Epoxy resin composition, cured product, semiconductor device, and method for producing semiconductor device

Abstract

Provided is an epoxy resin composition having a low viscosity and a short gap filling time.　This epoxy resin composition comprises (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (D) core-shell rubber particles, wherein the shell layer of the core-shell rubber particles (D) contains (meth)acrylic acid and butyl (meth)acrylate as constituent units.

Description

Epoxy resin composition, cured product, semiconductor device, and method for manufacturing semiconductor device

[0001] The present invention relates to an epoxy resin composition, a cured product, a semiconductor device, and a method for producing a semiconductor device.

[0002] Semiconductor devices are required to have higher performance, more functionality, and lower power consumption. Until now, the mainstream technology was SoC (System on Chip), which increases the transistor integration density on a single chip to provide all functions. However, this approach has faced problems such as rising manufacturing costs and reduced yields due to larger chips. In response, SiP (System in Package) has emerged, which divides the system into multiple chips and then integrates them at high density. SiP uses a substrate called a silicon interposer. The silicon interposer is placed on the package substrate, and multiple chips are arranged closely together horizontally on top of it. Furthermore, a multilayer wiring circuit is formed on the upper side of the silicon interposer and connected to the resin substrate below by through-silicon vias (TSVs). Because silicon interposers do not contain active elements such as transistors, they are easier to enlarge than chips. Therefore, the mainstream approach is to enlarge silicon interposers and mount more chips on them. Furthermore, in order to achieve further increases in size, various interposers, such as an interposer in which silicon is embedded in a molding resin, are being considered.

[0003] The interposer and the resin substrate are connected via bump electrodes. When a thermal load such as a temperature cycle is applied, stress is applied to the bump electrodes due to differences in the linear thermal expansion coefficients of each component, which can cause defects such as cracks in the bump electrodes. For this reason, the gap between the interposer and the resin substrate is sealed with a liquid sealing material called underfill to improve resistance to thermal loads (thermal cycle resistance) and the ability to protect the package from heat and external forces (package protection) (Patent Documents 1 and 2). Another known method involves adding a rubber component (e.g., core-shell rubber particles) to the underfill to reduce the elastic modulus of the cured product (sealant) (Patent Document 3).

[0004] JP 2017-171754 A JP 2016-108358 A JP 2019-81816 A

[0005] In recent years, interposers have become larger and larger in order to improve the performance and functionality of semiconductor devices. As interposers become larger, the stress applied to the encapsulant also increases. For this reason, there is a demand for underfills that can alleviate the stress applied to the encapsulant, suppress the occurrence of cracks in the encapsulant, and provide high bump protection.

[0006] Although the elastic modulus of the encapsulant can be reduced by adding core-shell rubber particles to the underfill, increasing the amount of rubber component increases the viscosity of the underfill, resulting in poor handling. Another problem is that the time required to fill the gap between the interposer and the resin substrate with the underfill (gap filling time) increases. In this specification, the latter characteristic is described as "injectability." For example, a short gap filling time is described as excellent injectability.

[0007] Therefore, an object of the present invention is to provide an epoxy resin composition containing core-shell rubber particles, which has low viscosity and excellent injectability, a cured product of the epoxy resin composition, a semiconductor device including the cured product, and a method for manufacturing the semiconductor device.

[0008] As a result of extensive research into achieving the above object, the present inventors have found that the above problems can be solved by using an epoxy resin composition containing specific core-shell rubber particles. The present invention was completed based on these findings.

[0009] That is, the present invention provides an epoxy resin composition comprising: an epoxy resin (A); a curing agent (B); an inorganic filler (C); and core-shell rubber particles (D), wherein the core-shell rubber particles (D) comprise core-shell rubber particles (D1) whose shell layer contains, as structural units, (meth)acrylic acid and butyl (meth)acrylate.

[0010] The shell layer of the core-shell rubber particles (D1) preferably further contains, as a structural unit, at least one selected from the group consisting of methyl (meth)acrylate and glycidyl (meth)acrylate.

[0011] The content of the core-shell rubber particles (D1) relative to the total amount (100% by mass) of the epoxy resin (A) and the curing agent (B) is preferably 1 to 30% by mass.

[0012] The average particle size of the core-shell rubber particles (D1) is preferably 0.03 to 1.0 μm.

[0013] The content of the inorganic filler (C) relative to the epoxy resin composition (100% by mass) is preferably 50% by mass or more.

[0014] The epoxy resin composition preferably contains silica having an average particle size of 100 nm or less as the inorganic filler (C).

[0015] The epoxy resin (A) preferably contains at least one selected from the group consisting of bisphenol-type epoxy resins, aminophenol-type epoxy resins, and naphthalene-type epoxy resins.

[0016] The curing agent (B) is preferably an amine-based curing agent.

[0017] It is preferable that the shell layer of the core-shell rubber particles (D1) is substantially free of styrene, acrylonitrile, and methacrylonitrile as constituent units.

[0018] The epoxy resin composition is preferably used for semiconductor encapsulation.

[0019] The present invention also provides a cured product of the above epoxy resin composition.

[0020] The present invention also provides a semiconductor device comprising: a substrate; a semiconductor element disposed on the substrate; and the cured product that encapsulates the semiconductor element.

[0021] The present invention also provides a method for manufacturing a semiconductor device, comprising the steps of: filling a gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition; and heating and curing the epoxy resin composition.

[0022] The epoxy resin composition of the present invention has low viscosity and is therefore easy to handle. Furthermore, its excellent injectability allows efficient filling of gaps with the epoxy resin composition, even when manufacturing semiconductor devices using large substrates such as interposers. Furthermore, due to the above-mentioned properties, the composition can contain a larger amount of core-shell rubber particles than conventional epoxy resin compositions. Therefore, it is possible to adjust the cured product of the epoxy resin composition to exhibit a low modulus of elasticity. Therefore, a semiconductor device comprising a cured product of the epoxy resin composition can encapsulate semiconductor elements with high precision using the cured product, and exhibits high reliability due to reduced stress applied to the cured product of the epoxy resin composition.

[0023] 1A to 1C are diagrams illustrating "Evaluation 2: Gap filling test" in the examples.

