TWI894208B - Resin composition - Google Patents

Abstract

The present invention is directed to providing a resin composition capable of producing a cured product with suppressed warping; a resin sheet comprising the resin composition; and a printed circuit board and semiconductor device having an insulating layer formed using the resin composition. The present invention addresses this problem by providing a resin composition comprising (A) an epoxy resin, (B) a hardener, and (C) an inorganic filler, wherein component (A) comprises an epoxy resin having a hyperbranched structure.

Description

Resin composition

The present invention relates to a resin composition and, moreover, to a resin sheet, a printed circuit board, and a semiconductor device obtained using the resin composition.

As a manufacturing technology for printed circuit boards, a build-up method of alternately stacking insulating layers and conductive layers is known.

As an insulating material for a printed circuit board used as such an insulating layer, for example, Patent Document 1 discloses a resin composition. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2019-53092

[The problem that the invention aims to solve]

Furthermore, in recent years, insulating layers used in embedded circuit boards, for example, are required to suppress warping that occurs during the formation of the insulating layers.

The present invention provides a resin composition capable of producing a cured product with suppressed warping; a resin sheet comprising the resin composition; and a printed circuit board and a semiconductor device having an insulating layer formed using the resin composition. [Means for Solving the Problem]

The present inventors have diligently examined the above-mentioned issues and have discovered that the above-mentioned issues can be solved by including an epoxy resin having a hyperbranched structure as an epoxy resin, thereby ultimately completing the present invention.

That is, the present invention includes the following contents. [1] A resin composition comprising (A) an epoxy resin, (B) a hardener, and (C) an inorganic filler, (A) component comprises an epoxy resin having a hyperbranched structure. [2] The resin composition as described in [1], wherein the molecular weight of the epoxy resin having a hyperbranched structure is greater than 1,000 and less than 10,000. [3] The resin composition as described in [1] or [2], wherein the epoxy resin having a hyperbranched structure has an epoxy equivalent of greater than 250 g/eq. and less than 700 g/eq. [4] The resin composition according to any one of [1] to [3], wherein the epoxy resin having a hyperbranched structure has a multi-branched structure in which a structure derived from a trifunctional or higher compound and a structure derived from a bifunctional compound are alternately bonded. [5] The resin composition according to any one of [1] to [4], wherein the epoxy resin having a hyperbranched structure includes a cyclic structure. [6] The resin composition according to [4], wherein the structure derived from a bifunctional compound includes a cyclic structure. [7] The resin composition according to any one of [1] to [6], wherein the content of the epoxy resin having a hyperbranched structure is 3% by mass or more and 10% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. [8] The resin composition according to any one of [1] to [7], wherein the content of the epoxy resin having a hyperbranched structure is 20% by mass or more and 50% by mass or less, taking the total weight of component (A) as 100% by mass. [9] The resin composition according to any one of [1] to [8], wherein the component (B) comprises any one of an active ester curing agent, a phenol curing agent, a benzophenone curing agent, and a carbodiimide curing agent. [10] The resin composition according to any one of [1] to [9], further comprising (D) a thermoplastic resin. [11] A resin sheet comprising a support and a resin composition layer comprising the resin composition described in any one of [1] to [10] and disposed on the support. [12] A printed circuit board comprising an insulating layer formed by a cured product of the resin composition described in any one of [1] to [10]. [13] A semiconductor device comprising the printed circuit board described in [12]. [Effects of the Invention]

According to the present invention, there are provided a resin composition capable of obtaining a cured product with suppressed warping; a resin sheet comprising the resin composition; and a printed circuit board and a semiconductor device having an insulating layer formed using the resin composition.

[Form of implementing the invention]

The present invention is described in detail below with reference to suitable embodiments. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified and implemented without departing from the scope of the invention application and its equivalents.

[Resin Composition] The resin composition of the present invention comprises (A) an epoxy resin, (B) a hardener, and (C) an inorganic filler. Component (A) comprises an epoxy resin having a hyperbranched structure. In the present invention, the inclusion of a hyperbranched epoxy resin as component (A) results in a cured product with suppressed warping. Furthermore, the present invention generally achieves excellent coating adhesion, even after reliability testing, and exhibits a low coefficient of linear thermal expansion (CTE).

The resin composition may further contain optional components in combination with components (A) to (C). Examples of optional components include (D) thermoplastic resin, (E) curing accelerator, (F) flame retardant, and (G) other additives. The following describes each component of the resin composition in detail.

<(A) Epoxy Resin> The resin composition contains (A) epoxy resin as component (A), wherein component (A) comprises an epoxy resin having a hyperbranched structure. The inclusion of component (A) in the resin composition results in a cured product with suppressed warping.

An epoxy resin having a hyperbranched structure is an epoxy resin having a multi-branched structure with multiple branches and having an epoxy group at the end. An epoxy resin having a hyperbranched structure preferably has an epoxy group at the end of a branch chain having 4 or more (preferably 6 or more, more preferably 8 or more), and particularly preferably has an epoxy group at the end of all of its branches. An epoxy resin having a hyperbranched structure preferably has a multi-branched structure in which a structure derived from a trifunctional or higher compound and a structure derived from a difunctional compound are alternately bonded, and has an epoxy group at the end. Such a preferred epoxy resin having a hyperbranched structure can be obtained by reacting a trifunctional or higher compound, which serves as the center of the molecular structure, with a difunctional compound. Hyperbranched epoxy resins have multiple branches, creating free spaces around the branches. These free spaces prevent the resin composition from shrinking and generating stress even as it hardens, which is thought to suppress warping.

From the perspective of significantly achieving the effects of the present invention, epoxy resins having a hyperbranched structure preferably have a cyclic structure, and more preferably an aromatic structure. An aromatic structure is generally defined as an aromatic chemical structure, and also includes polycyclic aromatics and aromatic heterocycles. Examples of cyclic structures include a bisphenol skeleton, a phenylene skeleton, a naphthylene skeleton, a dimethylmethylenedicyclohexylene skeleton, and an anthracene skeleton. A bisphenol skeleton is preferred. Examples of the bisphenol skeleton include bisphenol A skeleton, bisphenol F skeleton, bisphenol AP skeleton, bisphenol AF skeleton, bisphenol B skeleton, bisphenol BP skeleton, bisphenol S skeleton, bisphenol Z skeleton, bisphenol C skeleton, bisphenol TMC skeleton, bisphenol AF skeleton, bisphenol E skeleton, bisphenol G skeleton, bisphenol M skeleton, and bisphenol PH skeleton. Preferred is the bisphenol A skeleton.

The cyclic structure is preferably present in any one of a structure derived from a trifunctional or higher-functional compound and a structure derived from a bifunctional compound, and more preferably present in a structure derived from a bifunctional compound.

The ring in the cyclic structure may have a substituent. Examples of such a substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group, an arylalkyl group having 7 to 12 carbon atoms, a silanyl group, an acyl group, an acyloxy group, a carboxyl group, a sulfo group, a cyano group, a nitro group, a hydroxyl group, a hydroxyl group, and a sulfoxyl group.

A trifunctional or higher functional compound is a compound that can form the core of a hyperbranched structure and has a functional group that can react with a difunctional compound. A trifunctional or higher functional compound is a structure derived from a trifunctional or higher functional compound within a hyperbranched structure. Preferred trifunctional or higher functional compounds are trifunctional compounds and tetrafunctional compounds, and more preferred are tetrafunctional compounds.

Examples of the functional groups possessed by trifunctional or higher functional compounds include OH groups (including phenolic hydroxyl groups), amino groups, epoxy groups, and epoxypropyl ether groups, with OH groups being preferred.

Specific examples of trifunctional or higher functional compounds include pentaerythritol, glycerol, and compounds represented by the following formulas (1) to (12). Among them, pentaerythritol is preferred as the trifunctional or higher functional compound.

