained by condensing or co-condensing phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc. with aliphatic aldehyde compounds such as formaldehyde, acetaldehyde, propionaldehyde, etc. under an acidic catalyst; triphenylmethane-type epoxy resins obtained by epoxidizing triphenylmethane-type phenolic resins obtained by condensing or co-condensing phenols with aromatic aldehyde compounds such as phenols 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-type phenolic compounds; sulfur-atom-containing epoxy resins which are diglycidyl ethers of bisphenol S, etc. resins; 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 active hydrogen bonded to nitrogen atoms of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is substituted with a glycidyl group; alicyclic epoxy resins such as vinylcyclohexene diepoxide and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate in which intramolecular olefin bonds are epoxidized; 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; cyclopentadiene-modified epoxy resins which are glycidyl ethers of cyclopentadiene-modified phenolic resins; halogenated phenol novolac-type epoxy resins;Examples of the epoxy resin include 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 such as phenol aralkyl resins. Further examples of the epoxy resin include epoxidized silicone resins and epoxidized acrylic resins. These other epoxy resins may be used alone or in combination of two or more.

[0045] The other epoxy resin may include at least one of a biphenyl-type epoxy resin and a sulfur-atom-containing epoxy resin, or may include both a biphenyl-type epoxy resin and a sulfur-atom-containing epoxy resin.

[0046] The epoxy equivalent of the other epoxy resin is not particularly limited. From the viewpoint of a balance of various properties such as moldability, reflow resistance, and electrical reliability, the functional group equivalent of the other epoxy resin is preferably 100 g / eq to 1000 g / eq, and more preferably 150 g / eq to 500 g / eq. The epoxy equivalent of the epoxy resin is a value measured by a method in accordance with JIS K 7236:2009.

[0047] When the specific epoxy resin or other epoxy resin is solid, its softening point or melting point is not particularly limited. From the viewpoints of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during preparation of the epoxy resin composition, it is more preferably 50°C to 130°C. The melting points of the specific epoxy resin and other epoxy resins are values ​​measured by differential scanning calorimetry (DSC). The softening points of the specific epoxy resin and other epoxy resins are values ​​measured by a method (ring and ball method) in accordance with JIS K 7234:1986.

[0048] The content of the specific epoxy resin relative to the total epoxy resin is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, and even more preferably 15% by mass to 30% by mass.

[0049] When the epoxy resin contains other epoxy resins, the content of the other epoxy resins relative to the total amount of the epoxy resins may be 50% by mass to 95% by mass, 60% by mass to 90% by mass, or 70% by mass to 85% by mass.

[0050] When the other epoxy resins include a biphenyl-type epoxy resin, the content of the biphenyl-type epoxy resin relative to the total amount of epoxy resins may be 45% by mass to 80% by mass, 50% by mass to 75% by mass, or 55% by mass to 65% by mass.

[0051] When the other epoxy resins include a sulfur atom-containing epoxy resin, the content of the sulfur atom-containing epoxy resin relative to the total amount of epoxy resins may be 5% by mass to 30% by mass, 10% by mass to 25% by mass, or 15% by mass to 20% by mass.

[0052] The total content of the specific epoxy resin and other epoxy resins in the epoxy resin composition is preferably 0.5% by mass to 50% by mass, more preferably 2% by mass to 30% by mass, from the viewpoints of strength, viscosity, heat resistance, moldability, etc.

[0053] [Curing Agent] The epoxy resin composition of the present disclosure contains a curing agent. Examples of the curing agent include phenolic curing agents having a phenolic hydroxyl group in the molecule.

[0054] 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 biphenol; 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, m-cresol, p-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, propionaldehyde, benzaldehyde, and salicylaldehyde, under an acidic catalyst; and copolymers of the above-mentioned phenolic compounds with dimethoxyparaxylene, bis(methoxymethyl)biphenol, and the like. Examples of suitable phenol curing agents include aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins synthesized from phenyl or the like; 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-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 condensing or co-condensing the above-mentioned 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.

[0055] The functional group equivalent of the curing agent (hydroxyl group equivalent for a curing agent having a phenolic hydroxyl group in the molecule) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g / eq to 1000 g / eq, and more preferably 80 g / eq to 500 g / eq.

[0056] The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a curing agent having a phenolic hydroxyl group in the molecule) may be a value measured by a method in accordance with JIS K 0070:1992, for example.

[0057] When the curing agent is solid, its softening point or melting point is not particularly limited, but from the viewpoints of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during production of the epoxy resin composition, it is more preferably 50°C to 130°C.

[0058] The melting point or softening point of the curing agent is a value measured in the same manner as the melting point or softening point of the epoxy resin.

[0059] The equivalent ratio of the epoxy resin to the curing agent, i.e., the ratio of the number of functional groups in the curing agent to the number of epoxy groups in the epoxy resin (number of functional groups in the curing agent / number of epoxy groups in the epoxy resin), is not particularly limited. In order to minimize the amount of unreacted components, it is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the viewpoints of moldability and reflow resistance, it is even more preferably set in the range of 0.8 to 1.2.

[0060] [Curing Accelerator] The epoxy resin composition may contain a curing accelerator. The type of curing accelerator is not particularly limited and can be selected depending on the type of epoxy resin, the desired properties of the epoxy resin composition, and the like.

