JP7517510B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition. It also relates to a resin sheet, a printed wiring board, and a semiconductor device obtained using the resin composition.

A known manufacturing technique for printed wiring boards is the build-up method, in which insulating layers and conductor layers are stacked alternately.

For example, Patent Document 1 discloses a resin composition as an insulating material for printed wiring boards used in such insulating layers.

JP 2018-199797 A

An insulating layer is generally formed by laminating a resin composition layer onto a substrate and thermally curing the layer. As a result of intensive research, the present inventors have found that when an insulating layer is formed by laminating a resin composition layer containing a conventional resin composition, the uniformity of the insulating layer surface decreases and unevenness is likely to occur (unevenness after lamination). If there is such unevenness on the insulating layer surface, the wiring formability of the insulating layer may be deteriorated.

The object of the present invention is to provide a resin composition capable of suppressing unevenness that occurs when a resin composition is laminated; a resin sheet containing the resin composition; a printed wiring board having an insulating layer formed using the resin composition, and a semiconductor device.

As a result of intensive research into the above-mentioned problems, the inventors discovered that the above-mentioned problems could be solved by incorporating an active ester compound having a specific group, and thus completed the present invention.

（式中、＊は結合手を表す。式（３）中、ｎは１～５の整数を表す。）
［２］ （Ｂ）成分が、下記一般式（ｂ－１）で表される活性エステル系化合物である、［１］に記載の樹脂組成物。

（一般式（ｂ－１）中、
Ａｒ^１１は、それぞれ独立に式（１）で表される基、式（２）で表される基、又は式（３）で表される基を表し、
Ａｒ^１２は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基を表し、
Ａｒ^１３は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基、置換基を有していてもよい２価の脂肪族炭化水素基、酸素原子、硫黄原子、又はこれらの組み合わせからなる２価の基を表す。ａは１～６の整数を表し、ｂは０～１０の整数を表す。）
［３］ 一般式（ｂ－１）中のＡｒ^１３が、それぞれ独立に置換基を有していてもよい２価の芳香族炭化水素基及び酸素原子を組み合わせた２価の基を表す、［２］に記載の樹脂組成物。
［４］ （Ｂ）成分が、下記一般式（ｂ－３）で表される活性エステル系化合物である、［１］～［３］のいずれかに記載の樹脂組成物。

（一般式（ｂ－３）中、
Ａｒ^３１は、それぞれ独立に式（１）で表される基、式（２）で表される基、又は式（３）で表される基を表す。ａ２は１～６の整数を表し、ｃ２は１～５の整数を表し、ｄはそれぞれ独立に０～６の整数を表す。）
［５］ さらに、（Ｃ）無機充填材を含有する、［１］～［４］のいずれかに記載の樹脂組成物。
［６］ 絶縁層形成用である、［１］～［５］のいずれかに記載の樹脂組成物。
［７］ 導体層を形成するための絶縁層形成用である、［１］～［６］のいずれかに記載の樹脂組成物。
［８］ 支持体と、該支持体上に設けられた、［１］～［７］のいずれかに記載の樹脂組成物を含む樹脂組成物層とを含む、樹脂シート。
［９］ ［１］～［７］のいずれかに記載の樹脂組成物の硬化物により形成された絶縁層を含む、プリント配線板。
［１０］ ［９］に記載のプリント配線板を含む、半導体装置。 That is, the present invention includes the following.
[1] A resin composition comprising: (A) an epoxy resin; and (B) an active ester compound having at least one of groups represented by the following formulas (1) to (3):

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5.)
[2] The resin composition according to [1], wherein the component (B) is an active ester compound represented by the following general formula (b-1):

(In general formula (b-1),
Ar ¹¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3);
Ar ¹² each independently represents a divalent aromatic hydrocarbon group which may have a substituent;
Ar ¹³ each independently represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aliphatic hydrocarbon group which may have a substituent, an oxygen atom, a sulfur atom, or a divalent group consisting of a combination thereof. a represents an integer of 1 to 6, and b represents an integer of 0 to 10.
[3] The resin composition according to [2], wherein Ar ¹³ in general formula (b-1) represents a divalent group combining a divalent aromatic hydrocarbon group which may have a substituent and an oxygen atom.
[4] The resin composition according to any one of [1] to [3], wherein the component (B) is an active ester compound represented by the following general formula (b-3):

(In general formula (b-3),
Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3). a2 represents an integer of 1 to 6, c2 represents an integer of 1 to 5, and d each independently represents an integer of 0 to 6.
[5] The resin composition according to any one of [1] to [4], further comprising (C) an inorganic filler.
[6] The resin composition according to any one of [1] to [5], which is for forming an insulating layer.
[7] The resin composition according to any one of [1] to [6], which is for forming an insulating layer for forming a conductor layer.
[8] A resin sheet comprising a support and a resin composition layer provided on the support, the resin composition layer comprising the resin composition according to any one of [1] to [7].
[9] A printed wiring board comprising an insulating layer formed from a cured product of the resin composition according to any one of [1] to [7].
[10] A semiconductor device comprising the printed wiring board according to [9].

The present invention provides a resin composition that can suppress unevenness after lamination that occurs when a resin composition is laminated; a resin sheet that includes the resin composition; a printed wiring board that includes an insulating layer formed from a cured product of the resin composition; and a semiconductor device.

The present invention will be described in detail below based on its preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and can be modified as desired without departing from the scope of the claims of the present invention and their equivalents.

（式中、＊は結合手を表す。式（３）中、ｎは１～５の整数を表す。） [Resin composition]
The resin composition of the present invention contains (A) an epoxy resin, and (B) an active ester compound having at least one of the groups represented by the following formulas (1) to (3). By including the component (B) in the resin composition, it is possible to suppress the occurrence of unevenness after lamination that may occur when a resin composition layer containing the resin composition is laminated. Furthermore, in the present invention, it is also possible to obtain a cured product that is usually excellent in plating peel strength, copper foil adhesion, and copper foil adhesion after HAST, and further has low dielectric properties and a low arithmetic average roughness (Ra).

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5.)

The resin composition may further contain optional components in combination with components (A) and (B). Examples of optional components include (C) inorganic filler, (D) curing agent, (E) curing accelerator, and (F) other additives. Each component contained in the resin composition is described in detail below.

<(A) Epoxy Resin>
The resin composition contains an epoxy resin (A) as component (A). Examples of component (A) 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 ester type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, and tetraphenylethane type epoxy resins. The epoxy resin may be used alone or in combination of two or more kinds.

The resin composition preferably contains, as component (A), an epoxy resin having two or more epoxy groups in one molecule. From the viewpoint of obtaining the desired effect of the present invention significantly, the ratio of the epoxy resin having two or more epoxy groups in one molecule to 100% by mass of the non-volatile components of component (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, only solid epoxy resins, or a combination of liquid epoxy resins and solid epoxy resins as component (A), but from the viewpoint of significantly achieving the desired effects of the present invention, it is preferable to contain only solid epoxy resins.

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.

As solid epoxy resins, bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins are preferred, with naphthol type epoxy resins being more preferred.

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", and "HP-7200H" (dicyclopentadiene ether type epoxy resins); DIC Corporation's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether type epoxy resins); Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC3000H", "NC3000", and "NC3000L" ","NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; " Examples of such epoxy resins include "YX8800" (anthracene 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" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; and "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical. These may be used alone or in combination of two or more types.

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, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, with naphthalene type epoxy resins being more preferable.

Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "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); and Mitsubishi Chemical's "630" and "630LSD" (glycidylamine type epoxy resins). ); "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation; "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation; "PB-3600" (epoxy resin having a butadiene structure) manufactured by Daicel Corporation; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. 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 component (A), the ratio by mass between them (liquid epoxy resin:solid epoxy resin) is preferably 1:1 to 1:20, more preferably 1:1.5 to 1:15, and particularly preferably 1:2 to 1:10. When the ratio between the liquid epoxy resin and the solid epoxy resin is within this range, the desired effects of the present invention can be significantly obtained. Furthermore, when used in the form of a resin sheet, appropriate adhesion is usually achieved. Furthermore, when used in the form of a resin sheet, sufficient flexibility is usually obtained, improving handling. Furthermore, a cured product having sufficient breaking strength can usually be obtained.

The epoxy equivalent of component (A) is preferably 50 g/eq. to 5000 g/eq., more preferably 50 g/eq. to 3000 g/eq., even more preferably 80 g/eq. to 2000 g/eq., and even more preferably 110 g/eq. to 1000 g/eq. Within this range, the crosslink density of the cured product of the resin composition layer is sufficient, resulting in an insulating layer with small surface roughness. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the component (A) is preferably 100 to 5,000, more preferably 200 to 3,000, and even more preferably 250 to 1,500, from the viewpoint of prominently obtaining the desired effects of the present invention.
The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene equivalent value.

From the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulating reliability, the content of the (A) component is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. From the viewpoint of significantly obtaining the desired effects of the present invention, the upper limit of the epoxy resin content is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less.
In the present invention, the content of each component in the resin composition is a value when the non-volatile components in the resin composition are taken as 100 mass %, unless otherwise specified.

<(B) Active ester compound having at least one of groups represented by the following formulas (1) to (3)>
The resin composition contains, as component (B), an active ester compound having at least one of the groups represented by the following formulas (1) to (3). By including component (B) in the resin composition, it becomes possible to suppress the occurrence of unevenness after lamination. Furthermore, by including component (B) in the resin composition, it is possible to obtain a cured product that is usually excellent in plating peel strength, copper foil adhesion, and copper foil adhesion after HAST, and further has low dielectric properties and a low arithmetic average roughness (Ra).

（式中、＊は結合手を表す。式（３）中、ｎは１～５の整数を表す。）

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5.)

The (B) component can be a compound having at least one of the groups represented by formulas (1) to (3) and having an active ester moiety capable of reacting with the (A) component. The (B) component preferably has at least one of the groups represented by formulas (1) to (3) at its terminal. The (B) component may have different terminals or the same terminals.

The group represented by formula (1) may be a cresol-derived group as shown below. The methyl group in the group represented by formula (1) is preferably bonded to the oxygen atom at the ortho, meta, or para position, and more preferably at the ortho position.

The group represented by formula (2) may be a group derived from phenylphenol as shown below. The phenyl group in the group represented by formula (2) is preferably bonded to the oxygen atom of the phenol moiety at any one of the ortho, meta, and para positions, and more preferably at the ortho position.