A bifunctional compound is a compound capable of bonding to a functional group of a trifunctional or higher functional compound, and has a functional group that reacts with a functional group of a trifunctional or higher functional compound. A bifunctional compound is a compound that has a hyperbranched structure derived from a bifunctional compound.

Examples of the functional group possessed by the bifunctional compound include epoxy groups, epoxypropyl ether groups, OH groups (including phenolic hydroxyl groups), and amino groups. Preferred are epoxy groups and epoxypropyl ether groups, and more preferred are epoxypropyl ether groups.

From the viewpoint of excellent heat resistance, the bifunctional compound preferably has a cyclic structure, and more preferably has an aromatic structure.

Specific examples of bifunctional compounds include compounds represented by the following formulae (13) to (41). Among them, the compound represented by formula (13) is preferred.

Epoxy resins having a hyperbranched structure can be prepared by reacting a trifunctional or higher functional compound, a bifunctional compound, and an epoxy compound.

Epoxy compounds are compounds with an epoxy group introduced at the end. Examples of epoxy compounds include epichlorohydrin, with epichlorohydrin being preferred.

The reaction temperature is preferably 90°C or higher, more preferably 100°C or higher, and particularly preferably 1100°C or higher, and is preferably 200°C or lower, more preferably 150°C or lower, and particularly preferably 120°C or lower.

The reaction time is preferably 2 hours or longer, more preferably 3 hours or longer, and particularly preferably 4 hours or longer, and is preferably 7 hours or shorter, more preferably 6 hours or shorter, and particularly preferably 5 hours or shorter.

From the perspective of significantly achieving the effects of the present invention, the molecular weight of the epoxy resin having a hyperbranched structure is preferably 1000 or greater, more preferably 1200 or greater, and particularly preferably 1400 or greater, and is preferably 10000 or less, more preferably 7500 or less, and particularly preferably 5000 or less. The molecular weight can be measured with a mass spectrometer.

To significantly achieve the effects of the present invention, the weight average molecular weight of the epoxy resin having a hyperbranched structure is preferably 1000 or greater, more preferably 1200 or greater, and particularly preferably 1400 or greater. It is preferably 10,000 or less, more preferably 7,500 or less, and particularly preferably 5,000 or less. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

From the perspective of significantly achieving the effects of the present invention, the epoxy equivalent weight of the epoxy resin having a hyperbranched structure is preferably 250 g/eq. or greater, more preferably 300 g/eq. or greater, and particularly preferably 350 g/eq. or greater, and is preferably 700 g/eq. or less, more preferably 500 g/eq. or less, and particularly preferably 450 g/eq. or less or 400 g/eq. or less. The epoxy equivalent weight is the mass of the epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent weight can be measured in accordance with JIS K7236.

Specific examples of epoxy resins having a hyperbranched structure include "PHE4h," "PHE5," and "PHE15," described in RSC Adv., 2015, 5, 35080-35088.

As the component (A), an epoxy resin other than the epoxy resin having a hyperbranched structure may be contained (hereinafter, the epoxy resin other than the epoxy resin having a hyperbranched structure may also be simply referred to as "component (A-1)"). Examples of such epoxy resins include bixylenol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butylcatechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, Epoxy resins such as epoxy propylamine type epoxy resins, epoxy propyl ester type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, aliphatic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, oxadiene type epoxy resins, oxadiene dimethanol type epoxy resins, naphthyl ether type epoxy resins, trihydroxymethyl type epoxy resins, and tetraphenylethane type epoxy resins may be used. Component (A-1) may be used alone or in combination of two or more.

Component (A-1) is preferably an epoxy resin having two or more epoxy groups per molecule. From the perspective of significantly achieving the desired effects of the present invention, the proportion of the epoxy resin having two or more epoxy groups per molecule relative to 100% by mass of the non-volatile component of component (A-1) is preferably 50% by mass or greater, more preferably 60% by mass or greater, and particularly preferably 70% by mass or greater.

The component (A-1) includes a component (A-1) that is liquid at a temperature of 20°C and a component (A-1) that is solid at a temperature of 20°C. The component (A-1) may contain only the liquid component (A-1), only the solid component (A-1), or a combination of the liquid and solid components. However, from the perspective of significantly achieving the desired effect of the present invention, a combination of the solid and liquid components (A-1) is preferred.

The solid component (A-1) is preferably a solid component (A-1) having three or more epoxy groups in one molecule, and more preferably an aromatic solid component (A-1) having three or more epoxy groups in one molecule.

Preferred solid component (A-1) includes bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthyl ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins, and more preferred is biphenyl-type epoxy resin.

Specific examples of the solid component (A-1) include "HP4032H" (naphthalene-based epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene-based tetrafunctional epoxy resin) manufactured by DIC Corporation; "N-690" (cresol novolac-based epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac-based epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP-7 200H" (dicyclopentadiene type epoxy resin); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthyl ether type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (triphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC300" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. 0H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemicals & Materials Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemicals & Materials Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (xylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation Epoxy resin); "YX8800" manufactured by Mitsubishi Chemical Corporation (anthracene-type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YL7760" manufactured by Mitsubishi Chemical Corporation (bisphenol AF-type epoxy resin); "YL7800" manufactured by Mitsubishi Chemical Corporation (fluorene-type epoxy resin); "jER1010" manufactured by Mitsubishi Chemical Corporation (solid bisphenol A-type epoxy resin); "jER1031S" manufactured by Mitsubishi Chemical Corporation (tetraphenylethane-type epoxy resin). These can be used alone or in combination.

The liquid component (A-1) is preferably one having two or more epoxy groups in one molecule.

Preferred liquid component (A-1) includes bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AF epoxy resin, naphthalene epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, phenol novolac epoxy resin, aliphatic epoxy resin having an ester skeleton, oxalic acid epoxy resin, oxadiene dimethanol epoxy resin, glycidylamine epoxy resin, and epoxy resin having a butadiene structure, and bisphenol A epoxy resin is more preferred.

Specific examples of the liquid component (A-1) include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US", "jER828EL", "825", and "Epikote" manufactured by Mitsubishi Chemical Corporation; "828EL" (bisphenol A type epoxy resin); "jER807" and "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630" and "630LSD" (epoxypropylamine type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemicals & Materials Co., Ltd.; "EX-721" (epoxypropyl ester type epoxy resin) manufactured by Nagase ChemteX; "Celloxide 2021P" (a butadiene-based epoxy resin); DAICEL's "PB-3600" (a butadiene-based epoxy resin); and Nippon Steel Chemicals & Materials' "ZX1658" and "ZX1658GS" (liquid 1,4-epoxypropylhexane-based epoxy resins). These can be used alone or in combination.

When a liquid component (A-1) and a solid component (A-1) are used in combination, the mass ratio thereof (liquid component (A-1) : solid component (A-1)) is preferably 1:1 to 1:20, more preferably 1:1.5 to 1:15, and particularly preferably 1:2 to 1:10. When the mass ratio of the liquid component (A-1) to the solid component (A-1) is within this range, the desired effects of the present invention can be significantly achieved. Furthermore, when the composition is typically used in the form of a resin sheet, moderate adhesion is achieved. Furthermore, when the composition is typically used in the form of a resin sheet, sufficient flexibility is achieved, and workability is improved. Furthermore, a cured product having sufficient breaking strength can typically be obtained.

The epoxy equivalent weight of component (A-1) is preferably 50 g/eq. to 5000 g/eq., more preferably 50 g/eq. to 3000 g/eq., particularly preferably 80 g/eq. to 2000 g/eq., and even more preferably 110 g/eq. to 1000 g/eq. Within this range, the cured resin composition has a sufficient crosslinking density, resulting in an insulating layer with minimal surface roughness.

The weight average molecular weight (Mw) of the component (A-1) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500, from the viewpoint of significantly achieving the desired effects of the present invention.