[0024] (Epoxy Resin Composition) The epoxy resin composition includes an epoxy resin (A), a curing agent (B), an inorganic filler (C), and core-shell rubber particles (D). The core-shell rubber particles (D) include core-shell rubber particles (D1) whose shell layer contains (meth)acrylic acid and butyl (meth)acrylate as structural units. The epoxy resin composition may further include a curing accelerator (E), a coupling agent (F), and other components (G) described below. In this specification, "(meth)acrylic acid" refers to a concept that includes acrylic acid and methacrylic acid. Similarly, "(meth)acrylate" refers to a concept that includes acrylate and methacrylate.

[0025] Epoxy Resin (A) The epoxy resin composition contains the epoxy resin (A), which allows it to form a cured product with high electrical insulation. The number of epoxy groups in the epoxy resin (A) is not particularly limited as long as it is one or more, but it is preferably two or more (i.e., a polyfunctional epoxy resin). The epoxy resin (A) can be used alone or in combination of two or more.

[0026] The epoxy resin (A) may be liquid or solid at room temperature (25° C.), but is preferably liquid from the viewpoint of the viscosity of the epoxy resin composition. A solid epoxy resin can also be preferably used when it is used in combination with a liquid epoxy resin to form a liquid mixture.

[0027] The epoxy resin (A) is not particularly limited, and examples thereof include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and bisphenol AF-type epoxy resins, bixylenol-type epoxy resins, cyclohexane-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins (glycidylamine-type epoxy resins having no aromatic structure or glycidylamine-type epoxy resins having an aromatic structure), glycidyl ester-type epoxy resins (glycidyl ester-type epoxy resins having no aromatic structure or glycidyl ester-type epoxy resins having an aromatic structure), cresol novolac-type epoxy resins, biphenyl-type epoxy resins, and linear aliphatic epoxy resins (linear aliphatic epoxy resins having no aromatic structure).

[0033] Examples of the epoxy resin include aromatic or aliphatic epoxy resins such as epoxy resins having a butadiene structure (epoxy resins having a butadiene structure without an aromatic structure or epoxy resins having a butadiene structure with an aromatic structure), alicyclic epoxy resins (alicyclic epoxy resins having a butadiene structure without an aromatic structure or alicyclic epoxy resins having an aromatic structure), heterocyclic epoxy resins, spiro ring-containing epoxy resins (spiro ring-containing epoxy resins having a spiro ring without an aromatic structure or spiro ring-containing epoxy resins having an aromatic structure), cyclohexanedimethanol-type epoxy resins (cyclohexanedimethanol-type epoxy resins having a non-aromatic structure or cyclohexanedimethanol-type epoxy resins having an aromatic structure), naphthylene ether-type epoxy resins, trimethylol-type epoxy resins (trimethylol-type epoxy resins having a non-aromatic structure or trimethylol-type epoxy resins having an aromatic structure), tetraphenylmethane-type epoxy resins, aminophenol-type epoxy resins, and silicone-modified epoxy resins.

[0028] Among these, the epoxy resin (A) preferably contains at least one selected from the group consisting of bisphenol-type epoxy resins, naphthalene-type epoxy resins, aminophenol-type epoxy resins, cyclohexane-type epoxy resins, and glycidylamine-type epoxy resins, more preferably contains at least one selected from the group consisting of bisphenol F-type epoxy resins, naphthalene-type epoxy resins, aminophenol-type epoxy resins, and cyclohexane-type epoxy resins (particularly, 1,4-glycidylcyclohexane), and even more preferably contains at least one selected from the group consisting of bisphenol-type epoxy resins, aminophenol-type epoxy resins, and naphthalene-type epoxy resins.

[0029] The content of the bisphenol-type epoxy resin relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is preferably, for example, 0 to 100% by mass. The content of the naphthalene-type epoxy resin relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is preferably, for example, 0 to 50% by mass. The content of the aminophenol-type epoxy resin relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is preferably, for example, 0 to 90% by mass. The content of the cyclohexane-type epoxy resin relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is preferably, for example, 0 to 30% by mass.

[0030] Specific examples of liquid epoxy resins include "YDF-8170" (bisphenol F type epoxy resin), "YDF-8125" (bisphenol A type epoxy resin), "ZX-1658" and "ZX-1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "HP-4032", "HP-4032D", and "HP-4032SS" (naphthalene type epoxy resin) manufactured by DIC Corporation; and "jER828US", "jER828EL" (bisphenol A type epoxy resin), "jER806", and "jER807" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation. Examples of epoxy resins include "bisphenol A epoxy resin" (phenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "jER630", "jER630LSD", "EP3980S" (aminophenol type epoxy resin), "YX7400" (high impact resilience epoxy resin), "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd., "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation, and "Celloxide 2021P" (alicyclic epoxy resin) manufactured by Daicel Corporation.

[0031] Specific examples of solid epoxy resins include "HP-4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200", "HP-7200L", "HP-7200HH", "HP-7200H", "HP-7200HHH" (dicyclopentadiene-type epoxy resin), "EXA7311", and "EXA7311-G3" manufactured by DIC Corporation. , "EXA7311-G4", "EXA7311-G4S", "HP6000" (naphthylene ether type epoxy resin), "EPPN-502H" (trisphenol type epoxy resin), "NC-7000-L" (naphthol novolac type epoxy resin), "NC-3000-H", "NC-3000", "NC-3000-L", "NC-3100" (biphenyl type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd., "ESN475V" (naphthol type epoxy resin), "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. bisphenol A type epoxy resin), "YX4000H" and "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YL7760" (bisphenol AF type epoxy resin), "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd., "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation, Examples include "jER1031S" (tetraphenylethane type epoxy resin), "jER157S70" (bisphenol novolac type epoxy resin), "YX4000HK" (bixylenol type epoxy resin) and "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd., "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, and "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

[0032] The epoxy equivalent of the epoxy resin (A) is not particularly limited, but is preferably, for example, 30 to 1000 g / eq, more preferably 40 to 500 g / eq, and even more preferably 50 to 300 g / eq.

[0033] The content of the epoxy resin (A) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more. Furthermore, it is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, and particularly preferably 40% by mass or less. When the content of the epoxy resin (A) is within the above range, the thermal expansion of the cured product tends to be reduced and the toughness tends to be improved. Furthermore, the epoxy resin composition tends to have low viscosity and excellent injectability.

