JP7568015B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition. Furthermore, the present invention relates to a cured product of the resin composition, and a resin sheet, a printed wiring board, and a semiconductor device obtained by using the resin composition.

A known manufacturing technique for printed wiring boards is a build-up method in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, the insulating layers are generally formed by curing a resin composition. An example of such a resin composition is the resin composition disclosed in Patent Document 1.

JP 2020-29494 A

The cured product formed by curing the resin composition can be used as an insulating layer for the printed wiring board of a semiconductor device. For this reason, it is required that the dielectric tangent of the cured product is low. In addition, from the viewpoint of improving heat resistance, it is desirable that the glass transition temperature of the cured product is high.

The present invention has been devised in view of the above problems, and aims to provide a resin composition capable of producing a cured product having a low dielectric tangent and a high glass transition temperature; a cured product of the resin composition; a resin sheet having a resin composition layer containing the resin composition; a printed wiring board including an insulating layer formed of a cured product of the resin composition; and a semiconductor device including the printed wiring board.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result have found that a resin composition comprising (A) a maleimide compound, (B) an epoxy resin, and (C) an active ester-based curing agent, in which the (A) maleimide compound comprises (A-1) a maleimide compound containing a trimethylindane skeleton, can solve the above-mentioned problems, and have completed the present invention.
That is, the present invention includes the following.

（式（Ａ４）において、
Ａｒ^ａ１は、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；
Ｒ^ａ１は、それぞれ独立に、炭素原子数１～１０のアルキル基、炭素原子数１～１０のアルキルオキシ基、炭素原子数１～１０のアルキルチオ基、炭素原子数６～１０のアリール基、炭素原子数６～１０のアリールオキシ基、炭素原子数６～１０のアリールチオ基、炭素原子数３～１０のシクロアルキル基、ハロゲン原子、ニトロ基、水酸基、又は、メルカプト基を表し；
Ｒ^ａ２は、それぞれ独立に、炭素原子数１～１０のアルキル基、炭素原子数１～１０のアルキルオキシ基、炭素原子数１～１０のアルキルチオ基、炭素原子数６～１０のアリール基、炭素原子数６～１０のアリールオキシ基、炭素原子数６～１０のアリールチオ基、炭素原子数３～１０のシクロアルキル基、ハロゲン原子、水酸基、又は、メルカプト基を表し；
Ｒ^ａ３は、それぞれ独立に、２価の脂肪族炭化水素基を表し；
ｎ_ａ１は、正の整数を表し；
ｎ_ａ２は、それぞれ独立に、０～４の整数を表し；
ｎ_ａ３は、それぞれ独立に、０～３の整数を表す。
Ｒ^ａ１のアルキル基、アルキルオキシ基、アルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、及びシクロアルキル基の水素原子は、ハロゲン原子で置換されていてもよい。
Ｒ^ａ２のアルキル基、アルキルオキシ基、アルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、及びシクロアルキル基の水素原子は、ハロゲン原子で置換されていてもよい。
ｎ_ａ２が２～４の場合、Ｒ^ａ１は、同一環内で同じであってもよく異なっていてもよい。
ｎ_ａ３が２～３の場合、Ｒ^ａ２は、同一環内で同じであってもよく異なっていてもよい。）
〔３〕 （Ａ－１）成分の量が、樹脂組成物中の樹脂成分１００質量％に対して、０．５質量％以上７０質量％以下である、〔１〕又は〔２〕に記載の樹脂組成物。
〔４〕 （Ａ）成分の量が、樹脂組成物中の樹脂成分１００質量％に対して、０．５質量％以上７０質量％以下である、〔１〕～〔３〕のいずれか一項に記載の樹脂組成物。
〔５〕 （Ｂ）成分の量が、樹脂組成物中の樹脂成分１００質量％に対して、３質量％以上５０質量％以下である、〔１〕～〔４〕のいずれか一項に記載の樹脂組成物。
〔６〕 （Ｃ）成分の量が、樹脂組成物中の樹脂成分１００質量％に対して、６質量％以上８０質量％以下である、〔１〕～〔５〕のいずれか一項に記載の樹脂組成物。
〔７〕 さらに、（Ｄ）無機充填材を含む、〔１〕～〔６〕のいずれか一項に記載の樹脂組成物。
〔８〕 （Ｄ）成分の量が、樹脂組成物中の不揮発成分１００質量％に対して、２０質量％以上９０質量％以下である、〔７〕に記載の樹脂組成物。
〔９〕 絶縁層形成用である、〔１〕～〔８〕のいずれか１項に記載の樹脂組成物。
〔１０〕 〔１〕～〔９〕のいずれか１項に記載の樹脂組成物の硬化物。
〔１１〕 支持体と、該支持体上に〔１〕～〔９〕のいずれか１項に記載の樹脂組成物で形成された樹脂組成物層と、を備える、樹脂シート。
〔１２〕 〔１〕～〔９〕のいずれか１項に記載の樹脂組成物の硬化物で形成された絶縁層を含む、プリント配線板。
〔１３〕 〔１２〕に記載のプリント配線板を含む、半導体装置。 [1] A composition comprising: (A) a maleimide compound; (B) an epoxy resin; and (C) an active ester-based curing agent;
A resin composition, comprising: (A) a maleimide compound comprising (A-1) a maleimide compound having a trimethylindane skeleton.
[2] The resin composition according to [1], wherein the component (A-1) includes a structure represented by the following formula (A4):

