resin composition

Abstract

To provide a novel resin composition that can give a cured product having excellent dielectric properties, the resin composition also having excellent flowability.SOLUTION: A resin composition comprises a substituted styrene monomer (A) represented by general formula (1) and an epoxy resin (B) (where R1 is an optionally substituted C1 to 6 alkyl group, or an optionally substituted aryl group, R2 is a substituent, and n is a number selected from 0-4).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition. This resin composition exhibits excellent properties, including fluidity, and can be suitably applied, for example, to adhesives, casting materials, fiber-reinforced composite materials, semiconductor encapsulants, underfill materials, and mold underfill materials. The present invention further relates to cured products, semiconductor chip packages, and semiconductor devices obtained using this resin composition. [Background technology]

[0002] Resin compositions containing epoxy resins have been widely used as insulating materials for electronic components such as semiconductor chip packages and printed circuit boards because they produce cured products with excellent insulation, heat resistance, and adhesion. Furthermore, resin compositions using liquid epoxy resins or acid anhydrides as curing agents are liquid at room temperature and have excellent fluidity, so they have been used in liquid compounded products such as adhesives, casting materials, fiber-reinforced composite materials, semiconductor encapsulants, underfill materials, and mold underfill materials.

[0003] In recent years, particularly with the increasing multi-die design of semiconductors, chips have tended to become larger in area, and underfill materials used to fill the narrow gap between printed circuit boards and semiconductor chips are increasingly required to have high fluidity. The same demand for high fluidity exists for other liquid compound products as well. For example, in semiconductor encapsulants and mold underfill materials, the further miniaturization, higher integration, and multi-functionality of electronic devices have led to smaller bump diameters, narrower pitches, and narrower gaps due to the increase in the number of pins. Furthermore, there is a demand for encapsulating large areas at once, such as in wafer-level packages (WLP) and panel-level packages (PLP), and the flow path of the encapsulant during encapsulation molding has become more complex, thus requiring even better fluidity.

[0004] As resin compositions with excellent fluidity, for example, Patent Documents 1 and 2 disclose resin compositions containing a liquid epoxy resin and a carboxyl group-containing radical polymerizable monomer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-24316 [Patent Document 2] Japanese Patent Publication No. 2011-38049 [Overview of the project] [Problems that the invention aims to solve]

[0006] On the other hand, in high-speed communications such as fifth-generation mobile communication systems (5G), transmission loss when operating in a high-frequency environment becomes a problem. Therefore, insulating materials with dramatically superior dielectric properties (low dielectric constant, low dielectric loss tangent) are required. In particular, semiconductor devices operating in high-frequency environments require extremely low dielectric constant and dielectric loss tangent.

[0007] In this regard, resin compositions containing epoxy resins tend to have deteriorated dielectric properties because a high concentration of hydroxyl groups is generated during the curing reaction. Liquid epoxy resins, in particular, have a particularly high concentration of epoxy groups due to their low molecular weight, and therefore a particularly high concentration of hydroxyl groups is generated in the cured product, which further deteriorates the dielectric properties of the cured product. For example, Patent Documents 1 and 2 disclose resin compositions with excellent fluidity, but although the resin compositions described in these patent documents have significantly lower viscosity and excellent fluidity compared to conventional resin compositions using acid anhydride curing agents, their dielectric properties are not improved and do not overcome the tendency of dielectric properties of epoxy resin cured products (deterioration of dielectric properties due to the use of liquid epoxy resins) mentioned above.

[0008] In recent years, active ester-based curing agents that do not generate hydroxyl groups during the curing reaction have become widespread. However, because these active ester-based curing agents are solid resins with high viscosity and high softening points, they do not become liquid when mixed with liquid epoxy resins. Furthermore, inorganic fillers are sometimes added to the resin composition from the viewpoint of obtaining cured products with even lower dielectric loss tangents, but the fluidity tends to deteriorate as the content of inorganic fillers in the resin composition increases.

[0009] Based on such technological trends and technical knowledge, there is a strong demand for a resin composition that can provide a cured product with excellent dielectric properties and also has good fluidity.

[0010] An object of the present invention is to provide a novel resin composition that can provide a cured product with excellent dielectric properties and also has good fluidity.

Means for Solving the Problems

[0011] As a result of intensive studies, the present inventors have found that by using a specific substituted styrene monomer having an organic carbonyloxy group in combination with an epoxy resin, a resin composition can be realized that exhibits excellent fluidity before curing and excellent dielectric properties after curing. According to such a resin composition, from the viewpoint of obtaining a cured product with a lower dielectric tangent, it is possible to ensure good fluidity even when an inorganic filler is blended, and it has also been found that a cured product with extremely excellent dielectric properties can be realized by highly blending components such as an inorganic filler. The present invention is based on such findings.

[0012] That is, the present invention includes the following contents. [1] A resin composition containing a substituted styrene monomer (A) represented by the following general formula (1) and an epoxy resin (B).

Chemical formula

[10] The resin composition according to any one of [1] to [9], wherein the molar ratio of the total epoxy groups in component (A) and component (B) (component (A): total epoxy groups in component (B)) is in the range of 70:30 to 30:70. [[ID=,15]]

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

[10] , having a viscosity at 25 °C of 100 mPa·s or less.

[12] The resin composition according to any one of [1] to [,11], wherein when the non-volatile components in the resin composition are 100% by mass, the content of the inorganic filler is 60% by mass or more.

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

[10] ,

[12] , wherein when the non-volatile components in the resin composition are 100% by mass, the content of the inorganic filler is 85% by mass or more and the viscosity at 25 °C is 1000 mPa·s or less.

[14] The resin composition according to

[12] or

[13] , wherein when the non-volatile components in the resin composition are 100% by mass, the content of the organic filler is 1% by mass or more and the viscosity at 25 °C is 1000 mPa·s or less.

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

[14] , which is for an adhesive, a casting material, a fiber reinforced composite material, semiconductor encapsulation, an underfill, or a mold underfill.

[16] A cured product of any of the resin compositions described in [1] to

[15] .

[17] The cured product according to

[16] , wherein the dielectric constant at 5.8 GHz is 3.0 or less.

[18] The cured product according to

[16] or

[17] , wherein the dielectric loss tangent at 5.8 GHz is 0.012 or less.

[19] A semiconductor chip package comprising a cured product of any of the resin compositions described in [1] to

[15] .

[20] A fan-out type semiconductor chip package, as described in

[19] .

[21] A semiconductor device comprising a cured product of any of the resin compositions described in [1] to

[15] . [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a novel resin composition that yields a cured product with excellent dielectric properties and good fluidity.

[0014] According to the resin composition of the present invention, good fluidity can be ensured even when inorganic fillers are incorporated, and it is also possible to achieve a cured product with exceptionally superior dielectric properties by incorporating inorganic fillers and other components in extremely high concentrations. [Modes for carrying out the invention]

[0015] <Explanation of Terms> In this specification, the term “may have substituents” with respect to a compound or group means both cases where the hydrogen atoms of the compound or group are not substituted with substituents, and cases where some or all of the hydrogen atoms of the compound or group are substituted with substituents.

[0016] In this specification, the term "substituent" means, unless otherwise specified, a halogen atom, alkyl group, alkenyl group, cycloalkyl group, alkoxy group, cycloalkyloxy group, aryl group, aryloxy group, arylalkyl group, arylalkoxy group, monovalent heterocyclic group, alkylidene group, amino group, silyl group, carboxyl group, sulfo group, cyano group, nitro group, hydroxyl group, mercapto group, and oxo group.

[0017] Examples of halogen atoms used as substituents include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The alkyl group used as a substituent may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3. The alkenyl group used as a substituent may be linear or branched. The number of carbon atoms in the alkenyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 or 3. The number of carbon atoms in the cycloalkyl group used as a substituent is preferably 3 to 12, more preferably 3 to 6. The alkoxy group used as a substituent may be linear or branched. The number of carbon atoms in the alkoxy group is preferably 1 to 12, more preferably 1 to 6. The number of carbon atoms in the cycloalkyloxy group used as a substituent is preferably 3 to 12, more preferably 3 to 6. The aryl group used as a substituent is a group obtained by removing one hydrogen atom from the aromatic ring of an aromatic hydrocarbon. The number of carbon atoms in the aryl group used as a substituent is preferably 6 to 14, more preferably 6 to 10. The number of carbon atoms in the aryloxy group used as a substituent is preferably 6 to 14, more preferably 6 to 10. The number of carbon atoms in the arylalkyl group used as a substituent is preferably 7 to 15, more preferably 7 to 11. The number of carbon atoms in the arylalkoxy group used as a substituent is preferably 7 to 15, more preferably 7 to 11. A monovalent heterocyclic group used as a substituent refers to a group obtained by removing one hydrogen atom from the heterocycle of a heterocyclic compound. The number of carbon atoms in the monovalent heterocyclic group is preferably 3 to 15, more preferably 3 to 9. An alkylidene group used as a substituent refers to a group obtained by removing two hydrogen atoms from the same carbon atom of an alkane. The number of carbon atoms in the alkylidene group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3. The above substituents may have further substituents (hereinafter sometimes referred to as "secondary substituents"). Unless otherwise specified, the same substituents as above may be used as secondary substituents.

[0018] The present invention will be described in detail below with reference to its preferred embodiments. However, the present invention is not limited to the embodiments and examples described below, and can be implemented with modifications as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0019] [Resin composition] The resin composition of the present invention is characterized by comprising a substituted styrene monomer (A) represented by the following general formula (1) and an epoxy resin (B).

[0020] [ka] (In the formula, R 1 This represents an alkyl group having 1 to 6 carbon atoms, which may have substituents, or an aryl group, which may have substituents. R 2 This indicates a substituent, n represents a number between 0 and 4.

