JP7658250B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition.

A known manufacturing technique for printed wiring boards is the build-up method, in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, the insulating layers are generally formed from a cured product obtained by curing a resin composition (Patent Document 1).

JP 2020-23714 A

The cured product contained in the insulating layer is required to have a low dielectric tangent. One method for obtaining a cured product with a low dielectric tangent is to blend a high concentration of an active ester compound and an inorganic filler into the resin composition. However, when an insulating layer is formed using a resin composition blended with a high concentration of an active ester compound and an inorganic filler, the insulating layer tends to show a decrease in adhesion with the conductor layer after a highly accelerated life test (HAST test) under a high temperature and high humidity environment.

For example, an insulating layer may be formed from a cured resin composition, and a conductor layer may be formed on the insulating layer by plating. However, when a resin composition containing a high concentration of an active ester compound and an inorganic filler is used, the adhesion between the insulating layer and the conductor layer formed by plating tends to be low after the HAST test.

Furthermore, in the manufacturing process of printed wiring boards, an insulating layer is sometimes formed on a conductor layer as a base using a resin composition. The conductor layer as a base is usually a metal foil at the time the insulating layer is formed. Therefore, the insulating layer is required to have excellent adhesion to the metal foil as the base. However, when a resin composition containing a high concentration of an active ester compound and an inorganic filler is used, there is a tendency for the adhesion between the insulating layer and the metal foil as the base to be reduced after the HAST test.

The present invention was devised in view of the above problems, and aims to provide a resin composition capable of producing a cured product having a low dielectric tangent and high adhesion to a conductor layer after a HAST test; a cured product of the resin composition; a sheet-like laminate material containing the resin composition; a resin sheet having a resin composition layer formed from the resin composition; a printed wiring board having an insulating layer including a cured product of the resin composition; and a semiconductor device having the printed wiring board.

The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by a resin composition containing in combination (A) an epoxy resin, (B) an active ester compound in a specific range, (C) an inorganic filler in a specific range, and (D) an antioxidant in a specific range, and have thus completed the present invention.
That is, the present invention includes the following.

〔４〕 （Ａ）エポキシ樹脂が、液状エポキシ樹脂を含む、〔１〕～〔３〕のいずれか一項に記載の樹脂組成物。
〔５〕 フェノール系硬化剤及びカルボジイミド系硬化剤からなる群より選ばれる１種類以上の（Ｆ）硬化剤を含む、〔１〕～〔４〕のいずれか一項に記載の樹脂組成物。
〔６〕 （Ｇ）硬化促進剤を含む、〔１〕～〔５〕のいずれか一項に記載の樹脂組成物。
〔７〕 （Ｈ）熱可塑性樹脂を含む、〔１〕～〔６〕のいずれか一項に記載の樹脂組成物。
〔８〕 絶縁層形成用である、〔１〕～〔７〕のいずれか一項に記載の樹脂組成物。
〔９〕 〔１〕～〔８〕の何れか１項に記載の樹脂組成物の硬化物。
〔１０〕 〔１〕～〔８〕の何れか１項に記載の樹脂組成物を含有する、シート状積層材料。
〔１１〕 支持体と、当該支持体上に〔１〕～〔８〕の何れか１項に記載の樹脂組成物で形成された樹脂組成物層と、を有する樹脂シート。
〔１２〕 〔１〕～〔８〕の何れか１項に記載の樹脂組成物の硬化物を含む絶縁層を備える、プリント配線板。
〔１３〕 〔１２〕に記載のプリント配線板を備える、半導体装置。 [1] A resin composition comprising (A) an epoxy resin, (B) an active ester compound, (C) an inorganic filler, and (D) an antioxidant,
A resin composition, in which the content of (C) an inorganic filler is 60 mass% or more and the content of (B) an active ester compound is 10 mass% or more, based on 100 mass% of non-volatile components in the resin composition.
[2] The resin composition according to [1], wherein the content of the antioxidant (D) is 0.1% by mass or more and 10% by mass or less, based on 100% by mass of the resin component in the resin composition.
[3] The resin composition according to [1] or [2], wherein the antioxidant (D) contains a compound represented by any one of the following formulas (D1) to (D4):

[4] The resin composition according to any one of [1] to [3], wherein the epoxy resin (A) includes a liquid epoxy resin.
[5] The resin composition according to any one of [1] to [4], further comprising one or more curing agents (F) selected from the group consisting of phenolic curing agents and carbodiimide curing agents.
[6] The resin composition according to any one of [1] to [5], further comprising a curing accelerator (G).
[7] The resin composition according to any one of [1] to [6], comprising a thermoplastic resin (H).
[8] The resin composition according to any one of [1] to [7], which is for forming an insulating layer.
[9] A cured product of the resin composition according to any one of [1] to [8].
[10] A sheet-like laminate material containing the resin composition according to any one of [1] to [8].
[11] A resin sheet comprising a support and a resin composition layer formed on the support from the resin composition according to any one of [1] to [8].
[12] A printed wiring board having an insulating layer containing a cured product of the resin composition according to any one of [1] to [8].
[13] A semiconductor device comprising the printed wiring board according to [12].

The present invention can provide a resin composition capable of producing a cured product having a low dielectric tangent and high adhesion to a conductor layer after a HAST test; a cured product of the resin composition; a sheet-like laminate material containing the resin composition; a resin sheet having a resin composition layer formed from the resin composition; a printed wiring board having an insulating layer containing a cured product of the resin composition; and a semiconductor device having the printed wiring board.

The present invention will be described below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified as desired without departing from the scope of the claims and their equivalents.

In the following description, the term "(meth)acrylic acid ester" includes acrylic acid ester, methacrylic acid ester, and combinations thereof, unless otherwise specified. In the following description, the term "(meth)acrylate" includes acrylate, methacrylate, and combinations thereof, unless otherwise specified.

[1. Overview of resin composition]
A resin composition according to an embodiment of the present invention includes a combination of an epoxy resin (A), an active ester compound (B) in a specific range of amounts, an inorganic filler (C) in a specific range of amounts, and an antioxidant (D). This resin composition can provide a cured product having a low dielectric tangent and high adhesion to a conductor layer after a HAST test.

The inventors speculate as follows about the mechanism by which the cured product of the resin composition according to this embodiment has the above-mentioned excellent advantages. However, the technical scope of the present invention is not limited by the mechanism described below.

A cured product of a conventional resin composition containing an epoxy resin, an active ester compound, and an inorganic filler can usually have a low dielectric tangent. However, the cured product of the resin composition generally tends to have poor adhesion to a conductor layer after a HAST test.

Generally, HAST testing is performed in a high temperature and high humidity environment. In high temperature and high humidity environments, the bonds between the molecules of the resin components contained in the cured product are easily broken. For example, when an epoxy resin reacts with an active ester compound, an ester bond is formed. This ester bond can be easily broken by hydrolysis in a high temperature and high humidity environment. When such bonds are broken, the mechanical strength of the cured product decreases and peeling accompanied by resin destruction is likely to occur, so there is a tendency for adhesion after the HAST test to be low.

In contrast, the (D) antioxidant contained in the resin composition according to this embodiment can function as a radical trap. Thus, the (D) antioxidant traps radicals that may be generated in the HAST test environment, and thus it is possible to suppress the severing of bonds between the molecules of the resin components contained in the cured product. This therefore prevents the mechanical strength of the cured product from decreasing, and therefore it is possible to suppress peeling that accompanies resin destruction after the HAST test, thereby obtaining high adhesion.

In addition, the (D) antioxidant can trap radicals not only during the HAST test, but also when the resin composition is cured. This can prevent oxygen from being introduced into the cured product as the resin composition cures. This can prevent polar groups from being formed in the cured product due to the introduced oxygen. Therefore, the dielectric tangent of the cured product can be reduced not only by the action of the (B) active ester compound and (C) inorganic filler, but also by the (D) antioxidant.

The resin composition according to this embodiment can preferably have a low minimum melt viscosity. Furthermore, the cured product of the resin composition according to this embodiment usually has excellent adhesion to the conductor layer not only after the HAST test but also before the HAST test. This cured product can be suitably used, for example, as a material for the insulating layer of a printed wiring board.

[2. (A) Epoxy resin]
The resin composition according to the present embodiment includes an epoxy resin (A) as component (A). The epoxy resin (A) may be a curable resin having an epoxy group.

(A) Examples of 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-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, glycidylamine type epoxy resins, glycidyl ether Examples of the epoxy resin include ester type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexane dimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthalimidine type epoxy resin, etc. (A) The epoxy resin may be used alone or in combination of two or more types.

From the viewpoint of obtaining a cured product having excellent heat resistance, it is preferable that the (A) epoxy resin contains an epoxy resin containing an aromatic structure. An aromatic structure is a chemical structure generally defined as aromatic, and also includes polycyclic aromatic rings and aromatic heterocycles. Examples of epoxy resins containing an aromatic structure include 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-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, bisxylenol type epoxy resins, glycidylamine type epoxy resins having an aromatic structure, glycidyl ester type epoxy resins having an aromatic structure, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins having an aromatic structure, epoxy resins having a butadiene structure having an aromatic structure, alicyclic epoxy resins having an aromatic structure, heterocyclic epoxy resins, spiro ring-containing epoxy resins having an aromatic structure, cyclohexane dimethanol type epoxy resins having an aromatic structure, naphthylene ether type epoxy resins, trimethylol type epoxy resins having an aromatic structure, and tetraphenylethane type epoxy resins having an aromatic structure.