(In formula (A4),
Ar ^a1 represents a divalent aromatic hydrocarbon group which may have a substituent;
R ^a1 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group;
R ^a2 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group;
Each R ^a3 independently represents a divalent aliphatic hydrocarbon group;
n _a1 represents a positive integer;
Each n _a2 independently represents an integer of 0 to 4;
Each of n _{and a3} independently represents an integer of 0 to 3.
The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group and cycloalkyl group of R ^a1 may be substituted with a halogen atom.
The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group and cycloalkyl group of R ^a2 may be substituted with a halogen atom.
When n _a2 is 2 to 4, R ^a1 may be the same or different in the same ring.
When n _a3 is 2 to 3, R ^a2 may be the same or different in the same ring.
[3] The resin composition according to [1] or [2], wherein the amount of the component (A-1) is 0.5% by mass or more and 70% by mass or less, based on 100% by mass of the resin components in the resin composition.
[4] The resin composition according to any one of [1] to [3], wherein the amount of the component (A) is 0.5% by mass or more and 70% by mass or less, based on 100% by mass of the resin components in the resin composition.
[5] The resin composition according to any one of [1] to [4], wherein the amount of the component (B) is 3% by mass or more and 50% by mass or less, based on 100% by mass of the resin components in the resin composition.
[6] The resin composition according to any one of [1] to [5], wherein the amount of the component (C) is 6% by mass or more and 80% by mass or less, based on 100% by mass of the resin components in the resin composition.
[7] The resin composition according to any one of [1] to [6], further comprising (D) an inorganic filler.
[8] The resin composition according to [7], wherein the amount of the (D) component is 20% by mass or more and 90% by mass or less, based on 100% by mass of non-volatile components in the resin composition.
[9] The resin composition according to any one of [1] to [8], which is for forming an insulating layer.
[10] A cured product of the resin composition according to any one of [1] to [9].
[11] A resin sheet comprising a support and a resin composition layer formed on the support from the resin composition according to any one of [1] to [9].
[12] A printed wiring board comprising an insulating layer formed from a cured product of the resin composition according to any one of [1] to [9].
[13] A semiconductor device comprising the printed wiring board according to [12].

The present invention can provide a resin composition capable of producing a cured product having a low dielectric tangent and a high glass transition temperature; a cured product of the resin composition; a resin sheet having a resin composition layer containing the resin composition; a printed wiring board including an insulating layer formed of a cured product of the resin composition; and a semiconductor device including the printed wiring board.