[0034] Curing agent (B) The curing agent (B) is not particularly limited as long as it initiates, progresses, or accelerates the polymerization of the epoxy resin, and examples thereof include amine-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents. The curing agent (B) may be solid or liquid at room temperature (25°C), and is preferably liquid. The curing agent (B) may be used alone or in combination of two or more.

[0035] Examples of the amine curing agent include aromatic amines such as 4,4'-methylenebis(2-ethylaniline), ethyltoluenediamine, diethyltoluenediamine (3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine, etc.), 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane, and dimethylthiotoluenediamine. Examples of the acid anhydride curing agent include alkylated tetrahydrophthalic anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, phthalic anhydride, dodecenyl succinic anhydride, and methylnadic anhydride. Examples of the phenolic curing agent include phenol novolac resin, cresol novolac resin, naphthol-modified phenolic resin, dicyclopentadiene-modified phenolic resin, and p-xylene-modified phenolic resin. Examples of the imidazole curing agent include 2-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-imidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole. The imidazole curing agent also includes a microcapsule-type imidazole curing agent. From the viewpoints of temperature cycle resistance, moisture resistance, and reliability of the semiconductor device, the curing agent (B) is preferably the above-mentioned amine curing agent, more preferably an aromatic amine, and even more preferably a liquid aromatic amine.

[0036] The equivalent weight (molecular weight per functional group) of the curing agent (B) is not particularly limited, but is, for example, preferably 10 to 300 g / eq, more preferably 20 to 160 g / eq, and even more preferably 30 to 100 g / eq.

[0037] The content of the curing agent (B) is not particularly limited, but is preferably an amount such that the stoichiometric equivalent ratio (curing agent equivalent / epoxy group equivalent) with the epoxy resin (A) is, for example, 0.5 to 1.5, and more preferably an amount such that the equivalent ratio is 0.8 to 1.2.

[0038] The content of the curing agent (B) relative to the epoxy resin composition (100% by mass) of the present invention is not particularly limited, but is preferably, for example, 2% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more. Also, for example, it is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 12% by mass or less. When the content of the curing agent (B) is within the above range, the thermal expansion of the cured product tends to be reduced and the toughness tends to be improved. Furthermore, the epoxy resin composition tends to have low viscosity and excellent injectability.

[0039] Inorganic Filler (C) The inorganic filler (C) is not particularly limited, but is preferably (1) one having the property of suppressing volumetric shrinkage (cure shrinkage) resulting from the curing reaction of the epoxy resin composition, (2) one having the property of suppressing volumetric change due to heating of the cured product (thermal shrinkage), i.e., one having the effect of lowering the linear expansion coefficient when added, or (3) one having both of these properties.

[0040] Examples of inorganic fillers (C) include silica (silicon dioxide), silicon carbide, silicon nitride, alumina (aluminum oxide), aluminum nitride, aluminum hydroxide, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, barium sulfate, barium carbonate, titanium oxide, lime sulfate, potassium titanate, magnesium carbonate, zinc oxide, boron nitride, zirconia (zirconium oxide), and inorganic particles whose surfaces have been treated. Among these, silica is preferred from the viewpoint of increasing the loading amount, and it is more preferable to contain silica with an average particle size of 100 nm or less (sometimes referred to as "nanosilica"). Furthermore, alumina is preferred from the viewpoint of increasing thermal conductivity. The inorganic filler (C) can be used alone or in combination of two or more.

[0041] In order to maintain the viscosity of the epoxy resin composition within an appropriate range, the inorganic filler (C) is preferably surface-treated with a coupling agent having a functional group such as an epoxy group, a (meth)acryloyl group, or an amino group (particularly a phenylamino group). Examples of the coupling agent include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. For the surface treatment of the inorganic filler (C), one of the above coupling agents can be used alone, or two or more can be used in combination.

[0042] The shape of the inorganic filler (C) is not particularly limited, and examples thereof include spherical (e.g., spherical, nearly spherical), polyhedral, rod-like (e.g., cylindrical, prismatic), plate-like, flaky, and irregular shapes. Among these, spherical shapes are preferred from the viewpoint of achieving a high loading amount.

[0043] The average particle size of the inorganic filler (C) is not particularly limited, but is preferably 1 nm to 10 μm, more preferably 0.1 to 8 μm, and even more preferably 0.3 to 5 μm. When the average particle size of the inorganic filler (C) is within the above range, the viscosity of the epoxy resin composition falls within an appropriate range, and a decrease in the gap filling rate tends to be less likely to occur. Two or more fillers with different average particle sizes may be used in combination to adjust the viscosity of the epoxy resin composition. In this specification, the method for measuring the average particle size of the inorganic filler (C) is not particularly limited, but can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer (product name: LS 13 320, manufactured by Beckman Coulter, Inc.).

[0044] The content of the inorganic filler (C) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and particularly preferably 50% by mass or more. It is also preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. By having the inorganic filler (C) content within the above range, the thermal expansion coefficient of the epoxy resin composition tends to be reduced while maintaining good workability, such as low viscosity and excellent injectability. When nanosilica is contained, its content is not particularly limited, but is, for example, 0.1 to 30% by mass, more preferably 0.1 to 20% by mass, even more preferably 0.1 to 10% by mass, and particularly preferably 0.3 to 5% by mass relative to the inorganic filler (C) (100% by mass).

[0045] Core-shell rubber particles (D) The core-shell rubber particles (D) have the effect of suppressing the occurrence and progression of fillet cracks when the epoxy resin composition is used as an underfill. Specifically, the incorporation of the core-shell rubber particles (D) reduces the modulus of elasticity of the cured product of the epoxy resin composition, thereby reducing the stress generated in the fillet portion and suppressing the occurrence of fillet cracks. Furthermore, if fillet cracks occur, the core-shell rubber particles (D) act as a stress relaxation agent and suppress the progression of the fillet cracks.

[0046] The core-shell rubber particles (D) refer to rubber particles composed of a core and one or more shell layers covering the core. The core-shell rubber particles (D) have a core composed of a material with excellent flexibility and a shell layer composed of a material with excellent affinity for the components contained in the epoxy resin composition, particularly the epoxy resin (A), thereby exhibiting good dispersibility in the epoxy resin composition and achieving a low elastic modulus of the cured product.