The resin composition preferably contains, as the epoxy resin (A), an epoxy resin having two or more epoxy groups in one molecule. The proportion of the epoxy resin having two or more epoxy groups in one molecule relative to 100% by mass of the non-volatile components of the epoxy resin (A) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain only liquid epoxy resins as the epoxy resin, or may contain only solid epoxy resins, or may contain a combination of liquid epoxy resins and solid epoxy resins. From the viewpoint of obtaining a resin composition with a low minimum melt viscosity, it is preferable that the (A) epoxy resin contains a liquid epoxy resin.

Preferably, the liquid epoxy resin has two or more epoxy groups in one molecule.

Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, and epoxy resins having a butadiene structure.

Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "828EL", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F type epoxy resins); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630", "630LSD", and "604" (glycidylamine type epoxy resins); ADEKA's "ED-523T" (glycilol type epoxy resin); ADEKA's "EP-3950L", "EP-3980S" ( glycidylamine type epoxy resin); ADEKA's "EP-4088S" (dicyclopentadiene type epoxy resin); Nippon Steel Chemical & Material Chemical's "ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase Chemtex's "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celloxide 2021P" (alicyclic epoxy resin with ester structure); Daicel's "PB-3600", Nippon Soda's "JP-100" and "JP-200" (epoxy resin with butadiene structure); Nippon Steel Chemical & Material's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin). These may be used alone or in combination of two or more.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

Preferred solid epoxy resins are bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, naphthol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, phenol aralkyl type epoxy resins, tetraphenylethane type epoxy resins, and phenolphthalimidine type epoxy resins.

Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin); DIC's "N-690" (cresol novolac type epoxy resin); DIC's "N-695" (cresol novolac type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resin); and DIC's "EXA-7311". , "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN475V", "ESN4 100V (naphthalene type epoxy resin); "ESN485" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "Y Examples of epoxy resins include "X7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical; and "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more types.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the (A) epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

The epoxy equivalent of the (A) epoxy resin is preferably 50 g/eq. to 5,000 g/eq., more preferably 60 g/eq. to 3,000 g/eq., even more preferably 80 g/eq. to 2,000 g/eq., and particularly preferably 110 g/eq. to 1,000 g/eq. The epoxy equivalent represents the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the (A) epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

The content of the (A) epoxy resin in the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, particularly preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, particularly preferably 10% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. When the (A) epoxy resin content is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be effectively improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, to increase the adhesion of the cured product before the HAST test, and to reduce the surface roughness of the cured product after the roughening treatment.

The content of the epoxy resin (A) in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 20% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, particularly preferably 40% by mass or less, when the resin components in the resin composition are taken as 100% by mass. The resin components of the resin composition refer to the non-volatile components of the resin composition excluding the inorganic filler (C). When the content of the epoxy resin (A) is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be effectively improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, increase the adhesion of the cured product before the HAST test, and reduce the surface roughness of the cured product after the roughening treatment.

[3. (B) Active ester compound]
The resin composition according to the present embodiment contains an active ester compound (B) as the component (B). This active ester compound (B) does not include those corresponding to the above-mentioned component (A). The active ester compound (B) can function as an epoxy resin curing agent that reacts with the epoxy resin (A) to cure the resin composition. The active ester compound (B) may be used alone or in combination of two or more types.

(B) As the active ester compound, generally, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferably used. The active ester compound is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester compound obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester compound obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is 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 phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, 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, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refer to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, the active ester compound (B) is preferably a dicyclopentadiene-type active ester compound, a naphthalene-type active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, or an active ester compound containing a benzoylated product of phenol novolac, and among these, at least one selected from a dicyclopentadiene-type active ester compound and a naphthalene-type active ester compound is more preferable. As the dicyclopentadiene-type active ester compound, an active ester compound containing a dicyclopentadiene-type diphenol structure is preferable.

(B) Commercially available active ester compounds include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation); active ester compounds containing a naphthalene structure such as "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", and "EXB-81 Examples of such active ester compounds include "EXB9401" (manufactured by DIC Corporation), which is a phosphorus-containing active ester compound; "DC808" (manufactured by Mitsubishi Chemical Corporation), which is an active ester compound that is an acetylated product of phenol novolac; "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), which are active ester compounds that are benzoylated products of phenol novolac; and "PC1300-02-65MA" (manufactured by Air Water Inc.), which is an active ester compound that contains a styryl group and a naphthalene structure.

The active ester group equivalent of the (B) active ester compound is preferably 50 g/eq. to 500 g/eq., more preferably 50 g/eq. to 400 g/eq., and even more preferably 100 g/eq. to 300 g/eq. The active ester group equivalent represents the mass of the active ester compound per equivalent of the active ester group.

When the number of epoxy groups in the (A) epoxy resin is taken as 1, the number of active ester groups in the (B) active ester compound is preferably 0.1 or more, more preferably 0.5 or more, even more preferably 1.0 or more, and preferably 8.0 or less, more preferably 6.0 or less, and particularly preferably 4.0 or less. The "number of epoxy groups in the (A) epoxy resin" refers to the total value obtained by dividing the mass of the non-volatile components of the (A) epoxy resin present in the resin composition by the epoxy equivalent. The "number of active ester groups in the (B) active ester compound" refers to the total value obtained by dividing the mass of the non-volatile components of the (B) active ester compound present in the resin composition by the active ester group equivalent.

The content of the (B) active ester compound in the resin composition is usually 10% by mass or more, preferably 11% by mass or more, more preferably 12% by mass or more, even more preferably 13% by mass or more, particularly preferably 14% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, particularly preferably 20% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. When the amount of the (B) active ester compound is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be improved. Furthermore, the minimum melt viscosity of the resin composition can usually be lowered, the adhesion of the cured product before the HAST test can be increased, and the surface roughness of the cured product after the roughening treatment can be reduced.

The content of the (B) active ester compound in the resin composition is preferably 30% by mass or more, more preferably 40% by mass or more, particularly preferably 50% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, particularly preferably 70% by mass or less, when the resin component in the resin composition is taken as 100% by mass. When the amount of the (B) active ester compound is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be effectively improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, increase the adhesion of the cured product before the HAST test, and reduce the surface roughness of the cured product after the roughening treatment.

[4. (C) Inorganic filler]
The resin composition according to the present embodiment contains an inorganic filler (C) as component (C). The inorganic filler (C) is usually contained in the resin composition in the form of particles.

(C) An inorganic compound is used as the material for the inorganic filler. (C) Examples of the material for the inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferred as the silica. (C) The inorganic filler may be used alone or in combination of two or more types.

(C) Inorganic fillers can be classified into hollow inorganic fillers that have internal voids and solid inorganic fillers that do not have internal voids. As the (C) inorganic filler, only hollow inorganic fillers may be used, only solid inorganic fillers may be used, or hollow inorganic fillers and solid inorganic fillers may be used in combination. When hollow inorganic fillers are used, the relative dielectric constant of the cured product of the resin composition can usually be reduced.

Since the hollow inorganic filler has pores, it usually has a porosity of more than 0 volume percent. From the viewpoint of reducing the relative dielectric constant of the insulating layer containing the cured product of the resin composition, the porosity of the hollow inorganic filler is preferably 10 volume percent or more, more preferably 15 volume percent or more, and particularly preferably 20 volume percent or more. Also, from the viewpoint of the mechanical strength of the cured product of the resin composition, the porosity of the hollow inorganic filler is preferably 95 volume percent or less, more preferably 90 volume percent or less, and particularly preferably 85 volume percent or less.

The porosity P (volume %) of a particle is defined as the volume ratio of the total volume of one or more pores present inside the particle to the total volume of the particle based on the outer surface of the particle (total volume of pores/volume of particle). This porosity P can be calculated by the following formula (X1) using the measured value D _M (g/cm ³ ) of the actual density of the particle and the theoretical value D _T (g/cm ³ ) of the material density of the material forming the particle.

The hollow inorganic filler may be produced, for example, by the methods described in Japanese Patent No. 5940188 and Japanese Patent No. 5864299 or methods equivalent thereto.

(C) Commercially available inorganic fillers include, for example, "UFP-30" manufactured by Denka Chemical Industry Co., Ltd.; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatechs Co., Ltd.; "UFP-30" manufactured by Denka Company; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs Co., Ltd.; "DAW-03" and "FB-105FD" manufactured by Denka Company; and "MG-005" manufactured by Taiheiyo Cement Corporation.

The average particle size of the inorganic filler (C) is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more, from the viewpoint of significantly obtaining the desired effects of the present invention, and is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less.