[0021] The inventors have discovered that by using the substituted styrene monomer (A) represented by the above general formula (1) in combination with an epoxy resin, it is possible to realize a resin composition that yields a cured product exhibiting excellent dielectric properties regardless of the type of epoxy resin used. For example, they have found that even when using a liquid epoxy resin, it is possible to achieve excellent dielectric properties without using conventional active ester-based curing agents. Furthermore, they have found that a resin composition containing a combination of the substituted styrene monomer (A) and an epoxy resin exhibits exceptionally low viscosity and excellent fluidity. With such a resin composition, it is possible to ensure good fluidity even when inorganic fillers are incorporated, from the viewpoint of obtaining a cured product with an even lower dielectric loss tangent, and it is also possible to achieve a cured product with exceptionally excellent dielectric properties by incorporating extremely high concentrations of inorganic fillers and other components. Thus, the resin composition of the present invention, containing a combination of the substituted styrene monomer (A) and an epoxy resin, can realize a cured product with excellent dielectric properties and can also contribute to the improvement of fluidity, thus significantly contributing to the provision of various liquid compounded products that require good fluidity, including insulating materials with low transmission loss required for 5G applications.

[0022] -Substituted styrene monomer (A)- The substituted styrene monomer (A) has a structure represented by general formula (1). Such a substituted styrene monomer (A) exhibits low viscosity and excellent fluidity when combined with epoxy resin (B), and can react with epoxy resin (B) without generating hydroxyl groups during curing. Furthermore, it can crosslink with other substituted styrene monomers (A) (and with the radical polymerizable monomer (C) described later, if present) via the vinyl groups in its structure, thus enabling the creation of a cured product with extremely excellent dielectric properties.

[0023] In general formula (1), R 1 This represents an alkyl group having 1 to 6 carbon atoms, which may have substituents, or an aryl group, which may have substituents.

[0024] R 1The alkyl group having 1 to 6 carbon atoms in [compound] refers to a monovalent group obtained by removing one hydrogen atom from a saturated hydrocarbon having 1 to 6 carbon atoms, and may be either linear or branched. From the viewpoint of realizing a resin composition excellent in both fluidity and dielectric properties in combination with the epoxy resin (B), the number of carbon atoms of the alkyl group is in the range of 1 to 6, preferably 1 to 5, more preferably 1 to 4, and even more preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group.

[0025] R 1 The aryl group in [compound] refers to a monovalent group obtained by removing one hydrogen atom on the aromatic ring from an aromatic hydrocarbon. From the viewpoint of realizing a resin composition excellent in both fluidity and dielectric properties in combination with the epoxy resin (B), the number of carbon atoms of the aryl group is preferably 6 to 14, more preferably 6 to 10. Examples of the aryl group include a phenyl group, a naphthyl group, and an anthracenyl group.

[0026] R 1 The substituent that the alkyl group or aryl group in [compound] may have is as described above. Among them, from the viewpoint of realizing a resin composition more excellent in both fluidity and dielectric properties in combination with the epoxy resin (B), one or more selected from a halogen atom, an alkyl group, and an aryl group are preferable, and one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms are more preferable.

[0027] Among them, from the viewpoint of realizing a resin composition even more excellent in both fluidity and dielectric properties in combination with the epoxy resin (B), R in the general formula (1) 1 preferably represents an alkyl group having 1 to 3 carbon atoms which may have a substituent, or an aryl group having 6 carbon atoms which may have a substituent (that is, a phenyl group), and more preferably represents an alkyl group having 1 to 3 carbon atoms which may have a substituent. The preferred types of the substituent are as described above.

[0028] In general formula (1), formula: -OC(=O)-R 1 The bonding position of the monovalent group represented by is not particularly limited, but in combination with epoxy resin (B), from the viewpoint of realizing a resin composition that is even better in both fluidity and dielectric properties, it is preferably the meta or para position in relation to the bonding position of the vinyl group, and the para position is particularly preferred.

[0029] In general formula (1), R 2 R indicates a substituent. 2 The substituents represented by are as described above. In particular, in combination with epoxy resin (B), from the viewpoint of realizing a resin composition that is excellent in both fluidity and dielectric properties, one or more selected from halogen atoms, alkyl groups, and aryl groups are preferred, and one or more selected from fluorine atoms, alkyl groups having 1 to 6 carbon atoms, and aryl groups having 6 to 10 carbon atoms are more preferred. 2 If multiple instances exist, they may be identical or distinct from one another.

[0030] In general formula (1), n ​​represents a number between 0 and 4. For example, R 2 If represents a halogen atom, n can be appropriately determined within the range of 0 to 4, and R 2 If n represents an atom other than a halogen atom, then n is preferably 0 to 2, more preferably 0 or 1.

[0031] In combination with epoxy resin (B), from the viewpoint of realizing a resin composition that is even superior in both fluidity and dielectric properties, the substituted styrene monomer (A) is preferably one or more selected from the group consisting of optionally substituted C1-C3 alkylcarbonyloxystyrene and optionally substituted C6 arylcarbonyloxystyrene, more preferably optionally substituted C1 alkylcarbonyloxystyrene (i.e., acetoxystyrene), and among these, acetoxystyrene is particularly preferred.

[0032] In the resin composition of the present invention, the substituted styrene monomer (A) may be used alone or in combination of two or more types.

[0033] In the resin composition of the present invention, the content of substituted styrene monomer (A) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, 22% by mass or more, 24% by mass or more, or 25% by mass or more, when the resin components in the resin composition are considered as 100% by mass, and the upper limit is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, 54% by mass or less, 52% by mass or less, or 50% by mass or less. In the present invention, "resin components" as used in reference to the resin composition refers to the non-volatile components constituting the resin composition, excluding the inorganic fillers described later.

[0034] The method for synthesizing the substituted styrene monomer (A) is not particularly limited, and it may be synthesized according to any conventionally known method as long as the structure represented by the general formula (1) above is realized. For example, it may be synthesized according to a method using acyloxyphenylmethylcarbinol as a starting material (U.S. Patent Nos. 5,041,614 and 5,151,546), a method by hydrogenation of acyloxyacetophenone (U.S. Patent No. 5,084,533), or a method by acyloxylation of phenylmethylcarbinol (Japanese Patent Publication No. 2000-502045). The acyloxy group in the starting material (-OC(=O)-R in the general formula (1) above) 1 The type of (corresponding to) and substituents on the benzene ring in the raw material (R in the above general formula (1)) 2 By making various changes to the (corresponding to) the above, a substituted styrene monomer (A) having the desired structure can be synthesized.

[0035] Furthermore, commercially available substituted styrene monomers (A) may also be used. Commercially available substituted styrene monomers (A) include, for example, "acetoxystyrene" (4-acetoxystyrene) manufactured by Tokyo Chemical Industry Co., Ltd., as well as 3-acetoxystyrene, 2-acetoxystyrene, 4-vinylphenylbenzoate, and other substituted styrene monomers available from various suppliers.

[0036] -Epoxy resin (B)- In the resin composition of the present invention, the type of epoxy resin (B) is not particularly limited, as long as it can be cured in the presence of a substituted styrene monomer (A).

[0037] In combination with a substituted styrene monomer (A), from the viewpoint of realizing a resin composition that is excellent in both fluidity and dielectric properties, it is preferable that the epoxy resin (B) is a liquid epoxy resin at 25°C (hereinafter also referred to as "liquid epoxy resin"). Therefore, in one preferred embodiment, the epoxy resin (B) is liquid at 25°C. In the present invention, "liquid" with respect to the epoxy resin means that the viscosity of the epoxy resin at 25°C is 30,000 mPa·s or less, and more preferably 25,000 mPa·s or less, more preferably 20,000 mPa·s or less, and even more preferably 15,000 mPa·s or less, 10,000 mPa·s or less, 8,000 mPa·s or less, 6,000 mPa·s or less, or 5,000 mPa·s or less.

[0038] According to the present invention, which uses a substituted styrene monomer (A), even when using a low-viscosity liquid epoxy resin (which, as mentioned above, tends to cause deterioration of the dielectric properties of the cured product), it is possible to achieve excellent dielectric properties without using conventional active ester-based curing agents.

[0039] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0040] Preferred liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, hydrogenated bisphenol A type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure.

[0041] Specific examples of liquid epoxy resins include DIC's "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "828EL," "jER828EL," and "825" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac-type epoxy resin); Mitsubishi Chemical's "630," "630LSD," and "604" (glycidylamine-type epoxy resin); ADEKA's "ED-523T" (glycyrrol-type epoxy resin); ADEKA's "EP-3950L" and "EP-3980S" (glycidylamine-type epoxy resin); and ADEKA's "EP-4088S" (glycidylamine-type epoxy resin). Examples include: chloropentadiene-type epoxy resin; "ZX1059" from Nippon Steel Chemical & Material (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin); "EX-721" from Nagase ChemteX (glycidyl ester-type epoxy resin); "Celoxide 2021P" from Daicel Corporation (alicyclic epoxy resin with an ester skeleton); "PB-3600" from Daicel Corporation, "JP-100" and "JP-200" from Nippon Soda Co., Ltd. (epoxy resins with a butadiene structure); "ZX1658" and "ZX1658GS" from Nippon Steel Chemical & Material (1,4-glycidylcyclohexane-type epoxy resin); "YX8000" from Mitsubishi Chemical Corporation (hydrogenated bisphenol A-type epoxy resin); and "KF-101" from Shin-Etsu Chemical Co., Ltd. (epoxy-modified silicone resin).

[0042] The epoxy group equivalent of epoxy resin (B) is preferably in the range of 50 g / eq. to 300 g / eq., with its upper limit more preferably 250 g / eq. or less, even more preferably 240 g / eq. or less, 220 g / eq. or less, 200 g / eq. or less, or 180 g / eq. or less. The epoxy group equivalent is the mass of resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0043] In the resin composition of the present invention, epoxy resin (B) may be used alone or in combination of two or more types.

[0044] From the viewpoint of realizing a resin composition that is excellent in both fluidity and dielectric properties, it is preferable to include components (A) and (B) in a ratio such that the molar ratio of the substituted styrene monomer (A) to the total epoxy groups in the epoxy resin (B) (component (A): total epoxy groups in component (B)) is preferably in the range of 70:30 to 30:70, more preferably in the range of 60:40 to 40:60.