To achieve the desired effects of the present invention, the content of the epoxy resin having a hyperbranched structure is preferably 3% by mass or greater, more preferably 4% by mass or greater, and particularly preferably 5% by mass or greater, based on the non-volatile components in the resin composition being 100% by mass. To achieve the desired effects of the present invention, the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 7% by mass or less. In the present invention, the content of each component in the resin composition is based on the non-volatile components in the resin composition being 100% by mass, unless otherwise specified.

From the perspective of obtaining an insulating layer exhibiting excellent mechanical strength and insulation reliability, the content of component (A-1) is preferably 1% by mass or greater, more preferably 5% by mass or greater, and particularly preferably 8% by mass or greater, based on 100% by mass of the non-volatile components in the resin composition. From the perspective of significantly achieving the desired effects of the present invention, the upper limit of the content of the epoxy resin is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

From the perspective of significantly achieving the effects of the present invention, the total content of component (A) is preferably 1% by mass or greater, more preferably 5% by mass or greater, and particularly preferably 10% by mass or greater, based on 100% by mass of the non-volatile components in the resin composition. From the perspective of significantly achieving the desired effects of the present invention, the upper limit of the content of the epoxy resin is preferably 35% by mass or less, more preferably 30% by mass or less, and particularly preferably 25% by mass or less.

From the viewpoint of significantly achieving the effects of the present invention, the content of the epoxy resin having a hyperbranched structure is preferably 20% by mass or more, more preferably 25% by mass or more, and particularly preferably 30% by mass or more, based on 100% by mass of the total component (A). From the viewpoint of significantly achieving the desired effects of the present invention, the upper limit is preferably 50% by mass or less, more preferably 45% by mass or less, and particularly preferably 40% by mass or less.

When the content of the non-volatile components in the resin composition of the hyper-branched epoxy resin is taken as 100 mass %, and the content of the non-volatile components in the resin composition of the component (A-1) is taken as e (mass %), from the viewpoint of significantly achieving the effects of the present invention, h/(h+e) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more, and is preferably 5 or less, more preferably 3 or less, and even more preferably 1 or less.

<(B) Hardener> The resin composition contains a hardener as component (B). The (B) hardener typically reacts with component (A) to harden the resin composition. A single (B) hardener may be used, or two or more types may be combined in any ratio.

As the hardener (B), a compound capable of reacting with the component (A) to harden the resin composition can be used. Examples thereof include active ester hardeners, phenolic hardeners, benzophenone hardeners, carbodiimide hardeners, acid anhydride hardeners, amine hardeners, and cyanate hardeners. Among these, from the perspective of significantly achieving the effects of the present invention, active ester hardeners, phenolic hardeners, benzophenone hardeners, and carbodiimide hardeners are preferred, and active ester hardeners and phenolic hardeners are more preferred.

Examples of active ester curing agents include those having one or more active ester groups per molecule. Preferred active ester curing agents include highly reactive compounds having two or more ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxylamine esters, and esters of heterocyclic hydroxyl compounds. These active ester curing agents are preferably obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxyl compound and/or a thiol compound. In particular, from the perspective of improving heat resistance, active ester curing agents derived from carboxylic acid compounds and hydroxyl compounds are preferred, and those derived from carboxylic acid compounds and phenol compounds and/or naphthol compounds are even more preferred.

Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, reduced phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxydiphenyl ketone, trihydroxydiphenyl ketone, tetrahydroxydiphenyl ketone, phloroglucinol, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolac. The "dicyclopentadiene-type diphenol compound" referred to here refers to a diphenol compound obtained by condensing two phenol molecules with one dicyclopentadiene molecule.

Preferred examples of active ester-based hardeners include active ester compounds containing a dicyclopentadiene diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing acetylated phenol novolacs, and active ester compounds containing benzoylated phenol novolacs. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene diphenol structure are more preferred. The term "dicyclopentadiene diphenol structure" refers to a divalent structure consisting of a phenylene group, a dicyclopentylene group, and a phenylene group.

Examples of commercially available active ester curing agents include those containing a dicyclopentadiene-type diphenol structure, such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", "HPC-8150-62T", "EXB-8000L", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation); and those containing a naphthalene structure, such as "EXB-8100L-65T", "EXB-8150L-65 T", "EXB9416-70BK" (manufactured by DIC Corporation); among active ester compounds containing acetylated phenol novolacs, "DC808" (manufactured by Mitsubishi Chemical Corporation) can be cited; among active ester compounds containing benzoylated phenol novolacs, "YLH1026" (manufactured by Mitsubishi Chemical Corporation) can be cited; among active ester hardeners containing acetylated phenol novolacs, "DC808" (manufactured by Mitsubishi Chemical Corporation) can be cited; among active ester hardeners containing benzoylated phenol novolacs, "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) can be cited.

Examples of phenolic hardeners include those containing one or more, preferably two or more, hydroxyl groups bonded to aromatic rings (such as benzene rings and naphthalene rings) per molecule. Compounds containing hydroxyl groups bonded to benzene rings are particularly preferred. Furthermore, from the perspective of heat resistance and water resistance, phenolic hardeners having a novolac structure are preferred. Furthermore, from the perspective of adhesion, nitrogen-containing phenolic hardeners are preferred, and phenolic hardeners containing a tris-indium skeleton are even more preferred. In particular, phenolic novolac hardeners containing a tris-indium skeleton are particularly preferred, as they offer excellent heat resistance, water resistance, and adhesion.

Specific examples of phenol-based hardeners and naphthol-based hardeners include "MEH-7700", "MEH-7810", "MEH-7851", and "MEH-8000H" manufactured by Meiwa Chemicals; "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku; and "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", and "SN-170" manufactured by Nippon Steel Chemicals & Materials. SN-375", "SN-395"; DIC Corporation's "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", "KA-1165"; Qun Rong Chemical Corporation's "GDP-6115L", "GDP-6115H", "ELPC75", etc.

Specific examples of benzophenone-based hardeners include "HFB2006M" manufactured by Showa High Polymer Co., Ltd., and "P-d" and "F-a" manufactured by Shikoku Chemical Industries, Ltd.

Specific examples of carbodiimide-based hardeners include "V-03," "V-05," and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.; and Stabaxol (registered trademark) P manufactured by LAN Chemical Co., Ltd.

Examples of the acid anhydride curing agent include those having one or more acid anhydride groups in one molecule. Specific examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, benzene Examples of these hardeners include pyrotetracarboxylic anhydride, diphenyl ketone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonium tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(trimellitic anhydride), and polymer-type acid anhydrides such as styrene-maleic acid resins copolymerized with maleic acid. Examples of commercially available anhydride-based hardeners include "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

Examples of amine-based hardeners include those having one or more amino groups per molecule, such as aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines. Among these, aromatic amines are preferred from the perspective of achieving the desired effects of the present invention. Amine-based hardeners are preferably primary or secondary amines, and more preferably primary amines. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfonate, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfonate, 3,3'-diaminodiphenylsulfonate, metaphenylenediamine, metaxylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-aminobenzidine), -4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfonium, bis(4-(3-aminophenoxy)phenyl)sulfonium, etc. Amine hardeners that can be used are commercially available products, such as "KAYABOND C-200S", "KAYABOND C-100", "Kayahard A-A", "Kayahard A-B", and "Kayahard A-S" manufactured by Nippon Kayaku Co., Ltd., and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

Examples of cyanate curing agents include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane) ), bifunctional cyanate resins such as bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)sulfide and bis(4-cyanatephenyl)ether, multifunctional cyanate resins derived from phenol novolac and cresol novolac, and partially tri-hydrated prepolymers of these cyanate resins. Specific examples of cyanate-based hardeners include "PT30" and "PT60" manufactured by LONZA Japan (both phenol novolac-type multifunctional cyanate resins); "ULL-950S" (a multifunctional cyanate resin); and "BA230" and "BA230S75" (prepolymers obtained by partially or completely triturating bisphenol A dicyanate to form a trimer).