(C) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is used as the average particle size. The measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The measurement sample is measured using a laser diffraction particle size distribution measuring device with blue and red light source wavelengths, and the volume-based particle size distribution of the inorganic filler is measured using a flow cell method, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. An example of a laser diffraction particle size distribution measuring device is the "LA-960" manufactured by Horiba, Ltd.

From the viewpoint of significantly obtaining the desired effects of the present invention, the specific surface area of the inorganic filler (C) is preferably 0.1 m ² /g or more, more preferably 0.5 m ² /g or more, even more preferably 1 m ² /g or more, particularly preferably 3 m ² /g or more, and is preferably 100 m ² /g or less, more preferably 70 m ² /g or less, even more preferably 50 m ² /g or less, particularly preferably 40 m ² /g or less. The specific surface area of the inorganic filler can be measured according to the BET method by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

(C) From the viewpoint of improving moisture resistance and dispersibility, it is preferable that the inorganic filler is treated with a surface treatment agent. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. One type of surface treatment agent may be used alone, or two or more types may be used in any combination.

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

From the viewpoint of improving the dispersibility of the inorganic filler, it is preferable that the degree of surface treatment with the surface treatment agent falls within a specific range. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and even more preferably 0.2 mg/m ² or more. On the other hand, from the viewpoint of suppressing an increase in the melt viscosity of the resin composition, it is preferably 1.0 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

(C) The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. An example of a carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

The content of the inorganic filler (C) in the resin composition is preferably 60% by mass or more, more preferably 65% by mass or more, particularly preferably 70% by mass or more, and preferably 85% by mass or less, more preferably 83% by mass or less, particularly preferably 80% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. When the amount of the inorganic filler (C) is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, increase the adhesion of the cured product before the HAST test, and reduce the surface roughness of the cured product after the roughening treatment.

[5. (D) Antioxidants]
The resin composition according to the present embodiment contains an antioxidant (D) as component (D). This antioxidant (D) does not include those that fall under the above-mentioned components (A) to (C). The antioxidant (D) may be used alone or in combination of two or more kinds.

Examples of antioxidants include phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

Examples of phenol-based antioxidants include 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 4,4',4''-(1-methylpropanylidene)tris(6-tert-butyl-m-cresol), 6,6'-di-tert-butyl-4,4'-butylidene-di-m-cresol, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methyl 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and the like.

Examples of sulfur-based antioxidants include 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diyl=bis[3-(dodecylthio)propionate] and di(tridecyl)-3,3'-thiodipropionate.

Examples of phosphorus-based antioxidants include triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris(tridecyl) phosphite, trioleyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, trilauryl trithio phosphite, tetraphenyl dipropylene glycol diphosphite, tetra(C12-C15 alkyl bis(3-methyl-6-t-butylphenyl ditridecyl phosphite), bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, etc.

Among these, compounds represented by any one of the following formulas (D1) to (D4) are preferred. The compound represented by formula (D1) is 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, available as, for example, "Adeka STAB AO-330" manufactured by ADEKA. The compound represented by formula (D2) is di(tridecyl)-3,3'-thiodipropionate, available as, for example, "Adeka STAB AO-503" manufactured by ADEKA. The compound represented by formula (D3) is triphenyl phosphite, available as, for example, "JP-360" manufactured by Johoku Chemical. The compound represented by formula (D4) is bis(decyl)pentaerythritol diphosphite, available as, for example, "JPE-10" manufactured by Johoku Chemical.

During the HAST test, hydrolysis of the ester bond derived from the (B) active ester compound is particularly likely to occur. Therefore, from the viewpoint of suppressing this hydrolysis and increasing the adhesion after the HAST test, it is preferable to use an appropriate amount of the (D) antioxidant relative to the (B) active ester compound. Specifically, the ratio W _D /W _B of the mass W _B of the (B) active ester compound in the resin composition to the mass W _D of the (D) antioxidant is preferably 0.001 or more, more preferably 0.01 or more, particularly preferably 0.02 or more, and preferably 0.50 or less, more preferably 0.20 or less, particularly preferably 0.10 or less.

In addition, the ester bond in the cured product may be generated by the reaction of the (B) active ester compound with the (A) epoxy resin. Therefore, it is preferable that the amount of the (D) antioxidant has an appropriate relationship with the total amount of the (A) epoxy resin and the (B) active ester compound. Specifically, the ratio W D /(W _A +W B ) of the total W _A +W _B of the mass W _A of the (A) epoxy resin and the mass W _B of the (B) active ester compound in the resin composition to the mass W _D of the ( _D ) antioxidant is preferably 0.001 or more, more preferably 0.005 or more, particularly preferably 0.01 _or more, and preferably 0.20 or less, more preferably 0.10 or less, particularly preferably 0.05 or less.

The content of the (D) antioxidant in the resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, particularly preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 2% by mass or less, particularly preferably 1% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. When the amount of the (D) antioxidant is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, to increase the adhesion of the cured product before the HAST test, and to reduce the surface roughness of the cured product after the roughening treatment.

The content of the (D) antioxidant in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 1.0% by mass or more, and preferably 10% by mass or less, more preferably 6% by mass or less, particularly preferably 4% by mass or less, when the resin component in the resin composition is taken as 100% by mass. When the amount of the (D) antioxidant is within the above range, the dielectric tangent of the cured product of the resin composition and the adhesion to the conductor layer after the HAST test can be effectively improved. Furthermore, it is usually possible to lower the minimum melt viscosity of the resin composition, to increase the adhesion of the cured product before the HAST test, and to reduce the surface roughness of the cured product after the roughening treatment.

[6. (E) Radically polymerizable compound]
The resin composition according to the present embodiment may further contain an arbitrary radical polymerizable compound (E) as an optional component in combination with the above-mentioned components (A) to (D). The radical polymerizable compound (E) as the component (E) does not include those corresponding to the above-mentioned components (A) to (D). The radical polymerizable compound (E) may be used alone or in combination of two or more types.

(E) The radical polymerizable compound may have an ethylenically unsaturated bond. (E) The radical polymerizable compound may have a radical polymerizable group such as an unsaturated hydrocarbon group such as an allyl group, a 3-cyclohexenyl group, a 3-cyclopentenyl group, a p-vinylphenyl group, a m-vinylphenyl group, or an o-vinylphenyl group; or an α,β-unsaturated carbonyl group such as an acryloyl group, a methacryloyl group, or a maleimide group (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl group). (E) The radical polymerizable compound preferably has two or more radical polymerizable groups.

(E) Examples of radically polymerizable compounds include (meth)acrylic radically polymerizable compounds, styrene radically polymerizable compounds, allyl radically polymerizable compounds, and maleimide radically polymerizable compounds.

The (meth)acrylic radical polymerizable compound is, for example, a compound having one or more, preferably two or more, acryloyl groups and/or methacryloyl groups. Examples of the (meth)acrylic radical polymerizable compound include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-no aliphatic (meth)acrylic acid ester compounds having a low molecular weight (molecular weight less than 1000), such as nandiol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; Examples of the ether-containing (meth)acrylic acid ester compound include low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds such as 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resin. Commercially available (meth)acrylic radical polymerizable compounds include, for example, "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate) and "DCP" (tricyclodecane dimethanol dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic modified polyphenylene ether) manufactured by SABIC Innovative Plastics.

A styrene-based radical polymerizable compound is, for example, a compound having one or more, preferably two or more, vinyl groups directly bonded to an aromatic carbon atom. Examples of styrene-based radical polymerizable compounds include low molecular weight (molecular weight less than 1000) styrene-based compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether; high molecular weight (molecular weight 1000 or more) styrene-based compounds such as vinylbenzyl-modified polyphenylene ether resin and styrene-divinylbenzene copolymer. Commercially available styrene-based radical polymerizable compounds include, for example, "ODV-XET (X03)", "ODV-XET (X04)", and "ODV-XET (X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Co., Inc.

An allyl-based radical polymerizable compound is, for example, a compound having one or more, preferably two or more, allyl groups. Examples of the allyl radical polymerizable compound include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, and diallyl 2,3-naphthalenecarboxylate; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyl diphenyl silane. Commercially available allyl radical polymerizable compounds include, for example, "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Wako Pure Chemical Industries, Ltd., "DAND" (2,3-diallyl naphthalene carboxylate) manufactured by Nippon Distillation Industry Co., Ltd., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane manufactured by Shikoku Kasei Corporation, "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Kasei Corporation.

The maleimide radical polymerizable compound is, for example, a compound having one or more, preferably two or more, maleimide groups. The maleimide radical polymerizable compound may be an aliphatic maleimide compound containing an aliphatic amine skeleton, or an aromatic maleimide compound containing an aromatic amine skeleton. Commercially available maleimide radical polymerizable compounds include, for example, "SLK-2600" manufactured by Shin-Etsu Chemical Co., Ltd., "BMI-1500", "BMI-1700", "BMI-3000J", "BMI-689", and "BMI-2500" (dimer diamine structure-containing maleimide compounds) manufactured by Designer Molecules, Inc., "BMI-6100" (aromatic maleimide compound) manufactured by Designer Molecules, "MIR-5000-60T" and "MIR-3000-70MT" (biphenylaralkyl-type maleimide compounds) manufactured by Nippon Kayaku Co., Ltd., "BMI-70" and "BMI-80" manufactured by Kei-I Chemical Co., Ltd., and "BMI-2300" and "BMI-TMH" manufactured by Daiwa Kasei Kogyo Co., Ltd. In addition, as a maleimide-based radical polymerizable compound, a maleimide resin (maleimide compound containing an indane ring skeleton) disclosed in the Japan Institute of Invention and Innovation's Technical Journal Publication No. 2020-500211 may be used.