[0045] In the resin composition of the present invention, the content of epoxy resin (B) may be appropriately determined to satisfy the content of substituted styrene monomer (A) and the above-mentioned preferred molar ratio. From the viewpoint of realizing a resin composition that is excellent in both fluidity and dielectric properties, when the resin component in the resin composition is taken as 100% by mass, it is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, 22% by mass or more, 24% by mass or more, or 25% by mass or more, and the upper limit is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, 54% by mass or less, 52% by mass or less, or 50% by mass or less.

[0046] -Radical polymerizable monomer (C)- The resin composition of the present invention may further contain a radical polymerizable monomer (C) other than component (A). By including component (C), a resin composition with even better fluidity and dielectric properties can be realized.

[0047] The radical polymerizable monomer (C) is not particularly limited in type as long as it is a monomer having a radical polymerizable unsaturated group, but vinyl monomers are preferred, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and hydroxyethyl (meth)acrylate. (Meth)acrylic acid esters such as cyclododecyl lylate; unsaturated monomers containing carboxyl groups such as methyl, such as meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, maleic anhydride, etc.; unsaturated monomers containing tertiary amines such as N,N-dimethylaminopropyl(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, 2-(dimethylamino)ethyl(meth)acrylate, N,N-dimethylaminopropyl(meth)acrylate, etc.; N-2-hydroxy-3-acryloyloxypropyl -N,N,N-trimethylammonium chloride, N-methacryloylaminoethyl-N,N,N-dimethylbenzylammonium chloride and other quaternary ammonium base-containing unsaturated monomers; epoxy group-containing unsaturated monomers such as (meth)acrylate glycidyl; styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, pt-butylstyrene, pn-butylstyrene, p-tert-butoxystyrene, 2-hydroxymethylstyrene, 2-chlorostyrene, 4- Aromatic unsaturated monomers (styrene-based monomers) such as chlorostyrene, 2,4-dichlorostyrene, 1-vinylnaphthalene, divinylbenzene, p-styrenesulfonic acid or its alkali metal salts (sodium salt, potassium salt, etc.); heterocyclic unsaturated monomers such as 2-vinylthiophene, N-methyl-2-vinylpyrrole, 1-vinyl-2-pyrrolidone, 2-vinylpyridine, and 4-vinylpyridine; vinylamides such as N-vinylformamide and N-vinylacetamide; α-olefins such as 1-hexene, 1-octene, and 1-decene;Examples include dienes such as butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene; carbonyl group-containing unsaturated monomers such as methyl vinyl ketone and ethyl vinyl ketone; (meth)acrylamide monomers such as vinyl acetate, vinyl benzoate, hydroxyethyl (meth)acrylate, (meth)acrylonitrile, (meth)acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N,N-dimethyl(meth)acrylamide; and vinyl chloride and vinylidene chloride.

[0048] In particular, in combination with a substituted styrene monomer (A) and an epoxy resin (B), from the viewpoint of realizing a resin composition that is even superior in both fluidity and dielectric properties, the radical polymerizable monomer (C) is preferably one or more selected from (meth)acrylic acid esters, carboxyl group-containing unsaturated monomers, epoxy group-containing unsaturated monomers, aromatic unsaturated monomers (styrene-based monomers), α-olefins, carbonyl group-containing unsaturated monomers, and (meth)acrylamide-based monomers; more preferably one or more selected from (meth)acrylic acid esters, carboxyl group-containing unsaturated monomers, and aromatic unsaturated monomers (styrene-based monomers); and even more preferably one or more selected from (meth)acrylic acid esters and aromatic unsaturated monomers (styrene-based monomers).

[0049] In one embodiment, the radical polymerizable monomer (C) includes a carboxyl group-containing radical polymerizable monomer (for example, the carboxyl group-containing unsaturated monomer described above). In such an embodiment, from the viewpoint of realizing a resin composition that is even better in both fluidity and dielectric properties, when the total of components (A), (B), and (C) is 100% by mass, the content of the carboxyl group-containing radical polymerizable monomer is preferably 20% by mass or less, more preferably 15% by mass or less, 10% by mass or less, or 5% by mass or less. The lower limit of the content is not particularly limited and may be 0% by mass, or it may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more.

[0050] When the resin composition of the present invention contains a radical polymerizable monomer (C), the content of component (C) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, 22% by mass or more, 24% by mass or more, or 25% by mass or more, when the total resin components in the resin composition are considered as 100% by mass, and the upper limit is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, 54% by mass or less, 52% by mass or less, or 50% by mass or less.

[0051] - Radical polymerization catalyst - The resin composition of the present invention may further contain a radical polymerization catalyst. By including a radical polymerization catalyst, the reaction of component (A) and, if present, component (C) during the curing of the resin composition of the present invention can be promoted, and the curing time and curing temperature can be efficiently adjusted.

[0052] As the radical polymerization catalyst, it is preferable to use a thermal radical polymerization catalyst that generates radicals by applying thermal energy.

[0053] Examples of thermal radical generators include dialkyl peroxides such as di-t-butyl peroxide, dicumyl peroxide, and t-hexyl peroxy-2-ethylhexanoate; diacyl peroxides such as lauroyl peroxide, benzoyl peroxide, benzoyl toluyl peroxide, and toluyl peroxide; peracid esters such as t-butyl peracetate, t-butyl peroxyoctoate, and t-butyl peroxybenzoate; ketone peroxides; peroxycarbonates; peroxyketals such as 1,1-di(t-amyl peroxy)cyclohexane; 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), and 2,2'-azobis(2-methylbutyro Examples include azonitrile compounds such as nitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), azoamide compounds such as 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, azoamidine compounds such as 2,2'-azobis(2-amidinopropane) dihydrochloride and 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, azoalkane compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 4,4'-azobis(4-cyanopentanoic acid), azo compounds having an oxime skeleton such as 2,2'-azobis(2-methylpropionamide oxime), and azo compounds such as 2,2'-azobis(isobutyric acid)dimethyl. A thermal radical polymerization catalyst may be used alone or in combination of two or more types. Among the radical polymerization catalysts mentioned above, dialkyl peroxides, diacyl peroxides, peracid esters, ketone peroxides, peroxycarbonates, and peroxyketals are collectively referred to as "peroxide-based radical polymerization catalysts."

[0054] As a radical polymerization catalyst, it is preferable to use a peroxide-based thermal radical polymerization catalyst from the viewpoint of being able to better enjoy the effects of the present invention.

[0055] When the resin composition of the present invention contains a radical polymerization catalyst, the content of the radical polymerization catalyst is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, when the resin components in the resin composition are considered as 100% by mass, and the upper limit is preferably 3% by mass or less, more preferably 2% by mass or less, 1.8% by mass or less, 1.6% by mass or less, or 1.5% by mass or less.

[0056] -Organic bases- The resin composition of the present invention may further contain an organic base. By including an organic base, the reaction of components (A) and (B) during the curing of the resin composition of the present invention can be promoted, and the curing time and curing temperature can be efficiently adjusted.

[0057] As the organic base, it is preferable to use one or more selected from conventionally known amine-based curing accelerators, organophosphorus-based curing accelerators, and imidazole-based curing accelerators as curing accelerators for epoxy resins.

[0058] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0059] As the organophosphorus curing accelerator, one or more selected from the group consisting of phosphonium salts and phosphines are preferred.

[0060] Examples of phosphonium salts include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium) pyromelitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butylmethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, and butyltriphenyl Examples include aromatic phosphonium salts such as phenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

[0061] Examples of phosphines include aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, tricyclohexylphosphine; dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, and tris(2,5-dimethylphenyl)phosphine. Tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2- Examples include aromatic phosphines such as bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether; aromatic phosphine-borane complexes such as triphenylphosphine and triphenylborane; and aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products.

[0062] Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct Examples include imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins.

[0063] When the resin composition of the present invention contains an organic base, the content of the organic base is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, when the resin components in the resin composition are considered as 100% by mass, and the upper limit is preferably 3% by mass or less, more preferably 2% by mass or less, 1.8% by mass or less, 1.6% by mass or less, or 1.5% by mass or less.

[0064] -Inorganic filler- The resin composition of the present invention may further contain an inorganic filler. By including an inorganic filler, the linear thermal expansion coefficient and dielectric loss tangent can be further reduced.

[0065] Examples of inorganic fillers include silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate. Among these, silica is preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is also preferred. Inorganic fillers may be used individually or in combination of two or more types. Examples of commercially available inorganic fillers include "UFP-30" (manufactured by Denka Co., Ltd.), "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", "SO-C1", "SC-C2" (all manufactured by Admatex Co., Ltd.), and "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" (manufactured by Tokuyama Co., Ltd.).

[0066] The average particle size of the inorganic filler is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less, from the viewpoint of achieving a low roughness on the surface of the cured product (insulating layer) and facilitating the formation of fine wiring. The lower limit of the average particle size is not particularly limited and can be, for example, 0.01 μm or more, 0.02 μm or more, 0.03 μm or more, etc. The average particle size of the inorganic filler can be measured by the laser diffraction-scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis using a laser diffraction-scattering particle size distribution analyzer, and the average particle size can be measured by taking the median diameter as the average particle size. Preferably, a sample of inorganic filler dispersed in water by ultrasound can be used as the measurement sample. As a laser diffraction-scattering particle size distribution analyzer, the LA-950 manufactured by Horiba, Ltd., etc., can be used.

[0067] Inorganic fillers are preferably surface-treated with surface treatment agents such as aminosilane coupling agents, ureidosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, vinylsilane coupling agents, styrylsilane coupling agents, acrylatesilane coupling agents, isocyanatesilane coupling agents, sulfidosilane coupling agents, organosilazane compounds, and titanate coupling agents to improve their moisture resistance and dispersibility.