The group represented by formula (3) may be a group derived from styrenated phenol shown below. The styrene moiety in the group represented by formula (3) is preferably bonded to the oxygen atom of the phenol moiety at the ortho, meta, or para position, and more preferably at the ortho position.

（式中、ｎ１は、式（３）中のｎと同じである。）
（Ｂ）成分は、下記一般式（ｂ－１）で表される化合物であることが好ましい。

（一般式（ｂ－１）中、Ａｒ^１１は、それぞれ独立に式（１）で表される基、式（２）で表される基、又は式（３）で表される基を表し、Ａｒ^１２は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基を表し、Ａｒ^１３は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基、置換基を有していてもよい２価の脂肪族炭化水素基、酸素原子、硫黄原子、又はこれらの組み合わせからなる２価の基を表す。ａは１～６の整数を表し、ｂは０～１０の整数を表す。） In formula (3), n represents an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably an integer of 1 or 2.

(In the formula, n1 is the same as n in formula (3).)
The component (B) is preferably a compound represented by the following general formula (b-1).

(In general formula (b-1), Ar ¹¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3); Ar ¹² each independently represents a divalent aromatic hydrocarbon group which may have a substituent; and Ar ¹³ each independently represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aliphatic hydrocarbon group which may have a substituent, an oxygen atom, a sulfur atom, or a divalent group consisting of a combination thereof; a represents an integer of 1 to 6, and b represents an integer of 0 to 10.)

In general formula (b-1), Ar ¹¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3). The groups represented by formulas (1) to (3) are as described above. Among them, the group represented by formula (1) and the group represented by formula (2) are preferred.

In the general formula (b-1), Ar ¹² each independently represents a divalent aromatic hydrocarbon group which may have a substituent. Examples of the divalent aromatic hydrocarbon group include an arylene group and an aralkylene group, and an arylene group is preferred. As the arylene group, an arylene group having 6 to 30 carbon atoms is preferred, an arylene group having 6 to 20 carbon atoms is more preferred, and an arylene group having 6 to 10 carbon atoms is even more preferred. Examples of such an arylene group include a phenylene group, a naphthylene group, an anthracenylene group, and a biphenylene group. As the aralkylene group, an aralkylene group having 7 to 30 carbon atoms is preferred, an aralkylene group having 7 to 20 carbon atoms is more preferred, and an aralkylene group having 7 to 15 carbon atoms is even more preferred. Among these, a phenylene group is preferred.

In general formula (b-1), Ar ¹³ each independently represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aliphatic hydrocarbon group which may have a substituent, an oxygen atom, a sulfur atom, or a divalent group consisting of a combination thereof, and a divalent group consisting of a combination thereof is preferable. The divalent aromatic hydrocarbon group is the same as the divalent aromatic hydrocarbon group represented by Ar ¹² .

As the divalent aliphatic hydrocarbon group, a divalent saturated aliphatic hydrocarbon group is more preferable, an alkylene group or a cycloalkylene group is more preferable, and a cycloalkylene group is more preferable.

As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, an alkylene group having 1 to 6 carbon atoms is more preferable, and an alkylene group having 1 to 3 carbon atoms is even more preferable. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a 1-methylmethylene group, a 1,1-dimethylmethylene group, a 1-methylethylene group, a 1,1-dimethylethylene group, a 1,2-dimethylethylene group, a butylene group, a 1-methylpropylene group, a 2-methylpropylene group, a pentylene group, and a hexylene group.

The cycloalkylene group is preferably a cycloalkylene group having 3 to 20 carbon atoms, more preferably a cycloalkylene group having 3 to 15 carbon atoms, and even more preferably a cycloalkylene group having 5 to 10 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclopentylene group, and a cycloheptylene group.

As a divalent group consisting of these combinations, a divalent group consisting of a divalent aromatic hydrocarbon group which may have a substituent and an oxygen atom is preferred, a divalent group consisting of a divalent aromatic hydrocarbon group which may have one or more substituents and an alternating combination of one or more oxygen atoms is more preferred, and a divalent group consisting of a naphthylene group which may have one or more substituents and an alternating combination of one or more oxygen atoms is even more preferred. Thus, a naphthyleneoxy group which may have a substituent is even more preferred.

The divalent aromatic hydrocarbon group represented by Ar ¹² , the divalent aromatic hydrocarbon group represented by Ar ¹³ , and the divalent aliphatic hydrocarbon group may have a substituent. The number of the substituent may be one or more. Examples of the substituent include an aryl group having 6 to 20 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a halogen atom. The substituent may be contained alone or in combination of two or more kinds.

Examples of aryl groups having 6 to 20 carbon atoms include benzyl, phenyl, naphthyl, anthracenyl, tolyl, and xylyl groups, with benzyl being preferred.

Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, 1,2-dimethylpropyl, n-hexyl, isohexyl, n-nonyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclononyl.

Examples of alkoxy groups having 1 to 10 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, 2-ethylhexyloxy, octyloxy, and nonyloxy.

Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The above-mentioned substituents may further have a substituent (hereinafter, sometimes referred to as a "secondary substituent"). Unless otherwise specified, the secondary substituent may be the same as the above-mentioned substituent.

In general formula (b-1), a represents an integer of 1 to 6, preferably an integer of 1 to 5, and more preferably an integer of 1 to 3. When the compound represented by general formula (b-1) is an oligomer or polymer, a represents the average value.

In general formula (b-1), b represents an integer from 0 to 10, preferably an integer from 0 to 5, more preferably an integer from 0 to 3, and even more preferably 0. When the compound represented by general formula (b-1) is an oligomer or polymer, b represents the average value.

（一般式（ｂ－２）中、Ａｒ^２１は、それぞれ独立に式（１）で表される基、式（２）で表される基、又は式（３）で表される基を表し、Ａｒ^２２は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基を表し、Ａｒ^２３は、それぞれ独立に、置換基を有していてもよい２価の芳香族炭化水素基を表す。ａ１は１～６の整数を表し、ｃ１は１～５の整数を表す。） The component (B) is preferably a compound represented by general formula (b-2).

(In general formula (b-2), Ar ²¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3); Ar ²² each independently represents a divalent aromatic hydrocarbon group which may have a substituent; and Ar ²³ each independently represents a divalent aromatic hydrocarbon group which may have a substituent. a1 represents an integer of 1 to 6, and c1 represents an integer of 1 to 5.)

Ar ²¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3). The groups represented by formulas (1) to (3) are as described above. Among them, the group represented by formula (1) and the group represented by formula (2) are preferred.

Each Ar ²² independently represents a divalent aromatic hydrocarbon group which may have a substituent, and Ar ²² is the same as Ar ¹² in general formula (b-1).

Each Ar ²³ independently represents a divalent aromatic hydrocarbon group which may have a substituent. Ar ²³ is the same as the divalent aromatic hydrocarbon group which may have a substituent of Ar ¹³ in general formula (b-1).

In general formula (b-2), a1 represents an integer from 1 to 6. a1 is the same as a in general formula (b-1).

In general formula (b-2), c1 represents an integer of 1 to 5. It is preferable that c1 represents an integer of 1 to 4, and more preferably an integer of 1 to 3.

（一般式（ｂ－３）中、Ａｒ^３１は、それぞれ独立に式（１）で表される基、式（２）で表される基、又は式（３）で表される基を表す。ａ２は１～６の整数を表し、ｃ２は１～５の整数を表し、ｄはそれぞれ独立に０～６の整数を表す。） The component (B) is preferably a compound represented by general formula (b-3).

(In general formula (b-3), Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3). a2 represents an integer of 1 to 6, c2 represents an integer of 1 to 5, and d each independently represents an integer of 0 to 6.)

Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3). The groups represented by formulas (1) to (3) are as described above. Among them, the group represented by formula (1) and the group represented by formula (2) are preferred.

In general formula (b-3), a2 represents an integer from 1 to 6. a2 is the same as a in general formula (b-1).

In general formula (b-3), c2 represents an integer from 1 to 5. c2 is the same as c1 in general formula (b-2).

In general formula (b-3), each d independently represents an integer from 0 to 6. It is preferable that d represents an integer from 1 to 5, and more preferably an integer from 1 to 4.

Component (B) may be synthesized by a known method, for example, by the method described in the following examples. Component (B) can be synthesized by the method described in WO 2018/235424 or WO 2018/235425, for example.

From the viewpoint of obtaining a significant effect of the present invention, the weight average molecular weight of component (B) is preferably 150 or more, more preferably 200 or more, and even more preferably 250 or more, and is preferably 4000 or less, more preferably 3000 or less, and even more preferably 2500 or less. The weight average molecular weight of component (B) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

From the viewpoint of obtaining a significant effect of the present invention, the active ester equivalent (unsaturated bond equivalent) of component (B) is preferably 50 g/eq or more, more preferably 100 g/eq. or more, even more preferably 150 g/eq., and is preferably 2000 g/eq. or less, more preferably 1000 g/eq. or less, even more preferably 500 g/eq. or less. The active ester equivalent is the mass of component (B) containing one equivalent of an unsaturated bond.

The ratio of the amount of the (A) component to the (B) component is the ratio of [total number of epoxy groups in the (A) component] to [total number of active ester groups in the (B) component], and is preferably in the range of 1:0.01 to 1:20, more preferably 1:0.1 to 1:10, and even more preferably 1:0.5 to 1:5. Here, the "total number of epoxy groups in the (A) component" refers to the total value obtained by dividing the mass of the non-volatile components of the (A) component present in the resin composition by the epoxy equivalent. In addition, the "total number of active ester groups in the (B) component" refers to the total value obtained by dividing the mass of the non-volatile components of the (B) component present in the resin composition by the active ester group equivalent. By setting the ratio of the (A) component to the (B) component within this range, the effects of the present invention can be obtained significantly.

From the viewpoint of suppressing the occurrence of unevenness after lamination, the content of component (B) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on 100% by mass of non-volatile components in the resin composition, and is preferably 30% by mass or less, preferably 25% by mass or less, and more preferably 20% by mass or less.

<(C) Inorganic filler>
The resin composition may further contain an inorganic filler as component (C) as an optional component in addition to the above-mentioned components. By using the inorganic filler (C), the curing of the resin composition is improved. The dielectric properties and insulating performance of the material can be improved.

As the material of the inorganic filler, an inorganic compound is used. Examples of the material of 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 is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferable as the silica. (C) The inorganic filler may be used alone or in combination of two or more types.

Examples of commercially available products of component (C) include "UFP-30" manufactured by Denka; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials; "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatechs; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; and "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs.