The ethylenically unsaturated bond equivalent of the (E) radical polymerizable compound is preferably 20 g/eq. to 3000 g/eq., more preferably 50 g/eq. to 2500 g/eq., even more preferably 70 g/eq. to 2000 g/eq., and particularly preferably 90 g/eq. to 1500 g/eq. The ethylenically unsaturated bond equivalent represents the mass of the radical polymerizable compound per equivalent of the ethylenically unsaturated bond.

The weight average molecular weight (Mw) of the radical polymerizable compound (E) is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. The lower limit is not particularly limited, but may be, for example, 150 or more.

The content of the (E) radical polymerizable compound in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, particularly preferably 0.50% by mass or more, and is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, particularly preferably 2.0% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of the (E) radical polymerizable compound in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, particularly preferably 1.0% by mass or more, and is preferably 20% by mass or less, more preferably 15.0% by mass or less, particularly preferably 10.0% by mass or less, assuming that the resin component in the resin composition is 100% by mass.

7. (F) Optional Hardeners
The resin composition according to the present embodiment may further contain an optional curing agent (F) as an optional component in combination with the above-mentioned components (A) to (E). The optional curing agent (F) as the component (F) does not include those corresponding to the above-mentioned components (A) to (E). The optional curing agent (F), like the above-mentioned active ester compound (B), may function as an epoxy resin curing agent that reacts with the epoxy resin (A) to cure the resin composition. The optional curing agent (F) may be used alone or in combination of two or more types.

(F) Examples of optional curing agents include phenol-based curing agents, carbodiimide-based curing agents, acid anhydride-based curing agents, amine-based curing agents, benzoxazine-based curing agents, cyanate ester-based curing agents, and thiol-based curing agents. Of these, it is preferable to use one or more curing agents selected from the group consisting of phenol-based curing agents and carbodiimide-based curing agents.

As the phenol-based hardener, a hardener having one or more, preferably two or more, hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring in one molecule can be used. From the viewpoint of heat resistance and water resistance, a phenol-based hardener having a novolac structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenol-based hardener is preferred, and a triazine skeleton-containing phenol-based hardener is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, a triazine skeleton-containing phenol novolac resin is preferred. Specific examples of phenol-based curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation.

As the carbodiimide-based curing agent, a curing agent having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of carbodiimide-based curing agents include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane bis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly( Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(naphthylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide curing agents include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Co., Ltd.; and "Stavaxol P," "Stavaxol P400," and "Hi-Kasil 510" manufactured by Rhein Chemie.

As the acid anhydride curing agent, a curing agent having one or more acid anhydride groups in one molecule can be used, and a curing agent having two or more acid anhydride groups in one molecule is preferable. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride. anhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric acid anhydrides such as styrene-maleic acid resin in which styrene and maleic acid are copolymerized. Examples of commercially available acid anhydride curing agents include "HNA-100", "MH-700", "MTA-15", "DDSA", and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" manufactured by Hitachi Chemical Co., Ltd.; and "EF-30", "EF-40", "EF-60", and "EF-80" manufactured by Clay Valley.

As the amine-based curing agent, a curing agent having one or more, preferably two or more, amino groups in one molecule can be used. Examples of the amine-based curing agent include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc., and among these, aromatic amines are preferred. The amine-based curing agent is preferably a primary amine or secondary amine, and more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propane. 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)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, and the like. Commercially available amine-based curing agents include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", and "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

Specific examples of benzoxazine-based curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "P-d" and "F-a" manufactured by Shikoku Chemical Industry Co., Ltd.

Examples of cyanate ester curing agents include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanate phenyl-1-(methylethylidene))benzene, bis(4-cyanate phenyl)thioether, and bis(4-cyanate phenyl)ether; polyfunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins have been partially converted to triazine. Specific examples of cyanate ester-based hardeners include Lonza Japan's "PT30" and "PT60" (both of which are phenol novolac-type multifunctional cyanate ester resins), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been converted to triazine and formed into a trimer).

Examples of thiol-based curing agents include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

(F) The reactive group equivalent of any curing agent is preferably 50 g/eq. to 3000 g/eq., more preferably 100 g/eq. to 1000 g/eq., even more preferably 100 g/eq. to 500 g/eq., and particularly preferably 100 g/eq. to 300 g/eq. The reactive group equivalent represents the mass of the curing agent per equivalent of reactive group.

When the number of epoxy groups in the (A) epoxy resin is taken as 1, the number of reactive groups in the (F) optional curing agent may be 0 or may be greater than 0, and is preferably 0.01 or more, more preferably 0.10 or more, particularly preferably 0.20 or more, and is preferably 2.0 or less, more preferably 1.0 or less, particularly preferably 0.5 or less. The "number of reactive groups in the (F) optional curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the (F) optional curing agent present in the resin composition by the reactive group equivalent.

The content of the optional curing agent (F) in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 1.0% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, particularly preferably 5% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of the optional curing agent (F) in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and particularly preferably 5.0% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less, assuming that the resin components in the resin composition are 100% by mass.

[8. (G) Curing Accelerator]
The resin composition according to the present embodiment may further contain a curing accelerator (G) as an optional component in combination with the above-mentioned components (A) to (F). The curing accelerator (G) as the component (G) does not include those that correspond to the above-mentioned components (A) to (F). The curing accelerator (G) functions as a curing catalyst that accelerates the curing of the epoxy resin (A).

(G) Examples of the curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. Among these, imidazole-based curing accelerators are preferred. (G) Curing accelerators may be used alone or in combination of two or more types.

Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, and tetraphenyl Aromatic phosphonium salts such as phosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; tributylphosphine, tri- Aliphatic phosphines such as tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine; dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenyl ether and other aromatic phosphines.

Examples of urea-based hardening accelerators include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. Examples of aromatic dimethylureas include toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

Examples of guanidine-based curing accelerators include dicyandiamide, 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, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds and epoxy resins. Commercially available imidazole curing accelerators include, for example, "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", and "C11Z-A" manufactured by Shikoku Chemical Industry Co., Ltd.; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Metal-based curing accelerators include, for example, 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, organonickel complexes such as nickel (II) acetylacetonate, and organomanganese complexes such as manganese (II) acetylacetonate. Organometallic salts include, for example, zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene. Commercially available amine-based curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd.

The content of the (G) curing accelerator in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, particularly preferably 0.05% by mass or more, and is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of the (G) curing accelerator in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.10% by mass or more, and is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and particularly preferably 0.5% by mass or less, assuming that the resin components in the resin composition are 100% by mass.

[9. (H) Thermoplastic resin]
The resin composition according to the present embodiment may further contain a thermoplastic resin (H) as an optional component in combination with the above-mentioned components (A) to (G). The thermoplastic resin (H) as the component (H) does not include those corresponding to the above-mentioned components (A) to (G).

(H) Thermoplastic resins include, for example, phenoxy resins, polyimide resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, polyester resins, etc. (H) Thermoplastic resins may be used alone or in combination of two or more types.

Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482" and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; and the like.

Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd.

Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins 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 Denki Kagaku Kogyo Co., 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 Co., Ltd.

Examples of polyolefin resins include ethylene-based copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; polyolefin-based polymers such as polypropylene and ethylene-propylene block copolymer.

Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxyl group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxyl group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, polyphenylene ether-polybutadiene resins, etc.

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

An example of a polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

A specific example of a polyphenylene ether resin is NORYL SA90 manufactured by SABIC. A specific example of a polyetherimide resin is ULTEM manufactured by GE.

Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Chemicals Corporation, and "C-1090", "C-2090", and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd. Specific examples of polyether ether ketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

The weight average molecular weight (Mw) of the (H) thermoplastic resin is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and particularly preferably 50,000 or less.

The content of the (H) thermoplastic resin in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, particularly preferably 0.20% by mass or more, and is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, particularly preferably 1.0% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of the (H) thermoplastic resin in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, and particularly preferably 0.50% by mass or more, and is preferably 10% by mass or less, more preferably 5.0% by mass or less, and particularly preferably 3.0% by mass or less, assuming that the resin components in the resin composition are 100% by mass.

10. (I) Optional Additives
The resin composition according to the present embodiment may further contain (I) any additive as an optional non-volatile component in addition to the above-mentioned components (A) to (H). (I) Examples of optional additives include radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; thermosetting resins other than epoxy resins such as epoxy acrylate resins, urethane acrylate resins, urethane resins, cyanate resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, and silicone resins; organic fillers such as rubber particles; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; defoamers such as silicone-based defoamers, acrylic defoamers, fluorine-based defoamers, and vinyl resin-based defoamers. surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The optional additives (I) may be used alone or in combination of two or more kinds.