[0068] When the resin composition of the present invention contains an inorganic filler, the content of the inorganic filler in the resin composition may be determined according to the properties required for the resin composition. However, when the non-volatile components in the resin composition are considered to be 100% by mass, for example, it is 5% by mass or more, 10% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. According to the resin composition of the present invention, which contains a combination of a substituted styrene monomer (A) and an epoxy resin (B), it is possible to further increase the content of the inorganic filler while ensuring good fluidity (low viscosity). The content of the inorganic filler in the resin composition may be increased to, for example, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, or 85% by mass or more. According to the resin composition of the present invention, which contains a combination of a substituted styrene monomer (A) and an epoxy resin (B), even when the content of the inorganic filler in the resin composition is extremely high, such as 86% by mass or more, 88% by mass or more, or 90% by mass or more, it is possible to exhibit fillable fluidity. As a result, the resin composition of the present invention satisfies fluidity, including narrow gap filling ability, while exhibiting exceptionally low dielectric loss tangent, excellent heat resistance, moisture resistance, and low warping properties, and depending on the type of inorganic filler, can produce a cured product with high heat dissipation. The upper limit of the inorganic filler content in the resin composition is not particularly limited, but can be, for example, 96% by mass or less, 94% by mass or less. Therefore, in a preferred embodiment, the inorganic filler content in the resin composition of the present invention is 60% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass.

[0069] -Organic filler- The resin composition of the present invention may further contain an organic filler.

[0070] As the organic filler, any organic filler that can be used when forming insulating materials for electronic components such as semiconductor chip packages and printed circuit boards may be used, and examples include rubber particles, polyamide fine particles, and silicone particles.

[0071] The rubber particles are not particularly limited as long as they are fine particles of resin that have been chemically crosslinked to make them insoluble and infusible in organic solvents, and examples include acrylonitrile butadiene rubber particles, butadiene rubber particles, and acrylic rubber particles. Specifically, examples of rubber particles include XER-91 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Stafiloid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (all manufactured by Aica Kogyo Co., Ltd.), and Paraloid EXL2655, EXL2602 (both manufactured by Dow Chemical).

[0072] The average particle size of the organic filler is preferably in the range of 0.005 μm to 1 μm, and more preferably in the range of 0.2 μm to 0.6 μm. The average particle size of the organic filler can be measured using dynamic light scattering. For example, the organic filler can be uniformly dispersed in a suitable organic solvent using ultrasound or the like, and a particle size distribution of the organic filler can be created on a mass basis using a concentrated particle size analyzer (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.), and the median diameter can be used as the average particle size for measurement.

[0073] When the resin composition of the present invention contains an organic filler, the content of the organic filler in the resin composition is preferably 0.5% by mass, more preferably 1% or more by mass, 1.5% or more by mass, or 2% or more by mass, when the nonvolatile components in the resin composition are taken as 100% by mass, and the upper limit is preferably 10% or less by mass, more preferably 8% or less by mass, 6% or less by mass, or 5% or less by mass.

[0074] -Optional additives- The resin composition of the present invention may further contain any additives, as long as they do not impair the effects of the present invention. Examples of such additives include thermosetting resins other than component (B), such as benzocyclobutene resin, epoxy acrylate resin, urethane acrylate resin, urethane resin, cyanate resin, polyimide resin, benzoxazine resin, unsaturated polyester resin, phenol resin, melamine resin, silicone resin, and phenoxy resin; radical polymerizable resins other than component (A) and (C), such as maleimide resin, (meth)acrylic resin, and styryl resin; thermoplastic resins such as phenoxy resin, polyvinyl acetal resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polyetheretherketone resin, and polyester resin; epoxy resin curing agents such as phenolic curing agents, benzoxazine curing agents, acid anhydride curing agents, cyanate ester curing agents, and active ester curing agents; organometallic compounds such as organocenium compounds, organozinc compounds, and organocenium compounds; and phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, and carbon black. Colorants; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone-based defoaming agents, acrylic-based defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents; UV absorbers such as benzotriazole-based UV absorbers; adhesion improvers such as urea silane; adhesion ferrants such as triazole-based adhesion ferrants, tetrazole-based adhesion ferrants, and triazine-based adhesion ferrants; hinder Antioxidants such as phenolic antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants;Examples of stabilizers include borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The content of such additives may be determined according to the required properties of the resin composition.

[0075] -Organic solvents- The resin composition of the present invention may further contain an organic solvent as a volatile component. Examples of organic solvents include: ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples include ether ester solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. Organic solvents may be used individually or in combination of two or more.

[0076] If the resin composition of the present invention contains an organic solvent, the content of the organic solvent in the resin composition may be determined according to the properties required for the resin composition. However, if the total components in the resin composition are considered to be 100% by mass, the content may be, for example, 20% by mass or less, 15% by mass or less, or 10% by mass or less.

[0077] In the past, resin compositions have been prepared by adding organic solvents as diluents to reduce their viscosity. However, when such resin compositions are used to form insulating materials for electronic components such as semiconductor chip packages and printed circuit boards, problems such as void formation during the encapsulation molding process, the need for large-scale waste disposal equipment for organic solvents, and residual organic solvents in the resulting insulating layer occur. In contrast, the resin composition of the present invention, which contains a combination of substituted styrene monomer (A) and epoxy resin (B), is preferable because it exhibits good fluidity during molding even when the organic solvent content is low or even when no organic solvent is present. The organic solvent content in the resin composition of the present invention may be as low as, for example, 5% by mass or less, 4% by mass or less, 2% by mass or less, 1% by mass or less, or 0.5% by mass or less, and may even be 0% by mass (solvent-free system).

[0078] The resin composition of the present invention can be prepared by appropriately mixing the necessary components from the above components, and, if necessary, by kneading or mixing using kneading means such as a three-roll mill, ball mill, bead mill, or sand mill, or stirring means such as a super mixer or planetary mixer.

[0079] The resin composition of the present invention, comprising a combination of a substituted styrene monomer (A) and an epoxy resin (B), can produce a cured product with excellent dielectric properties and achieve good fluidity.

[0080] In one embodiment, the resin composition of the present invention exhibits low viscosity at room temperature (25°C) and fluidity that allows for filling narrow gaps. For example, as described in the [Fluidity] section below, when measured with a vibrating viscometer or an E-type viscometer, the viscosity of the resin composition of the present invention at 25°C is preferably 500,000 mPa·s or less, more preferably 100,000 mPa·s or less, even more preferably 50,000 mPa·s or less, 30,000 mPa·s or less, 10,000 mPa·s or less, 5,000 mPa·s or less, 3,000 mPa·s or less, 1,000 mPa·s or less, 800 mPa·s or less, 500 mPa·s or less, 300 mPa·s or less, 200 mPa·s or less, or 150 mPa·s or less. According to the resin composition of the present invention, which contains a combination of a substituted styrene monomer (A) and an epoxy resin (B), an even lower viscosity can be achieved. For example, the viscosity of the resin composition of the present invention at 25°C may be 100 mPa·s or less, 80 mPa·s or less, 60 mPa·s or less, or 50 mPa·s or less. The lower limit of the viscosity is not particularly limited, but may be, for example, 0.5 mPa·s or more, 1 mPa·s or more, 2 mPa·s or more, etc. Therefore, in a preferred embodiment, the viscosity of the resin composition of the present invention at 25°C is 100 mPa·s or less.

[0081] As described above, the resin composition of the present invention exhibits low viscosity and good fluidity at room temperature (25°C), even when a high amount of inorganic filler is included. For example, even when the inorganic filler content (in terms of non-volatile components) in the resin composition is 60% by mass or more, the viscosity of the resin composition of the present invention at 25°C is preferably 300 mPa·s or less, more preferably 200 mPa·s or less, even more preferably 100 mPa·s or less, 80 mPa·s or less, 60 mPa·s or less, or 50 mPa·s or less. The lower limit of the viscosity is as described above. Therefore, in a preferred embodiment, when the non-volatile components in the resin composition are 100% by mass, the inorganic filler content is 60% by mass or more, and the viscosity at 25°C is 100 mPa·s or less.

[0082] In another preferred embodiment, when the non-volatile components in the resin composition are considered to be 100% by mass, the inorganic filler content is 85% by mass or more, and the viscosity at 25°C is 1000 mPa·s or less (more preferably 800 mPa·s or less).

[0083] In yet another preferred embodiment, when the nonvolatile components in the resin composition are considered to be 100% by mass, the inorganic filler content is 60% by mass or more (more preferably 65% ​​by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, or 85% by mass or more), the organic filler content is 1% by mass or more, and the viscosity at 25°C is 1000 mPa·s or less (more preferably 800 mPa·s or less).

[0084] In one embodiment, the cured product of the resin composition of the present invention exhibits a low dielectric constant (Dk). For example, as described in the [Dielectric Properties] section below, when measured at 5.8 GHz, the dielectric constant (Dk) of the cured product of the resin composition of the present invention may be preferably 3.8 or less, more preferably 3.6 or less, 3.4 or less, 3.2 or less, or 3.1 or less, and even more preferably 3.0 or less, 2.9 or less, or 2.8 or less.

[0085] In one embodiment, the cured product of the resin composition of the present invention exhibits a low dielectric loss tangent (Df). For example, as described in the [Dielectric Properties] section below, when measured at 5.8 GHz, the dielectric loss tangent (Df) of the cured product of the resin composition of the present invention may be preferably 0.012 or less, more preferably 0.011 or less, 0.01 or less, 0.009 or less, 0.008 or less, 0.006 or less, 0.005 or less, 0.004 or less, or 0.003 or less.

[0086] Furthermore, the resin composition of the present invention, which contains a combination of substituted styrene monomer (A) and epoxy resin (B), also exhibits excellent storage stability.

[0087] In one embodiment, the resin composition of the present invention exhibits the characteristic of suppressing viscosity increase during storage. For example, if the viscosity at 25°C of the resin composition immediately after preparation is V1 (mPa·s), and the viscosity at 25°C of the resin composition after 168 hours of storage at 25°C and 50% humidity is V2 (mPa·s), then the ratio of V2 / V1 can preferably be 4 or less, more preferably 3 or less, 2 or less, 1.8 or less, or 1.7 or less.