[0061] From the viewpoint of curability and viscosity, the curing accelerator preferably contains a phosphonium compound.Specific examples of the phosphonium compound include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl / alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkoxyphenyl compounds having intramolecular polarization obtained by adding a tertiary phosphine such as alkylarylphosphine, dialkylarylphosphine or alkyldiarylphosphine to a compound having a π bond such as 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 or phenyl-1,4-benzoquinone, or diazophenylmethane; The fin compounds and 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodophenol, 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-tert-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol Examples of the compound include compounds having intramolecular polarization obtained by reacting a halogenated phenol compound such as 4-bromo-4'-hydroxybiphenyl with a halogenated phenol compound, followed by a dehydrohalogenation step; tetra-substituted phosphonium compounds such as tetraphenylphosphonium, tetra-substituted phosphonium compounds and tetra-substituted borates having no phenyl group bonded to the boron atom, such as tetra-p-tolylborate; salts of tetra-substituted phosphonium compounds with anions obtained by removing a proton from a phenol compound, and salts of tetra-substituted phosphonium compounds with anions obtained by removing a proton from a carboxylic acid compound.

[0062] Among the above phosphonium compounds, the compound represented by the following general formula (I-1) (hereinafter also referred to as a specific curing accelerator) is preferred.

[0063]

[0064] In formula (I-1), R １ ~R ３ are each independently a hydrocarbon group having 1 to 18 carbon atoms, and R １ ~R ３ Two or more of R may be bonded to each other to form a cyclic structure, ４ ~R ７ are each independently a hydrogen atom, a hydroxyl group, or a monovalent organic group having 1 to 18 carbon atoms, and R ４ ~R ７ Two or more of these may be bonded to each other to form a cyclic structure.

[0065] R in general formula (I-1) １ ~R ３ The "hydrocarbon group having 1 to 18 carbon atoms" described above includes an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms.

[0066] From the viewpoint of viscosity, the aliphatic hydrocarbon group having 1 to 18 carbon atoms preferably has 1 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 4 to 6 carbon atoms.

[0067] The aliphatic hydrocarbon group having 1 to 18 carbon atoms may be a linear or branched aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an alicyclic hydrocarbon group having 3 to 18 carbon atoms. From the viewpoint of ease of production, a linear or branched aliphatic hydrocarbon group is preferred.

[0068] Specific examples of linear or branched aliphatic hydrocarbon groups having 1 to 18 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, as well as allyl and vinyl groups. The linear or branched aliphatic hydrocarbon groups may or may not have a substituent. Examples of the substituent include alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy, aryl groups such as phenyl and naphthyl, hydroxyl groups, amino groups, and halogen atoms. The linear or branched aliphatic hydrocarbon groups may have two or more substituents, and in such cases, the substituents may be the same or different. When the linear or branched aliphatic hydrocarbon group has a substituent, it is preferable that the total number of carbon atoms contained in the aliphatic hydrocarbon group and the substituent is 1 to 18. From the viewpoint of curability, unsubstituted alkyl groups are preferred, unsubstituted alkyl groups having 1 to 8 carbon atoms are more preferred, and n-butyl, isobutyl, n-pentyl, n-hexyl and n-octyl groups are even more preferred.

[0069] Specific examples of alicyclic hydrocarbons having 3 to 18 carbon atoms include cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl, and cycloalkenyl groups such as cyclopentenyl and cyclohexenyl. The alicyclic hydrocarbon group may or may not have a substituent. Examples of the substituent include alkyl groups such as methyl, ethyl, butyl, and tert-butyl; alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy; aryl groups such as phenyl and naphthyl; hydroxyl groups; amino groups; and halogen atoms. The alicyclic hydrocarbon group may have two or more substituents, and in such cases, the substituents may be the same or different. When the alicyclic hydrocarbon group has a substituent, the total number of carbon atoms contained in the alicyclic hydrocarbon group and the substituent is preferably 3 to 18. When the alicyclic hydrocarbon group has a substituent, the position of the substituent is not particularly limited. From the viewpoint of curability, unsubstituted cycloalkyl groups are preferred, unsubstituted cycloalkyl groups having 4 to 10 carbon atoms are more preferred, and cyclohexyl, cyclopentyl and cycloheptyl groups are even more preferred.

[0070] The aromatic hydrocarbon group having 6 to 18 carbon atoms preferably has 6 to 14 carbon atoms, and more preferably 6 to 10 carbon atoms. The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include alkyl groups such as methyl, ethyl, butyl, and t-butyl; alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy; aryl groups such as phenyl and naphthyl; hydroxyl groups; amino groups; and halogen atoms. The aromatic hydrocarbon group may have two or more substituents, and in such cases, the substituents may be the same or different. When the aromatic hydrocarbon group has a substituent, the total number of carbon atoms contained in the aromatic hydrocarbon group and the substituent is preferably 6 to 18. When the aromatic hydrocarbon group has a substituent, the position of the substituent is not particularly limited.

[0071] Specific examples of aromatic hydrocarbon groups having 6 to 18 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, tolyl, dimethylphenyl, ethylphenyl, butylphenyl, t-butylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, and t-butoxyphenyl. The position of the substituent in these aromatic hydrocarbon groups may be any of the ortho, meta, and para positions. From the viewpoint of viscosity, unsubstituted aryl groups having 6 to 12 carbon atoms or 6 to 12 carbon atoms including substituents are preferred, unsubstituted aryl groups having 6 to 10 carbon atoms or 6 to 10 carbon atoms including substituents are more preferred, and phenyl, p-tolyl, and p-methoxyphenyl are even more preferred.