The specific surface area of component (C) is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, and particularly preferably 3 m ² /g or more. There is no particular upper limit, but it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area is obtained according to the BET method by adsorbing nitrogen gas onto the surface of a sample 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.

From the viewpoint of significantly obtaining the desired effects of the present invention, the average particle size of component (C) is preferably 0.01 μm or more, more preferably 0.05 μm or more, and particularly preferably 0.1 μm or more, and is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less.

The average particle size of component (C) 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 wavelengths as the light source, and the volume-based particle size distribution of component (C) 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 improving moisture resistance and dispersibility, it is preferable that the (C) component is treated with a surface treatment agent. Examples of the surface treatment agent include vinylsilane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. Among them, from the viewpoint of obtaining the effects of the present invention significantly, vinylsilane coupling agents, (meth)acrylic coupling agents, and aminosilane coupling agents are preferred. Moreover, the surface treatment agent may be used alone or in any combination of two or more types.

Commercially available surface treatment agents include, for example, Shin-Etsu Chemical Co., Ltd.'s "KBM1003" (vinyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM503" (3-methacryloxypropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxy silane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc.

From the 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 specified range. Specifically, 100 parts by mass of the inorganic filler is preferably surface-treated with 0.2 parts by mass to 5 parts by mass of the surface treatment agent, more preferably with 0.2 parts by mass to 3 parts by mass, and more preferably with 0.3 parts by mass to 2 parts by mass.

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 the increase in the melt viscosity of the resin varnish and the melt viscosity in the sheet form, it is preferably 1 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.

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.

In order to obtain a significant effect of the present invention, the content of the inorganic filler is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

<(D) Curing Agent>
In addition to the above-mentioned components, the resin composition may further contain a curing agent as an optional component (D), except for those corresponding to the component (B).

As the (D) curing agent, a compound capable of reacting with the (A) component to cure the resin composition can be used, and examples thereof include active ester-based curing agents not corresponding to the (B) component, phenol-based curing agents, benzoxazine-based curing agents, carbodiimide-based curing agents, acid anhydride-based curing agents, amine-based curing agents, cyanate ester-based curing agents, maleimide-based curing agents, polyphenylene ether-based curing agents (styrene-based curing agents), etc. Among these, from the viewpoint of obtaining the effects of the present invention significantly, any of the phenol-based curing agents, carbodiimide-based curing agents, maleimide-based curing agents, and polyphenylene ether-based curing agents is preferable.

Examples of active ester curing agents include curing agents having one or more active ester groups in one molecule. Among them, active ester curing agents are preferably 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. The active ester curing agent 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, active ester curing agents obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester curing agents obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound are more preferred.

Examples of carboxylic acid compounds 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" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specific examples of preferred active ester-based curing agents include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, and active ester compounds containing a benzoylated product of phenol novolac. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The term "dicyclopentadiene-type diphenol structure" refers to a divalent structure consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", and "EXB-8000L-65TM" (manufactured by DIC Corporation); active ester compounds containing a naphthalene structure such as "HPC-8150-62T", "EXB-8100L-65T", "EXB-8150L-65T", "EXB9416-70BK", and "HPC-8900-70BK". (manufactured by DIC Corporation); "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing a benzoylated product of phenol novolac; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester-based hardener which is an acetylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester-based hardeners which are benzoylated products of phenol novolac; and the like.

Examples of phenol-based hardeners include hardeners 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. Among these, compounds having a hydroxyl group bonded to a benzene ring are preferred. From the viewpoint of heat resistance and water resistance, phenol-based hardeners having a novolac structure are preferred. From the viewpoint of adhesion, nitrogen-containing phenol-based hardeners are preferred, and triazine skeleton-containing phenol-based hardeners are more preferred. In particular, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, triazine skeleton-containing phenol novolac hardeners are preferred.

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

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

Specific examples of carbodiimide-based curing agents include "V-03", "V-05", and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.; and Stavaxol (registered trademark) P manufactured by Rhein Chemie.

Examples of acid anhydride curing agents include curing agents having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 4-methylhexahydrophthalic 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, and benzophenone. Examples of the acid anhydride include tetracarboxylic dianhydride, 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 resins in which styrene and maleic acid are copolymerized. Commercially available acid anhydride curing agents may be used, such as "MH-700" manufactured by New Japan Chemical Co., Ltd.

Amine-based curing agents include curing agents having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Among these, aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. 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), diphenyldiaminosulfone, 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, 2,2-bis(3-amino-4-hydroxyphenyl)-2,2'-diphenyl ... bis(4-aminophenoxy)phenyl)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 may be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", and "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd., and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

Examples of cyanate 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 phenol novolac-type multifunctional cyanate ester resins); "ULL-950S" (multifunctional cyanate ester resin); "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been converted to triazine and formed into a trimer); and others.

The maleimide-based curing agent is a compound containing a maleimide group represented by the following formula (D-1) in the molecule. The maleimide-based curing agent may be used alone or in combination of two or more kinds.

The number of maleimide groups per molecule of the maleimide-based curing agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more, from the viewpoint of significantly obtaining the desired effect of the present invention, and is preferably 10 or less, more preferably 6 or less, and particularly preferably 3 or less.

From the viewpoint of significantly achieving the desired effects of the present invention, the maleimide-based curing agent preferably has either an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and more preferably has an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

As the aliphatic hydrocarbon group, a divalent aliphatic hydrocarbon group is preferable, a divalent saturated aliphatic hydrocarbon group is more preferable, and an alkylene group is even more preferable. As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, an alkylene group having 1 to 6 carbon atoms is more preferable, an alkylene group having 1 to 3 carbon atoms is even more preferable, and a methylene group is particularly preferable.

As the aromatic hydrocarbon group, monovalent and divalent aromatic hydrocarbon groups are preferred, and aryl and arylene groups are more preferred. As the arylene group, an arylene group having 6 to 30 carbon atoms is preferred, an arylene group having 6 to 20 carbon atoms is more preferred, and an arylene group having 6 to 10 carbon atoms is even more preferred. Examples of such arylene groups include phenylene groups, naphthylene groups, anthracenylene groups, aralkyl groups, biphenylene groups, and biphenylaralkyl groups, among which phenylene groups, aralkyl groups, biphenylene groups, and biphenylaralkyl groups are preferred, and phenylene groups, aralkyl groups, and biphenylene groups are more preferred. As the aryl group, an aryl group having 6 to 30 carbon atoms is preferred, an aryl group having 6 to 20 carbon atoms is more preferred, an aryl group having 6 to 10 carbon atoms is even more preferred, and a phenyl group is particularly preferred.

In the maleimide-based curing agent, in order to obtain the desired effect of the present invention significantly, it is preferable that the nitrogen atom of the maleimide group is directly bonded to a monovalent or divalent aromatic hydrocarbon group. Here, "directly" means that there is no other group between the nitrogen atom of the maleimide group and the aromatic hydrocarbon group.

式（Ｄ－２）中、Ｒ^３１及びＲ^３６はマレイミド基を表し、Ｒ^３２、Ｒ^３３、Ｒ^３４及びＲ^３５は、それぞれ独立に水素原子、アルキル基、又はアリール基を表し、Ｄはそれぞれ独立に２価の芳香族基を表す。ｍ１及びｍ２はそれぞれ独立に１～１０の整数を表し、ａは１～１００の整数を表す。 The maleimide-based curing agent preferably has a structure represented by the following formula (D-2).

In formula (D-2), R ³¹ and R ³⁶ represent a maleimide group, R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represent a hydrogen atom, an alkyl group or an aryl group, and D each independently represents a divalent aromatic group. m1 and m2 each independently represent an integer of 1 to 10, and a represents an integer of 1 to 100.

In formula (D-2), R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represent a hydrogen atom, an alkyl group or an aryl group, and preferably a hydrogen atom.

As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, and an alkyl group having 1 to 3 carbon atoms is even more preferable. The alkyl group may be linear, branched, or cyclic. Examples of such alkyl groups include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and an isopropyl group.

The aryl group is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms. The aryl group may be a single ring or a condensed ring. Examples of such aryl groups include a phenyl group, a naphthyl group, and an anthracenyl group.

The alkyl group and the aryl group may have a substituent. Examples of the substituent include a halogen atom, -OH, -O-C _1-6 alkyl group, -N(C _1-10 alkyl group) ₂ , a C _1-10 alkyl group, a C _6-10 aryl group, -NH ₂ , -CN, -C(O)O-C _1-10 alkyl group, -COOH, -C(O)H, and -NO _2. Here, the term "C _p-q " (p and q are positive integers, and p<q is satisfied) indicates that the number of carbon atoms in the organic group described immediately after this term is p to q. For example, the expression "C _1-10 alkyl group" indicates an alkyl group having 1 to 10 carbon atoms. These substituents may be bonded to each other to form a ring, and the ring structure also includes a spiro ring and a fused ring.

D in formula (D-2) represents a divalent aromatic group. Examples of the divalent aromatic group include a phenylene group, a phthalene group, an anthracenylene group, an aralkyl group, a biphenylene group, and a biphenylaralkyl group. Among them, a biphenylene group and a biphenylaralkyl group are preferable, and a biphenylene group is more preferable. The divalent aromatic group may have a substituent. The substituent is the same as the substituent that the alkyl group represented by R ³² in general formula (D-2) may have.

m1 and m2 each independently represent an integer from 1 to 10, preferably 1 to 6, more preferably 1 to 3, even more preferably 1 to 2, and even more preferably 1.

a represents an integer from 1 to 100, preferably from 1 to 50, more preferably from 1 to 20, and even more preferably from 1 to 5.

式（Ｄ－３）中、Ｒ^３７及びＲ^３８はマレイミド基を表す。ａ１は１～１００の整数を表す。 As the maleimide-based curing agent, a resin represented by formula (D-3) is preferable.

In formula (D-3), R ³⁷ and R ³⁸ each represent a maleimide group, and a1 represents an integer of 1 to 100.

a1 is the same as a in formula (D-2), and the preferred range is also the same.

Such maleimide-based curing agents can be commercially available. For example, "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. can be used.

Another embodiment of the maleimide-based curing agent is a compound having at least one maleimide group in the molecule.

In this maleimide-based curing agent, it is preferable that the alkyl group having 5 or more carbon atoms and the alkylene group having 5 or more carbon atoms are directly bonded to the nitrogen atom of the maleimide group.