[0047] In the core-shell rubber particles (D), examples of materials constituting the core include silicone-based rubbers such as polydimethylsiloxane, butadiene-based rubbers, styrene-based rubbers, acrylic rubbers, polyolefin-based rubbers, and silicone / acrylic composite rubbers.

[0048] Materials constituting the shell layer include monomers having an epoxy group and monomers not having an epoxy group, i.e., the shell layer contains monomers having an epoxy group and / or monomers not having an epoxy group as constituent units.

[0049] Examples of the monomer having an epoxy group include glycidyl group-containing (meth)acrylates such as glycidyl (meth)acrylate, glycidyl methyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether; and glycidyl group-containing vinyl monomers such as allyl glycidyl ether.

[0050] Examples of the monomer not having an epoxy group include unsaturated carboxylic acids, (meth)acrylates not having an epoxy group, aromatic vinyl compounds, and vinylcyan compounds. Examples of the unsaturated carboxylic acids include (meth)acrylic acid, itaconic acid, crotonic acid, and maleic anhydride. Examples of the (meth)acrylates not having an epoxy group include C monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. １－５ Examples of the aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, and vinylbenzenes such as divinylbenzene. Examples of the vinylcyan compounds include acrylonitriles and methacrylonitriles.

[0051] The epoxy resin composition of the present invention contains, as the core-shell rubber particles (D), core-shell rubber particles (D1) in which the shell layer contains (meth)acrylic acid and butyl (meth)acrylate as structural units. The epoxy resin composition may also contain core-shell rubber particles (D2) other than the core-shell rubber particles (D1). The core-shell rubber particles (D) may be used alone or in combination of two or more.

[0052] By including the core-shell rubber particles (D1) in the epoxy resin composition, the viscosity of the epoxy resin composition can be adjusted to a low level, resulting in good handleability. Furthermore, the injectability of the epoxy resin composition is improved, allowing for efficient gap filling. Furthermore, since the core-shell rubber particles (D1) have the above properties, they can be added in larger amounts to the epoxy resin composition than conventional core-shell rubber particles. Therefore, it is possible to adjust the cured product of the epoxy resin composition to exhibit a lower elastic modulus.

[0053] The core-shell rubber particles (D1) may further contain methyl (meth)acrylate and a glycidyl group-containing (meth)acrylate (e.g., glycidyl (meth)acrylate) as structural units in the shell layer. On the other hand, it is preferable that the core-shell rubber particles (D1) are substantially free of styrene, acrylonitrile, and methacrylonitrile as structural units. When the core-shell rubber particles (D1) have the above structure, the epoxy resin composition tends to have low viscosity and excellent injectability.

[0054] The average particle size of the core-shell rubber particles (D) (preferably core-shell rubber particles (D1)) is not particularly limited, but is preferably 0.03 to 1.0 μm, more preferably 0.04 to 0.8 μm, and even more preferably 0.05 to 0.7 μm. The average particle size of the core-shell rubber particles (D) can be measured, for example, by observing the cross section of the cured product obtained by curing the epoxy resin composition using a scanning electron microscope (SEM). Specifically, the average particle size of the core-shell rubber particles (D) can be measured by any 100 μm ２The range is observed with an SEM, and 10 locations are arbitrarily selected from the particle diameters of the core-shell rubber particles (D) or the diameters of the recesses where the core-shell rubber particles (D) have fallen out, and the average value thereof can be used as the average particle diameter of the core-shell rubber particles (D).

[0055] The content of the core-shell rubber particles (D) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less. Also, for example, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 1.5% by mass or more.

[0056] The content of the core-shell rubber particles (D1) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less. Also, for example, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 1.5% by mass or more. When the content of the core-shell rubber particles (D1) is within the above range, the epoxy resin composition tends to have low viscosity and excellent injectability.

[0057] The content of the core-shell rubber particles (D) relative to the total amount (100% by mass) of the epoxy resin (A) and the curing agent (B) is not particularly limited, but is, for example, preferably 1 to 60% by mass, more preferably 1 to 45% by mass, and even more preferably 1 to 30% by mass.

[0058] The content of the core-shell rubber particles (D1) relative to the total amount (100% by mass) of the epoxy resin (A) and the curing agent (B) is not particularly limited, but is, for example, preferably 1 to 60% by mass, more preferably 1 to 45% by mass, and even more preferably 1 to 30% by mass. When the content of the core-shell rubber particles (D1) is within the above range, the epoxy resin composition tends to have low viscosity and excellent injectability.

[0059] The core-shell rubber particles (D) can be produced using known or conventional means, and can be produced, for example, via the following core part-forming step and shell layer-forming step. Core part-forming step: This is a step of forming a material for forming the core part described above. Examples include forming a polysiloxane by emulsion polymerization, or polymerizing a monomer containing an alkyl (meth)acrylate in the presence of an emulsifier and an initiator to form an acrylic rubber. Shell layer-forming step: This is a step of adding a monomer having an epoxy group and / or a monomer not having an epoxy group, and optionally an initiator, to a system containing the core particles obtained in the core part-forming step, and copolymerizing the monomers in the presence of the core particles to form a shell layer.

[0060] Curing Accelerator (E) The curing accelerator (E) has the property of accelerating the curing of epoxy resins. The curing accelerator is not particularly limited, but examples thereof include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole. Commercially available products include 2-phenyl-4-methylimidazole (manufactured by Shikoku Chemical Industries, Ltd., product name "2P4MZ"), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (manufactured by Shikoku Chemical Industries, Ltd., product name "2MZA"), and dicyandiamide. Alternatively, encapsulated imidazole, also known as microencapsulated imidazole or epoxy adduct imidazole, may also be used. For example, "HX3941HP", "HXA3942HP", "HXA3922HP", "HXA3792", "HX3748", "HX3721", "HX3722", "HX3088", "HX3741", "HX3742", "HX3613" (all manufactured by Asahi Kasei Chemicals Corporation), "PN-23J", "PN-40J", "PN-50" (manufactured by Ajinomoto Fine-Techno Co., Ltd.), "FXR-1121" (manufactured by Fuji Chemical Industry Co., Ltd.), etc. The curing accelerator (E) can be used alone or in combination of two or more.