[0072] R in general formula (I-1) １ ~R ３ The term "R １ ~R ３ Two or more of R may be bonded to each other to form a cyclic structure １ ~R ３ In this case, two or three of the R １ ~R ３Examples of the substituent include alkylene groups such as ethylene, propylene, butylene, pentylene, and hexylene, alkenylene groups such as ethyleneylene, propylene, butylene, and butylene, aralkylene groups such as methylenephenylene, and arylene groups such as phenylene, naphthylene, and anthracenylene, which can bond to form a cyclic structure with a phosphorus atom. These substituents may be further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxyl group, a halogen atom, or the like.

[0073] R in the above general formula (I-1) ４ ~R ７ The "monovalent organic group having 1 to 18 carbon atoms" described above is intended to include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, aliphatic hydrocarbonoxy groups, aromatic hydrocarbonoxy groups, acyl groups, hydrocarbonoxycarbonyl groups, and acyloxy groups, which have 1 to 18 carbon atoms and may be substituted or unsubstituted.

[0074] Examples of the aliphatic hydrocarbon group and aromatic hydrocarbon group include R １ ~R ３ Examples of the aliphatic hydrocarbon group and aromatic hydrocarbon group represented by the formula (I) include those mentioned above.

[0075] Examples of the aliphatic hydrocarbon oxy group include oxy groups having a structure in which an oxygen atom is bonded to the above-mentioned aliphatic hydrocarbon group, such as a methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, 2-butoxy group, t-butoxy group, cyclopropyloxy group, cyclohexyloxy group, cyclopentyloxy group, allyloxy group, and vinyloxy group, as well as those aliphatic hydrocarbon oxy groups which are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxyl group, a halogen atom, or the like.

[0076] Examples of the aromatic hydrocarbon oxy group include oxy groups having a structure in which an oxygen atom is bonded to the above-mentioned aromatic hydrocarbon group, such as a phenoxy group, a methylphenoxy group, an ethylphenoxy group, a methoxyphenoxy group, a butoxyphenoxy group, or a phenoxyphenoxy group, and these aromatic hydrocarbon oxy groups are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, or the like.

[0077] Examples of the acyl group include aliphatic hydrocarbon carbonyl groups such as formyl, acetyl, ethylcarbonyl, butyryl, cyclohexylcarbonyl, and allylcarbonyl; aromatic hydrocarbon carbonyl groups such as phenylcarbonyl and methylphenylcarbonyl; and these aliphatic hydrocarbon carbonyl groups or aromatic hydrocarbon carbonyl groups which are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, or the like.

[0078] Examples of the hydrocarbon oxycarbonyl group include aliphatic hydrocarbon oxycarbonyl groups such as a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, an allyloxycarbonyl group, and a cyclohexyloxycarbonyl group; aromatic hydrocarbon oxycarbonyl groups such as a phenoxycarbonyl group and a methylphenoxycarbonyl group; and these aliphatic hydrocarbon carbonyloxy groups or aromatic hydrocarbon carbonyloxy groups which are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, or the like.

[0079] Examples of the acyloxy group include aliphatic hydrocarbon carbonyloxy groups such as a methylcarbonyloxy group, an ethylcarbonyloxy group, a butylcarbonyloxy group, an allylcarbonyloxy group, and a cyclohexylcarbonyloxy group; aromatic hydrocarbon carbonyloxy groups such as a phenylcarbonyloxy group and a methylphenylcarbonyloxy group; and these aliphatic hydrocarbon carbonyloxy groups or aromatic hydrocarbon carbonyloxy groups which are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, or the like.

[0080] R in the above general formula (I-1) ４ ~R ７ The term "two or more R ４ ~R ７ may be bonded to each other to form a cyclic structure" means that 2 to 4 R ４ ~R ７ may be bonded to form a single divalent to tetravalent organic group as a whole. ４ ~R ７ Examples of the cyclic group include substituents capable of forming a cyclic structure, such as alkylene groups such as ethylene, propylene, butylene, pentylene, and hexylene, alkenylene groups such as ethyleneylene, propylene, and butylene, aralkylene groups such as methylenephenylene, and arylene groups such as phenylene, naphthylene, and anthracenylene, as well as oxy or dioxy groups thereof. These substituents may be further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxyl group, a halogen atom, or the like.

[0081] R in the above general formula (I-1) ４ ~R ７ is not particularly limited. For example, it is preferable that each independently be selected from a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group. Among these, from the viewpoint of availability of raw materials, a hydrogen atom, a hydroxyl group, an aryl group unsubstituted or substituted with at least one selected from the group consisting of an alkyl group and an alkoxy group, or a linear or cyclic alkyl group is preferred. Examples of an unsubstituted aryl group substituted with at least one selected from the group consisting of an alkyl group and an alkoxy group include a phenyl group, a p-tolyl group, an m-tolyl group, an o-tolyl group, and a p-methoxyphenyl group. Examples of a linear or cyclic alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a 2-butyl group, a t-butyl group, an octyl group, and a cyclohexyl group. From the viewpoint of curability, R ４ ~R ７ are all hydrogen atoms, or R ４ ~R ７It is preferred that at least one of the groups is a hydroxyl group and the rest are all hydrogen atoms.