The number of maleimide groups per molecule of the maleimide curing agent may be one, but is preferably two or more, and is preferably ten or less, more preferably six or less, and particularly preferably three or less. By using a maleimide curing agent having two or more maleimide groups per molecule, the effects of the present invention can be significantly obtained.

一般式（Ｄ－４）中、Ｍは置換基を有していてもよい炭素原子数が５以上のアルキレン基を表し、Ｌは単結合又は２価の連結基を表す。 The maleimide-based curing agent is preferably represented by the following general formula (D-4).

In formula (D-4), M represents an alkylene group having 5 or more carbon atoms which may have a substituent, and L represents a single bond or a divalent linking group.

M represents an alkylene group having 5 or more carbon atoms which may have a substituent. The alkylene group of M is the same as the alkylene group having 5 or more carbon atoms described above. The substituent of M is the same as the substituent that may be possessed by the alkyl group represented by R ³² in general formula (D-2), and the substituent is preferably an alkyl group having 5 or more carbon atoms.

L represents a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, -C(=O)-, -C(=O)-O-, -NR ⁰ - (R ⁰ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms), an oxygen atom, a sulfur atom, C(=O)NR ⁰ -, a divalent group derived from phthalimide, a divalent group derived from pyromellitic diimide, and a group consisting of a combination of two or more of these divalent groups. The alkylene group, the alkenylene group, the alkynylene group, the arylene group, the divalent group derived from phthalimide, the divalent group derived from pyromellitic diimide, and a group consisting of a combination of two or more of these divalent groups may have an alkyl group having 5 or more carbon atoms as a substituent. The divalent group derived from phthalimide represents a divalent group derived from phthalimide, and specifically, is a group represented by the general formula (D-5). The divalent group derived from pyromellitic diimide refers to a divalent group derived from pyromellitic diimide, specifically, a group represented by general formula (D-6), in which "*" represents a bond.

The alkylene group as the divalent linking group in L is preferably an alkylene group having 1 to 50 carbon atoms, more preferably an alkylene group having 1 to 45 carbon atoms, and particularly preferably an alkylene group having 1 to 40 carbon atoms. This alkylene group may be linear, branched, or cyclic. Examples of such alkylene groups include methylethylene, cyclohexylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, heptadecylene, hexatriacontylene, groups having an octylene-cyclohexylene structure, groups having an octylene-cyclohexylene-octylene structure, and groups having a propylene-cyclohexylene-octylene structure.

The alkenylene group as the divalent linking group in L is preferably an alkenylene group having 2 to 20 carbon atoms, more preferably an alkenylene group having 2 to 15 carbon atoms, and particularly preferably an alkenylene group having 2 to 10 carbon atoms. This alkenylene group may be linear, branched, or cyclic. Examples of such alkenylene groups include a methylethylenylene group, a cyclohexenylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group.

The alkynylene group as the divalent linking group in L is preferably an alkynylene group having 2 to 20 carbon atoms, more preferably an alkynylene group having 2 to 15 carbon atoms, and particularly preferably an alkynylene group having 2 to 10 carbon atoms. This alkynylene group may be linear, branched, or cyclic. Examples of such alkynylene groups include a methylethynylene group, a cyclohexynylene group, a pentynylene group, a hexynylene group, a heptynylene group, and an octynylene group.

The arylene group as the divalent linking group in L is preferably an arylene group having 6 to 24 carbon atoms, more preferably an arylene group having 6 to 18 carbon atoms, even more preferably an arylene group having 6 to 14 carbon atoms, and even more preferably an arylene group having 6 to 10 carbon atoms. Examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenylene group.

The alkylene group, alkenylene group, alkynylene group, and arylene group which are the divalent linking group in L may have a substituent. The substituent is the same as the substituent which the alkyl group represented by R ³² in the general formula (D-2) may have, and is preferably an alkyl group having 5 or more carbon atoms.

Examples of groups consisting of a combination of two or more divalent groups in L include a divalent group consisting of a combination of an alkylene group, a divalent group derived from phthalimide, and an oxygen atom; a divalent group consisting of a combination of a divalent group derived from phthalimide, an oxygen atom, an arylene group, and an alkylene group; a divalent group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide; and the like. A group consisting of a combination of two or more divalent groups may form a ring such as a condensed ring by the combination of the respective groups. In addition, a group consisting of a combination of two or more divalent groups may have a repeating unit number of 1 to 10.

Among these, L in the general formula (D-4) is preferably an oxygen atom, an arylene group having 6 to 24 carbon atoms which may have a substituent, an alkylene group having 1 to 50 carbon atoms which may have a substituent, an alkyl group having 5 or more carbon atoms, a divalent group derived from phthalimide, a divalent group derived from pyromellitic diimide, or a divalent group consisting of a combination of two or more of these groups. Among these, L is more preferably an alkylene group; a divalent group having a structure of an alkylene group-phthalimide-derived divalent group-oxygen atom-phthalimide-derived divalent group; an alkylene group-phthalimide-derived divalent group-oxygen atom-arylene group-alkylene group-arylene group-oxygen atom-phthalimide-derived divalent group; or an alkylene-pyromellitic diimide-derived divalent group structure.

一般式（Ｄ－７）中、Ｍ^１はそれぞれ独立に置換基を有していてもよい炭素原子数が５以上のアルキレン基を表し、Ｚはそれぞれ独立に置換基を有していてもよい炭素原子数が５以上のアルキレン基又は置換基を有していてもよい芳香環を有する２価の基を表す。ｔは１～１０の整数を表す。 The maleimide-based curing agent represented by general formula (D-4) is preferably represented by general formula (D-7).

In formula (D-7), M ¹ 's each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent, Z's each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent or a divalent group having an aromatic ring which may have a substituent, and t represents an integer from 1 to 10.

Each ^M1 independently represents an alkylene group having 5 or more carbon atoms which may have a substituent. ^M1 is the same as M in formula (D-4).

Each Z independently represents an alkylene group having 5 or more carbon atoms which may have a substituent, or a divalent group having an aromatic ring which may have a substituent. The alkylene group in Z may be linear, branched, or cyclic, and is preferably a cyclic alkylene group having 5 or more carbon atoms which may have a substituent. The number of carbon atoms in the alkylene group is preferably 6 or more, more preferably 8 or more, preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. Examples of such alkylene groups include groups having an octylene-cyclohexylene structure, groups having an octylene-cyclohexylene-octylene structure, and groups having a propylene-cyclohexylene-octylene structure.

Examples of the aromatic ring in the divalent group having an aromatic ring represented by Z include a benzene ring, a naphthalene ring, an anthracene ring, a phthalimide ring, a pyromellitic diimide ring, and an aromatic heterocycle, and the like are mentioned, with a benzene ring, a phthalimide ring, and a pyromellitic diimide ring being preferred. That is, examples of the divalent group having an aromatic ring include a divalent group having a benzene ring which may have a substituent, a divalent group having a phthalimide ring which may have a substituent, and a divalent group having a pyromellitic diimide ring which may have a substituent. Examples of the divalent group having an aromatic ring include a group consisting of a combination of a divalent group derived from phthalimide and an oxygen atom; a group consisting of a combination of a divalent group derived from phthalimide, an oxygen atom, an arylene group, and an alkylene group; a group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide; a divalent group derived from pyromellitic diimide; a group consisting of a combination of a divalent group derived from phthalimide and an alkylene group; and the like. The above arylene group and alkylene group are the same as the arylene group and alkylene group in the divalent linking group represented by L in general formula (F-4).

The alkylene group and the divalent group having an aromatic ring represented by Z may have a substituent. The substituent is the same as the substituent that the alkyl group represented by R ³² in the general formula (D-2) may have.

Specific examples of the group represented by Z include the following groups: In the formula, "*" represents a bond.

一般式（Ｄ－８）中、Ｍ^２及びＭ^３はそれぞれ独立に置換基を有していてもよい炭素原子数が５以上のアルキレン基を表し、Ｒ^４０はそれぞれ独立に、酸素原子、アリーレン基、アルキレン基、又はこれらの基の２以上の組み合わせからなる２価の基を表す。ｔ１は１～１０の整数を表す。
一般式（Ｄ－９）中、Ｍ^４、Ｍ^６及びＭ^７はそれぞれ独立に置換基を有していてもよい炭素原子数が５以上のアルキレン基を表し、Ｍ^５はそれぞれ独立に置換基を有していてもよい芳香環を有する２価の基を表し、Ｒ^４１及びＲ^４２はそれぞれ独立に炭素原子数が５以上のアルキル基を表す。ｔ２は０～１０の整数を表し、ｕ１及びｕ２はそれぞれ独立に０～４の整数を表す。 The maleimide curing agent represented by general formula (D-4) is preferably any one of a maleimide curing agent represented by general formula (D-8) and a maleimide curing agent represented by general formula (D-9).

In formula (D-8), ^M2 and ^M3 each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent, ^R40 each independently represent an oxygen atom, an arylene group, an alkylene group, or a divalent group consisting of a combination of two or more of these groups, and t1 represents an integer from 1 to 10.
In formula (D-9), ^M4 , ^M6 , and ^M7 each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent, ^M5 each independently represent a divalent group having an aromatic ring which may have a substituent, ^R41 and ^R each independently represent an alkyl group having 5 or more carbon atoms, t2 represents an integer of 0 to 10, and u1 and u2 each independently represent an integer of 0 to 4.

^M2 and ^M3 each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent. ^M2 and ^M3 are the same as the alkylene group having 5 or more carbon atoms represented by M in general formula (D-4), and are preferably a hexatriacontylene group.

Each R ⁴⁰ independently represents an oxygen atom, an arylene group, an alkylene group, or a group consisting of a combination of two or more of these divalent groups. The arylene group and the alkylene group are the same as the arylene group and the alkylene group in the divalent linking group represented by L in the general formula (F-4). R ⁴⁰ is preferably an oxygen atom or a group consisting of a combination of two or more of these divalent groups.

Examples of the group consisting of a combination of two or more divalent groups in ^R40 include a combination of an oxygen atom, an arylene group, and an alkylene group. Specific examples of the group consisting of a combination of two or more divalent groups include the following groups. In the formula, "*" represents a bond.

M ⁴ , M ⁶ and M ⁷ each independently represent an alkylene group having 5 or more carbon atoms which may have a substituent. M ⁴ , M ⁶ and M ⁷ are the same as the alkylene group having 5 or more carbon atoms which may have a substituent represented by M in general formula (D-4), and are preferably a hexylene group, a heptylene group, an octylene group, a nonylene group or a decylene group, and more preferably an octylene group.