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

(J) The content of the solvent is not particularly limited, but when all components in the resin composition are taken as 100% by mass, it may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or it may even be 0% by mass.

[12. Method for producing resin composition]
The resin composition according to the present embodiment can be produced, for example, by mixing the above-mentioned components. The above-mentioned components may be mixed in part or in whole simultaneously, or in sequence. In the process of mixing each component, the temperature may be appropriately set, and thus heating and/or cooling may be performed temporarily or throughout. In addition, stirring or shaking may be performed in the process of mixing each component.

[13. Physical properties of resin composition]
The resin composition according to the present embodiment can provide a cured product with a low dielectric loss tangent. For example, when the dielectric loss tangent of the cured product is measured under the conditions described in the section "Method of Measuring Dielectric Properties" in the Examples described later, a low dielectric loss tangent can be obtained. The dielectric loss tangent of the cured product is preferably 0.0040 or less, more preferably 0.0030 or less, and particularly preferably 0.0028 or less.

The resin composition according to the present embodiment can provide a cured product that has excellent adhesion to the conductor layer after the HAST test. Therefore, for example, when a conductor layer is formed on a cured product of the resin composition by plating, the adhesion between the conductor layer and the cured product can be increased after the HAST test. To give a specific example, when the plating peel strength after the HAST test is measured under the conditions described in the section on [Method of measuring plating adhesion (plating peel strength)] in the examples described later, the plating peel strength can be increased. The plating peel strength represents the magnitude of the force required to peel off the conductor layer formed on the cured product of the resin composition by plating, and the greater the plating peel strength, the better the plating adhesion. The plating peel strength after the HAST test is preferably 0.29 kgf/cm or more, more preferably 0.30 kgf/cm or more, and particularly preferably 0.31 kgf/cm or more.

For example, when a layer of the resin composition according to the present embodiment is formed on a metal foil and cured to form a cured product, the adhesion between the metal foil and the cured product can be increased after the HAST test. To give a specific example, when the copper foil peel strength after the HAST test is measured under the conditions described in the section [Method of evaluating metal foil adhesion] in the examples described later, the copper foil peel strength can be increased. The copper foil peel strength indicates the magnitude of the force required to peel the copper foil as a conductor layer from the cured product of the resin composition, and the higher the copper foil peel strength, the better the metal foil adhesion. The copper foil peel strength after the HAST test is preferably 0.40 kgf/cm or more, more preferably 0.50 kgf/cm or more, and particularly preferably 0.55 kgf/cm or more.

The resin composition according to this embodiment can usually obtain a cured product that has excellent adhesion to the conductor layer not only after the HAST test but also before the HAST test. Therefore, for example, when a conductor layer is formed on a cured product of the resin composition by plating, the adhesion between the conductor layer and the cured product can usually be increased before the HAST test. As a specific example, when the plating peel strength before the HAST test is measured under the conditions described in the section on [Method of measuring plating adhesion (plating peel strength)] in the examples described later, the plating peel strength can be increased. The plating peel strength before the HAST test is preferably 0.30 kgf/cm or more, more preferably 0.35 kgf/cm or more, and particularly preferably 0.40 kgf/cm or more.

For example, when the resin composition according to this embodiment is used to form a layer of the resin composition on a metal foil and then cured to form a cured product, the adhesion between the metal foil and the cured product can usually be increased before the HAST test. As a specific example, when the copper foil peel strength before the HAST test is measured under the conditions described in the section [Method of evaluating metal foil adhesion] in the Examples below, the copper foil peel strength can be increased. The copper foil peel strength before the HAST test is preferably 0.50 kgf/cm or more, more preferably 0.55 kgf/cm or more, and particularly preferably 0.60 kgf/cm or more.

The cured product of the resin composition according to this embodiment can usually have a small surface roughness when roughening treatment is performed. For example, when the arithmetic mean roughness Ra of the cured product after roughening treatment is measured under the conditions described in the section "Method for evaluating arithmetic mean roughness (Ra)" in the examples described later, a small arithmetic mean roughness Ra can be obtained. The arithmetic mean roughness Ra is preferably 150 nm or less, more preferably 100 nm or less, and particularly preferably 80 nm or less. There is no particular restriction on the lower limit, and it can be 10 nm or more, 20 nm or more, etc.

The resin composition according to this embodiment can usually give a cured product with a low dielectric constant. For example, when the dielectric constant of the cured product is measured under the conditions described in the section "Method of Measuring Dielectric Properties" in the Examples below, a low dielectric constant can be obtained. The dielectric constant of the cured product is preferably 4.0 or less, more preferably 3.8 or less, and particularly preferably 3.5 or less.

The resin composition according to this embodiment preferably has a low minimum melt viscosity. For example, when the minimum melt viscosity is measured under the conditions described in the section "Method of measuring minimum melt viscosity" in the Examples below, a low minimum melt viscosity can be obtained. The minimum melt viscosity of the resin composition is preferably less than 2000 poise.

[14. Uses of resin composition]
The resin composition according to the present embodiment can be used as a resin composition for insulating purposes, and can be particularly suitably used as a resin composition for forming an insulating layer (resin composition for forming an insulating layer). For example, the resin composition according to the present embodiment can be used as a resin composition for forming an insulating layer of a printed wiring board, taking advantage of the fact that a cured product having a low dielectric tangent can be obtained.

In particular, the resin composition according to the present embodiment can be suitably used as a resin composition for forming an interlayer insulating layer (a resin composition for interlayer insulation) by utilizing the advantage of excellent adhesion (plating adhesion) with a conductor layer formed on a cured product of the resin composition by plating. In general, a printed wiring board having an interlayer insulating layer is manufactured by forming a conductor layer, an interlayer insulating layer, and another conductor layer in this order. Therefore, the interlayer insulating layer is required to have high adhesion with the conductor layer formed earlier, and is also required to have high adhesion with the conductor layer formed later. Here, the adhesion between the conductor layer formed earlier and the interlayer insulating layer corresponds to the adhesion between the metal foil and the cured product (metal foil adhesion). On the other hand, since the formation of a conductor layer on the interlayer insulating layer is generally performed by plating, the adhesion between the conductor layer formed later and the interlayer insulating layer corresponds to the adhesion between the conductor layer (plated conductor layer) formed on the cured product by plating and the cured product (plating adhesion). While metal foil adhesion and plating adhesion can usually be different, the resin composition according to this embodiment can provide a cured product with excellent plating adhesion, and preferably a cured product with excellent plating adhesion and metal foil adhesion. Therefore, the resin composition according to this embodiment can be suitably used as a material for an interlayer insulating layer.

The resin composition according to the present embodiment may be used as a resin composition for forming a rewiring formation layer (resin composition for forming a rewiring formation layer). The rewiring formation layer refers to an insulating layer for forming a rewiring layer. The rewiring layer refers to a conductor layer formed on the rewiring formation layer as an insulating layer. For example, when a semiconductor chip package is manufactured through the following steps (1) to (6), the resin composition according to the present embodiment may be used as a resin composition for forming a rewiring formation layer. In addition, when a semiconductor chip package is manufactured through the following steps (1) to (6), a rewiring layer may be further formed on the sealing layer. In these cases, a conductor layer as a rewiring layer can be formed on the cured product of the resin composition by plating, so it is beneficial to use the resin composition according to the present embodiment that can obtain a cured product with excellent plating adhesion.
(1) A step of laminating a temporary fixing film on a substrate;
(2) A step of temporarily fixing a semiconductor chip on a temporary fixing film;
(3) forming an encapsulation layer on the semiconductor chip;
(4) peeling the substrate and the temporary fixing film from the semiconductor chip;
(5) forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off; and (6) forming a rewiring layer as a conductor layer on the rewiring formation layer.

Furthermore, the resin composition according to this embodiment can be used in a wide range of applications where resin compositions are used, such as sheet-like laminate materials such as resin sheets and prepregs, solder resists, underfill materials, die bonding materials, semiconductor encapsulation materials, hole filling resins, and component embedding resins.

[15. Sheet-like laminated material]
The resin composition according to the present embodiment may be used by coating in the form of a varnish, but from an industrial perspective, it is preferable to use the resin composition in the form of a sheet-like laminate material containing the resin composition.

The following resin sheets and prepregs are preferred as sheet-like laminate materials.

In one embodiment, the resin sheet includes a support and a resin composition layer provided on the support. The resin composition layer is formed from the resin composition according to this embodiment. Thus, the resin composition layer typically includes a resin composition, and preferably includes only a resin composition.

The thickness of the resin composition layer is preferably 50 μm or less, more preferably 40 μm or less, from the viewpoint of making the printed wiring board thinner and being able to provide a cured product with excellent insulating properties even if the cured product of the resin composition is a thin film. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be 5 μm or more, 10 μm or more, etc.

Examples of the support include films made of plastic materials, metal foils, and release paper, with films made of plastic materials and metal foils being preferred.

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 sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, 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. As the copper foil, a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

The support may be subjected to a matte treatment, corona treatment, or antistatic treatment on the surface that is to be bonded to the resin composition layer.