[0082] In general formula (I-1), R １ ~R ３ two or more of R are alkyl groups having 1 to 18 carbon atoms or cycloalkyl groups having 3 to 18 carbon atoms; ４ ~R ７ are all hydrogen atoms, or at least one is a hydroxyl group and the rest are all hydrogen atoms. １ ~R ３ are all alkyl groups having 1 to 18 carbon atoms or cycloalkyl groups having 3 to 18 carbon atoms, and R ４ ~R ７ are all hydrogen atoms, or at least one is a hydroxyl group and the rest are all hydrogen atoms.

[0083] From the viewpoint of rapid curing, the specific curing accelerator is preferably a compound represented by the following general formula (I-2).

[0084]

[0085] In formula (I-2), R １ ~R ３ are each independently a hydrocarbon group having 1 to 18 carbon atoms, and R １ ~R ３ Two or more of R may be bonded to each other to form a cyclic structure, ４ ~R ６ are each independently a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and R ４ ~R ６ Two or more of these may be bonded to each other to form a cyclic structure.

[0086] R in general formula (I-2) １ ~R ６ Specific examples of the groups are R in general formula (I-1). １ ~R ６ The specific examples and preferred ranges are the same as those of the above.

[0087] Specific examples of the specific curing accelerator include an addition reaction product of triphenylphosphine and 1,4-benzoquinone, an addition reaction product of tri-n-butylphosphine and 1,4-benzoquinone, an addition reaction product of tricyclohexylphosphine and 1,4-benzoquinone, an addition reaction product of dicyclohexylphenylphosphine and 1,4-benzoquinone, an addition reaction product of cyclohexyldiphenylphosphine and 1,4-benzoquinone, an addition reaction product of triisobutylphosphine and 1,4-benzoquinone, and an addition reaction product of tricyclopentylphosphine and 1,4-benzoquinone.

[0088] The specific curing accelerator can be obtained, for example, as an adduct of a tertiary phosphine compound and a quinone compound. Specific examples of the tertiary phosphine compound include triphenylphosphine, tributylphosphine, dibutylphenylphosphine, butyldiphenylphosphine, ethyldiphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(isopropylphenyl)phosphine, tris(t-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, and tris(4-ethoxyphenyl)phosphine. From the viewpoint of moldability, triphenylphosphine and tributylphosphine are preferred.

[0089] Specific examples of the quinone compound include o-benzoquinone, p-benzoquinone, diphenoquinone, 1,4-naphthoquinone, anthraquinone, etc. From the viewpoints of moisture resistance and storage stability, p-benzoquinone is preferred.

[0090] The epoxy resin composition may contain a curing accelerator other than the phosphonium compound. Specific examples of curing accelerators other than phosphonium compounds include 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 combinations of these compounds with maleic anhydride, quinone compounds such as 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. compounds having intramolecular polarization obtained by adding a compound having a π bond, such as a compound having tetraphenylborate of DBU, a tetraphenylborate of DBN, a tetraphenylborate of 2-ethyl-4-methylimidazole, or a tetraphenylborate of N-methylmorpholine; cyclic amidinium compounds such as the tetraphenylborate salt of DBU, the tetraphenylborate salt of DBN, the tetraphenylborate salt of 2-ethyl-4-methylimidazole, or the tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, or tris(dimethylaminomethyl)phenol; derivatives of the above-mentioned tertiary amine compounds; and ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, or tetrapropylammonium hydroxide.

[0091] When the epoxy resin composition contains a specific curing accelerator as a curing accelerator, the content of the specific curing accelerator is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more of the total curing accelerator, as long as it is 100% by mass or less of the total curing accelerator.

[0092] When the epoxy resin composition contains a curing accelerator, the amount thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin components. When the amount of the curing accelerator is 0.1 part by mass or more per 100 parts by mass of the resin components, the composition tends to cure well in a short time. When the amount of the curing accelerator is 30 parts by mass or less per 100 parts by mass of the resin components, the curing speed is not too fast, and a good molded product tends to be obtained.

[0093] [Inorganic Filler] The epoxy resin composition contains an inorganic filler. The type of inorganic filler is not particularly limited. Specific examples include inorganic materials such as fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, and mica. An inorganic filler having a flame-retardant effect may also be used. Examples of inorganic fillers having a flame-retardant effect include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium-zinc composite hydroxide, and zinc borate. Among these, fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. The inorganic filler may be used alone or in combination of two or more. The inorganic filler may be in the form of powder, beads formed by spheroidizing powder, or fibers.

[0094] The term "combined use of two or more inorganic fillers" refers to, for example, the use of two or more inorganic fillers having the same components but different average particle sizes, the use of two or more inorganic fillers having the same average particle size but different components, and the use of two or more inorganic fillers having different average particle sizes and types.

[0095] The content of the inorganic filler is 87.0% by mass or more relative to the entire epoxy resin composition, and from the viewpoints of suppressing warpage of electronic component devices and viscosity, it is preferably 88.0% by mass to 95.0% by mass, more preferably 89.0% by mass to 94.0% by mass, and even more preferably 90.0% by mass to 93.0% by mass, and may be 91.0% by mass to 93.0% by mass.