M ⁵ each independently represents a divalent group having an aromatic ring which may have a substituent. M ⁵ is the same as the divalent group having an aromatic ring which may have a substituent represented by Z in the general formula (D-7), and is preferably a group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide; a group consisting of a combination of a divalent group derived from phthalimide and an alkylene group, and more preferably a group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide. The arylene group and alkylene group are the same as the arylene group and alkylene group in the divalent linking group represented by L in the general formula (D-4).

Specific examples of the group represented by ^M5 include the following groups: In the formula, "*" represents a bond.

R ⁴¹ and R ⁴² each independently represent an alkyl group having 5 or more carbon atoms. R ⁴¹ and R ⁴² are the same as the alkyl group having 5 or more carbon atoms described above, and are preferably a hexyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group, and more preferably a hexyl group or an octyl group.

u1 and u2 each independently represent an integer from 1 to 15, preferably an integer from 1 to 10.

Specific examples of the maleimide-based curing agent include the following compounds (D1) to (D3). However, the maleimide-based curing agent is not limited to these specific examples. In the formula, v represents an integer of 1 to 10.

Specific examples of maleimide-based curing agents include "BMI1500" (compound of formula (D1)), "BMI1700" (compound of formula (D2)), and "BMI689" (compound of formula (D3)), all manufactured by DMI Corporation.

From the viewpoint of significantly obtaining the desired effect of the present invention, the maleimide group equivalent of the maleimide-based curing agent is preferably 50 g/eq. to 2000 g/eq., more preferably 100 g/eq. to 1000 g/eq., and even more preferably 150 g/eq. to 500 g/eq. The maleimide group equivalent is the mass of the maleimide-based curing agent containing one equivalent of maleimide group.

（＊は結合手を表す。） The polyphenylene ether-based curing agent is a curing agent having a vinylphenyl group, which is a group having the structure shown below.

(* represents a bond.)

In order to obtain a cured product with a low dielectric tangent, it is preferable that the polyphenylene ether curing agent has two or more vinyl phenyl groups per molecule.

The polyphenylene ether curing agent preferably has a cyclic structure from the viewpoint of obtaining a cured product with a low dielectric tangent. The cyclic structure is preferably a divalent cyclic group. The divalent cyclic group may be either a cyclic group containing an alicyclic structure or a cyclic group containing an aromatic ring structure. In addition, the polyphenylene ether curing agent may have a plurality of divalent cyclic groups.

From the viewpoint of significantly obtaining the desired effect of the present invention, the divalent cyclic group is preferably a 3-membered ring or more, more preferably a 4-membered ring or more, and even more preferably a 5-membered ring or more, and is preferably a 20-membered ring or less, more preferably a 15-membered ring or less, and even more preferably a 10-membered ring or less. In addition, the divalent cyclic group may be a monocyclic structure or a polycyclic structure.

The ring in the divalent cyclic group may have a ring skeleton formed by heteroatoms in addition to carbon atoms. Examples of heteroatoms include oxygen atoms, sulfur atoms, and nitrogen atoms, with oxygen atoms being preferred. The ring may have one heteroatom or two or more heteroatoms.

（２価の基（ｉ）、（ｉｉ）中、Ｒ^５１、Ｒ^５２、Ｒ^５５、Ｒ^５６、Ｒ^５７、Ｒ^６１、及びＲ^６２は、それぞれ独立にハロゲン原子、炭素原子数が６以下のアルキル基、又はフェニル基を表し、Ｒ^５３、Ｒ^５４、Ｒ^５８、Ｒ^５９、及びＲ^６０は、それぞれ独立に水素原子、ハロゲン原子、炭素原子数６以下のアルキル基、又はフェニル基を表す。） Specific examples of the divalent cyclic group include the following divalent groups (i) and (ii).

(In the divalent groups (i) and (ii), R ⁵¹ , R ⁵² , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ , R ⁶¹ , and R ⁶² each independently represent a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, and R ⁵³ , R ⁵⁴ , R ⁵⁸ , R ⁵⁹ , and R ⁶⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.)

Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Examples of alkyl groups having 6 or less carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and are preferably methyl. ^{R 51} , R ⁵² , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ , R ⁶¹ , and R ⁶² are preferably methyl groups. R ⁵³ , R ⁵⁴ , R ⁵⁸ , R ⁵⁹ , and R ⁶⁰ are preferably hydrogen atoms or methyl groups.

（式（Ｄ４）中、Ｒ^７１、Ｒ^７２、Ｒ^７５、Ｒ^７６、Ｒ^７７、Ｒ^８１、Ｒ^８２、Ｒ^８５及びＲ^８６は、それぞれ独立にハロゲン原子、炭素原子数が６以下のアルキル基、又はフェニル基を表し、Ｒ^７３、Ｒ^７４、Ｒ^７８、Ｒ^７９、Ｒ^８０、Ｒ^８３及びＲ^８４は、それぞれ独立に水素原子、ハロゲン原子、炭素原子数６以下のアルキル基、又はフェニル基を表す。ｄ１及びｄ２は、０～３００の整数を表す。但し、ｄ１及びｄ２の一方は０である場合を除く。） In addition, the divalent cyclic group may be a combination of a plurality of divalent cyclic groups. Specific examples of the combination of divalent cyclic groups include the divalent cyclic groups represented by the following formula (D4).

(In formula (D4), R ⁷¹ , R ⁷² , R ⁷⁵ , R ⁷⁶ , R ⁷⁷ , R ⁸¹ , R ⁸² , R ⁸⁵ and R ⁸⁶ each independently represent a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group; R ⁷³ , R ⁷⁴ , R ⁷⁸ , R ⁷⁹ , R ⁸⁰ , R ⁸³ and R ⁸⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group; d1 and d2 each independently represent an integer of 0 to 300, except for the case where one of d1 and d2 is 0.)

R ⁷¹ , R ⁷² , R ⁸⁵ and R ⁸⁶ are the same as R ⁵¹ in formula (i). R ⁷³ , R ⁷⁴ , R ⁸³ and R ⁸⁴ are the same as R ⁵³ in formula (i). R ⁷⁵ , R ⁷⁶ , R ⁷⁷ , R ⁸¹ and R ⁸² are the same as R ⁵⁵ in formula (ii). R ⁷⁸ , R ⁷⁹ and R ⁸⁰ are the same as R ⁵⁸ in formula (ii).

d1 and d2 represent integers from 0 to 300, except when one of d1 and d2 is 0. d1 and d2 preferably represent integers from 1 to 100, more preferably from 1 to 50, and even more preferably from 1 to 10. d1 and d2 may be the same or different.

The divalent cyclic group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an arylalkyl group, a silyl group, an acyl group, an acyloxy group, a carboxy group, a sulfo group, a cyano group, a nitro group, a hydroxy group, a mercapto group, and an oxo group. An alkyl group is preferable.

The vinylphenyl group may be directly bonded to the divalent cyclic group, or may be bonded via a divalent linking group. Examples of the divalent linking group include alkylene groups, alkenylene groups, arylene groups, heteroarylene groups, -C(=O)O-, -O-, -NHC(=O)-, -NC(=O)N-, -NHC(=O)O-, -C(=O)-, -S-, -SO-, -NH-, and the like, and may be groups in which a plurality of these are combined. As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, an alkylene group having 1 to 6 carbon atoms is more preferable, an alkylene group having 1 to 5 carbon atoms, or an alkylene group having 1 to 4 carbon atoms is even more preferable. The alkylene group may be linear, branched, or cyclic. Examples of such alkylene groups include methylene, ethylene, propylene, butylene, pentylene, hexylene, and 1,1-dimethylethylene groups, with methylene, ethylene, and 1,1-dimethylethylene being preferred. As the alkenylene group, an alkenylene group having 2 to 10 carbon atoms is preferred, an alkenylene group having 2 to 6 carbon atoms is more preferred, and an alkenylene group having 2 to 5 carbon atoms is even more preferred. As the arylene group and heteroarylene group, an arylene group or heteroarylene group having 6 to 20 carbon atoms is preferred, and an arylene group or heteroarylene group having 6 to 10 carbon atoms is more preferred. As the divalent linking group, an alkylene group is preferred, with a methylene group being preferred.

（式（Ｄ－１０）中、Ｒ^９１及びＲ^９２はそれぞれ独立に２価の連結基を表す。環Ｂ１は、２価の環状基を表す。） The polyphenylene ether-based curing agent is preferably represented by the following formula (D-10).

(In formula (D-10), R ⁹¹ and R ⁹² each independently represent a divalent linking group. Ring B1 represents a divalent cyclic group.)

R ⁹¹ and R ⁹² each independently represent a divalent linking group. The divalent linking group is the same as the divalent linking group described above.

Ring B1 represents a divalent cyclic group. Ring B1 is the same as the divalent cyclic group described above.

Ring B1 may have a substituent. The substituent is the same as the substituent that the divalent cyclic group may have.

（ｑ１は、式（Ｄ４）中のｄ１と同じであり、ｑ１は、式（Ｄ４）中のｄ２と同じである。） Specific examples of polyphenylene ether-based curing agents are shown below, but the present invention is not limited to these.

(q1 is the same as d1 in formula (D4), and q1 is the same as d2 in formula (D4).)

The polyphenylene ether-based hardener may be a commercially available product, such as "OPE-2St" manufactured by Mitsubishi Gas Chemical Company, Inc. One type of polyphenylene ether-based hardener may be used alone, or two or more types may be used in combination.

The number average molecular weight of the polyphenylene ether-based curing agent is preferably 3000 or less, more preferably 2500 or less, even more preferably 2000 or less, or 1500 or less, from the viewpoint of significantly obtaining the desired effects of the present invention. The lower limit is preferably 100 or more, more preferably 300 or more, even more preferably 500 or more, or 1000 or more. The number average molecular weight is the number average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC).

The content of (D) the curing agent is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of non-volatile components in the resin composition, in order to obtain a significant effect of the present invention.

When the number of epoxy groups in component (A) is taken as 1, the number of active groups in the (D) curing agent is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 2 or less, more preferably 1.8 or less, even more preferably 1.6 or less, and particularly preferably 1.4 or less. Here, the "number of active groups in the (D) curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the (D) curing agent present in the resin composition by the active group equivalent. When the number of epoxy groups in component (A) is taken as 1, the desired effect of the present invention can be significantly obtained by having the number of active groups in the (D) curing agent within the above range.