As the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. The support with a release layer may be a commercially available product, such as "SK-1", "AL-5", and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, "Purex" manufactured by Teijin Limited, and "Unipeel" manufactured by Unitika Limited, which are PET films having a release layer mainly composed of an alkyd resin-based release agent.

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

In one embodiment, the resin sheet may further include an optional layer as necessary. For example, such an optional layer may be a protective film similar to the support provided on the surface of the resin composition layer that is 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. By laminating the protective film, it is possible to suppress adhesion of dirt and scratches on the surface of the resin composition layer.

The resin sheet can be produced, for example, by preparing a liquid (varnish-like) resin composition as is or by dissolving the resin composition in a solvent to prepare a liquid (varnish-like) resin composition, applying this onto a support using a die coater or the like, and then drying to form a resin composition layer.

Examples of the solvent include the same solvents as those described as components of the resin composition. One type of solvent may be used alone, or two or more types may be used in combination.

Drying may be performed by heating, blowing hot air, or other methods. There are no particular limitations on the drying conditions, but drying is usually performed so that the solvent content in the resin composition layer is 10% by mass or less, and preferably 5% by mass or less. Although it varies depending on the boiling point of the solvent in the resin composition, for example, when using a resin composition containing 30% by mass to 60% by mass of solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

The resin sheet can be stored in a roll. If the resin sheet has a protective film, it can usually be used by peeling off the protective film.

In one embodiment, the prepreg is formed by impregnating a sheet-like fiber substrate with the resin composition according to this embodiment.

The sheet-like fiber substrate used for the prepreg may be, for example, a commonly used substrate for prepregs, such as glass cloth, aramid nonwoven fabric, or liquid crystal polymer nonwoven fabric. From the viewpoint of thinning the printed wiring board, the thickness of the sheet-like fiber substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. There is no particular lower limit to the thickness of the sheet-like fiber substrate, and it is usually 10 μm or more.

Prepregs can be manufactured using methods such as the hot melt method and the solvent method.

The thickness of the prepreg can be in the same range as the resin composition layer in the resin sheet described above.

The sheet-like laminate material can be suitably used to form an insulating layer of a printed wiring board (for the insulating layer of a printed wiring board), and can be even more suitably used to form an interlayer insulating layer of a printed wiring board (for the interlayer insulating layer of a printed wiring board).

[16. Printed Wiring Board]
The printed wiring board according to one embodiment of the present invention includes an insulating layer containing a cured product obtained by curing the resin composition according to the present embodiment. This printed wiring board can be manufactured, for example, by using the above-mentioned resin sheet by a method including the following steps (I) and (II).
(I) A step of laminating a resin sheet on an inner layer substrate such that the resin composition layer of the resin sheet is bonded to the inner layer substrate.
(II) A step of curing the resin composition layer to form an insulating layer.

The "inner layer substrate" used in step (I) is a member that will be the substrate of the printed wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may have a conductor layer on one or both sides, and the conductor layer may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate is sometimes called an "inner layer circuit substrate." In addition, intermediate products on which an insulating layer and/or a conductor layer is to be formed during the manufacture of a printed wiring board are also included in the above-mentioned "inner layer substrate." When the printed wiring board is a component-embedded circuit board, an inner layer substrate with a component embedded may be used.

The inner layer substrate and the resin sheet can be laminated, for example, by heat-pressing the resin sheet to the inner layer substrate from the support side. Examples of the member for heat-pressing the resin sheet to the inner layer substrate (hereinafter also referred to as the "heat-pressing member") include a heated metal plate (such as a SUS panel) or a metal roll (SUS roll). Note that rather than pressing the heat-pressing member directly onto the resin sheet, it is preferable to press it via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently follow the surface irregularities of the inner layer substrate.

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

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

After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example by pressing a heat-pressure bonding member from the support side. The pressing conditions for the smoothing treatment may be the same as the heat-pressure bonding conditions for the lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

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

In step (II), the resin composition layer is cured to form an insulating layer made of a cured product of the resin composition. The resin composition layer is usually cured by thermal curing. The specific curing conditions for the resin composition layer may be the conditions usually adopted when forming an insulating layer for a printed wiring board.

For example, the thermal curing conditions for the resin composition layer vary depending on the type of resin composition, but in one embodiment, the curing temperature is preferably 120°C to 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 the resin composition layer is thermally cured, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

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

In another embodiment, the printed wiring board can be manufactured using the above-mentioned prepreg. The manufacturing method can be basically the same as when a resin sheet is used.

Step (III) is a step of drilling holes in the insulating layer, which allows holes such as via holes and through holes to be formed in the insulating layer. Step (III) may be performed using, for example, a drill, a laser, plasma, etc., depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be appropriately determined depending on the design of the printed wiring board.

Step (IV) is a step of roughening the insulating layer. Usually, smears are also removed in this step (IV). The procedure and conditions of the roughening treatment are not particularly limited, and known procedures and conditions that are usually used when forming an insulating layer for a printed wiring board can be adopted. For example, the insulating layer can be roughened by carrying out a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

Examples of the swelling liquid used in the roughening treatment include an alkaline solution, a surfactant solution, etc., and an alkaline solution is preferred. As the alkaline solution, a sodium hydroxide solution and a potassium hydroxide solution are more preferred. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. The swelling treatment using a swelling liquid can be performed, for example, by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40°C to 80°C for 5 to 15 minutes.

The oxidizing agent used in the roughening treatment may be, for example, an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include, for example, alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotech Japan.

The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product is, for example, "Reduction Solution Securigant P" manufactured by Atotech Japan. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, etc., it is preferable to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

In one embodiment, the arithmetic mean roughness (Ra) of the insulating layer surface after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, etc. The root mean square roughness (Rq) of the insulating layer surface after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, etc. The arithmetic mean roughness (Ra) and root mean square roughness (Rq) of the insulating layer surface can be measured using a non-contact surface roughness meter.

Step (V) is a step of forming a conductor layer, and the conductor layer is formed on the insulating layer. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. The conductor layer may be a single metal layer or an alloy layer, and examples of the alloy layer include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy and copper-titanium alloy). Among these, from the viewpoints of versatility in forming the conductor 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 a nickel-chromium alloy, a copper-nickel alloy, or a 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 a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

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

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

In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. Below, an example of forming a conductor layer by a semi-additive method is shown.

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 to expose a portion of the plating seed layer corresponding to the desired wiring pattern. A metal layer is formed on the exposed plating seed layer by electrolytic plating, and the mask pattern is then removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, and a conductor layer having the desired wiring pattern can be formed.

In another embodiment, the conductor layer may be formed using a metal foil. When the conductor layer is formed using a metal foil, it is preferable to perform step (V) between steps (I) and (II). For example, after step (I), the support is removed, and a metal foil is laminated on the exposed surface of the resin composition layer. The lamination of the resin composition layer and the metal foil may be performed by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having a desired wiring pattern can be formed by a conventionally known technique such as a subtractive method or a modified semi-additive method using the metal foil on the insulating layer.

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

[17. Semiconductor Device]
A semiconductor device according to an embodiment of the present invention includes the above-mentioned printed wiring board. The semiconductor device can be manufactured using the printed wiring board.

Semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. In addition, the temperature and pressure conditions, unless otherwise specified, were room temperature (25°C) and atmospheric pressure (1 atm).

[Example 1]
Eight parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) and two parts of a naphthalene type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.) were heated and dissolved in 15 parts of solvent naphtha with stirring. This was cooled to room temperature to prepare a dissolved composition of the epoxy resin.

To this epoxy resin solution, 0.4 parts of a phenolic antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-330"), 30 parts of an active ester compound (DIC CORPORATION's "HPC-8150-62T", active ester group equivalent of about 220 g/eq., toluene solution with non-volatile content of 62% by mass), and spherical silica (Admatechs CORPORATION's "SO-C2", average particle size 0.5 μm, specific surface area 5.8 ^m2 ) surface-treated with a silane coupling agent (Shin-Etsu Chemical Co., Ltd.'s "KBM-573") were added. /g) 90 parts, triazine skeleton-containing phenolic curing agent (DIC Corporation "LA-3018-50P", active group equivalent of about 151 g / eq., 2-methoxypropanol solution with non-volatile content of 50%), carbodiimide curing agent (Nisshinbo Chemical Co., Ltd. "V-03", active group equivalent of about 216 g / eq., toluene solution with non-volatile content of 50%) 5 parts, imidazole curing accelerator (Shikoku Chemical Industry Co., Ltd. "1B2PZ", 1-benzyl-2-phenylimidazole), and phenoxy resin (Mitsubishi Chemical Corporation "YX7553BH30", 1:1 solution of MEK and cyclohexanone with non-volatile content of 30% by mass) were mixed and uniformly dispersed with a high-speed rotating mixer to prepare a resin composition.

[Example 2]
Instead of 0.4 parts of the phenol-based antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-330"), 0.4 parts of a sulfur-based antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-503") was used. Except for the above, a resin composition was prepared in the same manner as in Example 1.