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

[1. Overview of resin composition]
A resin composition according to one embodiment of the present invention includes (A) a maleimide compound, (B) an epoxy resin, and (C) an active ester-based curing agent. The maleimide compound (A) includes (A-1) a maleimide compound containing a trimethylindane skeleton.

With such a resin composition, it is possible to obtain a cured product with a low dielectric tangent and a high glass transition temperature. In addition, the cured product of the resin composition can usually have a low dielectric constant. Furthermore, when an insulating layer is formed with the cured product of the resin composition, it is usually possible to reduce the surface roughness of the insulating layer and increase the plating peel strength.

The resin composition may further contain optional components such as (D) an inorganic filler, (E) an optional curing agent, and (F) a curing accelerator, as necessary.

[2. (A) Maleimide compound]
The maleimide compound as component (A) contained in the resin composition represents a compound containing one or more maleimide groups in the molecule. The maleimide group is represented by the following formula (A2). In formula (A2), * represents a bond. The number of maleimide groups contained in one molecule of the maleimide compound (A) is usually 1 or more, preferably 2 or more. There is no particular limit to the upper limit, and it can be, for example, 22 or less, 10 or less, 6 or less, 4 or less, or 3 or less.

The maleimide compound (A) contained in the resin composition according to this embodiment includes a maleimide compound (A-1) containing a trimethylindane skeleton. In the following description, the "maleimide compound containing a trimethylindane skeleton" may be referred to as a "specific maleimide compound." The trimethylindane skeleton refers to the skeleton shown in the following formula (A3).

The benzene ring contained in the trimethylindane skeleton may have a substituent bonded thereto, for example, an alkyl group, an alkyloxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, a cycloalkyl group, a halogen atom, a hydroxyl group, and a mercapto group.
The number of carbon atoms in the alkyl group is preferably 1 to 10. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a t-butyl group.
The number of carbon atoms in the alkyloxy group is preferably 1 to 10. Examples of the alkyloxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
The number of carbon atoms in the alkylthio group is preferably 1 to 10. Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, and a butylthio group.
The number of carbon atoms in the aryl group is preferably 6 to 10. Examples of the aryl group include a phenyl group and a naphthyl group.
The number of carbon atoms in the aryloxy group is preferably 6 to 10. Examples of the aryloxy group include a phenyloxy group and a naphthyloxy group.
The number of carbon atoms in the arylthio group is preferably 6 to 10. Examples of the arylthio group include a phenylthio group and a naphthylthio group.
The number of carbon atoms in the cycloalkyl group is preferably 3 to 10. Examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, and an iodine atom.

Among the above-mentioned substituents, the hydrogen atoms of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group may be substituted with halogen atoms.

The number of substituents bonded to one benzene ring contained in the trimethylindane skeleton may be 1 or 2 or more. The number of substituents bonded to a benzene ring contained in the trimethylindane skeleton is usually 0 to 3. When the number of substituents is 2 or more, the 2 or more substituents may be the same or different. In particular, it is preferable that no substituents are bonded to the benzene ring contained in the trimethylindane skeleton.

The number of trimethylindane structures contained in one molecule of the specific maleimide compound (A-1) may be 1 or 2 or more. The upper limit may be, for example, 10 or less, 8 or less, 7 or less, or 6 or less.

The (A-1) specific maleimide compound preferably further contains an aromatic ring skeleton in addition to the above-mentioned trimethylindane skeleton. The number of ring-constituting carbon atoms of the aromatic ring skeleton is preferably 6 to 10. Examples of aromatic ring skeletons include a benzene ring skeleton and a naphthalene ring skeleton. The number of the aromatic ring skeletons contained in one molecule of the (A-1) specific maleimide compound is preferably 1 or more, more preferably 2 or more, and preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less. When the (A-1) specific maleimide compound contains two or more aromatic ring skeletons in addition to the trimethylindane skeleton, the aromatic ring skeletons may be the same or different.