From the viewpoint of significantly achieving the effects of the present invention, the content of the hardener (B) is preferably 1% by mass or more, more preferably 5% by mass or more, and particularly preferably 10% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

When the number of epoxy groups in component (A) is assumed to be 1, the number of active groups in the hardener (B) is preferably 0.1 or greater, more preferably 0.2 or greater, and particularly preferably 0.3 or greater, and is preferably 2 or less, more preferably 1.8 or less, particularly preferably 1.6 or less, and particularly preferably 1.4 or less. Herein, the "number of epoxy groups in component (A)" refers to the total value obtained by dividing the mass of the nonvolatile components of component (A) present in the resin composition by the epoxy equivalent. Furthermore, the "number of active groups in the hardener (B)" refers to the total value obtained by dividing the mass of the nonvolatile components of the hardener (B) present in the resin composition by the active group equivalent. Since the number of active groups of the curing agent (B) is within the aforementioned range, assuming the number of epoxy groups in the component (A) is 1, the desired effects of the present invention can be significantly achieved.

<(C) Inorganic Filler> The resin composition contains an inorganic filler as component (C). The inclusion of the inorganic filler (C) in the resin composition yields a cured product with a low coefficient of linear thermal expansion.

Inorganic compounds are used as the inorganic filler. Examples of inorganic filler materials include silica, alumina, glass, cordierite, silica oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, hydroaluminite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanium oxide, calcium titanium oxide, magnesium titanium oxide, bismuth titanium oxide, titanium oxide, zirconium oxide, barium titanium oxide, barium zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is particularly preferred. (C) The inorganic filler may be used alone or in combination of two or more.

Examples of commercially available inorganic fillers (C) include "UFP-30" manufactured by Denka Kagaku Kogyo Co., Ltd.; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials Corporation; "YC100C," "YA050C," "YA050C-MJE," and "YA010C" manufactured by ADMATECHS; "UFP-30" manufactured by DENKA Corporation; "Silfill NSS-3N," "Silfill NSS-4N," and "Silfill NSS-5N" manufactured by Tokuyama Corporation; and "SC2500SQ," "SO-C4," "SO-C2," "SO-C1," and "SC2050-SXF" manufactured by ADMATECHS.

(C) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and preferably 5 μm or less, more preferably 2 μm or less, and particularly preferably 1 μm or less, from the viewpoint of significantly achieving the desired effects of the present invention.

(C) The average particle size of an inorganic filler can be measured using a laser diffraction/scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler can be prepared on a volume basis using a laser diffraction scattering particle size distribution measuring device, and the median particle size can be used as the average particle size for measurement. The measurement sample can be prepared by weighing 100 mg of an inorganic filler and 10 g of methyl ethyl ketone in a vial and ultrasonically dispersing them for 10 minutes. For the measurement sample, a laser diffraction particle size distribution measuring device is used, and the wavelength of the light source used is set to blue and red. The particle size distribution of the inorganic filler on a volume basis is measured using a flow cell method. From the obtained particle size distribution, the average particle size is calculated as the median particle size. Examples of laser diffraction particle size distribution measuring devices include the "LA-960" manufactured by Horiba, Ltd.

(C) From the perspective of significantly achieving the desired effects of the present invention, the specific surface area of the inorganic filler is preferably 1 ^m² /g or greater, more preferably 2 ^m² /g or greater, and particularly preferably 3 ^m² /g or greater. There is no particular upper limit, but it is preferably 60 ^m² /g or less, 50 ^m² /g or less, or 40 ^m² /g or less. The specific surface area of the inorganic filler is measured using a BET fully automatic specific surface area measuring device (Macsorb HM-1210, manufactured by MOUNTECH) by adsorbing nitrogen gas onto the sample surface and calculating the specific surface area using the BET multipoint method.

From the perspective of improving moisture resistance and dispersibility, the inorganic filler (C) is preferably treated with a surface treatment agent. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane-based coupling agents, epoxysilane-based coupling agents, hydroxysilane-based coupling agents, silane-based coupling agents, alkoxysilanes, organosilazane compounds, and titanium ester-based coupling agents. Surface treatment agents may be used singly or in combination of two or more.

Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-hydroxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and "KBM573" (N-phenyl- 3-Aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc.

From the perspective of improving the dispersibility of the inorganic filler, the degree of surface treatment by the surface treatment agent is preferably within a specific range. Specifically, 0.2 to 5 parts by mass of the surface treatment agent is preferably applied to 100 parts by mass of the inorganic filler, more preferably 0.2 to 3 parts by mass, and even more preferably 0.3 to 2 parts by mass.

The degree of surface treatment achieved by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. To improve the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/ ^m² or greater, more preferably 0.1 mg/ ^m² or greater, and particularly preferably 0.2 mg/ ^m² or greater. On the other hand, to prevent an increase in the melt viscosity of the resin varnish and the melt viscosity of the flaky form, the amount of carbon per unit surface area is preferably 1 mg/ ^m² or less, more preferably 0.8 mg/m² or ^less , and particularly preferably 0.5 mg/ ^m² or less.

(C) The amount of carbon per unit surface area of an inorganic filler can be measured by washing the surface-treated inorganic filler with a solvent, such as methyl ethyl ketone (MEK). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent, and ultrasonically cleaned at 25°C for 5 minutes. After removing the supernatant and drying the solid components, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. As a carbon analyzer, the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

From the viewpoint of significantly achieving the effects of the present invention, the content of the inorganic filler (C) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 75% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

<(D) Thermoplastic Resin> The resin composition may further contain (D) a thermoplastic resin as an optional component in addition to the above components.

Examples of the thermoplastic resin as component (D) include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamide imide resins, polyetherimide resins, polysulfate resins, polyethersulfate resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins. Among these, phenoxy resins are preferred from the perspective of significantly achieving the desired effects of the present invention. The thermoplastic resins may be used alone or in combination of two or more.

Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a novolac skeleton, a biphenyl skeleton, a fluorene skeleton, a dicyclopentadiene skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The termini of the phenoxy resins may be phenolic hydroxyl groups, epoxy groups, or other functional groups.

Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (a phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (a phenoxy resin containing a bisphenol acetophenone skeleton); and "Phenoxy Propanol" manufactured by Nippon Steel Chemical & Materials Co., Ltd. "FX280" and "FX293" manufactured by Material Company; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482" manufactured by Mitsubishi Chemical Corporation.

Examples of polyvinyl acetal resins include polyvinyl formaldehyde resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP manufactured by Denka Chemical Industries, Ltd.; and S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemical Industries, Ltd.

Specific examples of polyimide resins include "Rikacoat SN20" and "Rikacoat PN20" manufactured by Shin Nippon Rika Co., Ltd. Specific examples of polyimide resins include modified polyimides such as linear polyimides obtained by reacting bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimides described in Japanese Patent Application Laid-Open No. 2006-37083), and polyimides containing a polysiloxane skeleton (polyimides described in Japanese Patent Application Laid-Open No. 2002-12667 and Japanese Patent Application Laid-Open No. 2000-319386).

Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Other specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imides containing a polysiloxane skeleton) manufactured by Hitachi Chemical Co., Ltd.

Specific examples of polyether sulphate resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of polyphenylene ether resins include "OPE-2St 1200," an oligophenylene ether styrene resin manufactured by Mitsubishi Gas Chemical Co., Ltd.

Specific examples of polyol resins include polyols "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

(D) The weight average molecular weight (Mw) of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 70,000 or less, more preferably 60,000 or less, and particularly preferably 50,000 or less, from the viewpoint of significantly achieving the desired effects of the present invention.