[0096] When the inorganic filler contains alumina, the alumina content is preferably 40% by mass to 80% by mass, more preferably 50% by mass to 80% by mass, and even more preferably 60% by mass to 75% by mass of the entire inorganic filler.

[0097] The average particle diameter of the inorganic filler is not particularly limited. For example, the volume average particle diameter is preferably 0.2 μm to 80 μm, and more preferably 0.5 μm to 70 μm. When the volume average particle diameter is 0.2 μm or more, an increase in the viscosity of the epoxy resin composition tends to be further suppressed. When the volume average particle diameter is 80 μm or less, the ability to fill narrow gaps tends to be further improved. The volume average particle diameter of the inorganic filler can be measured as the volume average particle diameter (D50) using a laser diffraction scattering particle size distribution analyzer.

[0098] The volume-average particle size of the inorganic filler in an epoxy resin composition or a cured product thereof can be measured by a known method. For example, the inorganic filler is extracted from the epoxy resin composition or the cured product using an organic solvent, nitric acid, aqua regia, or the like, and then thoroughly dispersed using an ultrasonic disperser or the like to prepare a dispersion. Using this dispersion, the volume-average particle size of the inorganic filler can be measured from the volume-based particle size distribution measured using a laser diffraction / scattering particle size distribution analyzer. Alternatively, the cured product can be embedded in a transparent epoxy resin or the like, polished, and the resulting cross-section observed using a scanning electron microscope to obtain the volume-based particle size distribution. Furthermore, the volume-average particle size of the inorganic filler can also be measured by continuously observing two-dimensional cross-sections of the cured product using an FIB device (focused ion beam SEM) or the like, followed by three-dimensional structural analysis.

[0099] The maximum particle size (also referred to as cut point) of the inorganic filler is not particularly limited. From the viewpoint of filling into narrow gaps, the maximum particle size of the inorganic filler is preferably 150 μm or less, more preferably 75 μm or less, and even more preferably 55 μm or less.

[0100] From the viewpoint of kneadability of the epoxy 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.

[0101] When a cured product with high thermal conductivity is to be obtained, the inorganic filler preferably contains alumina, and more preferably contains alumina as the main component. When the inorganic filler contains alumina, the average particle size of the alumina is not particularly limited. For example, the volume average particle size of the alumina is preferably 0.2 μm to 80 μm, and more preferably 0.5 μm to 70 μm. When the volume average particle size is 0.2 μm or more, an increase in the viscosity of the epoxy resin composition tends to be suppressed. When the volume average particle size is 80 μm or less, the ability to fill narrow gaps tends to be improved.

[0102] The maximum particle size of the alumina is not particularly limited. From the viewpoint of filling narrow gaps, the maximum particle size of the alumina is preferably 150 μm or less, more preferably 75 μm or less, and even more preferably 55 μm or less.

[0103] In a preferred embodiment, alumina having a volume average particle size of 0.1 μm to 2.0 μm, preferably 0.2 μm to 1.5 μm, more preferably 0.3 μm to 1.0 μm, may be used in combination with alumina having a volume average particle size of more than 2.0 μm to 75 μm or less, preferably 5.0 μm to 55 μm, more preferably 8.0 μm to 20 μm. By using two or more types of alumina having different average particle sizes in combination, the packing property tends to be favorable.

[0104] The shape of the alumina is not particularly limited, but from the viewpoint of kneadability of the epoxy resin composition, the alumina particles are preferably spherical.

[0105] When the inorganic filler contains alumina, it is preferable that the inorganic filler also contains silica in addition to alumina. When the inorganic filler contains silica, the viscosity tends to decrease and kneadability and flowability tend to be improved. In particular, the use of fine silica in combination tends to suppress the occurrence of burrs when the cured product is formed. In particular, the inorganic filler preferably contains fine silica, for example, silica having a volume average particle diameter of 0.01 μm to 2.0 μm, more preferably 0.1 μm to 1.5 μm, and even more preferably 0.2 μm to 1.0 μm. From the viewpoint of reducing the modulus of elasticity and the coefficient of linear expansion, it is preferable that the inorganic filler contains large particle silica. Examples of large particle silica include silica having a volume average particle diameter of more than 2.0 μm but not more than 75 μm, more preferably 5.0 μm to 55 μm, and even more preferably 8.0 μm to 20 μm.

[0106] From the viewpoints of reflow resistance, suppression of viscosity increase, etc., the inorganic filler preferably contains silica, and may contain silica as a main component. When the inorganic filler contains silica, the average particle size of the silica is not particularly limited. For example, the volume average particle size of silica is preferably 0.2 μm to 80 μm, more preferably 0.5 μm to 70 μm. A volume average particle size of 0.2 μm or more tends to suppress the increase in viscosity of the epoxy resin composition. A volume average particle size of 80 μm or less tends to improve the filling ability into narrow gaps. Furthermore, the inorganic filler preferably contains fine silica, for example, silica having a volume average particle size of 0.01 μm to 2.0 μm, more preferably 0.1 μm to 1.5 μm, and even more preferably 0.2 μm to 1.0 μm. When the inorganic filler contains fine silica, the filling ability into narrow spaces tends to be improved and the occurrence of burrs when the composition is cured tends to be suppressed.