The aromatic ring contained in the aromatic ring skeleton may have a substituent bonded thereto. Examples of the substituent include the substituents described above as the substituents that may be bonded to the benzene ring contained in the trimethylindane skeleton, and a nitro group. The number of substituents bonded to one aromatic ring may be 1 or 2 or more. The number of substituents bonded to an aromatic ring is usually 0 to 4. When the number of substituents is 2 or more, the 2 or more substituents may be the same or different.

The specific maleimide compound (A-1) preferably further contains a divalent aliphatic hydrocarbon group in addition to the above-mentioned trimethylindane skeleton. In particular, when the specific maleimide compound (A-1) contains an aromatic ring skeleton other than the benzene ring contained in the trimethylindane skeleton, the specific maleimide compound (A-1) preferably contains a divalent aliphatic hydrocarbon group. In this case, it is preferable that the divalent aliphatic hydrocarbon group links between the benzene ring and the aromatic ring skeleton contained in the trimethylindane skeleton. It is also preferable that the divalent aliphatic hydrocarbon group links between the aromatic ring skeletons.

The number of carbon atoms in the divalent aliphatic hydrocarbon group is preferably 1 or more, and preferably 12 or less, more preferably 8 or less, and particularly preferably 5 or less. As the divalent aliphatic hydrocarbon group, an alkylene group as a saturated aliphatic hydrocarbon group is more preferable. Examples of the divalent aliphatic hydrocarbon group include linear alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups; and branched alkylene groups such as ethylidene (-CH(CH ₃ )-), propylidene (-CH(CH ₂ CH ₃ )-), isopropylidene (-C(CH ₃ ) ₂ -), ethylmethylmethylene (-C(CH ₃ )(CH ₂ CH ₃ )-), and diethylmethylene (-C(CH ₂ CH ₃ ) ₂ -). When the specific maleimide compound (A-1) contains two or more divalent aliphatic hydrocarbon groups in addition to the trimethylindane skeleton, those divalent aliphatic hydrocarbon groups may be the same or different.

The specific maleimide compound (A-1) preferably contains a structure shown in the following formula (A4). The specific maleimide compound (A-1) may have a structure shown in the formula (A4) as a whole, or a portion of the specific maleimide compound (A-1) may have a structure shown in the formula (A4).

(In formula (A4), Ar ^a1 represents a divalent aromatic hydrocarbon group which may have a substituent; R ^a1 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group; R ^a2 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group; R ^a3 each independently represents a divalent aliphatic hydrocarbon group; n _a1 represents a positive integer; n _a2 each independently represents an integer of 0 to 4; n _a3 each independently represents an integer of 0 to 3. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of ^{R a1} may be substituted with a halogen atom. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of R ^a2 may be substituted with a halogen atom. When _{n a2} is 2 to 4, R ^a1 may be the same or different within the same ring. When n _a3 is 2 to 3, R ^a2 may be the same or different within the same ring.)

In formula (A4), Ar ^a1 represents a divalent aromatic hydrocarbon group which may have a substituent. The number of carbon atoms in this divalent aromatic hydrocarbon group is preferably 6 or more, preferably 20 or less, more preferably 16 or less. Examples of the divalent aromatic hydrocarbon group include a phenylene group and a naphthylene group. Examples of the substituent that the divalent aromatic hydrocarbon group may have include an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, and a mercapto group. The hydrogen atom of each substituent may be further substituted with a halogen atom. Specific examples of these substituents include the same examples as the substituents which may be bonded to the benzene ring contained in the trimethylindane skeleton. When the divalent aromatic hydrocarbon group has a substituent, the number of the substituents is preferably 1 to 4. When the divalent aromatic hydrocarbon group has two or more substituents, the two or more substituents may be the same or different. Among them, Ar ^a1 is preferably a divalent aromatic hydrocarbon group having no substituent.