[0061] The content of the curing accelerator (E) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and is, for example, not particularly limited, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably 0.5% by mass or less.

[0062] Coupling Agent (F) The coupling agent (F) is not particularly limited, and examples thereof include various coupling agents such as vinyl-based, glycidoxy-based, methacryl-based, amino-based, mercapto-based, or imidazole-based silane coupling agents; alkoxide-based, chelate-based, or acylate-based titanium coupling agents; and long-chain spacer coupling agents such as glycidoxyoctyltrimethoxysilane or methacrylooctyltrimethoxysilane. The coupling agent (F) can be used alone or in combination of two or more.

[0063] Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane.

[0064] The content of the coupling agent (F) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more. The content is also not particularly limited, but is, for example, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.0% by mass or less.

[0065] Other Components (G) The epoxy resin composition may contain components other than the epoxy resin (A), curing agent (B), inorganic filler (C), core-shell rubber particles (D), curing accelerator (E), and coupling agent (F) (hereinafter referred to as "other components (G)"). Examples of other components (G) include curable compounds other than the epoxy resin (A), thermoplastic resins such as acrylic resins, polyethylene resins, polyester resins, polyurethane resins, and polyamide resins, ion trapping agents, surfactants, antioxidants, antifoaming agents, flame retardants, colorants, reactive diluents, and solvents. The other components (G) may be used alone or in combination of two or more.

[0066] The content of the other component (G) relative to the epoxy resin composition (100% by mass) is not particularly limited as long as it does not impair the effects of the present invention, but is, for example, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. Also, although not particularly limited, it is, for example, preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more.

[0067] (Physical Properties and Production Method of Epoxy Resin Composition) The viscosity of the epoxy resin composition at 25°C is not particularly limited, but is, for example, preferably 0.1 to 100 Pa·s, more preferably 1 to 60 Pa·s, even more preferably 3 to 50 Pa·s, and particularly preferably 5 to 40 Pa·s. Having a viscosity within the above range tends to facilitate filling into gaps. As in the examples described below, the viscosity can be measured using a Brookfield viscometer (model number: HBDV-1, manufactured by Brookfield) at a liquid temperature of 25°C, rotating at 50 rpm for 1 minute.

[0068] The epoxy resin composition can be prepared by a known, conventional method. For example, the epoxy resin (A), curing agent (B), inorganic filler (C), and core-shell rubber particles (D), as well as at least one component selected from the group consisting of curing accelerator (E), coupling agent (F), and other components (G), can be simultaneously or separately introduced into an appropriate mixer and, if necessary, heated to melt and stir / mix the components. If the epoxy resin (A) is solid, it is preferably liquefied or fluidized by heating before mixing. If it is difficult to uniformly disperse the inorganic filler (C) in the epoxy resin composition, the epoxy resin (A) and inorganic filler (C) can be heated and mixed to uniformly disperse the inorganic filler (C) in the epoxy resin (A), followed by cooling as necessary, and then mixing with components such as the curing agent (B). This allows the epoxy resin composition to be prepared.

[0069] The mixer is not particularly limited, and examples thereof include a roll mill equipped with a stirrer and a heater, a Raikai mixer, a Henschel mixer, a tumbler, a planetary mixer, etc. The mixing ratio of each component is appropriately set depending on the content of each component in the epoxy resin composition.

[0070] The epoxy resin composition can be preferably used as a material for encapsulating semiconductor elements, wiring, solder (solder bumps), and other materials disposed on a substrate in a semiconductor device (an epoxy resin composition for semiconductor encapsulation). By using the epoxy resin composition as an epoxy resin composition for semiconductor encapsulation, a highly reliable semiconductor device can be manufactured. The epoxy resin composition can also be preferably used as a material for encapsulating semiconductor elements, etc., disposed on a substrate in a flip-chip semiconductor device (an epoxy resin composition for flip-chip semiconductor encapsulation). Specifically, by filling the gap between the semiconductor element, etc., and the substrate with the epoxy resin composition and subjecting it to thermal curing, the bump electrodes present in the gap can be encapsulated while the semiconductor element and the substrate are fixed together as an encapsulant, thereby improving reliability.

[0071] The epoxy resin composition for semiconductor encapsulation is used, for example, as an underfill such as a capillary underfill, a liquid mold underfill, a secondary underfill, or a pre-applied underfill, a grab-top material, or a liquid compression molding material. The epoxy resin composition is not limited to the use as the epoxy resin composition for semiconductor encapsulation described above, and can also be used, for example, as an adhesive for fixing, joining, or protecting components that constitute electronic components.

[0072] (Cured Product of Epoxy Resin Composition) A cured product is formed by curing the epoxy resin composition. The curing method is not particularly limited, but for example, the curing can be carried out by subjecting the epoxy resin composition to a heat treatment. The temperature of the heat treatment is not particularly limited, but for example, 60 to 200°C is preferred, and 80 to 180°C is more preferred. The time of the heat treatment is not particularly limited, but for example, 0.1 to 5 hours is preferred, and 0.5 to 3 hours is more preferred.

[0073] (Semiconductor Device) The semiconductor device of the present invention comprises a substrate, a semiconductor element disposed on the substrate, and a cured product of the epoxy resin composition that encapsulates the semiconductor element. The semiconductor device is preferably a flip-chip type semiconductor device. A flip-chip type semiconductor device has a structure in which an electrode portion on a substrate and the semiconductor element are connected via bump electrodes. In addition, in the semiconductor device, the gap between the semiconductor element and the substrate is encapsulated with a cured product (encapsulant) of the epoxy resin composition.

[0074] A semiconductor device can be manufactured by filling the gap between the substrate and a semiconductor element disposed on the substrate with the epoxy resin composition (filling step) and then heating and curing the epoxy resin composition (sealing step). The method for filling the gap with the epoxy resin composition is not particularly limited; for example, the epoxy resin composition can be applied to one end of the substrate or the semiconductor element while heating the substrate to 50 to 120°C, thereby filling the gap between the substrate and the semiconductor element with the epoxy resin composition by capillary action. After filling the gap with the epoxy resin composition, the substrate is heated at a predetermined temperature for a predetermined time, specifically, at the temperature and for the time described above for the heat treatment in forming the cured product, thereby sealing the gap.