[0088] The resin composition of the present invention, comprising a combination of a substituted styrene monomer (A) and an epoxy resin (B), can achieve a good balance between fluidity and dielectric properties, and can be suitably used as an insulating material with low transmission loss required for 5G applications, as well as in various liquid compound products that require good fluidity. For example, the resin composition of the present invention can be suitably used as an adhesive, casting material, fiber-reinforced composite material, semiconductor encapsulant, underfill material, mold underfill material, and other liquid compound products that require good fluidity. Therefore, in a preferred embodiment, the resin composition of the present invention is for use as an adhesive, casting material, fiber-reinforced composite material, semiconductor encapsulant, underfill, or mold underfill.

[0089] In particular, from the viewpoint of enjoying the effects of the present invention, which is to achieve a good balance between fluidity and dielectric properties, the resin composition of the present invention can be suitably used as an insulating material for electronic components such as semiconductor chip packages and printed circuit boards (resin composition for insulating materials of electronic components). For example, it can be suitably used as a resin composition for sealing semiconductor chips (resin composition for semiconductor sealing), a resin composition for filling the gap between a printed circuit board and a semiconductor chip (resin composition for underfill), a resin composition for filling the gap between a printed circuit board and a semiconductor chip and sealing the semiconductor chip (resin composition for mold underfill), a resin composition for forming an insulating layer of a printed circuit board (resin composition for insulating layer of printed circuit board), and a resin composition for a redistribution forming layer as an insulating layer for forming a redistribution layer in a semiconductor chip package (resin composition for redistribution forming layer). Furthermore, the resin composition of the present invention can be used in a wide range of applications where a resin composition is required, such as sheet-like laminated materials such as resin sheets and prepregs, solder resists, hole-filling resins, and component-embedding resins.

[0090] -glue- The resin composition of the present invention achieves a good balance between fluidity and dielectric properties, making it suitable for use as an adhesive. Suitable applications as an adhesive include interlayer adhesives (interlayer insulating materials for printed circuit boards), die attach materials (die bonding materials), and adhesives for bonding electronic components to circuit boards or terminals on circuit boards. For example, when used as an interlayer insulating material for printed circuit boards, it may be used in the form of a sheet-like laminated material, as described later. An example of using it as an interlayer insulating material for printed circuit boards in the form of a sheet-like laminated material will be described later.

[0091] -Casting material- The resin composition of the present invention exhibits good fluidity and is therefore suitable for use as a casting material. While it can be used as a casting material without particular limitations as long as it is a resin material to be molded, it is particularly suitable for use as a casting material for molding and encapsulating various electronic elements such as transistors, inductors, diodes, and sensors, in order to better enjoy the advantages of the resin composition of the present invention, which has both good fluidity and excellent dielectric properties.

[0092] -Fiber-reinforced composite materials- The resin composition of the present invention exhibits good fluidity and is therefore suitable for use in forming fiber-reinforced composite materials. Fiber-reinforced composite materials are structural members formed by impregnating reinforcing fibers with the resin composition of the present invention and then heating and curing the resulting composite material. These materials are applicable to a wide range of uses, such as frames and body materials for bicycles, automobiles, and aircraft, as well as leisure and sports equipment such as fishing rods and golf clubs. Examples of reinforcing fibers include carbon fibers, glass fibers, aramid fibers, boron fibers, alumina fibers, and silicon carbide fibers, which may be appropriately selected and used depending on the properties required for the fiber-reinforced composite material. When forming a fiber-reinforced composite material using the resin composition of the present invention, the amount of fiber base material in the fiber-reinforced composite material is not particularly limited, but is usually in the range of 30 to 80% by mass, for example, 40 to 70% by mass, 50 to 70% by mass, etc.

[0093] - Semiconductor encapsulating material - The resin composition of the present invention achieves a good balance between fluidity and dielectric properties, making it particularly suitable for use as a semiconductor encapsulant. As mentioned above, with the further miniaturization, increased integration, and multi-functionality of electronic devices, there is a growing trend towards smaller bump diameters, narrower pitches, and narrower gaps due to the use of multiple pins. Furthermore, there is a demand for the simultaneous encapsulation of large areas, such as with WLP and PLP, making the flow path of the encapsulant during encapsulation molding more complex. The resin composition of the present invention exhibits low viscosity and good fluidity even when inorganic fillers are incorporated, resulting in excellent encapsulation moldability. Moreover, after curing, it exhibits extremely excellent dielectric properties, enabling the achievement of the low transmission loss required for 5G applications. An example of using the resin composition of the present invention as a semiconductor encapsulant will be described later.

[0094] -Underfill material / Molded underfill material- The resin composition of the present invention can achieve a good balance between fluidity and dielectric properties, and is particularly suitable for use as an underfill material or molded underfill material. As mentioned above, in recent years, chips have tended to become larger in area, especially with the multi-die development of semiconductors, and there is an increasing demand for high fluidity in underfill materials and molded underfill materials that fill the narrow gap between printed circuit boards and semiconductor chips. Furthermore, the features of the resin composition of the present invention described above in relation to semiconductor encapsulants are also applicable to molded underfill materials that encapsulate semiconductor chips.

[0095] -Sheet-like laminated materials (resin sheets, prepregs)- The resin composition of the present invention exhibits good fluidity and can therefore be suitably used as a liquid composition, but it may also be used in the form of a sheet-like laminate material containing the resin composition.

[0096] As sheet-like laminated materials, the following resin sheets and prepregs are preferred.

[0097] In one embodiment, the resin sheet comprises a support and a layer of a resin composition provided on the support (hereinafter simply referred to as the "resin composition layer"), wherein the resin composition layer is formed from the resin composition of the present invention.

[0098] The optimal thickness of the resin composition layer varies depending on the application and may be determined appropriately according to the application. For example, from the viewpoint of thinning printed circuit boards and semiconductor chip packages, the thickness of the resin composition layer is preferably 200 μm or less, more preferably 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 50 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, etc.

[0099] Examples of support materials include thermoplastic resin films, metal foils, and release paper, with thermoplastic resin films and metal foils being preferred. Therefore, in one preferred embodiment, the support material is a thermoplastic resin film or a metal foil.

[0100] When using a thermoplastic resin film as a support, examples of thermoplastic resins include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0101] When using metal foil as a support, examples of metal foil include copper foil and aluminum foil, with copper foil being preferred. As for copper foil, foil made of single-metal copper may be used, or foil made of an alloy of copper with another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0102] The support may have a matte finish, corona treatment, or antistatic treatment applied to the surface that bonds with the resin composition layer. Alternatively, a support with a release layer may be used, which has a release layer on the surface that bonds with the resin composition layer. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available support with a release layer may be used, for example, PET films having a release layer mainly composed of an alkyd resin-based release agent, such as "SK-1", "AL-5", and "AL-7" from Lintec Corporation, "Lumirror T60" from Toray Industries, Inc., "Purex" from Teijin Corporation, and "Unipeel" from Unitika Corporation.

[0103] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0104] When using metal foil as a support, a metal foil with a support substrate, which is formed by laminating a peelable support substrate onto a thin metal foil, may be used. In one embodiment, the metal foil with a support substrate includes a support substrate, a release layer provided on the support substrate, and a metal foil provided on the release layer. When using metal foil with a support substrate as a support, the resin composition layer is provided on the metal foil.

[0105] In a metal foil with a support substrate, the material of the support substrate is not particularly limited, but examples include copper foil, aluminum foil, stainless steel foil, titanium foil, copper alloy foil, etc. When copper foil is used as the support substrate, it may be electrolytic copper foil or rolled copper foil. Furthermore, the release layer is not particularly limited as long as it can be used to peel the metal foil from the support substrate, and examples include an alloy layer of elements selected from the group consisting of Cr, Ni, Co, Fe, Mo, Ti, W, and P; an organic coating, etc.

[0106] In a metal foil with a support substrate, the material of the metal foil is preferably, for example, copper foil or copper alloy foil.

[0107] In a metal foil with a support substrate, the thickness of the support substrate is not particularly limited, but is preferably in the range of 10 μm to 150 μm, and more preferably in the range of 10 μm to 100 μm. The thickness of the metal foil may be, for example, in the range of 0.1 μm to 10 μm.

[0108] In one embodiment, the resin sheet may further include any additional layer as needed. Such an additional layer may be, for example, a protective film provided on the side of the resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, the adhesion of dust and other debris to the surface of the resin composition layer and scratches can be suppressed.

[0109] Resin sheets can be manufactured, for example, by applying a resin varnish prepared by directly using a liquid resin composition or by dissolving the resin composition in an organic solvent, coating it onto a support using a die coater or the like, and then drying it to form a resin composition layer.

[0110] Examples of organic solvents include those similar to those described as components of the resin composition. Organic solvents may be used individually or in combination of two or more.

[0111] Drying may be carried out by known methods such as heating or blowing hot air. The drying conditions are not particularly limited, but the resin composition layer should be dried so that the content of the organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Depending on the boiling point of the organic solvent in the resin composition or resin varnish, for example, when using a resin composition or resin varnish containing 30% to 60% by mass of organic solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0112] The resin sheet can be stored by rolling it up. If the resin sheet has a protective film, it can be used after removing the protective film.

[0113] In one embodiment, the prepreg is formed by impregnating a sheet-like fibrous substrate with the resin composition of the present invention.

[0114] The sheet-like fibrous substrate used for the prepreg is not particularly limited, and commonly used prepreg substrates such as glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric can be used. From the viewpoint of thinning printed circuit boards and semiconductor chip packages, the thickness of the sheet-like fibrous substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. The lower limit of the thickness of the sheet-like fibrous substrate is not particularly limited, but is usually 10 μm or more.

[0115] Prepregs can be manufactured by known methods such as the hot melt method or the solvent method. Furthermore, the thickness of the prepreg can be within the same range as the resin composition layer in the resin sheet described above.

[0116] [Semiconductor chip package] The semiconductor chip package of the present invention includes a cured product of the resin composition of the present invention.