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

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

Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc., with triphenylphosphine and tetrabutylphosphonium decanoate being preferred.

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, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred.

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, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl Examples of the imidazole compounds include 1-dodecyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

Commercially available imidazole curing accelerators may be used, such as "P200-H50" manufactured by Mitsubishi Chemical Corporation.

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, Examples include o[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, and dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

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 octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

From the viewpoint of significantly achieving the desired effect of the present invention, the content of component (E) is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, and is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on 100% by mass of non-volatile components in the resin composition.

<(F) Other Additives>
The resin composition may further contain other additives as optional components in addition to the above-mentioned components. Examples of such additives include resin additives such as thermoplastic resins, flame retardants, thickeners, defoamers, leveling agents, and adhesion promoters. These additives may be used alone or in combination of two or more. The content of each additive can be appropriately set by a person skilled in the art.

The method for preparing the resin composition of the present invention is not particularly limited, and examples include a method in which the blending components are mixed and dispersed using a rotary mixer, etc., with the addition of a solvent, etc., as necessary.

<Physical properties and applications of resin composition>
The resin composition includes the (A) component and the (B) component. This can suppress the occurrence of unevenness that occurs when a resin composition layer containing the resin composition is laminated. In addition, in the present invention, it is also possible to obtain a cured product that is usually excellent in plating peel strength, copper foil adhesion, and copper foil adhesion after HAST, and further has low dielectric properties and low arithmetic average roughness (Ra).

The resin composition exhibits the characteristic of being able to suppress the occurrence of unevenness when a resin composition layer containing the resin composition is laminated. Specifically, this is performed according to the method described in the Examples below. At this time, usually no unevenness is observed at all, resulting in a completely uniform surface. Details of the evaluation of unevenness after lamination can be measured according to the method described in the Examples below.

The resin composition is thermally cured at 130°C for 30 minutes, and then at 170°C for 30 minutes. The roughened surface of the cured product is then subjected to a roughening treatment. The roughened surface usually exhibits a low arithmetic mean roughness (Ra). Thus, the cured product provides an insulating layer with a low arithmetic mean roughness. The arithmetic mean roughness is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. On the other hand, the lower limit of the arithmetic mean roughness may be 30 nm or more. The arithmetic mean roughness (Ra) can be measured according to the method described in the examples below.

The cured product obtained by thermally curing the resin composition at 190°C for 90 minutes usually exhibits low dielectric properties (dielectric loss tangent). Thus, the cured product produces an insulating layer with a low dielectric loss tangent. The dielectric loss tangent is preferably 0.005 or less, more preferably 0.004 or less, and even more preferably 0.003 or less. The lower limit of the dielectric loss tangent may be 0.0001 or more. The dielectric loss tangent can be measured according to the method described in the examples below.

The resin composition is thermally cured at 130°C for 30 minutes, then at 170°C for 30 minutes, and then at 200°C for 90 minutes, and the cured product usually exhibits the property of excellent peel strength between the resin composition and the conductor layer (plated conductor layer) formed by plating. Therefore, the cured product provides an insulating layer with excellent peel strength between the resin composition and the plated conductor layer. The peel strength is preferably 0.3 kgf/cm or more, more preferably 0.35 kgf/cm or more, and even more preferably 0.4 kgf/cm or more. The upper limit of the peel strength may be 10 kgf/cm or less. The peel strength of the plated conductor layer can be measured according to the method described in the examples below.

The resin composition is thermally cured at 130°C for 30 minutes, then at 170°C for 30 minutes, and then at 200°C for 90 minutes, and the cured product usually exhibits excellent peel strength (copper foil adhesion) between the resin composition and the copper foil. Therefore, the cured product provides an insulating layer with excellent peel strength between the resin composition and the copper foil. The peel strength is preferably 0.3 kgf/cm or more, more preferably 0.4 kgf/cm or more, and even more preferably 0.5 kgf/cm or more. The upper limit of the peel strength may be 10 kgf/cm or less. The copper foil adhesion can be measured according to the method described in the examples below.

The resin composition is thermally cured at 130°C for 30 minutes and then at 170°C for 30 minutes. The cured product usually exhibits excellent peel strength (copper foil adhesion after HAST) between the resin composition and the copper foil after a HAST test (130°C, 85% RH, 100 hours). Therefore, the cured product provides an insulating layer with excellent peel strength between the resin composition and the copper foil after HAST. The copper foil adhesion after HAST is preferably 0.15 kgf/cm or more, more preferably 0.2 kgf/cm or more, and even more preferably 0.25 kgf/cm or more. The upper limit of the copper foil adhesion after HAST can be 10 kgf/cm or less. The copper foil adhesion after HAST can be measured according to the method described in the examples below.

The resin composition of the present invention can suppress the occurrence of unevenness when a resin composition layer containing the resin composition is laminated. Therefore, the resin composition of the present invention can be suitably used as a resin composition for insulation purposes. Specifically, it can be suitably used as a resin composition for forming an insulating layer (resin composition for forming an insulating layer for forming a conductor layer) to form a conductor layer (including a rewiring layer) formed on an insulating layer.

In addition, in the multilayer printed wiring board described below, the resin composition can be suitably used as a resin composition for forming an insulating layer of a multilayer printed wiring board (resin composition for forming an insulating layer of a multilayer printed wiring board) and as a resin composition for forming an interlayer insulating layer of a printed wiring board (resin composition for forming an interlayer insulating layer of a printed wiring board).

Furthermore, for example, when a semiconductor chip package is manufactured through the following steps (1) to (6), the resin composition of the present invention can be suitably used as a resin composition for a rewiring formation layer serving as an insulating layer for forming a rewiring layer (resin composition for forming a rewiring formation layer) and as a resin composition for sealing a semiconductor chip (resin composition for sealing a semiconductor chip). When a semiconductor chip package is manufactured, a rewiring layer may be further formed on the sealing layer.
(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.

[Resin sheet]
The resin sheet of the present invention includes a support and a resin composition layer formed from the resin composition of the present invention provided on the support.

The thickness of the resin composition layer is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less, from the 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 can usually be 5 μm or more.

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, and inexpensive polyethylene terephthalate is 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 other layers as necessary. Examples of such other layers include 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 the like and scratches on the surface of the resin composition layer.

The resin sheet can be produced, for example, by preparing a resin varnish by dissolving a resin composition in an organic solvent, applying this resin varnish onto a support using a die coater or the like, and then drying it to form a resin composition layer.

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

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

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

[Printed wiring board]
The printed wiring board of the present invention includes an insulating layer formed from a cured product of the resin composition of the present invention.

The printed wiring board can be produced, for example, by using the above-mentioned resin sheet by a method including the following steps (I) and (II).
(I) a step of laminating the resin sheet on the inner layer substrate so that the resin composition layer of the resin sheet is bonded to the inner layer substrate; and (II) a step of thermally 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 may be 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 "inner layer substrate" of the present invention. When the printed wiring board is a component-embedded circuit board, an inner layer substrate with a component embedded therein may be used.

The lamination of the inner layer substrate and the resin sheet can be carried out, 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 a pressure 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 thermally cured to form an insulating layer. The thermal curing conditions for the resin composition layer are not particularly limited, and conditions that are typically used when forming an insulating layer for a printed wiring board may be used.

For example, the thermal curing conditions for the resin composition layer vary depending on the type of resin composition, but 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 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) at a temperature of 50°C or more and less than 120°C (preferably 60°C or more and 115°C or less, and more preferably 70°C or more and 110°C or less).

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 (II) to (V) may be repeated as necessary to form a multilayer wiring board.

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 of a printed wiring board can be adopted. For example, the insulating layer can be roughened by performing 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. The swelling liquid used for the roughening treatment is not particularly limited, but examples thereof include an alkaline solution, a surfactant solution, etc., and preferably an alkaline solution, and as the alkaline solution, a sodium hydroxide solution or a potassium hydroxide solution is more preferable. Examples of commercially available swelling liquids include "Swelling Dip Securigans P", "Swelling Dip Securigans SBU", and "Swelling Dip Securigant P" manufactured by Atotech Japan. The swelling treatment using the swelling liquid is not particularly limited, but can be performed by, for example, 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 is not particularly limited, but examples thereof include 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 performed by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. In addition, the concentration of the permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by Atotech Japan. In addition, an acidic aqueous solution is preferable as the neutralizing solution used for the roughening treatment, and an example of a commercially available product is "Reduction Solution Securiganth P" manufactured by Atotech Japan. Treatment with a neutralizing solution can be performed by immersing the treated surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 1 to 30 minutes. From the viewpoint of workability, etc., a method in which the object that has been roughened with an oxidizing agent is immersed in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes is preferable.

In one embodiment, the arithmetic mean roughness (Ra) of the insulating layer surface after the roughening treatment is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. There is no particular lower limit, but it is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more. The arithmetic mean roughness (Ra) of the insulating layer surface can be measured using a non-contact surface roughness meter.

Step (V) is a step of forming a 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, and from the viewpoint of ease of production, it is preferable to form the conductor layer by a semi-additive method. Below, an example of forming the 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.

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

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 semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. A "conductive portion" is a portion of a printed wiring board that transmits an electrical signal, and the portion may be either on the surface or embedded. There are no particular limitations on the semiconductor chip, so long as it is an electrical circuit element made of semiconductor material.

The method of mounting semiconductor chips when manufacturing semiconductor devices is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include wire bonding mounting, flip chip mounting, bumpless buildup layer (BBUL) mounting, anisotropic conductive film (ACF) mounting, non-conductive film (NCF) mounting, etc. Here, "bumpless buildup layer (BBUL) mounting" refers to "a mounting method in which a semiconductor chip is directly embedded in a recess in a printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board."

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

Synthesis Example 1: Synthesis of active ester compound (B-1)
In a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionating tube, and a stirrer, 320 g (2.0 mol) of 2,7-dihydroxynaphthalene, 184 g (1.7 mol) of benzyl alcohol, and 5.0 g of paratoluenesulfonic acid monohydrate were charged, and stirred at room temperature while blowing in nitrogen. The temperature was then raised to 150°C, and the mixture was stirred for 4 hours while distilling off the water produced. After the reaction was completed, 900 g of methyl isobutyl ketone and 5.4 g of a 20% aqueous sodium hydroxide solution were added for neutralization, and the aqueous layer was removed by separation, and the mixture was washed three times with 280 g of water. The methyl isobutyl ketone was removed under reduced pressure to obtain 460 g of a benzyl-modified naphthalene compound (A-1). The obtained benzyl-modified naphthalene compound (A-1) was a black solid, and had a hydroxyl equivalent of 180 g/equivalent.