[0075] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0076] The epoxy resin compositions of Examples 1 to 6 and Comparative Example 1 were prepared by mixing the epoxy resin (A), curing agent (B), inorganic filler (C), and core-shell rubber particles (D), as well as at least one selected from the group consisting of curing accelerator (E), coupling agent (F), and other component (G), as needed, in the blending ratios shown in Table 1. The numerical values ​​for each component in Table 1 indicate parts by mass.

[0077] Each component in Table 1 will be explained below. Epoxy resin (A) YDF-8170 (product name): bisphenol F type epoxy resin, epoxy equivalent 160 g / eq, liquid at 25°C, manufactured by Nippon Steel Chemical & Material Co., Ltd. HP-4032D (product name): naphthalene type epoxy resin, epoxy equivalent 140 g / eq, liquid at 25°C, manufactured by DIC Corporation jER630 (product name): aminophenol type epoxy resin, epoxy equivalent 98 g / eq, liquid at 25°C, manufactured by Mitsubishi Chemical Corporation ZX-1658GS (product name): 1,4-glycidylcyclohexane, epoxy equivalent 135 g / eq, liquid at 25°C, manufactured by Nippon Steel Chemical & Material Co., Ltd. Curing agent (B) HD A-A: product name / KAYAHARD A-A, 4,4'-methylenebis(2-ethylaniline), active hydrogen equivalent: 63 g / eq, manufactured by Nippon Kayaku Co., Ltd. EH-105L (product name): modified aromatic amine curing agent, active hydrogen equivalent: 61 g / eq, manufactured by ADEKA Corporation Ethacure 100plus (product name): diethyltoluenediamine, manufactured by Albemarle Corporation Inorganic filler (C) YA010A-JGP (product name): masterbatch of nanosilica with an average particle size of 10 nm and bisphenol F type epoxy resin (mass ratio of former: latter = 25:75), 2-(3,Nanosilica surface-treated with 4-epoxycyclohexyl)ethyltrimethoxysilane, manufactured by Admatechs Co., Ltd. The values ​​in Table 1 are the mass of nanosilica, and the mass of bisphenol F type epoxy resin is added to YDF-8170. SE5050-SEJ (product name): Silica surface-treated with 3-glycidoxypropyltrimethoxysilane, average particle size 1.5 μm, manufactured by Admatechs Co., Ltd. Core-shell rubber particles (D) Rubber particle 1: Core part / silicone rubber (polydimethylsiloxane), shell layer / core-shell rubber particles containing methacrylic acid, butyl acrylate, methyl methacrylate, and glycidyl methacrylate as constituent units (corresponding to core-shell rubber particles (D1)), average particle size: 0.3 μm Rubber particle 2: Core part / silicone rubber (polydimethylsiloxane), shell layer / core-shell rubber particles containing methyl methacrylate, glycidyl methacrylate, styrene, and acrylonitrile as constituent units (corresponding to core-shell rubber particles (D2)), average particle size: 0.3 μm. Curing accelerator (E) CG-1400 / product name is "AMICURE CG-1400": dicyandiamide, manufactured by Evonik Japan Co., Ltd. Coupling agent (F) KBM-403 (product name): 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. Other components (G) CB: Special Black 4 powder (product name), carbon black, manufactured by Orion Engineered Carbon Co., Ltd. TPP (product name): triphenylphosphine, thickening inhibitor, manufactured by Hokko Chemical Co., Ltd. Irganox 1010 (product name): pentaerythritol tetrakis[3-[3,5-di(tert-butyl)-4-hydroxyphenyl]propionate], antioxidant, manufactured by BASF Japan Ltd. KF-6013: polyether-modified silicone, surfactant, manufactured by Shin-Etsu Chemical Co., Ltd.

[0078] (Evaluation 1: Measurement of viscosity at 25°C) The viscosity (Pa s) at 25°C immediately after preparation of the epoxy resin compositions of Examples 1 to 6 and Comparative Example 1 was measured using a Brookfield viscometer (model number: HBDV-1, manufactured by Brookfield) at a liquid temperature of 25°C, while rotating at 50 rpm for 1 minute. The results are shown in the "25°C viscosity" column of the evaluation results in Table 1.

[0079] (Evaluation 2: Gap Filling Test) Preparation of Test Piece A test piece was obtained by sandwiching tape between two glass slides so that the gap between them was 50 μm, and then shifting the glass slides by 1 cm to secure the area where the evaluation sample was to be applied.

[0080] Test and Evaluation The above test piece was placed on a hot plate set at 110°C, and approximately 1 g of each of the epoxy resin compositions of Examples 1 to 6 and Comparative Example 1 was applied to the sample application section, and the time until the filling distance reached 20 mm was measured.

[0081] The gap filling test will be described using Figure 1. In Figure 1, 1 represents a test piece. 2 and 2' represent glass slides. 3 represents tape. 4 represents a gap. 5 represents an evaluation sample. (a) is a plan view of the test piece 1, with the longitudinal direction of the test piece 1 being vertical and the lateral direction being horizontal. (b) is a side view of the test piece 1 from the longitudinal direction. (c) is a side view of the test piece 1 from the lateral direction. The glass slide 2 is stacked on another glass slide 2' via tape 3. As shown in (b), the glass slide 2 and the glass slide 2' are stacked so that there is a 1 cm misalignment in the longitudinal direction. This misalignment is the application area (sample application area) of the evaluation sample 5. The gap 4 is a space surrounded by the glass slide 2 on its upper surface, the glass slide 2' on its lower surface, and two tapes 3 on its sides. In the gap 4, the distance between the glass slide 2 and the glass slide 2' is 50 μm, and the distance between the two tapes 3 is 10 mm. The longitudinal distance of the gap 4 is 70 mm. The test piece 1 is placed on a hot plate (not shown), and the evaluation sample 5 is applied to the sample application portion. The applied evaluation sample 5 moves downward through the gap 4 (a) due to capillary action. The time it takes for the evaluation sample 5 to reach the end of the glass slide 2' is measured and recorded as "gap filling time" in Table 1. The unit is seconds (s). It can be said that the shorter the gap filling time, the better the injectability.