From the viewpoint of significantly achieving the desired effects of the present invention, the content of the thermoplastic resin (D) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more, based on 100% by mass of the non-volatile components in the resin composition, and is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less.

<(E) Hardening Accelerator> In addition to the above components, the resin composition may further contain a hardening accelerator as component (E) as an optional component.

Examples of the component (E) include phosphorus-based hardening accelerators, amine-based hardening accelerators, imidazole-based hardening accelerators, guanidine-based hardening accelerators, and metal-based hardening accelerators. The component (E) may be used alone or in combination of two or more.

Examples of phosphorus-based hardening accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate. Preferred are triphenylphosphine and tetrabutylphosphonium decanoate.

Examples of the amine-based hardening accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene. 4-Dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferred.

Examples of the imidazole-based hardening accelerator 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-tris-imidazolium, 2,4-diamino- 6-[2'-Undecylimidazolyl-(1')]-ethyl-s-triacontium, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triacontium, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triacontium isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl-4,5-dihydroxy Imidazole compounds such as methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole.

As the imidazole-based hardening accelerator, a commercially available product can be used, for example, "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine-based hardening accelerator include cyanoguanidine, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, 1-(o-tolyl)biguanidine, etc., preferably cyanoguanidine and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

Examples of metal hardening accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonikel complexes such as nickel(II) acetylacetonate, and organomethane complexes such as manganese(II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc cycloalkanoate, cobalt cycloalkanoate, tin stearate, and zinc stearate.

From the viewpoint of significantly achieving the desired effects of the present invention, the content of component (E) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, based on 100% by mass of the non-volatile components in the resin composition, and is preferably 3% by mass or less, more preferably 1.5% by mass or less, and particularly preferably 1% by mass or less.

<(F) Flame Retardant> In addition to the above components, the resin composition may further contain a flame retardant as component (F) as an optional component.

Examples of the flame retardant (F) include phosphazene compounds, organophosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicon oxide flame retardants, and metal hydroxides. Phosphazene compounds are preferred. The flame retardant may be used alone or in combination of two or more.

The phosphazene compound is not particularly limited as long as it is a cyclic compound containing nitrogen and phosphorus as constituent elements, but the phosphazene compound is preferably a phosphazene compound having a phenolic hydroxyl group.

Specific examples of phosphazene compounds include "SPH-100", "SPS-100", "SPB-100", and "SPE-100" manufactured by Otsuka Chemical Co., Ltd., and "FP-100", "FP-110", "FP-300", and "FP-400" manufactured by Fushimi Pharmaceutical Co., Ltd., with "SPH-100" manufactured by Otsuka Chemical Co., Ltd. being preferred.

As flame retardants other than phosphazene compounds, commercially available products can be used, such as "HCA-HQ" manufactured by Sanko Corporation and "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd. Flame retardants that are not easily hydrolyzed are preferred, such as 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxo-10-phosphaphenanthrene-10-oxide.

(F) The content of the flame retardant, based on 100% by mass of the non-volatile components in the resin composition, is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more, in order to significantly achieve the effects of the present invention. The upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less.

<(G) Other Additives> In addition to the above-mentioned components, the resin composition may further contain other additives as optional components. Examples of such additives include thickeners, defoamers, leveling agents, and adhesion enhancers. These additives may be used singly or in combination. The amounts of these additives can be determined as appropriate by the resin industry.

The method for preparing the resin composition of the present invention is not particularly limited. For example, a method of adding the ingredients to a solvent as needed and mixing and dispersing them using a rotary mixer or the like can be cited.

<Resin Composition Properties and Applications> Because the resin composition contains a hyperbranched epoxy resin as component (A), it produces a cured product with suppressed warping. Furthermore, the resin composition generally exhibits excellent coating adhesion, even after reliability testing, and a low coefficient of linear thermal expansion.

The resin composition exhibits the ability to suppress warp. Specifically, when tested according to the methods described in the examples below, warp is reduced, with the warp size typically reaching less than 1 cm. Details of warp evaluation can be measured using the methods described in the examples below.

A cured product formed by heat-curing the resin composition at 130°C for 30 minutes, followed by 170°C for 30 minutes, generally exhibits excellent coating adhesion (peel strength) to the conductive layer formed by coating (coated conductive layer). Therefore, the cured product forms an insulating layer with excellent coating adhesion to the coated conductive layer. The coating adhesion is preferably 0.35 kgf/cm or greater, more preferably 0.40 kgf/cm or greater, and even more preferably 0.45 kgf/cm or greater. The upper limit of the peel strength can be set to 10 kgf/cm or less. The coating adhesion can be measured according to the method described in the examples below.

The cured product formed by heat curing the resin composition at 130°C for 30 minutes, followed by 170°C for 30 minutes, typically exhibits excellent adhesion (peel strength) to the conductive layer (plated conductive layer) formed after reliability testing (130°C, 85% RH, 200 hours). Therefore, the cured product provides an insulating layer with excellent adhesion to the plated conductive layer after reliability testing. The adhesion after reliability testing is preferably 0.25 kgf/cm or greater, more preferably 0.3 kgf/cm or greater, and even more preferably 0.35 kgf/cm or greater. The upper limit of the coating adhesion after the reliability test can be set to 10 kgf/cm or less. The coating adhesion after the reliability test can be measured according to the method described in the embodiment described below.

A cured product formed by thermally curing a resin composition at 190°C for 90 minutes typically exhibits a low linear thermal expansion coefficient. Therefore, the cured product provides an insulation layer having a low linear thermal expansion coefficient. The linear thermal expansion coefficient is preferably 30 ppm or less, more preferably 25 ppm or less, and even more preferably 22 ppm or less. Alternatively, the lower limit of the linear thermal expansion coefficient can be set to 1 ppm or greater. The linear thermal expansion coefficient can be measured according to the method described in the Examples below.

The resin composition can produce a cured product with suppressed warping. Furthermore, the resin composition generally produces a cured product with excellent coating adhesion and reliability testing, and a low coefficient of linear thermal expansion. Therefore, the resin composition of the present invention is suitable for use as a resin composition for insulating purposes. Specifically, it can be suitable for use as a resin composition for forming a conductive layer (recircuit layer) formed on an insulating layer (resin composition for forming an insulating layer for forming a conductive layer).

Furthermore, in the multilayer printed circuit board described later, it can be suitably used as a resin composition for forming an insulating layer of the multilayer printed circuit board (resin composition for forming an insulating layer of a multilayer printed circuit board) and a resin composition for forming an interlayer insulating layer of the printed circuit board (resin composition for forming an interlayer insulating layer of a printed circuit board).

Furthermore, for example, when a semiconductor chip package is manufactured through the following steps (1) to (6), the resin composition of the present invention can also be used as a resin composition for a recircuiting layer (resin composition for forming a recircuiting layer) for forming an insulating layer of the recircuiting layer, and a resin composition for sealing a semiconductor chip (resin composition for sealing a semiconductor chip). When manufacturing a semiconductor chip package, a recircuiting layer can be further formed on the sealing layer. (1) laminating a temporary fixing film on a substrate, (2) temporarily fixing a semiconductor chip on the temporary fixing film, (3) forming a sealing layer on the semiconductor chip, (4) peeling the substrate and the temporary fixing film from the semiconductor chip, (5) forming a recircuiting layer as an insulating layer on the surface of the semiconductor chip after the substrate and the temporary fixing film are peeled off, and (6) forming a recircuiting layer as a conductive layer on the recircuiting layer.

[Resin Sheet] The resin sheet of the present invention comprises a support and a resin composition layer formed from the resin composition of the present invention disposed on the support.

The thickness of the resin composition layer is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less, from the perspective of thinning the printed circuit board and providing a cured product with excellent insulation properties even in the form of a thin film. There is no particular lower limit to the thickness of the resin composition layer, but it can generally be set to 5 μm or more.

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, preferably a film made of a plastic material or a metal foil.