[Example 3]
Instead of a combination of 8 parts of a biphenyl-type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) and 2 parts of a naphthalene-type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.), 10 parts of a biphenyl-type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) was used.
Further, 0.4 parts of a phosphorus-based antioxidant ("JP-360" manufactured by Johoku Chemical Co., Ltd.) was used in place of 0.4 parts of a phenol-based antioxidant ("ADEKA STAB AO-330" manufactured by ADEKA Corporation).
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 4]
Instead of a combination of 8 parts of a biphenyl-type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) and 2 parts of a naphthalene-type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.), 10 parts of a naphthalene-type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.) was used.
Further, 0.4 parts of a phosphorus-based antioxidant ("JPE-10" manufactured by Johoku Chemical Co., Ltd.) was used in place of 0.4 parts of a phenol-based antioxidant ("ADEKA STAB AO-330" manufactured by ADEKA Corporation).
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 5]
Instead of 30 parts of an active ester compound ("HPC-8150-62T" manufactured by DIC Corporation, active ester group equivalent weight: about 220 g/eq., toluene solution with non-volatile content of 62% by mass), 30 parts of an active ester compound ("HPC-8000-65T" manufactured by DIC Corporation, active ester group equivalent weight: about 223 g/eq., toluene solution with non-volatile content of 65%) was used.
In addition, the amount of spherical silica (Admatechs' SO-C2, average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's KBM-573) was changed from 90 parts to 105 parts.
Furthermore, the amount of the phenolic antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-330") was changed from 0.4 parts to 1 part.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 6]
The amount of the phenolic antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-330") was changed from 0.4 parts to 0.2 parts.
Further, 0.2 parts of a sulfur-based antioxidant ("ADEKA STAB AO-503" manufactured by ADEKA CORPORATION) was added to the resin composition.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 7]
To the resin composition, 2 parts of biphenylaralkylnovolac maleimide ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., MEK/toluene mixed solution with non-volatile content of 70%) was further added. Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 8]
Two parts of methacrylic modified polyphenylene ether (SA9000-111 manufactured by SABIC Innovative Plastics) was further added to the resin composition. A resin composition was prepared in the same manner as in Example 1 except for the above.

[Example 9]
To the resin composition, 2 parts of vinylbenzyl-modified polyphenylene ether ("OPE-2St 2200" manufactured by Mitsubishi Gas Chemical Co., Ltd., a toluene solution with a non-volatile content of 65%) was further added. Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 10]
The amount of spherical silica (Admatechs'"SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's "KBM-573") was changed from 90 parts to 70 parts.
Further, 15 parts of hollow silica particles ("BA-S" manufactured by JGC Catalysts and Chemicals, average particle size 2.6 μm, porosity 25% by volume) were added to the resin composition.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Example 11]
Instead of 0.4 parts of the phenol-based antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-330"), 0.4 parts of a sulfur-based antioxidant (ADEKA CORPORATION's "ADEKA STAB AO-503") was used.
In addition, the amount of spherical silica (Admatechs'"SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's "KBM-573") was changed from 90 parts to 70 parts.
Furthermore, 15 parts of hollow silica particles ("BA-S" manufactured by JGC Catalysts and Chemicals, average particle size 2.6 μm, porosity 25% by volume) were added to the resin composition.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Comparative Example 1]
A resin composition was prepared in the same manner as in Example 1 except for the above-mentioned points, except that 0.4 parts of a phenol-based antioxidant (ADEKA STAB AO-330) was not used.

[Comparative Example 2]
Instead of a combination of 8 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) and 2 parts of a naphthalene type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.), 10 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) was used.
In addition, the amount of spherical silica (Admatechs'"SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's "KBM-573") was changed from 90 parts to 105 parts.
Furthermore, 0.4 parts of the phenol-based antioxidant ("ADEKA STAB AO-330" manufactured by ADEKA Corporation) was not used.
Further, 2 parts of biphenylaralkylnovolac type maleimide ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., a mixed solution of MEK/toluene with a non-volatile content of 70%) was added to the resin composition.
Except for the above, the resin composition was prepared in the same manner as in Example 7.

[Comparative Example 3]
Instead of a combination of 8 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) and 2 parts of a naphthalene type epoxy resin ("HP-4032-SS" manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent of about 145 g/eq.), 10 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 269 g/eq.) was used.
In addition, the amount of the active ester compound (DIC Corporation's "HPC-8150-62T", active ester group equivalent of about 220 g/eq., toluene solution with non-volatile content of 62% by mass) was changed from 30 parts to 10 parts.
Furthermore, the amount of spherical silica (Admatechs' SO-C2, average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's KBM-573) was changed from 90 parts to 65 parts.
In addition, 0.4 parts of the phenol-based antioxidant (ADEKA STAB AO-330) was not used.
Furthermore, the amount of triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-3018-50P", active group equivalent of about 151 g/eq., 2-methoxypropanol solution with non-volatile content of 50%) was changed from 2 parts to 10 parts.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Comparative Example 4]
Instead of 30 parts of an active ester compound ("HPC-8150-62T" manufactured by DIC Corporation, active ester group equivalent weight: about 220 g/eq., toluene solution with non-volatile content of 62% by mass), 40 parts of an active ester compound ("HPC-8000-65T" manufactured by DIC Corporation, active ester group equivalent weight: about 223 g/eq., toluene solution with non-volatile content of 65%) was used.
In addition, the amount of spherical silica (Admatechs'"SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² /g) surface-treated with a silane coupling agent (Shin-Etsu Chemical's "KBM-573") was changed from 90 parts to 35 parts.
Furthermore, 0.4 parts of the phenol-based antioxidant ("ADEKA STAB AO-330" manufactured by ADEKA Corporation) was not used.
Except for the above, the resin composition was prepared in the same manner as in Example 1.

[Preparation of resin sheet]
A polyethylene terephthalate film with a release layer ("AL5" manufactured by Lintec Corporation, thickness 38 μm) was prepared as a support. The resin compositions obtained in the examples and comparative examples were uniformly applied onto the release layer of this support so that the thickness of the resin composition layer after drying was 40 μm. Thereafter, the resin composition was dried at 80° C. to 100° C. (average 90° C.) for 4 minutes to obtain a resin sheet including a support and a resin composition layer.

[Evaluation method of arithmetic average roughness (Ra)]
<Fabrication of Evaluation Substrate A>
(1) Surface preparation for interior substrates:
As an inner layer substrate, a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic "R1515A") having copper foil on the surface was prepared. The copper foil on the surface of this inner layer substrate was etched with a microetching agent (Mech "CZ8101") to a copper etching amount of 1 μm, and roughening treatment was performed. Then, it was dried at 190° C. for 30 minutes.

(2) Lamination and curing of resin sheets:
The resin sheets obtained in the above-mentioned Examples and Comparative Examples were laminated on both sides of the inner layer substrate using a batch-type vacuum pressure laminator (a two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.) so that the resin composition layer was bonded to the inner layer substrate. This lamination was performed by reducing the pressure for 30 seconds to 13 hPa or less, and then pressing at a temperature of 100°C and a pressure of 0.74 MPa for 30 seconds.

The laminated resin sheet was then heat pressed at atmospheric pressure at 100°C and a pressure of 0.5 MPa for 60 seconds to smooth it. It was then placed in an oven at 130°C and heated for 30 minutes, and then transferred to an oven at 170°C and heated for 30 minutes. This heating caused the resin composition layer to thermally cure, forming an insulating layer made of the cured resin composition. The support was then peeled off to obtain an intermediate substrate having a layer structure of insulating layer/inner layer substrate/insulating layer.

(3) Roughening treatment:
The insulating layer of the intermediate substrate was subjected to a roughening treatment. Specifically, the intermediate substrate was immersed in a swelling liquid, Swelling Dip Securigant P manufactured by Atotech Japan, at 60° C. for 10 minutes. Next, the intermediate substrate was immersed in a roughening liquid, Concentrate Compact P manufactured by Atotech Japan (aqueous solution of KMnO ₄ : 60 g/L, NaOH: 40 g/L), at 80° C. for 20 minutes. Finally, the intermediate substrate was immersed in a neutralizing liquid, Reduction Solution Securigant P manufactured by Atotech Japan, at 40° C. for 5 minutes. The obtained substrate was designated as evaluation substrate A.

<Measurement of arithmetic mean roughness (Ra)>
The arithmetic mean roughness Ra of the insulating layer surface of evaluation substrate A was measured using a non-contact surface roughness meter (WYKO NT3300 manufactured by B-CO Instruments) in VSI mode with a 50x lens over a measurement range of 121 μm × 92 μm. Measurements were performed at 10 randomly selected points, and the average value was calculated and shown in the table below.

[Method of measuring plating adhesion (plating peel strength)]
<Preparation of Evaluation Substrate B>
Evaluation substrate A was immersed in an electroless plating solution containing _PdCl2 at 40 ° C for 5 minutes, and then immersed in an electroless copper plating solution at 25 ° C for 20 minutes. After heating at 150 ° C for 30 minutes to perform an annealing treatment, an etching resist was formed, and after pattern formation by etching, copper sulfate electroplating was performed to form a conductor layer with a thickness of 30 μm. Next, an annealing treatment was performed at 200 ° C for 60 minutes, and the obtained substrate was designated as evaluation substrate B.