203.0g of isophthalic acid chloride (molar number of acid chloride groups: 2.0 mol) and 1400g of toluene were charged into a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionating tube, and a stirrer, and the system was reduced in pressure and replaced with nitrogen to dissolve. Next, 72.4g (0.67 mol) of orthocresol and 240g of benzyl-modified naphthalene compound (A-1) (molar number of phenolic hydroxyl groups: 1.33 mol) were charged, and the system was reduced in pressure and replaced with nitrogen to dissolve. Then, 0.70g of tetrabutylammonium bromide was dissolved, and while applying a nitrogen gas purge, the system was controlled to 60°C or less, and 400g of 20% aqueous sodium hydroxide solution was dropped over 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was left to stand and separated, and the aqueous layer was removed. Water was then added to the toluene layer in which the reactants were dissolved, and the mixture was stirred and mixed for 15 minutes, then allowed to stand and separated to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Water was then removed by decanting to obtain an active ester compound (B-1) in a toluene solution state with a non-volatile content of 65% by mass. The active ester equivalent of the obtained active ester compound (B-1) was 238 g/eq.

<Synthesis Example 2: Synthesis of active ester compound (B-2)>
In a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionating tube, and a stirrer, 203.0 g of isophthalic acid chloride (molar number of acid chloride groups: 2.0 mol) and 1400 g of toluene were charged, and the system was purged with nitrogen under reduced pressure to dissolve. Next, 113.9 g (0.67 mol) of orthophenylphenol and 240 g of benzyl-modified naphthalene compound (A-1) (molar number of phenolic hydroxyl groups: 1.33 mol) were charged, and the system was purged with nitrogen under reduced pressure to dissolve. Thereafter, 0.70 g of tetrabutylammonium bromide was dissolved, and while purging with nitrogen gas, the system was controlled to 60°C or less, and 400 g of 20% aqueous sodium hydroxide solution was dropped over 3 hours. Then, stirring was continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was left to stand for liquid separation, and the aqueous layer was removed. Further, water was added to the toluene layer in which the reactant was dissolved, and the mixture was stirred and mixed for 15 minutes, and then the mixture was allowed to stand and separated to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by decanting to obtain an active ester compound (B-2) in the form of a toluene solution with a non-volatile content of 65% by mass. The active ester equivalent of the obtained active ester compound (B-2) was 206 g/eq.

Synthesis Example 3: Synthesis of active ester compound (B-3)
In a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionating tube, and a stirrer, 203.0 g of isophthalic acid chloride (molar number of acid chloride groups: 2.0 mol) and 1400 g of toluene were charged, and the system was substituted with nitrogen under reduced pressure to dissolve. Next, 132.7 g (0.67 mol) of styrenated phenol and 240 g of benzyl-modified naphthalene compound (A-1) (molar number of phenolic hydroxyl groups: 1.33 mol) were charged, and the system was substituted with nitrogen under reduced pressure to dissolve. Thereafter, 0.70 g of tetrabutylammonium bromide was dissolved, and while applying a nitrogen gas purge, the system was controlled to 60°C or less, and 400 g of 20% aqueous sodium hydroxide solution was dropped over 3 hours. Then, stirring was continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was left to stand for liquid separation, and the aqueous layer was removed. Further, water was added to the toluene layer in which the reactant was dissolved, and the mixture was stirred and mixed for 15 minutes, and then the mixture was allowed to stand and separated to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by decanting to obtain an active ester compound (B-3) in the form of a toluene solution with a non-volatile content of 65 mass %. The active ester equivalent of the obtained active ester compound (B-3) was 259 g/eq.

The active ester compound (B-1) to the active ester compound (B-3) were identified as follows. As a result of the identification, it was found that in the active ester compound (B-1), Ar ³¹ in the general formula (b-3) has a group represented by formula (1), in the active ester compound (B-2), Ar ³¹ in the general formula (b-3) has a group represented by formula (2), and in the active ester compound (B-3), Ar ³¹ in the general formula (b-3) has a group represented by formula (3) (n = 1 to 5).

<Example 1: Preparation of resin composition 1>
Epoxy resin solution A was obtained by dissolving 3 parts of an epoxy resin "ESN475V" (manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent: approximately 330 g/eq.) as component (A) and 7 parts of an epoxy resin "HP-4032-SS" (manufactured by DIC Corporation, epoxy equivalent: approximately 144 g/eq.) as component (A) in 10 parts of methyl ethyl ketone (MEK).
To the epoxy resin solution A, 25 parts of an active ester compound (B-1) as the component (B), 65 parts of spherical silica (average particle size 0.77 μm, manufactured by Admatechs Co., Ltd. "SO-C2") (hereinafter also referred to as "inorganic filler A") surface-treated with an amine-based alkoxysilane compound (manufactured by Shin-Etsu Chemical Co., Ltd. "KBM573") as the component (C) and 0.2 parts of an imidazole compound "1B2PZ" (manufactured by Shikoku Chemical Industry Co., Ltd.) as the component (E) were added, and the mixture was uniformly dispersed in a high-speed rotating mixer to prepare a resin varnish A.
The inorganic filler A had an average particle size of 0.5 μm and a specific surface area of 5.9 m ² /g.

<Example 2: Preparation of resin composition 2>
In Example 1, 25 parts of the active ester compound (B-1) was changed to 25 parts of the active ester compound (B-2).
Resin composition 2 was prepared in the same manner as in Example 1 except for the above.

<Example 3: Preparation of resin composition 3>
In Example 1, 25 parts of the active ester compound (B-1) was changed to 25 parts of the active ester compound (B-3).
Resin composition 3 was prepared in the same manner as in Example 1 except for the above.

<Example 4: Preparation of resin composition 4>
In Example 1,
The amount of the active ester compound (B-1) was changed from 25 parts to 22 parts.
The amount of imidazole compound (1B2PZ manufactured by Shikoku Chemical Industry Co., Ltd.) was changed from 0.2 parts to 0.02 parts.
Two parts of a triazine-containing cresol novolak resin (DIC's "LA-3018-50P", a methoxypropanol solution with a solid content of 50% by mass) and one part of a carbodiimide resin (Nisshinbo Chemical's "V-03", active group equivalent of approximately 216, a toluene solution with a solid content of 50% by mass) were used.
Resin composition 4 was prepared in the same manner as in Example 1 except for the above.

Example 5: Preparation of resin composition 5
In Example 2,
The amount of the active ester compound (B-2) was changed from 25 parts to 22 parts.
The amount of imidazole compound (1B2PZ manufactured by Shikoku Chemical Industry Co., Ltd.) was changed from 0.2 parts to 0.02 parts.
Two parts of a triazine-containing cresol novolak resin (DIC's "LA-3018-50P", a methoxypropanol solution with a solid content of 50% by mass) and one part of a carbodiimide resin (Nisshinbo Chemical's "V-03", active group equivalent of approximately 216, a toluene solution with a solid content of 50% by mass) were used.
Resin composition 5 was prepared in the same manner as in Example 2 except for the above.

<Example 6: Preparation of resin composition 6>
In Example 3,
The amount of the active ester compound (B-3) was changed from 25 parts to 22 parts.
The amount of imidazole compound (1B2PZ manufactured by Shikoku Chemical Industry Co., Ltd.) was changed from 0.2 parts to 0.02 parts.
Two parts of a triazine-containing cresol novolak resin (DIC's "LA-3018-50P", a methoxypropanol solution with a solid content of 50% by mass) and one part of a carbodiimide resin (Nisshinbo Chemical's "V-03", active group equivalent of approximately 216, a toluene solution with a solid content of 50% by mass) were used.
Resin composition 6 was prepared in the same manner as in Example 3 except for the above.

<Example 7: Preparation of resin composition 7>
In Example 1,
The amount of the active ester compound (B-1) was changed from 25 parts to 22 parts.
The amount of imidazole compound (1B2PZ manufactured by Shikoku Chemical Industry Co., Ltd.) was changed from 0.2 parts to 0.02 parts.
Using 2 parts of triazine-containing cresol novolak resin (DIC "LA-3018-50P", a methoxypropanol solution with a solid content of 50% by mass),
Two parts of vinylbenzyl resin ("OPE-2St" manufactured by Mitsubishi Gas Chemical Co., Ltd., a toluene solution with a solid content of 65% by mass) was used.
Resin composition 7 was prepared in the same manner as in Example 1 except for the above.

<Example 8: Preparation of resin composition 8>
In Example 7,
Two parts of vinylbenzyl resin ("OPE-2St" manufactured by Mitsubishi Gas Chemical Company, Inc., a toluene solution having a solid content of 65% by mass) was changed to two parts of maleimide resin ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., a toluene/MEK solution having a solid content of 70% by mass).
Resin composition 8 was prepared in the same manner as in Example 7 except for the above.

<Example 9: Preparation of resin composition 9>
In Example 7,
Two parts of vinylbenzyl resin ("OPE-2St" manufactured by Mitsubishi Gas Chemical Company, Inc., a toluene solution with a solid content of 65% by mass) was changed to one part of maleimide resin ("BMI-689" manufactured by DMI Corporation).
Resin composition 9 was prepared in the same manner as in Example 7 except for the above.

<Example 10: Preparation of resin composition 10>
In Example 7,
Two parts of vinylbenzyl resin ("OPE-2St" manufactured by Mitsubishi Gas Chemical Company, Inc., a toluene solution with a solid content of 65% by mass) was changed to one part of maleimide resin ("BMI-1500" manufactured by DMI Corporation).
Resin composition 10 was prepared in the same manner as in Example 7 except for the above.

<Comparative Example 1: Preparation of Resin Composition 11>
In Example 1, 25 parts of the active ester compound (B-1) was changed to 25 parts of another curing agent (active ester curing agent, manufactured by DIC Corporation, "HPC8150-62T", a toluene solution with a solid content of 62%).
Resin composition 11 was prepared in the same manner as in Example 1 except for the above.

<Comparative Example 2: Preparation of Resin Composition 12>
In Example 1, 25 parts of the active ester compound (B-1) was changed to 23 parts of another curing agent (active ester curing agent, manufactured by DIC Corporation, "HPC8000-65T", a toluene solution with a solid content of 65%).
Resin composition 12 was prepared in the same manner as in Example 1 except for the above.