[0082] (Evaluation 3: Elastic Modulus) - Preparation of Test Pieces The epoxy resin compositions of Example 1 and Comparative Example 1 were applied to a glass plate (120 mm x 120 mm, the silicone resin release agent being a mixture of toluene and KS841 (manufactured by Shin-Etsu Chemical Co., Ltd.) in a mass ratio of 5:1, further mixed with CAT-PL-50T (curing agent, manufactured by Shin-Etsu Chemical Co., Ltd.)) treated with a silicone resin release agent, to form a coating film measuring 50 mm x 10 mm or more. Another glass plate was then prepared, and the applied epoxy resin composition was sandwiched between the two. A 2.0 mm copper plate was sandwiched between the two plates, and the glass plate was secured with a 25 mm-wide double clip. The resulting mixture was left at 165°C for 2 hours to cure the coating. The cured coating was then peeled off from the glass plate and cut to the specified dimensions (50 mm x 10 mm x 2.0 mm) using a precision cutter to obtain test pieces.

[0083] Test and Evaluation The storage modulus (GPa) of the test specimen was measured by the DCB method using a DMA7100 manufactured by Hitachi High-Tech Science Corporation. The frequency was 1 Hz and the heating rate was 3°C / min. The storage modulus (GPa) at 30°C is shown in the "Elastic modulus (GPa)" of the evaluation results in Table 2.

[0084]

[0085]

[0086] The evaluation results can be considered as follows. (1) From the viewpoint of the viscosity and injectability of the epoxy resin composition, it is preferable that the shell layer of the core-shell rubber particles contain butyl (meth)acrylate as a structural unit. This is thought to be due to the fact that the number of carbon atoms in the side chain (acrylic group) is greater than when methyl (meth)acrylate or ethyl (meth)acrylate is contained as a structural unit, thereby improving the wettability between the core-shell rubber particles and the epoxy resin (A). The reason for the improved wettability is not clear, but the following reasons are thought to be the cause: (a) The long side chains of the shell layer make the shell layer more hydrophobic, improving compatibility with the epoxy resin; and (b) even if there is a portion of the core that is not covered by the shell layer (referred to as the "exposed portion"), the long side chains of the shell layer allow the side chains to cover the exposed portion, thereby enabling the core-shell rubber particles to exhibit high compatibility with the epoxy resin, as in (a). (2) From the viewpoint of compatibility with the epoxy resin (A), it is preferable that the shell layer of the core-shell rubber particles does not contain, as a constituent unit, an aromatic vinyl compound such as styrene or a vinyl cyanide compound such as acrylonitrile. In particular, since the molecular skeleton derived from the aromatic vinyl compound is large, it is thought that the liquid properties will be poor (for example, the viscosity will increase) due to steric hindrance.

[0087] It can be said that there is a certain degree of correlation between the low viscosity of an epoxy resin composition and excellent injectability. However, since injectability is affected not only by the viscosity of the epoxy resin composition but also by factors such as the contact angle, surface tension, and reactivity, reducing the viscosity does not necessarily lead to improved injectability. From this perspective, it can be said that the epoxy resin composition of the present invention is effective in that it has the characteristics of low viscosity and excellent injectability.

[0088] In summary, the configuration of the present disclosure and its variations are described below. [1] An epoxy resin composition comprising: an epoxy resin (A), a curing agent (B), an inorganic filler (C), and core-shell rubber particles (D), wherein the core-shell rubber particles (D) comprise core-shell rubber particles (D1) whose shell layers contain (meth)acrylic acid and butyl (meth)acrylate as structural units. [2] The epoxy resin composition according to [1], wherein the epoxy resin (A) comprises at least one selected from the group consisting of bisphenol-type epoxy resins, naphthalene-type epoxy resins, aminophenol-type epoxy resins, cyclohexane-type epoxy resins, and glycidylamine-type epoxy resins; at least one selected from the group consisting of bisphenol F-type epoxy resins, naphthalene-type epoxy resins, aminophenol-type epoxy resins, and cyclohexane-type epoxy resins (particularly 1,4-glycidylcyclohexane); or at least one selected from the group consisting of bisphenol-type epoxy resins, aminophenol-type epoxy resins, and naphthalene-type epoxy resins. [3] The epoxy resin composition according to [1] or [2], wherein the content of the bisphenol-type epoxy resin relative to the epoxy resin (A) (100% by mass) is 0 to 100% by mass. [4] The epoxy resin composition according to any one of [1] to [3], wherein the content of the naphthalene-type epoxy resin relative to the epoxy resin (A) (100% by mass) is 0 to 50% by mass. [5] The epoxy resin composition according to any one of [1] to [4], wherein the content of the aminophenol-type epoxy resin relative to the epoxy resin (A) (100% by mass) is 0 to 90% by mass. [6] The epoxy resin composition according to any one of [1] to [5], wherein the content of the cyclohexane-type epoxy resin relative to the epoxy resin (A) (100% by mass). [7] The epoxy resin composition according to any one of [1] to [6], wherein the epoxy equivalent of the epoxy resin (A) is 30 to 1000 g / eq, 40 to 500 g / eq, or 50 to 300 g / eq.[8] The epoxy resin composition according to any one of [1] to [7], wherein the content of the epoxy resin (A) is 5% by mass or more, 8% by mass or more, 10% by mass or more, or 12% by mass or more, and / or 60% by mass or less, 50% by mass or less, 45% by mass or less, or 40% by mass or less. [9] The epoxy resin composition according to any one of [1] to [8], wherein the curing agent (B) is at least one selected from the group consisting of an amine-based curing agent, an acid anhydride-based curing agent, and a phenol-based curing agent, or is an amine-based curing agent.

[10] The epoxy resin composition according to any one of [1] to [9], wherein the amine curing agent is an aromatic amine or at least one selected from the group consisting of 4,4'-methylenebis(2-ethylaniline), ethyltoluenediamine, diethyltoluenediamine (such as 3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine), 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane, and dimethylthiotoluenediamine.

[11] The epoxy resin composition according to any one of [1] to

[10] , wherein the equivalent weight (molecular weight per functional group) of the curing agent (B) is 10 to 300 g / eq, 20 to 160 g / eq, or 30 to 100 g / eq.