When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter also referred to as "PET") and polyethylene naphthalate (hereinafter also referred to as "PEN"); polycarbonate (hereinafter also referred to as "PC"); acrylics such as polymethyl methacrylate (hereinafter also referred to as "PMMA"); cyclic polyolefins, triacetyl cellulose (hereinafter also referred to as "TAC"), polyether sulfide (hereinafter also referred to as "PES"); polyether ketone; and polyimide. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be made of copper alone or an alloy of copper and other metals (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

The surface of the support body that is bonded to the resin composition layer may be subjected to matte treatment, corona treatment, and anti-static treatment.

Alternatively, a support with a release layer may be used, wherein the surface of the support that contacts the resin composition layer has a release layer. Examples of release agents used for the release layer of the support with a release layer include at least one selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. The support body with a release layer can be a commercially available product. For example, PET films having a release layer mainly composed of an alkyd resin release agent, such as "SK-1", "AL-5", and "AL-7" manufactured by LINTEC, "Lumirror T60" manufactured by Toray Industries, "Purex" manufactured by Teijin, and "Unipeel" manufactured by UNITIKA, can be cited.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. Furthermore, when using a support with a release layer, the thickness of the entire support with the release layer is preferably within the above range.

In one embodiment, the resin sheet may further include other layers as needed. Examples of these other layers include a protective film conforming to the support, applied to the surface of the resin composition layer not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. The addition of the protective film prevents dust and other substances from adhering to or damaging the surface of the resin composition layer.

The resin sheet can be manufactured by, for example, preparing a resin varnish in which a resin composition is dissolved in an organic solvent, applying the resin varnish to a support using a die coater, and drying the varnish to form a resin composition layer.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetates such as ethyl acetate, butyl acetate, celoxylate acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as celoxylate and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone. Organic solvents may be used alone or in combination.

Drying can be carried out by known methods such as heating and hot air spraying. Drying conditions are not particularly limited, but drying is performed so that the organic solvent content in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. While this varies depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% to 60% by mass of an organic solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

Resin sheets can be stored in rolls. If the resin sheet has a protective film, it can be used by peeling off the protective film.

[Printed Circuit Board] The printed circuit board of the present invention includes an insulating layer formed by a cured product of the resin composition of the present invention.

A printed circuit board can be manufactured, for example, using the above-mentioned resin sheet by a method comprising the following steps (I) and (II). (I) Laminating the resin composition layer of the resin sheet onto the inner substrate so that the resin composition layer is bonded to the inner substrate (II) Thermally curing the resin composition layer to form an insulating layer

The "inner substrate" used in step (I) is a component that becomes the substrate of the printed circuit board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. In addition, the substrate may have a conductive layer on one or both sides thereof, and the conductive layer may be patterned. An inner substrate having a conductive layer (circuit) formed on one or both sides of the substrate is sometimes referred to as an "inner circuit substrate." In addition, when manufacturing a printed circuit board, an intermediate product that forms an insulating layer and/or a conductive layer is also included in the "inner substrate" referred to in the present invention. When the printed circuit board is a circuit board with built-in components, an inner substrate with built-in components can be used.

The inner substrate and the resin sheet can be laminated, for example, by heat-pressing the resin sheet onto the inner substrate from the support body side. The member heat-pressing the resin sheet onto the inner substrate (hereinafter referred to as the "heat-pressing member") can be, for example, a heated metal plate (such as a SUS end plate) or a metal roller (such as a SUS roller). It is preferred that the heat-pressing member not be directly pressed against the resin sheet, but rather be pressed through an elastic material such as heat-resistant rubber, so that the resin sheet fully follows the surface irregularities of the inner substrate.

Lamination of the inner substrate and the resin sheet can be performed using a vacuum lamination method. The heat-pressing temperature during vacuum lamination is preferably between 60°C and 160°C, more preferably between 80°C and 140°C. The heat-pressing pressure is preferably between 0.098 MPa and 1.77 MPa, more preferably between 0.29 MPa and 1.47 MPa. The heat-pressing time is preferably between 20 seconds and 400 seconds, more preferably between 30 seconds and 300 seconds. Lamination is preferably performed under reduced pressure, with a pressure of no more than 26.7 hPa.

Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include the vacuum pressure laminator manufactured by Meiki Manufacturing Co., Ltd., the vacuum applicator manufactured by NIKKO Materials Co., Ltd., and the batch vacuum pressure laminator.

After lamination, the laminated resin sheets can be smoothed under normal pressure (atmospheric pressure), for example, by applying pressure from the support body side using a heat and pressure bonding member. The smoothing pressure conditions can be the same as those used for the heat and pressure bonding process described above. The smoothing process can be performed using a commercially available laminator. Furthermore, lamination and smoothing can be performed continuously using the aforementioned commercially available vacuum laminator.

The support may be removed between step (I) and step (II), or after step (II).

In step (II), the resin composition layer is thermally cured to form an insulating layer. The thermal curing conditions of the resin composition layer are not particularly limited, and the conditions commonly used in forming an insulating layer of a printed circuit board can be used.

For example, while the heat curing conditions for the resin composition layer vary depending on the type of resin composition, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

Before heat-hardening the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, before heat-hardening the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C or higher and lower than 120°C (preferably 60°C or higher and 115°C or lower, more preferably 70°C or higher and 110°C or lower) 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).

When manufacturing a printed circuit board, the following steps may be further performed: (III) forming a hole in the insulating layer; (IV) roughening the insulating layer; and (V) forming a conductive layer. Steps (III) through (V) may be performed using various methods known to those skilled in the art for manufacturing printed circuit boards. Furthermore, when the support is removed after step (II), the removal may be performed between step (II) and step (III), between step (III) and step (IV), or between step (IV) and step (V). Furthermore, if necessary, the steps (II) to (V) of forming the insulating layer and the conductive layer can be repeated to form a multi-layer circuit board.

Step (III) involves drilling holes in the insulating layer, thereby forming holes such as through-holes and through-holes. Step (III) can be performed using methods such as a drill, laser, or plasma, depending on the composition of the resin used to form the insulating layer. The size and shape of the holes can be determined appropriately based on the design of the printed circuit board.

Step (IV) is the step of roughening the insulating layer. Typically, this step (IV) also involves removing sludge. The sequence and conditions for the roughening treatment are not particularly limited and can be based on the well-known sequence and conditions commonly used when forming the insulating layer of a printed circuit board. For example, the insulating layer can be roughened by sequentially performing a swelling treatment with a swelling solution, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing solution. The swelling fluid used for the roughening treatment is not particularly limited, but examples include alkaline solutions and surfactant solutions. Alkaline solutions are preferred, and sodium hydroxide solutions and potassium hydroxide solutions are more preferred. Commercially available swelling fluids include "Swelling Dip Securiganth P," "Swelling Dip Securiganth SBU," and "Swelling Dip Securigant P" manufactured by ATOTECH Japan. The swelling treatment with the swelling fluid is not particularly limited, but for example, the insulating layer can be immersed in a swelling fluid at 30°C to 90°C for 1 to 20 minutes. To minimize swelling of the insulating layer resin, it is best to immerse the insulating layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes. The oxidizing agent used for the roughening treatment is not particularly limited, but examples include alkaline permanganic acid solutions containing potassium permanganate or sodium permanganate dissolved in an aqueous sodium hydroxide solution. Roughening treatment using oxidizing agents such as alkaline permanganic acid solutions is best performed by immersing the insulating layer in the oxidizing solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganic acid solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by ATOTECH Japan. Furthermore, the neutralizing solution used for the roughening treatment is preferably an acidic aqueous solution. A commercially available example is "Reduction Solution Securigant P" manufactured by ATOTECH Japan. Treatment with the neutralizing solution can be performed by immersing the roughened surface treated with the oxidizing agent in the neutralizing solution at 30°C to 80°C for 1 to 30 minutes. From the perspective of workability, a method in which the object to be roughened with an oxidizing agent is immersed in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes is preferred.