<Measurement of peel strength of plated conductor layer before HAST test>
A cut was made in the conductor layer of evaluation board B in a portion not including a via hole, surrounding a portion 10 mm wide and 150 mm long. One end of this portion was peeled off and gripped with the gripper of a tensile tester (Autocom type tester "AC-50C-SL" manufactured by TSE Corporation). The plated peel strength was measured as the load [kgf/cm] when 100 mm was peeled off by pulling in the vertical direction at a speed of 50 mm/min at room temperature (25°C). The load value obtained as a result of this measurement is referred to as the "plated peel strength before HAST test".

<Measurement of peel strength of plated conductor layer after HAST test>
The evaluation board B was subjected to an accelerated environmental test (HAST test) for 100 hours under high temperature and high humidity conditions of 130°C and 85%RH using a highly accelerated life tester (PM422 manufactured by Kusumoto Chemicals Co., Ltd.). Thereafter, the plating peel strength was measured using the evaluation board B after the HAST test in the same manner as in the above "<Measurement of peel strength (peel strength) of plating conductor layer before HAST test>". That is, a notch was made in the evaluation board B after the HAST test, and one end of the part surrounded by the notch was pulled vertically at a speed of 50 mm/min at room temperature (25°C) to peel off 100 mm, and the load [kgf/cm] was measured as the plating peel strength. The load value obtained as a result of this measurement is called the "plating peel strength after HAST test".

[Method of measuring dielectric properties]
The resin sheets obtained in each Example and Comparative Example were thermally cured at 190°C for 90 minutes, and the support was peeled off to obtain a sheet-like cured product. The cured product was cut to obtain a test piece having a width of 2 mm and a length of 80 mm. The dielectric loss tangent (tan δ) and the relative dielectric constant were measured for this test piece at a measurement frequency of 5.8 GHz by the cavity resonance method using a cavity resonator perturbation method dielectric constant measuring device "CP521" manufactured by Kanto Applied Electronics Development Co., Ltd. and a network analyzer "E8362B" manufactured by Agilent Technologies. However, the measurement of the relative dielectric constant was only performed in Examples 1, 2, 10 and 11. Measurements were performed on two test pieces, and the average value was calculated.

[Method for evaluating metal foil adhesion]
The metal foil adhesion was evaluated by measuring the copper foil peel strength according to the following procedure.

<Preparation of evaluation board>
(1) Copper foil preparation:
The shiny side of an electrolytic copper foil (Mitsui Mining & Smelting Co., Ltd. "3EC-III", thickness 35 μm) was etched to a depth of 1 μm with a microetching solution (Mech Co., Ltd. "CZ8101") to roughen the copper surface, and then an anti-rust treatment (CL8300) was performed. The copper foil whose surface was thus etched with the microetching agent may be referred to as "CZ copper foil" hereinafter. In this way, a CZ copper foil having a treated surface was obtained.

(2) Preparation of inner layer board:
A glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, Panasonic "R1515A") having copper foil on the surface and an inner layer circuit formed thereon was prepared. Both sides of this glass cloth-based epoxy resin double-sided copper-clad laminate were etched by 1 μm with a microetching solution (Mech "CZ8101") to roughen the copper surface. Further, the laminate was heated in an oven at 130° C. for 30 minutes to obtain an inner layer substrate.

(3) Lamination of resin composition layer:
The resin sheets prepared in the examples and comparative examples were laminated on both sides of the inner layer substrate. This lamination was performed using a batch-type vacuum pressure laminator (two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.) so that the resin composition layer was in contact with the inner layer substrate. The lamination was performed by reducing the pressure for 30 seconds to adjust the air pressure to 13 hPa or less, and then pressing at 120°C and a pressure of 0.74 MPa for 30 seconds. Next, the laminated resin sheet was heat-pressed at 100°C and a pressure of 0.5 MPa for 60 seconds. Then, the support was peeled off to expose the resin composition layer.

(4) Lamination of copper foil and curing of resin composition layer:
The treated surface of the CZ copper foil was laminated on the exposed resin composition layer under the same conditions as in "(3) Lamination of the resin composition layer" above. The resin composition layer was then cured at 200°C for 90 minutes to form a cured product (insulating layer). This resulted in an evaluation substrate C with CZ copper foil laminated on both sides. This evaluation substrate C had a layer structure of CZ copper foil/insulating layer/inner layer substrate/insulating layer/CZ copper foil.

<Measurement of copper foil peel strength before HAST test>
The evaluation board C was cut into small pieces of 150 mm x 30 mm. A cutter was used to make a cut in the CZ copper foil part of the small piece, surrounding a part of 10 mm width and 100 mm length. One end of this part was peeled off and gripped with a gripper of a tensile tester. At room temperature (normal temperature), the piece was pulled vertically at a speed of 50 mm/min, and the load [kgf/cm] when 35 mm was peeled off was measured as the copper foil peel strength. The load value obtained as a result of this measurement is called the "copper foil peel strength before HAST test". A tensile tester (TSE Autocom Universal Tester "AC-50C-SL") was used for the measurement. The measurement was performed in accordance with Japanese Industrial Standard JIS C6481.

<Measurement of copper foil peel strength after HAST>
The evaluation substrate C was subjected to an accelerated environmental test (HAST test) for 100 hours under high temperature and high humidity conditions of 130° C. and 85% RH using a highly accelerated life tester (Kusumoto Chemical Industries, Ltd., “PM422”). Thereafter, the copper foil peel strength was measured using the evaluation substrate C after the HAST test in the same manner as in “<Measurement of copper foil peel strength before HAST test>” above. That is, the evaluation substrate C after the HAST test was cut into small pieces, a cut was made in the CZ copper foil part, and one end of the part surrounded by the cut was pulled vertically at a speed of 50 mm/min at room temperature (normal temperature) to peel off 35 mm, and the load [kgf/cm] was measured as the copper foil peel strength. The load value obtained as a result of this measurement is called “copper foil peel strength after HAST test”. The measurement was performed in accordance with Japanese Industrial Standard JIS C6481.

[Method for measuring minimum melt viscosity]
25 resin composition layers of the resin sheet were stacked to obtain a resin composition layer having a thickness of 1 mm. This resin composition layer was punched out to a diameter of 20 mm to prepare a measurement sample. The minimum melt viscosity was measured by measuring the dynamic viscoelastic modulus of the prepared measurement sample using a dynamic viscoelasticity measuring device (UBM's "Rheogel-G3000") under the measurement conditions of a starting temperature of 60°C to 200°C, a heating rate of 5°C/min, a measurement temperature interval of 2.5°C, and a vibration frequency of 1 Hz. The obtained minimum melt viscosity was evaluated according to the following criteria.
"○": Less than 2000 poise.
"X": 2000 poise or more.

[result]
The results of the above-mentioned Examples and Comparative Examples are shown in the following table. In the table, the meanings of the abbreviations are as follows:
Plating Peel Strength Before HAST: Plating peel strength before HAST testing.
Plating peel strength after HAST: Plating peel strength after HAST test.
Copper foil adhesion before HAST: Copper foil peel strength before HAST testing.
Copper foil adhesion after HAST: Copper foil peel strength after HAST test.

Claims (12)

A resin composition comprising (A) an epoxy resin, (B) an active ester compound, (C) an inorganic filler, and (D) an antioxidant,
(B) the active ester compound has an active ester group equivalent of 50 g/eq. to 500 g/eq.,
(D) The antioxidant contains a compound represented by any one of the following formulas (D1) to (D3):

When the non-volatile components in the resin composition are taken as 100 mass%, the content of the inorganic filler (C) is 60 mass% or more , the content of the active ester compound ( B) is 10 mass% or more, and the content of the antioxidant (D) is 0.1 mass% or more and 1 mass% or less,
When the resin component in the resin composition is taken as 100% by mass, the content of the active ester compound (B) is 30% by mass or more,
A resin composition , wherein, when the number of epoxy groups in the epoxy resin (A) is taken as 1, the number of active ester groups in the active ester compound (B) is 0.5 or more . The resin composition according to claim 1, wherein the content of the antioxidant (D) is 0.1% by mass or more and 10% by mass or less, when the resin component in the resin composition is 100% by mass. The resin composition according to claim 1 or 2 , wherein the epoxy resin (A) comprises a liquid epoxy resin. The resin composition according to any one of claims 1 to 3 , further comprising one or more curing agents (F) selected from the group consisting of phenolic curing agents and carbodiimide curing agents. The resin composition according to any one of claims 1 to 4 , further comprising (G) a curing accelerator. The resin composition according to any one of claims 1 to 5 , further comprising a thermoplastic resin (H). The resin composition according to any one of claims 1 to 6 , which is for forming an insulating layer. A cured product of the resin composition according to any one of claims 1 to 7 . A sheet-like laminate material comprising the resin composition according to any one of claims 1 to 7 . A resin sheet comprising a support and a resin composition layer formed on the support from the resin composition according to any one of claims 1 to 7 . A printed wiring board comprising an insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 7 . A semiconductor device comprising the printed wiring board according to claim 11 .