[0117] In one embodiment, the semiconductor chip package of the present invention includes a circuit board, a semiconductor chip mounted on the circuit board, and a cured product of the resin composition of the present invention that encapsulates at least a portion of the semiconductor chip. Hereinafter, such an embodiment will also be referred to as the "first embodiment."

[0118] In the first embodiment, the circuit board may be a conventionally known circuit board used to form a semiconductor chip package, and may be manufactured, for example, in the same manner as a printed circuit board described later.

[0119] The bonding conditions between the circuit board and the semiconductor chip can be any conditions that allow for conductive connection between the terminal electrodes of the semiconductor chip and the circuit wiring of the circuit board. For example, conditions used in flip-chip mounting of semiconductor chips may be adopted.

[0120] One bonding method is to press the semiconductor chip onto the circuit board. The pressing conditions are typically a pressing temperature in the range of 120°C to 240°C (preferably 130°C to 200°C, more preferably 140°C to 180°C) and a pressing time in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds). Another bonding method is to place the semiconductor chip on the circuit board and bond it by reflow soldering. The reflow soldering conditions may be in the range of 120°C to 300°C.

[0121] After bonding the semiconductor chip to the circuit board, the gap between the semiconductor chip and the circuit board may be filled with an underfill material. As mentioned above, the resin composition of the present invention exhibits good fluidity and is therefore useful as such an underfill material. In this case, the semiconductor chip package of the present invention includes an underfill material made from a cured product of the resin composition of the present invention.

[0122] The semiconductor chip can be sealed by the same method as in step (3) of the second embodiment described later. As mentioned above, the resin composition of the present invention exhibits good fluidity and is therefore useful as a sealing material for such semiconductor chips. In this case, the semiconductor chip package of the present invention includes a sealing material made of a cured product of the resin composition of the present invention.

[0123] As mentioned above, since the resin composition of the present invention exhibits good fluidity, it may be used as a mold underfill material to simultaneously fill the gap between the semiconductor chip and the circuit board and encapsulate the semiconductor chip.

[0124] When manufacturing a semiconductor chip package using the resin composition of the present invention, it is preferable to use the resin composition of the present invention as a liquid resin composition, but it may also be used in the form of a sheet-like laminated material as described above.

[0125] In another embodiment (hereinafter also referred to as the "second embodiment"), the semiconductor chip package of the present invention can be manufactured, for example, by a method including the following steps (1) to (6) using the resin composition of the present invention. The resin composition of the present invention may be used to form the encapsulation layer in step (3) or the redistribution layer in step (5). An example of forming the encapsulation layer and redistribution layer using the resin composition is shown below, but the techniques for forming the encapsulation layer and redistribution layer of a semiconductor chip package are well known, and those skilled in the art can manufacture a semiconductor chip package using the resin composition of the present invention in accordance with known techniques. (1) A step of laminating a temporary fixing film onto the substrate, (2) A step of temporarily fixing the semiconductor chip onto a temporary fixing film, (3) A step of forming a sealing layer on a semiconductor chip, (4) Steps to peel off the substrate and temporary fixing film from the semiconductor chip, (5) A step of forming a rewiring layer as an insulating layer on the surface from which the substrate and temporary fixing film of the semiconductor chip have been peeled off, and (6) Step of forming a redistribution layer as a conductor layer on the redistribution formation layer.

[0126] -Process (1)- The material used for the substrate is not particularly limited. Examples of substrates include silicon wafers, glass wafers, glass substrates, metal substrates such as copper, titanium, stainless steel, and cold-rolled steel sheets (SPCC), substrates made by impregnating glass fibers with epoxy resin and heat-curing them (e.g., FR-4 substrates), and substrates made of bismaleimidotriazine resin (BT resin).

[0127] The temporary fixing film is not limited in material as long as it can be peeled off from the semiconductor chip in step (4) and temporarily fix the semiconductor chip. Commercially available temporary fixing films can be used. Examples of commercially available products include Riva Alpha manufactured by Nitto Denko Corporation.

[0128] -Process (2)- The semiconductor chip is temporarily fixed onto a temporary fixing film such that its electrode pad surface is in contact with the temporary fixing film. Temporary fixing of the semiconductor chip can be performed using known equipment such as a flip-chip bonder or die bonder. The layout and number of semiconductor chips can be appropriately set according to the shape and size of the temporary fixing film, the target production quantity of the semiconductor package, etc. For example, they can be temporarily fixed in a matrix arrangement of multiple rows and multiple columns.

[0129] -Process (3)- The resin composition of the present invention is applied to a semiconductor chip as a liquid composition and cured (e.g., by thermal curing) to form a sealing layer. Alternatively, the resin composition of the present invention may be laminated on a semiconductor chip in the form of the above-described resin sheet and cured (e.g., by thermal curing) to form a sealing layer.

[0130] By using the resin composition of the present invention, which contains a combination of a substituted styrene monomer (A) and an epoxy resin (B), good fluidity can be achieved during encapsulation molding, whether the resin composition is applied as a liquid composition or laminated as a resin sheet.

[0131] When used in the form of a resin sheet, the lamination of the semiconductor chip and the resin sheet can be performed by removing the protective film from the resin sheet and then heat-pressing the resin sheet onto the semiconductor chip from the support side. The lamination of the semiconductor chip and the resin sheet may also be carried out by a vacuum lamination method, and the lamination conditions are the same as those described later in relation to the manufacturing method of printed circuit boards, and the preferred range is also the same.

[0132] After lamination, the resin composition is heat-cured to form a sealing layer. The heat-curing conditions are the same as those described later in relation to the manufacturing method of printed circuit boards.

[0133] The resin sheet support may be peeled off after the resin sheet has been laminated onto the semiconductor chip and heat-cured, or the support may be peeled off before the resin sheet has been laminated onto the semiconductor chip.

[0134] When applying the resin composition of the present invention as a liquid composition to form a sealing layer, the application conditions may be the same as those for forming the resin composition layer described in relation to the resin sheet of the present invention. By using the resin composition of the present invention, good fluidity can be achieved at the application and molding temperatures.

[0135] -Process (4)- The method for peeling off the substrate and the temporary fixing film can be appropriately changed depending on the material of the temporary fixing film, etc. Examples include a method of peeling off the temporary fixing film by heating and foaming (or expanding) it, and a method of peeling off the temporary fixing film by irradiating it with ultraviolet light from the substrate side to reduce the adhesive strength of the temporary fixing film.

[0136] In the method of peeling off a temporary fixing film by heating and foaming (or expanding) it, the heating conditions are usually 100-250°C for 1-90 seconds or 5-15 minutes. In the method of peeling off a temporary fixing film by irradiating it with ultraviolet light from the substrate side to reduce its adhesive strength, the amount of ultraviolet light irradiated is usually 10 mJ / cm². 2 ~1000 mJ / cm 2 That is the case.

[0137] -Process (5)- The material used to form the redistribution layer (insulating layer) is not particularly limited as long as it has insulating properties when the redistribution layer (insulating layer) is formed. From the viewpoint of ease of manufacturing semiconductor chip packages, photosensitive resins and thermosetting resins are preferred. The redistribution layer may also be formed using the resin composition of the present invention.

[0138] After forming the redistribution layer, via holes may be formed in the redistribution layer to interlayer connect the semiconductor chip with the conductor layer described later. The via holes may be formed by known methods depending on the material of the redistribution layer.

[0139] -Process (6)- The material of the conductor layer formed on the rewiring layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single-metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, from the viewpoint of versatility in conductor layer formation, cost, and ease of patterning, single-metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred, single-metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single-metal layers of copper are even more preferred.

[0140] The conductive layer may be a single-layer structure, or it may be a multi-layer structure in which two or more single-metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductive layer is a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0141] The thickness of the conductor layer depends on the desired semiconductor chip package design, but is generally 1 μm to 35 μm, preferably 1 μm to 20 μm.

[0142] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the rewiring layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, it is preferable to form it by the semi-additive method. An example of forming the conductor layer by the semi-additive method is shown below.

[0143] First, a plating seed layer is formed on the surface of the rewiring layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electroplating, the mask pattern is removed. Then, the unnecessary plating seed layer can be removed by etching or other means to form a conductor layer (rewiring layer) having the desired wiring pattern.

[0144] Alternatively, steps (5) and (6) may be repeated to alternately stack the conductor layer (rewiring layer) and the rewiring forming layer (insulating layer) (build-up).

[0145] In manufacturing a semiconductor chip package, the following steps may be further performed: (7) forming a solder resist layer on a conductor layer (redistribution layer), (8) forming bumps, and (9) dicing multiple semiconductor chip packages into individual semiconductor chip packages. These steps may be carried out in accordance with various methods known to those skilled in the art for the manufacture of semiconductor chip packages.

[0146] The second embodiment described above is a method in which a semiconductor chip is first provided and a redistribution layer is formed on its electrode pad surface, i.e., Chip 1st (Chip-1 st This is an example of a manufacturing method. In addition to the chip 1st method, the semiconductor chip package of the present invention is manufactured by first providing a redistribution layer, and then providing a semiconductor chip on the redistribution layer in such a state that its electrode pad surface can be electrically connected to the redistribution layer, and then sealing it, i.e., redistribution layer 1st (RDL-1 stIt may also be manufactured by the following method. The resin composition of the present invention, which has excellent filling properties, is Chip-1 st Construction method and RDL-1 st Regardless of the manufacturing method, it is possible to realize semiconductor chip packages with extremely low transmission loss, which is required for 5G applications.

[0147] By forming a sealing layer, a redistribution layer, etc., using the resin composition of the present invention, which exhibits good fluidity during molding and provides excellent dielectric properties after curing, it is possible to realize a semiconductor chip package with extremely low transmission loss while suppressing the occurrence of flow marks and unfilled areas, regardless of whether the semiconductor package is a fan-in type package or a fan-out type package. In one embodiment, the semiconductor chip package of the present invention is a fan-out type package. The resin composition of the present invention can be applied to fan-out type panel-level packages (FOPLPs) and fan-out type wafer-level packages (FOWLPs). In one embodiment, the semiconductor package of the present invention is a fan-out type panel-level package (FOPLP). In another embodiment, the semiconductor package of the present invention is a fan-out type wafer-level package (FOWLP).