[0107] The maximum particle size of the silica is not particularly limited. From the viewpoint of filling narrow gaps, the maximum particle size of the silica is preferably 150 μm or less, more preferably 75 μm or less, and even more preferably 55 μm or less.

[0108] The shape of the silica is not particularly limited, but from the viewpoint of kneadability of the epoxy resin composition, the silica particle shape is preferably spherical.

[0109] When the inorganic filler contains silica, the content of silica is not particularly limited and may be 70% by mass to 100% by mass, 80% by mass to 100% by mass, or 90% by mass to 100% by mass, based on the total mass of the inorganic filler. Furthermore, when silica is used in combination with alumina, the content of silica may be 20% by mass to 60% by mass, 20% by mass to 50% by mass, or 25% by mass to 40% by mass, based on the total mass of the inorganic filler.

[0110] [Various Additives] In addition to the components described above, the epoxy resin composition may contain various additives such as coupling agents, ion exchangers, release agents, flame retardants, colorants, and stress relaxation agents, as exemplified below. The epoxy resin composition may also contain various additives known in the art, as needed, in addition to the additives exemplified below.

[0111] (Coupling Agent) When the epoxy resin composition contains an inorganic filler, it may contain a coupling agent to enhance adhesion between the resin component and the inorganic filler. Examples of the coupling agent include known coupling agents such as silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium-based compounds, aluminum chelate compounds, and aluminum / zirconium-based compounds.

[0112] When the epoxy resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 to 5 parts by mass, and 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.

[0113] (Ion Exchanger) The epoxy resin composition may contain an ion exchanger. In particular, when the epoxy resin composition is used as an encapsulating molding material, it is preferable to contain an ion exchanger from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of an electronic component device including an encapsulated element. The ion exchanger is not particularly limited, 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 exchangers may be used alone or in combination of two or more. Among these, hydrotalcites represented by the following general formula (A) are preferred.

[0114] Mg （１－Ｘ） Al Ｘ (OH) ２ (CO ３ ) Ｘ／２ ・mH ２ O ……(A) (0<X≦0.5, m is a positive number)

[0115] When the epoxy 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, etc. For example, the content is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin component.

[0116] (Mold Release Agent) The epoxy resin composition may contain a mold release agent from the viewpoint of obtaining good mold releasability during molding. There are no particular limitations on the mold release agent, 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 mold release agent may be used alone, or two or more types may be used in combination.

[0117] When the epoxy resin composition contains a release agent, the amount 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 resin component. When the amount of the release agent is 0.01 part by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When the amount is 15 parts by mass or less, better adhesion tends to be obtained.

[0118] In particular, the epoxy resin composition contains a release agent, and the content of the release agent is preferably more than 0% by mass and not more than 2.0% by mass, more preferably more than 0% by mass and not more than 1.5% by mass, and even more preferably more than 0% by mass and not more than 1.2% by mass, relative to the total mass of the epoxy resin composition. By including the release agent in the above content, it is possible to suppress significant deterioration in appearance, adhesive strength, and laser markability, compared to when a release agent is included in a content greater than the above content. Furthermore, according to the epoxy resin composition of the present disclosure, good release properties tend to be maintained even when the content of the release agent is within the above range.

[0119] (Flame Retardant) The epoxy resin composition may contain a flame retardant. There are no particular limitations on the flame retardant, 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.

[0120] When the epoxy resin composition contains a flame retardant, the amount thereof is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, the amount is preferably 1 to 300 parts by mass, and more preferably 2 to 150 parts by mass, per 100 parts by mass of the resin component.

[0121] (Colorant) The epoxy resin composition may further contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose, etc. The colorant may be used alone or in combination of two or more.

[0122] (Stress Relaxant) The epoxy resin composition may contain a stress relaxation agent such as silicone oil or silicone rubber particles. By including a stress relaxation agent, package warpage and package cracking can be further reduced. Examples of the stress relaxation agent include commonly used known stress relaxation agents (flexibilizers). Specific examples include thermoplastic elastomers such as silicone, styrene, olefin, urethane, polyester, polyether, polyamide, and polybutadiene elastomers; 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 relaxation agent may be used alone or in combination of two or more. Among these, silicone-based stress relaxation agents are preferred. Examples of silicone-based stress relaxation agents include those having epoxy groups, those having amino groups, and polyether-modified versions of these.

[0123] (Method for Preparing Epoxy Resin Composition) The method for preparing the epoxy resin composition is not particularly limited. A typical method involves 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 involves uniformly stirring and mixing predetermined amounts of the above-mentioned components, kneading the mixture using a kneader, roll, extruder, or the like preheated to 70°C to 140°C, cooling, and pulverizing the mixture. Furthermore, the particulate epoxy resin composition obtained by pulverization can be sieved through a sieve with a mesh size of 2.0 mm, and the pulverized material that passed through the sieve can be collected to obtain an epoxy resin composition with a maximum particle size of 2.0 mm or less. The maximum particle size of the epoxy resin composition can be adjusted by changing the mesh size of the sieve used.