In one embodiment, the arithmetic average roughness (Ra) of the insulating layer surface after the roughening treatment is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. The lower limit is not particularly limited, but is preferably 30 nm or greater, more preferably 40 nm or greater, and even more preferably 50 nm or greater. The arithmetic average roughness (Ra) of the insulating layer surface can be measured using a non-contact surface roughness meter.

Step (V) is a step of forming a conductive layer, and the conductive layer is formed on the insulating layer. The conductive material used for the conductive layer is not particularly limited. In a suitable embodiment, the conductive layer includes 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 conductive layer can be a single metal layer or an alloy layer. As an example of an alloy layer, a layer formed of an alloy of two or more metals selected from the above group (for example, nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy) can be cited. Among them, from the viewpoints of versatility in forming the conductive layer, cost, ease of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy is preferred. A single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy is more preferred, and a single metal layer of copper is particularly preferred.

The conductive layer may be a single layer or a composite structure comprising two or more single metal layers or alloy layers composed of different metals or alloys. When the conductive layer is a composite 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.

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

In one embodiment, the conductive layer can be formed by plating. For example, a conductive layer having a desired circuit pattern can be formed by plating on the surface of the insulating layer using known techniques such as semi-additive or full-additive plating. From the perspective of manufacturing simplicity, semi-additive plating is preferred. The following illustrates an example of forming a conductive layer using a semi-additive plating method.

First, a plating seed layer is formed on the surface of the insulating 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 circuit pattern. A metal layer is formed on the exposed plating seed layer by electrolytic plating, and the mask pattern is removed. The unwanted plating seed layer can then be removed by etching, etc., to form a conductive layer with the desired circuit pattern.

[Semiconductor Device] The semiconductor device of the present invention includes the printed circuit board of the present invention. The semiconductor device of the present invention can be manufactured using the printed circuit board of the present invention.

Examples of semiconductor devices include various semiconductor devices used in electronic products (such as computers, mobile phones, digital cameras, and televisions) and transportation vehicles (such as motorcycles, automobiles, trains, ships, and aircraft).

The semiconductor device of the present invention can be manufactured by mounting components (semiconductor chips) on conductive areas of a printed circuit board. "Conductive areas" are defined as areas on the printed circuit board where electrical signals are transmitted. These areas can be surface or embedded. Furthermore, the semiconductor chip is not particularly limited, as long as it is an electrical circuit component made of semiconductors.

The semiconductor chip mounting method used in manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip can effectively function. Specifically, examples include wire bonding, flip-chip, bumpless build-up layer (BBUL), anisotropic conductive film (ACF), and non-conductive film (NCF). Here, the term "bumpless build-up layer (BBUL) mounting method" refers to a mounting method in which the semiconductor chip is directly embedded in a recess of a printed circuit board (PCB) to connect the semiconductor chip to the circuitry on the PCB. [Example]

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples. In the following descriptions, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass" respectively.

<Synthesis Example 1: Synthesis of an Epoxy Resin with a Hyperbranched Structure> An epoxy resin with a hyperbranched structure was synthesized by polycondensation. 1.0 g of pentaerythritol (10% solids aqueous solution), 10 g of bisphenol A, and 21.64 g of epichlorohydrin were placed in a reaction vessel and reacted at 110°C for 4 hours. Then, 4.67 g of a 5N aqueous sodium hydroxide solution was added dropwise, and the temperature was raised from 60°C to 110°C, allowing the reaction to proceed for 30 minutes. After the reaction was complete, the reactants and 100 ml of toluene were placed in a separatory funnel for separation, separating the aqueous layer from the desired organic layer. Next, the organic layer was washed twice with a 15% sodium hydroxide aqueous solution and then dried at 70°C under vacuum to obtain PHE4h (epoxy equivalent weight approximately 394 g/eq., molecular weight 1430).

<Example 1: Preparation of Resin Composition 1> 20 parts of the hyperbranched epoxy resin synthesized in Synthesis Example 1 ("PHE4h", epoxy equivalent weight 394 g/eq., molecular weight 1430), 5 parts of a bisphenol A epoxy resin ("828US", manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 180 g/eq.), 15 parts of a bisphenol AF epoxy resin ("NC-3000L", manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight approximately 271 g/eq.), and 15 parts of a dixylenol epoxy resin ("YX4000H", manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 190 g/eq.) were stirred and dissolved in 60 parts of MEK under heating.

After cooling to room temperature, the mixture was mixed with 70 parts of an active ester hardener (DIC Corporation's "HPC-8000-65T," active group equivalent approximately 223 g/eq., 65% solid content in toluene solution), 6 parts of a phenolic hardener (DIC Corporation's "LA-3018-50P," active group equivalent approximately 151 g/eq., 50% solid content in 2-methoxypropanol solution), 10 parts of a hardening accelerator (4-dimethylaminopyridine (DMAP), 5% solid content in MEK solution), and spherical silica (ADMATECHS Corporation's "SC2050-SXF," with a specific surface area of 5.9 m2) surface-treated with N-phenyl-8-aminooctyl-trimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight 325.2) ^. /g, average particle size 0.77 μm) were uniformly dispersed with a high-speed rotary mixer and then filtered with a cartridge filter ("SHP020" manufactured by ROKITECHNO) to prepare resin composition 1.

<Example 2: Preparation of Resin Composition 2> In Example 1, (1) the amount of spherical silica ("SC2050-SXF", manufactured by ADMATECHS, with a specific surface area of 5.9 ^m2 /g and an average particle size of 0.77 μm) surface-treated with N-phenyl-8-aminooctyl-trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 325.2) was changed from 245 parts to 260 parts, (2) 9 parts of a thermoplastic resin ("YX7553BH30", manufactured by Mitsubishi Chemical Corporation, a 1:1 solution of MEK and cyclohexanone with a solid content of 30% by mass) was added, and (3) 3 parts of a flame retardant (PX-200, manufactured by Daihachi Chemical Co., Ltd.) was further added. Except for the above matters, the resin composition 2 was prepared in the same manner as in Example 1.

Comparative Example 1: Preparation of Resin Composition 3 In Example 1, 20 parts of the hyperbranched epoxy resin ("PHE4h," epoxy equivalent weight 394 g/eq., molecular weight 1430) were replaced with 20 parts of a naphthol aralkyl epoxy resin ("ESN-4100VEK75," manufactured by Nippon Steel Chemicals & Materials Co., Ltd., epoxy equivalent weight 363 g/eq.). Resin Composition 3 was prepared in the same manner as in Example 1 except for the above.

Comparative Example 2: Preparation of Resin Composition 4 In Example 2, 20 parts of a hyperbranched epoxy resin ("PHE4h," epoxy equivalent weight 394 g/eq., molecular weight 1430) were replaced with 20 parts of a naphthol aralkyl epoxy resin ("ESN-410DVEK75," manufactured by Nippon Steel Chemicals & Materials Co., Ltd., epoxy equivalent weight 363 g/eq.). Resin Composition 4 was prepared in the same manner as in Example 1 except for the above.

<Resin Sheet Preparation> As a support, a PET film (Toray Industries, Inc., "Lumirror R80," 38nm thick, softening point 130°C, hereinafter referred to as "released PET") was prepared. The film had been release-treated with an alkyd resin release agent (LINTEC, Inc., "AL-5").

Each resin composition was evenly applied to the release PET using a die coater, with the dried resin composition layer reaching a thickness of 25 μm. The layer was then dried at 80°C for 1 minute to form a resin composition layer on the release PET. Next, a polypropylene film ("Arufun MA-411" manufactured by Oji F-TEX, 15 μm thick) was laminated onto the surface of the resin composition layer not in contact with the support, with the rough surface of the film bonding to the resin composition layer. This resulted in a resin sheet composed of the release PET (support), resin composition layer, and protective film in this order.