Comparative Example 3: Preparation of Resin Composition 13
In Example 4, 22 parts of the active ester compound (B-1) was changed to 22 parts of another curing agent (active ester curing agent, manufactured by DIC Corporation, "HPC8150-62T", a toluene solution with a solid content of 62%).
Resin composition 13 was prepared in the same manner as in Example 4 except for the above.

<Comparative Example 4: Preparation of Resin Composition 14>
In Example 3, 22 parts of the active ester compound (B-2) was changed to 21 parts of another curing agent (active ester curing agent, manufactured by DIC Corporation, "HPC8000-65T", a toluene solution with a solid content of 65%).
Resin composition 14 was prepared in the same manner as in Example 3 except for the above.

<Evaluation of unevenness after lamination, arithmetic mean roughness, and measurement of peel strength of plated conductor layer>
(1) Preparation of resin sheet A having a resin composition layer thickness of 40 μm A polyethylene terephthalate film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) equipped with a release layer 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 A including a support and a resin composition layer.

(2) Preparation of Inner Layer Board Both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, board thickness 0.4 mm, Panasonic Corporation "R1515A") on which an inner layer circuit was formed was etched by 1 μm with a microetching agent (Mech Corporation "CZ8101") to roughen the copper surface.

(3) Lamination of resin sheet A Using a batch type vacuum pressure laminator (two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.), the resin composition layer was laminated on both sides of the inner layer substrate so that it 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, a heat press was performed at 100°C and a pressure of 0.5 MPa for 60 seconds.

(4) Thermal curing of resin composition layer The inner layer substrate laminated with resin sheet A 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 to thermally cure the resin composition layer and form an insulating layer. The support was then peeled off to obtain a cured substrate A having the insulating layer, the inner layer substrate, and the insulating layer in this order.

(5) Evaluation of Unevenness after Lamination The surface uniformity of the portions where the resin sheet A was laminated (the surfaces opposite the laminated plate) on both sides of the cured substrate A was visually observed and evaluated as follows.
◯: No unevenness was observed at all, and the surface was completely uniform.
×: Uneven areas were observed in the area where the resin sheet was laminated.

(6) Roughening Treatment A desmear treatment was carried out as a roughening treatment on the cured substrate A. As the desmear treatment, the following wet desmear treatment was carried out.

(Wet desmear treatment)
The cured substrate A was immersed in a swelling liquid (Atotech Japan's "Swelling Dip Securigant P", an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60° C. for 5 minutes, and then immersed in an oxidizing agent solution (Atotech Japan's "Concentrate Compact CP", an aqueous solution of potassium permanganate at about 6% and sodium hydroxide at about 4%) at 80° C. for 20 minutes. It was then immersed in a neutralizing liquid (Atotech Japan's "Reduction Solution Securigant P", an aqueous solution of sulfuric acid) at 40° C. for 5 minutes, and then dried at 80° C. for 15 minutes.

(7) Measurement of arithmetic mean roughness (Ra) of insulating layer surface after roughening treatment The arithmetic mean roughness (Ra) of the insulating layer surface after roughening treatment was determined using a non-contact surface roughness meter (WYKO NT3300 manufactured by Bruker Corp.) in VSI mode with a 50x lens to obtain a measurement range of 121 μm×92 μm. The measurements were performed by calculating the average value of 10 points.

(8) Formation of Conductive Layer According to the semi-additive method, a conductive layer was formed on the roughened surface of the insulating layer. That is, the substrate after the roughening treatment 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. Next, after heating at 150 ° C for 30 minutes and performing an annealing treatment, an etching resist was formed, and a pattern was formed by etching. Then, copper sulfate electrolytic plating was performed to form a conductive layer having a thickness of 25 μm, and an annealing treatment was performed at 190 ° C for 60 minutes. The obtained substrate is called "evaluation substrate B".

(9) Measurement of peel strength of plated conductor layer The peel strength of the insulating layer and conductor layer was measured in accordance with the Japanese Industrial Standards (JIS C6481). Specifically, a cut was made in the conductor layer of evaluation board B, measuring 10 mm wide and 100 mm long, and one end of the cut was peeled off and held with a gripper. The load (kgf/cm) when 35 mm was peeled off in the vertical direction at a speed of 50 mm/min at room temperature was measured to determine the peel strength. A tensile tester ("AC-50C-SL" manufactured by TSE) was used for the measurement.

<Evaluation of dielectric properties>
The dielectric properties were evaluated by measuring the dielectric loss tangent (Df). Specifically, a cured product B for evaluation was prepared as follows, and the dielectric loss tangent (Df) was measured.

The resin sheet A obtained in the examples and comparative examples was cured in an oven at 190°C for 90 minutes. The support was peeled off from the resin sheet A taken out of the oven to obtain a cured resin composition layer. The cured product was cut into a length of 80 mm and a width of 2 mm to be used as cured product B for evaluation.

For each evaluation cured product B, the dielectric tangent value (Df value) was measured by the cavity resonance perturbation method using an Agilent Technologies "HP8362B" at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. Measurements were performed on two test pieces, and the average was calculated.

<Measurement of copper foil adhesion (peel strength)>
(1) Preparation of Adhesion Evaluation Substrate A glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic "R1515A") was prepared as an inner layer substrate. The copper foil on the surface of this inner layer substrate was completely removed by etching. It was then dried at 190° C. for 30 minutes.

The resin sheet A obtained in the above-mentioned examples and comparative examples was laminated on both sides of the inner layer substrate 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 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.

Next, the laminated resin sheet A was heat-pressed at atmospheric pressure at 100°C and a pressure of 0.5 MPa for 60 seconds to smooth it. The support was then peeled off to obtain an "intermediate laminate I" containing a resin composition layer, an inner layer substrate, and a resin composition layer in this order.

On the other hand, copper foil with a shiny surface (thickness 35 μm, Mitsui Kinzoku Co., Ltd. "3EC-III") was prepared. The shiny surface of this copper foil was roughened by etching it with a microetching agent (Mec Co., Ltd. "CZ8101") with a copper etching amount of 1 μm. The copper foil obtained in this way is called "roughened copper foil."

This roughened copper foil was laminated to both sides of intermediate laminate I so that the roughened surface of the roughened copper foil was bonded to the resin composition layer of intermediate laminate I. This lamination was performed under the same conditions as the lamination of the resin sheet to the inner layer substrate described above. In this way, an "intermediate laminate II" was obtained that contained the roughened copper foil, resin composition layer, inner layer substrate, resin composition layer, and roughened copper foil in this order.

This intermediate laminate II was placed in a 100°C oven and heated for 30 minutes, then transferred to a 170°C oven and heated for 30 minutes. Next, the intermediate laminate II was removed from the oven to room temperature and placed in a 200°C oven and heated for an additional 90 minutes. This resulted in thermal curing of the resin composition layer, and an "evaluation substrate C" was obtained that contained, in this order, the roughened copper foil, an insulating layer as a cured product of the resin composition layer, an inner layer substrate, an insulating layer as a cured product of the resin composition layer, and the roughened copper foil. In this evaluation substrate C, the roughened copper foil corresponds to the conductor layer.

(2) Measurement of Copper Foil Adhesion (Peel Strength) The peel strength between the roughened copper foil and the insulating layer was measured using the evaluation substrate C. This peel strength measurement was performed in accordance with JIS C6481. Specifically, the peel strength measurement was performed by the following procedure.

A cut was made in the roughened copper foil of evaluation board C, surrounding a rectangular portion 10 mm wide and 100 mm long. One end of this rectangular portion was peeled off and gripped with a gripping tool (Autocom type testing machine "AC-50C-SL" manufactured by TSE Corporation). A range of 35 mm in length of the rectangular portion was peeled off vertically, and the load (kgf/cm) at the time of peeling was measured as the peel strength. The peeling was performed at room temperature at a speed of 50 mm/min. Furthermore, the copper foil adhesion (peel strength) was measured again after the HAST test (130°C, humidity 85% RH, 100 hours).

＊表中、「（Ｃ）成分の含有量」は、樹脂組成物中の不揮発成分を１００質量％とした場合の（Ｃ）成分の含有量を表す。

*In the table, "Content of component (C)" represents the content of component (C) when the total amount of non-volatile components in the resin composition is 100 mass %.

In Examples 1 to 10, it has been confirmed that even when components (C) to (E) are not included, the results are similar to those of the above examples, although to a lesser extent.

Claims (8)

(A) an epoxy resin,
(B) an active ester compound represented by the following general formula (b- 3 ), and (C) a resin composition containing an inorganic filler,
The content of the component (A) is 1% by mass or more when the total amount of non-volatile components in the resin composition is 100% by mass,
The content of the component (C) is 50% by mass or more, based on 100% by mass of the non-volatile components in the resin composition;
The resin composition is cured at 190°C for 90 minutes, and the cured product has a dielectric tangent value of 0.002 or less at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C according to a cavity resonance perturbation method.

(In general formula (b- 3 ),
Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2), or a group represented by formula (3);

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5. )
a2 represents an integer of 1 to 6, c2 represents an integer of 1 to 5, and each d independently represents an integer of 0 to 6 . (A) an epoxy resin ,
( B) an active ester compound represented by the following general formula (b- 3 ) , and
(C) a resin composition containing an inorganic filler ,
The content of the component (A) is 1% by mass or more when the total amount of non-volatile components in the resin composition is 100% by mass,
A resin composition, wherein the content of the component (C) is 50% by mass or more, relative to 100% by mass of non-volatile components in the resin composition .

(In general formula (b- 3 ),
Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2) , or a group represented by formula (3) ;

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5.)
a2 represents an integer of 1 to 6, c2 represents an integer of 1 to 5, and each d independently represents an integer of 1 to 6 . The resin composition according to claim 1 or 2 , which is for forming an insulating layer. The resin composition according to claim 1 or 2 , which is for forming an insulating layer for forming a conductor layer. A resin sheet comprising: a support; and a resin composition layer provided on the support, the resin composition layer comprising the resin composition according to claim 1 or 2 . A printed wiring board comprising an insulating layer formed from the cured product of the resin composition according to claim 1 or 2 . A semiconductor device comprising the printed wiring board according to claim 6 . An active ester compound represented by the following general formula (b- 3 ):

(In general formula (b- 3 ),
Ar ³¹ each independently represents a group represented by formula (1), a group represented by formula (2) , or a group represented by formula (3) ;

(In the formula, * represents a bond. In formula (3), n represents an integer of 1 to 5.)
a2 represents an integer of 1 to 6, c2 represents an integer of 1 to 5, and each d independently represents an integer of 1 to 6 .