[0124] An electronic component device according to an embodiment of the present disclosure includes an element and a cured product of the epoxy resin composition described above that encapsulates the element. Examples of the electronic component device include a support member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, or an organic substrate, on which elements (active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils) are mounted, and the resulting element portion is encapsulated with the epoxy resin composition. More specifically, 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), TQFP (Thin Quad Flat Package), etc., have a structure in which an element is fixed on a lead frame, and terminals of the element such as bonding pads are connected to leads by wire bonding, bumps, etc., and then sealed using an epoxy resin composition. Examples of suitable epoxy resin packages include common resin-sealed ICs such as tape carrier packages (TCPs), which have a structure in which elements connected to a tape carrier via bumps are sealed with an epoxy resin composition; chip-on-board (COB) modules, hybrid ICs, and multi-chip modules, which have a structure in which elements connected to wiring formed on a support member by wire bonding, flip-chip bonding, solder, or the like are sealed with an epoxy resin composition; and ball grid arrays (BGAs), chip size packages (CSPs), and multi-chip packages (MCPs), 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 side, and the elements are connected to the wiring formed on the support member by bumps or wire bonding, and then the elements are sealed with an epoxy resin composition. Epoxy resin compositions can also be suitably used in printed wiring boards.

[0125] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0126] [Preparation of Epoxy Resin Compositions] The following materials were mixed in the proportions shown in Table 1, and the mixture was kneaded using a twin-screw kneader at a kneading temperature of 100°C to prepare the respective epoxy resin compositions. The particulate epoxy resin composition obtained by pulverizing the aforementioned epoxy resin composition was sieved through a sieve with a mesh size of 1.0 mm, and the pulverized material that passed through the sieve was collected to obtain epoxy resin compositions of each Example and Comparative Example having a maximum particle size of 1.0 mm or less. Note that in the tables below, "-" means that the component in question was not blended.

[0127] (Epoxy resins) Epoxy resin 1: an epoxy resin having a biphenyl skeleton (epoxy equivalent: 196 g / eq, equivalent to other epoxy resins) Epoxy resin 2: an epoxy resin in which multiple naphthalene rings are bonded via ether groups, with one glycidyl ether group bonded to each of the two terminal naphthalene rings (epoxy equivalent: 250 g / eq, equivalent to a specific epoxy resin) Epoxy resin 3: a sulfur atom-containing epoxy resin that is a diglycidyl ether of bisphenol S (epoxy equivalent: 245 g / eq, equivalent to other epoxy resins)

[0128] (Curing agent) Curing agent: triphenylmethane type phenolic resin (hydroxyl group equivalent 104 g / eq) (Curing accelerator) Curing accelerator: addition reaction product of triphenylphosphine and 1,4-benzoquinone (Coupling agent) Coupling agent 1: 3-methacryloxypropyltrimethoxysilane Coupling agent 2: 3-mercaptopropyltrimethoxysilane (Ion trapping agent) Magnesium aluminum hydroxide carbonate hydrate (Additive) Mold release agent: Montan acid ester wax Colorant: carbon black (Stress relaxation agent) Stress relaxation agent 1: silicone-based stress relaxation agent having epoxy groups Stress relaxation agent 2: stress relaxation agent containing the following structural unit (Inorganic filler) Inorganic filler 1: fine particle silica (average particle diameter 0.5 μm) Inorganic filler 2: large particle silica (average particle diameter 10 μm) Inorganic filler 3: alumina / silica mixture with a volume ratio of 9 / 1 (average particle size: 10 μm)

[0129]

[0130] [Evaluation of Epoxy Resin Compositions] The properties of the epoxy resin compositions prepared in the Examples and Comparative Examples were evaluated by the following property tests. The results are shown in Table 1.

[0131] (1) Spiral Flow (SF) Using a spiral flow measurement mold conforming to EMMI-1-66, the epoxy resin composition was molded under the conditions of a mold temperature of 150°C, a molding pressure of 6.9 MPa, and a curing time of 180 seconds, and the flow distance (cm) was determined.

[0132] (2) Gel Time (GT) The gel time of the epoxy resin composition was measured using a Curastometer (JSR Trading Co., Ltd.) with a sample amount of 1.5 ml at 160° C. The time at which the torque on the obtained chart started to rise was taken as the gel time (seconds).

[0133] (3) Glass Transition Temperature (Tg), CTE1 (α1), and CTE2 (α2) Using the epoxy resin composition, molded articles measuring 4 mm x 4 mm x 20 mm were obtained using a transfer molding machine under conditions of a mold temperature of 175°C, a curing time of 90 seconds, and a molding pressure of 6.9 MPa. The resulting molded articles were fully cured at 175°C for 6 hours, and the coefficient of linear expansion (CTE) was measured using a thermomechanical analyzer (NETZSCH, TMA4000SE). The measurement temperature range was 30°C to 260°C, and the heating rate was 10°C / min. The average CTE value in the range of 40°C to 80°C was defined as α1, and the average CTE value in the range of 230°C to 250°C was defined as α2. The intersection of the tangent of the CTE in the range of 40°C to 80°C and the tangent of the CTE in the range of 230°C to 250°C was defined as the glass transition temperature (Tg).