<Determination of plating adhesion> (Preparation of test samples) (1) Substrate treatment of inner circuit substrate A glass cloth substrate with an inner circuit formed on both sides of an epoxy resin-coated copper laminate (copper foil thickness 18μm, substrate thickness 0.4mm, R1515A manufactured by PANASONIC) was etched to 1μm on both sides using "CZ8201" manufactured by MEC to roughen the copper surface.

(2) Lamination of the resin film with support The protective film was peeled off from each of the prepared resin sheets and laminated to both sides of the inner circuit board using a batch vacuum pressure laminator (manufactured by NIKKO Materials Co., Ltd., 2-stage expansion laminator, CVP700). Lamination was performed by reducing the pressure to below 13hPa for 30 seconds and then pressing at 130°C and 0.74MPa for 45 seconds. Subsequently, hot pressing was performed at 120°C and 0.5MPa for 75 seconds.

(3) Curing of the resin composition The laminated resin sheet is cured at 130°C for 30 minutes and then at 170°C for 30 minutes to form an insulating layer.

(4) Roughening treatment: The inner circuit substrate with the insulating layer formed thereon was immersed in Swelling Dip Securigant P (aqueous solution of glycol ethers and sodium hydroxide) containing diethylene glycol monobutyl ether manufactured by ATOTECH Japan Co., Ltd. as a swelling liquid at 60°C for 10 minutes. Then, it was immersed in Concentrate Compact P (aqueous solution of KMnO4: 60g/ _L , NaOH: 40g/L) manufactured by ATOTECH Japan Co., Ltd. as a roughening liquid at 80°C for 20 minutes. Finally, it was immersed in Reduction Solution Securigant P (aqueous solution of sulfuric acid) manufactured by ATOTECH Japan Co., Ltd. as a neutralizing liquid at 40°C for 5 minutes and then dried at 80°C for 30 minutes. This substrate was designated as "Evaluation Substrate A".

(5) Evaluation substrate A was immersed in an electroless plating solution containing _PdCl2 at 40°C for 5 minutes by semi-additive plating, and then immersed in an electroless copper plating solution at 25°C for 20 minutes. After annealing at 150°C for 30 minutes, an etching resist was formed. After patterning by etching, copper sulfate electrolytic plating was performed to form a conductive layer with a thickness of 20 μm. Subsequently, annealing was performed at 200°C for 60 minutes. This substrate is referred to as "Evaluation Substrate B."

(Determination of Coating Adhesion) A 10mm wide and 100mm long incision was made in the conductive layer of evaluation substrate B. One end of the incision was peeled off and gripped with a jig (Autocom testing machine AC-50C-SL, manufactured by TSE). The load (kgf/cm) required to tear 35mm vertically at a speed of 50mm/min at room temperature was measured.

(Determination of Coating Adhesion after Reliability Testing) The prepared samples were subjected to a highly accelerated life tester (ETAC "PM422") at 130°C, 85% relative humidity, and a 3.3V DC voltage for 200 hours. One end of the copper foil was then peeled off and grasped with a fixture (TSE Autocom AC-50C-SL). Using an Instron universal testing machine, the load required to tear 35 mm vertically at a speed of 50 mm/min at room temperature was measured in accordance with JIS C6481.

The following criteria were used to evaluate the adhesion of the coating and the adhesion after the reliability test: ○: 0.35 kgf/cm or higher ×: Less than 0.30 kgf/cm

<Evaluation of Curvature> (1) Lamination of Resin Sheets The resin sheets produced in the Examples and Comparative Examples were cut into 9.5 cm squares and laminated onto the roughened surface of Mitsui Mining & Co. copper foil "3EC-III" (thickness 35 μm) cut into 10 cm squares using a batch vacuum pressure laminator (manufactured by NIKKO Materials Co., Ltd., 2-stage expansion laminator, CVP700). Lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, then pressing the foil at 120°C for 30 seconds at a pressure of 0.74 MPa to produce a metal foil with a resin composition layer. The PET film serving as the support was then peeled off.

(2) Curing of the resin composition layer The four sides of the metal foil with the resin composition layer obtained in (1) above were adhered to a 1 mm thick SUS plate using polyimide tape in such a manner that the resin composition layer was on the upper side. The resin composition layer was cured at 190°C for 90 minutes.

(3) Determination of warp The polyimide tape was peeled off from three of the four sides of the metal foil with the resin composition layer obtained in (2) above. The warp value was determined by measuring the height of the highest point from the SUS plate and evaluating the following criteria. ○: The warp size is less than 1 cm. △: The warp size is 1 cm or more and less than 3 cm. ×: The warp size is 3 cm or more.

<Determination of Linear Thermal Expansion Coefficient> The resin sheets obtained in the Examples and Comparative Examples were cured by heating at 190°C for 90 minutes and then peeled from the PET film supporting the sheet to obtain a thin, cured product. The cured product was cut into test pieces with a width of 5 mm, a length of 15 mm, and a thickness of 30 mm. Thermomechanical analysis was performed using a thermomechanical analyzer (Thermo Plus TMA8310, manufactured by RIGAKU) using the tensile loading method. The test pieces were mounted in the apparatus and measured twice continuously under the conditions of a 1g load and a heating rate of 5°C/min. The average linear thermal expansion coefficient (ppm) from 25°C to 150°C was calculated for the second measurement.

*The content (mass %) of the hyperbranched epoxy resin is based on the non-volatile components in the resin composition being assumed to be 100% by mass. The content (mass %) of the hyperbranched epoxy resin in component (A) is based on the total content of component (A) being assumed to be 100% by mass.

In Examples 1 and 2, when it was confirmed that components (D) to (F) were not present, although the extent of the presence of components varied, the results were the same as those of the above examples.

Claims (12)

A resin composition comprising (A) an epoxy resin, (B) a hardener, and (C) an inorganic filler, wherein component (A) comprises an epoxy resin having a hyperbranched structure, and the content of component (A) as a whole is 5% by mass or more and 35% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. When the content of component (B) is 1% by mass or more and 25% by mass or less, and when the non-volatile components in the resin composition are taken as 100% by mass, the content of component (C) is 50% by mass or more and 90% by mass or less, and when the non-volatile components in the resin composition are taken as 100% by mass, the content of the epoxy resin having a hyperbranched structure is 3% by mass or more and 10% by mass or less. The resin composition of claim 1, wherein the molecular weight of the epoxy resin having a hyperbranched structure is greater than 1,000 and less than 10,000. The resin composition of claim 1, wherein the epoxy resin having a hyperbranched structure has an epoxy equivalent weight of 250 g/eq. or more and 700 g/eq. or less. The resin composition of claim 1, wherein the epoxy resin having a hyperbranched structure has a multi-branched structure formed by alternating bonds between structures derived from trifunctional or higher functional compounds and structures derived from bifunctional compounds. The resin composition of claim 1, wherein the epoxy resin having a hyperbranched structure comprises a cyclic structure. The resin composition of claim 4, wherein the structure derived from the bifunctional compound includes a cyclic structure. The resin composition of claim 1, wherein the content of the epoxy resin having a hyperbranched structure is 20% by mass or more and 50% by mass or less, taking the total weight of component (A) as 100% by mass. The resin composition of claim 1, wherein component (B) comprises an active ester hardener, a phenol hardener, a benzo Any of a hardener and a carbodiimide hardener. The resin composition of claim 1 further comprises (D) a thermoplastic resin. A resin sheet comprising a support and a resin composition layer disposed on the support comprising the resin composition of any one of claims 1 to 9. A printed circuit board comprising an insulating layer formed by curing the resin composition according to any one of claims 1 to 9. A semiconductor device comprising the printed circuit board of claim 11.