[0148] [Printed wiring board] A printed circuit board can be manufactured using the resin composition of the present invention. The present invention also provides such a printed circuit board. The printed circuit board of the present invention is characterized by including an insulating layer made of a cured product of the resin composition of the present invention.

[0149] Printed circuit boards can be manufactured, for example, using the above-mentioned resin sheet by a method including the following steps (I) and (II). (I) A process of laminating a resin sheet onto an inner layer substrate such that the resin composition layer of the resin sheet is bonded to the inner layer substrate. (II) A step of curing (e.g., thermal curing) the resin composition layer to form an insulating layer.

[0150] The "internal layer substrate" used in process (I) is a material that serves as the substrate for a printed wiring board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. The substrate may also have a conductive layer on one or both sides, and this conductive layer may be patterned. An internal layer substrate in which a conductive layer (circuit) is formed on one or both sides of the substrate is sometimes called an "internal layer circuit board." Furthermore, an intermediate product on which an insulating layer and / or a conductive layer is to be formed during the manufacturing of a printed wiring board is also included in the "internal layer substrate" as defined in this invention. If the printed wiring board is a circuit board with embedded components, an internal layer substrate with embedded components may be used.

[0151] The lamination of the inner layer substrate and the resin sheet can be performed, for example, by heating and pressing the resin sheet onto the inner layer substrate from the support side. Examples of the heating and pressing member used to heat and press the resin sheet onto the inner layer substrate (hereinafter also referred to as the "heat pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). The heating and pressing member may be pressed directly onto the resin sheet, or it may be pressed via an elastic material such as heat-resistant rubber so that the resin sheet can adequately follow the surface irregularities of the inner layer substrate.

[0152] Lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the heat-pressure temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressure pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-pressure time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination may preferably be carried out under reduced pressure conditions of 26.7 hPa or less.

[0153] Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Meiki Seisakusho Co., Ltd., vacuum applicators manufactured by Nikko Materials Co., Ltd., and batch-type vacuum pressure laminators.

[0154] After lamination, the laminated resin sheets may be smoothed by pressing a heat-sealing member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing process can be the same as the heat-sealing conditions for lamination. The smoothing process can be performed using a commercially available laminator. Lamination and smoothing may be performed continuously using the commercially available vacuum laminator mentioned above.

[0155] The support may be removed between steps (I) and (II), or after step (II). If a metal foil is used as the support, the conductive layer may be formed using the metal foil without peeling off the support. If a metal foil with a support substrate is used as the support, the support substrate (and release layer) should be peeled off. Then, the conductive layer can be formed using the metal foil.

[0156] In step (II), the resin composition layer is cured (e.g., by thermal curing) to form an insulating layer made of the cured resin composition. The curing conditions for the resin composition layer are not particularly limited, and conditions commonly used when forming an insulating layer for a printed circuit board may be used.

[0157] For example, the thermal curing conditions for the resin composition layer vary depending on the type of resin composition, but in one embodiment, the curing temperature is preferably 120°C to 250°C, more preferably 150°C to 240°C, and even more preferably 180°C to 230°C. The curing time can be preferably 5 minutes to 240 minutes, more preferably 10 minutes to 150 minutes, and even more preferably 15 minutes to 120 minutes.

[0158] Prior to thermal curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermal curing the resin composition layer, it may be preheated at a temperature of 50°C to 120°C, preferably 60°C to 115°C, more preferably 70°C to 110°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0159] In manufacturing printed circuit boards, the following steps may be further performed: (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming the conductor layer. These steps (III) through (V) may be carried out according to various methods known to those skilled in the art that are used in the manufacture of printed circuit boards. If the support is removed after step (II), the removal of the support may be carried out between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, if necessary, the formation of the insulating layer and the conductor layer in steps (I) through (V) may be repeated to form a multilayer circuit board.

[0160] In other embodiments, the printed circuit board can be manufactured using the prepreg described above. The manufacturing method is basically the same as when using a resin sheet.

[0161] Step (III) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (III) may be carried out using, for example, a drill, laser, plasma, etc., depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be appropriately determined according to the design of the printed circuit board.

[0162] Step (IV) is a process for roughening the insulating layer. Typically, smear removal (desmear) is also performed in this step (IV). The procedure and conditions for the roughening process are not particularly limited, and known procedures and conditions commonly used when forming the insulating layer of a printed circuit board can be adopted. For example, the insulating layer can be roughened by performing swelling treatment with a swelling solution, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution in this order.

[0163] The swelling solution used for the roughening treatment is not particularly limited, but examples include alkaline solutions and surfactant solutions, and is preferably an alkaline solution, with sodium hydroxide solution and potassium hydroxide solution being more preferred. Examples of commercially available swelling solutions include "Swelling Dip Securing P" and "Swelling Dip Securing SBU" manufactured by Atotec Japan. The swelling treatment with the swelling solution is not particularly limited, but can be carried out, for example, by immersing the insulating layer in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0164] The oxidizing agent used for the roughening treatment is not particularly limited, but examples include an alkaline permanganate solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Attec Japan.

[0165] Furthermore, an acidic aqueous solution is preferred as the neutralizing solution used in the roughening treatment. A commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan.

[0166] The neutralization treatment can be carried out by immersing the treated surface, which has been roughened with an oxidizing agent, in a neutralization solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, it is preferable to immerse the object, which has been roughened with an oxidizing agent, in a neutralization solution at 40°C to 70°C for 5 to 20 minutes.

[0167] Step (V) is a step in which a conductive layer is formed, and a conductive layer is formed on an insulating layer. Step (V) may be carried out in the same manner as step (6) described in relation to the manufacturing method of a semiconductor chip package.

[0168] The thickness of the conductor layer depends on the desired printed circuit board design, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

[0169] The conductive layer may also be formed using metal foil. When forming the conductive layer using metal foil, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed and the metal foil is laminated onto the surface of the exposed resin composition layer. The lamination of the resin composition layer and the metal foil may be carried out by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Subsequently, the metal foil on the insulating layer can be used to form a conductive layer having a desired wiring pattern by conventional known techniques such as the subtractive method or the modified semi-additive method.

[0170] Metal foils can be manufactured by known methods such as electrolysis and rolling. Examples of commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Nippon Oil & Metals Corporation, and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0171] Alternatively, as mentioned above, if a metal foil or a metal foil with a support substrate is used as the support for the resin sheet, the conductive layer may be formed using the metal foil.

[0172] [Semiconductor device] The semiconductor device of the present invention includes a layer made of a cured product of the resin composition of the present invention. The semiconductor device of the present invention can be manufactured using the semiconductor chip package or printed circuit board of the present invention.

[0173] Examples of semiconductor devices include various types of semiconductor devices used in electrical products (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft). [Examples]

[0174] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples. In the following, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "mass%", respectively. Unless otherwise specified, the temperature and pressure conditions are room temperature (25°C) and atmospheric pressure (1 atm).

[0175] <Inorganic fillers used> Inorganic filler 1: Spherical silica (average particle size 0.63 μm, specific surface area 11.2 m 2 Surface treated with 1 part N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts (g). Inorganic filler 2: Spherical silica (average particle size 6.0 μm, specific surface area 4.8 m²) 2 Surface treated with 1 part N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts (g).

[0176] <Example 1> (Preparation of resin composition 1) 51 parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy group equivalent approximately 165 g / eq.) and 49 parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Co., Ltd., 4-acetoxystyrene) were stirred. 1 part of an organic base (4-dimethylaminopyridine (DMAP)) and 1 part of a radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation) were added, and the mixture was uniformly dispersed using a high-speed rotary mixer to prepare resin composition 1.

[0177] <Example 2> (Preparation of resin composition 2) 36 parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 34 parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and 30 parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. 1 part of organic base (DMAP) and 1 part of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation) were added, and the mixture was uniformly dispersed using a high-speed rotary mixer to prepare resin composition 2.

[0178] <Example 3> (Preparation of resin composition 3) 26 parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 24 parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and 50 parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. 1 part of organic base (DMAP) and 1 part of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation) were added, and the mixture was uniformly dispersed using a high-speed rotary mixer to prepare resin composition 3.

[0179] <Example 4> (Preparation of resin composition 4) Resin composition 4 was prepared in the same manner as in Example 2, except that a substituted styrene monomer (3-acetoxystyrene) was used instead of the substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.).

[0180] <Example 5> (Preparation of resin composition 5) Resin composition 5 was prepared in the same manner as in Example 2, except that (i) 40 parts of substituted styrene monomer (4-vinylphenylbenzoate) were used instead of 34 parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and (ii) the amount of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.) was changed from 36 parts to 30 parts.

[0181] <Example 6> (Preparation of resin composition 6) Resin composition 6 was prepared in the same manner as in Example 2, except that a radical polymerizable monomer (methyl methacrylate, manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of a radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.).

[0182] <Example 7> (Preparation of resin composition 7) Resin composition 7 was prepared in the same manner as in Example 2, except that (i) the amount of substituted styrene monomer ("acetoxystyrene" manufactured by Tokyo Chemical Industry Co., Ltd.) was changed from 34 parts to 37 parts, and (ii) 33 parts of naphthalene skeleton epoxy resin ("HP-4032SS" manufactured by DIC Corporation, epoxy equivalent approximately 144 g / eq.) were used instead of 36 parts of bisphenol AF type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0183] <Example 8> (Preparation of resin composition 8) Resin composition 8 was prepared in the same manner as in Example 2, except that (i) the amount of substituted styrene monomer ("acetoxystyrene" manufactured by Tokyo Chemical Industry Co., Ltd.) was changed from 34 parts to 44 parts, and (ii) 26 parts of trifunctional glycidylamine type epoxy resin ("630" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent approximately 98 g / eq.) were used instead of 36 parts of bisphenol AF type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0184] <Example 9> (Preparation of resin composition 9) Fourteen parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), thirteen parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industries Co., Ltd.), and thirteen parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industries Co., Ltd.) were stirred. To this, 0.4 parts of organic base (DMAP), 0.4 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), and 62 parts of inorganic filler 1 were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 9.