[0134] (4) Room-Temperature Elastic Modulus and High-Temperature Elastic Modulus Using the epoxy resin composition, a molded product measuring 50 mm in length, 5 mm in width, and 2 mm in thickness was obtained using a transfer molding machine under conditions of a mold temperature of 175°C, a curing time of 90 seconds, and a molding pressure of 6.9 MPa. The molded product was completely cured at 175°C for 6 hours to obtain a cured product. Thereafter, the elastic modulus was measured using a viscoelasticity measuring device RSA-3 (TA Instruments) in a three-point bending mode at a heating rate of 10°C / min and a frequency of 1 Hz. From the measurement results, the elastic modulus at room temperature (25°C) (room-temperature elastic modulus) and the elastic modulus at 260°C (high-temperature elastic modulus) were determined.

[0135] (5) Hot Hardness Each epoxy resin composition was molded using a transfer molding machine under the conditions of a mold temperature of 175°C, a curing time of 90 seconds, and a molding pressure of 6.9 MPa, and the hot hardness at 175°C was measured using a Shore D hardness tester (Ueshima Seisakusho Co., Ltd., HD-1120 (Type D)).

[0136] (6) Viscosity at 140°C The epoxy resin composition was heated to melt, and the viscosity at 140°C was measured using a rheometer AR2000 (manufactured by TA Instruments) with 40 mm parallel plates at a shear rate of 32.5 / sec.

[0137] (7) Mold Shrinkage Using an epoxy resin composition, a molded product (corresponding to a cured product before post-curing) was obtained using a transfer molding machine under conditions of a mold temperature of 175°C, a curing time of 90 seconds, and a molding pressure of 6.9 MPa. The molded product obtained was completely cured at 175°C for 6 hours to obtain a cured product (corresponding to a cured product after post-curing). The mold shrinkage before and after post-curing was calculated using the following formula: Mold shrinkage (%) = {(length of cured product before post-curing - length of cured product after post-curing) / (length of cured product before post-curing)} × 100 The length of the cured product is the length of any one side of the rectangular cured product.

[0138] (8) Thermal Conductivity Test pieces for evaluating thermal conductivity were prepared by encapsulating a semiconductor element using an epoxy resin composition in a compression molding machine under the following conditions: mold temperature 175°C to 180°C, molding pressure 7 MPa, and curing time 150 seconds. The thermal conductivity of the test pieces was then measured by the xenon flash (Xe-flash) method.

[0139]

[0140] As shown in Table 1, the values ​​of α1 and α2 were smaller and the mold shrinkage rate also tended to be lower when the epoxy resin compositions of Examples 1 to 4 were used compared to when the epoxy resin compositions of Comparative Examples 1 and 2 were used. Therefore, by producing electronic component devices using the epoxy resin compositions of Examples 1 to 4, it was possible to suppress warpage in the electronic component devices.

[0141] [Evaluation of Solubility] An epoxy resin composition was prepared according to the formulation of Example 1 listed in Table 1. The prepared epoxy resin composition was pulverized to obtain a particulate epoxy resin composition, designated the epoxy resin composition of Comparative Example 3. The epoxy resin composition of Comparative Example 3 was not sieved, and the maximum particle size of the composition exceeded 2.0 mm. The solubility of the epoxy resin compositions of Examples 1 to 4, each with a maximum particle size of 1.0 mm or less, and the epoxy resin composition of Comparative Example 3 was evaluated as follows. First, an aluminum cup (Φ5.5 cm) was placed on a hot plate, and 5 g of each of the epoxy resin compositions of Examples 1 to 4 and Comparative Example 3 was horizontally spread inside the cup. The cups with the epoxy resin compositions spread therein were then heated at 175°C for 3 minutes, and the appearance of the epoxy resin compositions after heating was confirmed to confirm the degree of dissolution of the epoxy resin compositions. In Examples 1 to 4, the epoxy resin compositions were more uniformly dissolved than in Comparative Example 3, with almost no residual dissolution observed. This suggests that wire sweep can be suppressed by using the epoxy resin compositions of Examples 1 to 4.

[0142] The disclosure of Japanese Patent Application No. 2021-143465, filed on September 2, 2021, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An epoxy resin containing at least one of a polycyclic structure and two or more types of ring structures, a curing agent, an inorganic filler, comprising, wherein the content of the inorganic filler is 87.0% by mass or more based on the total amount of the epoxy resin composition for compression molding, and the maximum particle size of the epoxy resin composition for compression molding is 2.0 mm or less.

2. The epoxy resin composition for compression molding according to claim 1, wherein the epoxy resin contains at least one epoxy resin selected from the group consisting of a naphthalene-type epoxy resin, a dicyclopentadiene-type epoxy resin, and a biphenyl aralkyl-type epoxy resin.

3. The epoxy resin composition for compression molding according to claim 1 or claim 2, wherein the epoxy equivalent of the epoxy resin is 200 g / eq to 1000 g / eq.

4. The epoxy resin composition for compression molding according to claim 1 or claim 2, wherein the inorganic filler contains alumina.

5. The epoxy resin composition for compression molding according to claim 4, wherein the content of the alumina relative to the entire inorganic filler is 40% by mass to 80% by mass.

6. The epoxy resin composition for compression molding according to claim 1 or claim 2, wherein the content of the epoxy resin containing at least one of the polycyclic structure and two or more types of ring structures relative to the entire epoxy resin is 5% by mass to 50% by mass.

7. An electronic component device comprising an element and a cured product of the epoxy resin composition for compression molding according to claim 1 or claim 2 for encapsulating the element.