[12] The epoxy resin composition according to any one of [1] to

[11] , wherein the content of the curing agent (B) is an amount such that the stoichiometric equivalent ratio (curing agent equivalent / epoxy group equivalent) with the epoxy resin (A) is 0.5 to 1.5, or 0.8 to 1.2.

[13] The epoxy resin composition according to any one of [1] to

[12] , wherein the content of the curing agent (B) is 2% by mass or more, 4% by mass or more, or 5% by mass or more, and / or 30% by mass or less, 20% by mass or less, 15% by mass or less, or 12% by mass or less.

[14] The epoxy resin composition according to any one of [1] to

[13] , containing silica having an average particle size of 100 nm or less as the inorganic filler (C).

[15] The epoxy resin composition according to any one of [1] to

[14] , wherein the content of the inorganic filler (C) relative to the epoxy resin composition (100% by mass) is 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, and / or 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[16] The epoxy resin composition according to

[14] , wherein the content of silica having an average particle size of 100 nm or less relative to the inorganic filler (C) (100% by mass) is 0.1 to 30% by mass, 0.1 to 20% by mass, 0.1 to 10% by mass, or 0.3 to 5% by mass.

[17] The epoxy resin composition according to any one of [1] to

[16] , wherein the shell layer of the core-shell rubber particles (D1) further contains, as a structural unit, at least one selected from the group consisting of methyl (meth)acrylate and glycidyl (meth)acrylate.

[18] The epoxy resin composition according to any one of [1] to

[17] , wherein the core-shell rubber particles (D1) have an average particle size of 0.03 to 1.0 μm, 0.04 to 0.8 μm, or 0.05 to 0.7 μm.

[19] The epoxy resin composition according to any one of [1] to

[18] , wherein the content of the core-shell rubber particles (D) is 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, and / or 0.1% by mass or more, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more.

[20] The epoxy resin composition according to any one of [1] to

[19] , wherein the content of the core-shell rubber particles (D1) is 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, and / or 0.1% by mass or more, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more.

[21] The epoxy resin composition according to any one of [1] to

[20] , wherein the content of the core-shell rubber particles (D) relative to the total amount (100% by mass) of the epoxy resin (A) and the curing agent (B) is 1 to 60% by mass, 1 to 45% by mass, or 1 to 30% by mass.

[22] The epoxy resin composition according to any one of [1] to

[21] , wherein the content of the core-shell rubber particles (D1) relative to the total amount (100% by mass) of the epoxy resin (A) and the curing agent (B) is 1 to 60% by mass, 1 to 45% by mass, or 1 to 30% by mass.

[23] The epoxy resin composition according to any one of [1] to

[22] , wherein the shell layer of the core-shell rubber particles (D1) is substantially free of styrene, acrylonitrile, and methacrylonitrile as structural units.

[24] The epoxy resin composition according to any one of [1] to

[23] , which is used for semiconductor encapsulation.

[25] A cured product of the epoxy resin composition according to any one of [1] to

[24] .

[26] A semiconductor device comprising: a substrate; a semiconductor element disposed on the substrate; and the cured product according to

[25] that encapsulates the semiconductor element.

[27] A method for producing a semiconductor device, comprising: filling a gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition according to any one of [1] to

[24] ; and heating and curing the epoxy resin composition.

[0089] The epoxy resin composition of the present invention has low viscosity and is therefore easy to handle. Furthermore, its excellent injectability allows efficient filling of gaps with the epoxy resin composition, even when manufacturing semiconductor devices using large substrates such as interposers. Furthermore, due to the above-mentioned properties, the composition can contain a larger amount of core-shell rubber particles than conventional epoxy resin compositions. Therefore, it is possible to adjust the cured product of the epoxy resin composition to exhibit a low modulus of elasticity. Therefore, a semiconductor device comprising a cured product of the epoxy resin composition can encapsulate semiconductor elements with high precision using the cured product, and exhibits high reliability due to reduced stress applied to the cured product of the epoxy resin composition.

[0090] REFERENCE SIGNS LIST 1 Test piece 2 Slide glass 2' Slide glass 3 Tape 4 Gap 5 Evaluation sample

Claims

1. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B), an inorganic filler (C), and core-shell rubber particles (D), wherein the core-shell rubber particles (D) include core-shell rubber particles (D1) whose shell layer contains (meth)acrylic acid and butyl (meth)acrylate as structural units.

2. The epoxy resin composition according to claim 1, wherein the shell layer of the core-shell rubber particles (D1) further contains at least one structural unit selected from the group consisting of methyl (meth)acrylate and glycidyl (meth)acrylate.

3. The epoxy resin composition according to claim 1 or 2, wherein the content of the core-shell rubber particles (D1) is 1 to 30 mass% relative to the total amount (100 mass%) of the epoxy resin (A) and the curing agent (B).

4. The epoxy resin composition according to claim 1 or 2, wherein the core-shell rubber particles (D1) have an average particle size of 0.03 to 1.0 μm.

5. An epoxy resin composition according to claim 1 or 2, wherein the content of the inorganic filler (C) relative to the epoxy resin composition (100% by mass) is 50% by mass or more.

6. The epoxy resin composition according to claim 1 or 2, which contains silica having an average particle size of 100 nm or less as the inorganic filler (C).

7. The epoxy resin composition according to claim 1 or 2, wherein the epoxy resin (A) comprises at least one selected from the group consisting of bisphenol-type epoxy resins, aminophenol-type epoxy resins, and naphthalene-type epoxy resins.

8. The epoxy resin composition according to claim 1 or 2, wherein the curing agent (B) is an amine-based curing agent.

9. The epoxy resin composition according to claim 1 or 2, wherein the shell layer of the core-shell rubber particles (D1) is substantially free of styrene, acrylonitrile, and methacrylonitrile as structural units.

10. The epoxy resin composition according to claim 1 or 2, which is used for semiconductor encapsulation.

11. A cured product of the epoxy resin composition according to claim 1 or 2.

12. A semiconductor device comprising: a substrate; a semiconductor element disposed on the substrate; and the cured product according to claim 11 that seals the semiconductor element.

13. A method for manufacturing a semiconductor device, comprising: a step of filling a gap between a substrate and a semiconductor element arranged on the substrate with the epoxy resin composition according to claim 1 or 2; and a step of heating and curing the epoxy resin composition.

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