[0185] <Example 10> (Preparation of resin composition 10) Eight parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), seven parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and fifteen parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. To this, 0.3 parts of organic base (DMAP), 0.3 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), and 72 parts of inorganic filler 1 were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 10.

[0186] <Example 11> (Preparation of resin composition 11) Four parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), four parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and eight parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. To this, 0.2 parts of organic base (DMAP), 0.2 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), and 87 parts of inorganic filler 2 were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 11.

[0187] <Example 12> (Preparation of resin composition 12) Three parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), three parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and six parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. To this, 0.1 parts of organic base (DMAP), 0.1 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), and 90 parts of inorganic filler 2 were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 12.

[0188] <Example 13> (Preparation of resin composition 13) Two parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), two parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and four parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. To this, 0.1 parts of organic base (DMAP), 0.1 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), and 94 parts of inorganic filler 2 were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 13.

[0189] <Example 14> (Preparation of resin composition 14) Fourteen parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), thirteen parts of substituted styrene monomer (acetoxystyrene, manufactured by Tokyo Chemical Industry Co., Ltd.), and thirteen parts of radical polymerizable monomer (styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. To this, 0.4 parts of organic base (DMAP), 0.4 parts of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation), 65 parts of inorganic filler 1, and 2 parts of organic filler (EXL-2655, manufactured by Dow Chemical Co., Ltd.) were added and uniformly dispersed in a high-speed rotary mixer to prepare resin composition 14.

[0190] <Comparative Example 1> (Preparation of Resin Composition C1) 39 parts of bisphenol AF type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 31 parts of substituted styrene monomer (Millex PM, p-isopropenylphenol, manufactured by Tokyo Chemical Industry Co., Ltd.), and 30 parts of radical polymerizable monomer (Styrene, manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred. 1 part of organic base (DMAP) and 1 part of radical polymerization catalyst (Perhexyl O, manufactured by NOF Corporation) were added, and the mixture was uniformly dispersed using a high-speed rotary mixer to prepare resin composition C1.

[0191] Evaluation tests were conducted on the prepared resin compositions 1-14 and C1 according to the following procedure. The compositions of resin compositions 1-14 and C1 and the evaluation results are summarized in Table 1.

[0192] [Liquidity] The fluidity of the resin compositions was evaluated by their viscosity. Specifically, for resin compositions 1-8 and C1, the viscosity was measured using a vibrating viscometer (Sekonic VM-10A-L) while maintaining a temperature of 25±2°C. For resin compositions 9-12 and 14, the viscosity was measured using an E-type viscometer (Toki Sangyo RE-85U, cone plate: radius 24 mm, angle 1.34°, rotation speed: 100 rpm) while maintaining a temperature of 25±2°C. For resin composition 13, the viscosity was measured using an E-type viscometer (Toki Sangyo RE-85U, cone plate: radius 9.7 mm, angle 3°, rotation speed: 1 rpm) while maintaining a temperature of 25±2°C. The evaluation was then performed according to the following criteria.

[0193] Evaluation criteria: ◎: 100mPa·s or less ○: More than 100mPa·s but less than 1000mPa·s △: More than 1000mPa·s but less than 1000000mPa·s ×: More than 1000000mPa·s

[0194] [Dielectric properties] (1) Preparation of hardened material Resin compositions 1-14 and C1 were poured into an aluminum casting plate coated with a release agent (Daikin Corporation's "GA-9700"), and cured by heating in an air oven at 80°C for 1 hour, followed by 200°C for 2 hours. The cured material was removed from the casting plate to obtain a sheet-like material with a thickness of 1 mm.

[0195] (2) Evaluation of dielectric properties The hardened material was cut into strips using a diamond wire saw (DWS-3500P, manufactured by Meiwa Force Co., Ltd.). The relative permittivity and dielectric loss tangent were measured using the cavity resonance method at a measurement frequency of 5.8 GHz with a cavity resonator perturbation dielectric constant measuring device (CP521, manufactured by Kanto Applied Electronics Development Co., Ltd.) and a network analyzer (N5222B, manufactured by Agilent Technologies). Measurements were performed on three test pieces for each hardened material (n=3), and the average value was calculated. The results were then evaluated according to the following criteria.

[0196] Criteria for evaluating relative permittivity: ◎: 3.6 or less ○: More than 3.6 but less than 3.8 △: More than 3.8 but less than 4.0 ×: over 4.0

[0197] Criteria for evaluating dielectric loss tangent: ◎: 0.005 or less ○: More than 0.005 but less than 0.012 △: More than 0.012 but less than 0.015 ×: More than 0.015

[0198] [Table 1]

[0199] As shown in Table 1, the resin composition of the present invention, comprising a substituted styrene monomer (A) and an epoxy resin, was confirmed to exhibit good fluidity before curing and excellent dielectric properties after curing (Examples 1-14). The resin composition of the present invention, comprising a substituted styrene monomer (A) and an epoxy resin, was confirmed to exhibit good fluidity even when an inorganic filler is incorporated, and to achieve an even lower dielectric loss tangent after curing (Examples 9-14). For example, even when the inorganic filler content is as high as 60% by mass, the viscosity at 25°C can be kept below 100 mPa·s (Examples 9, 14), and even when the inorganic filler content is increased to 88% by mass, the viscosity at 25°C was confirmed to be well below 1000 mPa·s (Examples 9-12, 14). Furthermore, even when the inorganic filler content is extremely high at 92% by mass, the viscosity at 25°C was confirmed to be below 500,000 mPa·s, and it was confirmed to exhibit good fluidity in liquid form (Example 13). In other words, the resin composition of the present invention has been demonstrated to be beneficial for various liquid compound products that require good fluidity, including insulating materials with low transmission loss required for 5G applications, as it can achieve a good balance between fluidity and dielectric properties.

[0200] Furthermore, it was confirmed that the resin composition of the present invention, which contains a combination of substituted styrene monomer (A) and epoxy resin, also exhibits excellent storage stability. For example, when the viscosity at 25°C of the resin composition immediately after preparation is V1 (mPa·s), and the viscosity at 25°C of the resin composition after sealing it in a vial and storing it at 25°C for 168 hours is V2 (mPa·s), it was confirmed that the ratio of V2 / V1 is 1.7 or less.

Claims

1. A resin composition comprising a substituted styrene monomer (A) represented by the following general formula (1), an epoxy resin (B) that is liquid at 25°C, and an inorganic filler having an average particle size of 5 μm or less, wherein the content of the inorganic filler is 60% by mass or more when the nonvolatile components in the resin composition are taken as 100% by mass, and the viscosity at 25°C is 300 mPa·s or less. 【Chemistry 1】 (In the formula, R １ This refers to an alkyl group having 1 to 6 carbon atoms which may have one or more substituents selected from halogen atoms, alkyl groups, and aryl groups, or an aryl group which may have one or more substituents selected from halogen atoms, alkyl groups, and aryl groups. R ２ This represents one or more substituents selected from halogen atoms, alkyl groups, and aryl groups. n represents a number between 0 and 4.

2. A substituted styrene monomer (A) represented by the following general formula (1), Epoxy resin (B) that is liquid at 25°C, Inorganic fillers having an average particle size of 5 μm or less, and A resin composition comprising a radical polymerizable monomer (C) other than component (A), The radical polymerizable monomer (C) is one or more selected from (meth)acrylic acid esters and styrene monomers. When the non-volatile components in the resin composition are considered to be 100% by mass, the content of the inorganic filler is 60% by mass or more. A resin composition in which the dielectric loss tangent of the cured product of the resin composition is 0.012 or less at 5.8 GHz. 【Chemistry 2】 (In the formula, R1 represents an alkyl group having 1 to 6 carbon atoms which may have one or more substituents selected from halogen atoms, alkyl groups, and aryl groups, or an aryl group which may have one or more substituents selected from halogen atoms, alkyl groups, and aryl groups. R2 represents one or more substituents selected from halogen atoms, alkyl groups, and aryl groups. n represents a number between 0 and 4.

3. The resin composition according to claim 1 or 2, further comprising a radical polymerization catalyst.

4. A resin composition according to any one of claims 1 to 3, further comprising an organic base.

5. In general formula (1), R １ The resin composition according to any one of claims 1 to 4, wherein the alkyl group having 1 to 3 carbon atoms may have one or more substituents selected from halogen atoms, alkyl groups, and aryl groups.

6. (A) The resin composition according to any one of claims 1 to 5, wherein component (A) is acetoxystyrene.

7. The resin composition according to any one of claims 1 to 6, wherein the molar ratio of component (A) to the total epoxy groups in component (B) (component (A): total epoxy groups in component (B)) is in the range of 70:30 to 30:

70.

8. A resin composition according to any one of claims 2 to 7, wherein, when the nonvolatile components in the resin composition are taken as 100% by mass, the inorganic filler content is 85% by mass or more, and the viscosity at 25°C is 1000 mPa·s or less.

9. The resin composition according to claims 2 to 8, wherein, when the nonvolatile components in the resin composition are considered to be 100% by mass, the content of organic fillers is 1% by mass or more, and the viscosity at 25°C is 1000 mPa·s or less.

10. A resin composition according to any one of claims 1 to 9, which is for use as an adhesive, a casting material, a fiber-reinforced composite material, a semiconductor encapsulant, an underfill, or a mold underfill.

11. A cured product of the resin composition according to any one of claims 1 to 10.

12. The cured product according to claim 11, wherein the dielectric constant at 5.8 GHz is 3.0 or less.

13. The cured product according to claim 11 or 12, wherein the dielectric loss tangent at 5.8 GHz is 0.012 or less.

14. A semiconductor chip package comprising a cured product of the resin composition according to any one of claims 1 to 10.

15. The semiconductor chip package according to claim 14, which is a fan-out type package.

16. A semiconductor device comprising a cured product of the resin composition according to any one of claims 1 to 10.

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