In formula (A4), R ^a1 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. The hydrogen atoms of the alkyl group, the alkyloxy group, the alkylthio group, the aryl group, the aryloxy group, the arylthio group, and the cycloalkyl group may be substituted with a halogen atom. Specific examples of these groups include the same examples as the substituents that may be bonded to the benzene ring contained in the trimethylindane skeleton. Among them, R ^a1 is more preferably one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms, and is particularly preferably an alkyl group having 1 to 4 carbon atoms.

In formula (A4), R ^a2 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. The hydrogen atoms of the alkyl group, the alkyloxy group, the alkylthio group, the aryl group, the aryloxy group, the arylthio group, and the cycloalkyl group may be substituted with a halogen atom. Specific examples of these groups include the same examples as the substituents that may be bonded to the benzene ring contained in the trimethylindane skeleton. Among them, R ^a2 is more preferably one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

In formula (A4), each R ^a3 independently represents a divalent aliphatic hydrocarbon group. The preferred range of the divalent aliphatic hydrocarbon group is as described above.

In formula (A4), n _a1 represents a positive integer. n _a1 is preferably 1 or more and is preferably 10 or less, and more preferably 8 or less.

In formula (A4), n _a2 each independently represents an integer of 0 to 4. n _a2 is preferably 2 or 3, more preferably 2. Multiple n _a2 may be different, but are preferably the same. When n _a2 is 2 or more, multiple R ^a1 may be the same or different within the same ring.

In formula (A4), n _a3 each independently represents an integer of 0 to 3. Multiple n _a3 may be different, but are preferably the same. n _a3 is preferably 0.

It is particularly preferable that the specific maleimide compound (A-1) contains a structure shown in the following formula (A5). The entire specific maleimide compound (A-1) may have a structure shown in formula (A5), or a portion of the specific maleimide compound (A-1) may have a structure shown in formula (A5).

(In formula (A5), R ^b1 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group; R ^b2 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group; n _b1 represents a positive integer; n _b2 each independently represents an integer of 0 to 4; _b3 each independently represents an integer of 0 to 3. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of ^{R b1} may be substituted with a halogen atom. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of R ^b2 may be substituted with a halogen atom. When n _b2 is 2 to 4, R ^b1 may be the same or different in the same ring. When n _b3 is 2 to 3, R ^b2 may be the same or different in the same ring.)

In formula (A5), R ^b1 , R ^b2 , n _b1 , n _b2 and n _b3 are the same as R ^a1 , R ^a2 , n _a1 , n _a2 and n _a3 in formula (A4), respectively.

The specific maleimide compound (A-1) may further contain a structure shown in the following formula (A6).

In formula (A6), R ^c1 , R ^c2 , n _c2 and n _c3 are the same as R ^a1 , R ^a2 , n _a2 and n _a3 in formula (A4), respectively. In formula (A6), n _c1 is the number of repeating units and represents an integer of 1 to 20. In formula (A6), * represents a bond. For example, the specific maleimide compound (A-1) may contain a structure represented by formula (A6) in combination with the structure represented by formula (A4) when n _a2 is 3 or less and R ^a1 is not bonded to two or more of the ortho-positions and para-positions relative to the maleimide group of the benzene ring to which the maleimide group is bonded in formula (A4). Furthermore, for example, when n _b2 is 3 or less in formula (A5) and R b1 is not bonded to two or more of the ortho positions and para positions relative to the maleimide group of the benzene ring to which the maleimide group is bonded, the specific maleimide compound (A ^-1 ) can contain a structure represented by formula (A6) in combination with the structure represented by formula (A5).

The specific maleimide compound (A-1) as component (A-1) may be used alone or in combination of two or more types in any ratio.

The maleimide group equivalent of the specific maleimide compound (A-1) is preferably 50 g/eq. or more, more preferably 100 g/eq. or more, particularly preferably 200 g/eq. or more, and is preferably 2000 g/eq. or less, more preferably 1000 g/eq. or less, particularly preferably 800 g/eq. or less. The maleimide group equivalent represents the mass of the maleimide compound per equivalent of maleimide group. When the maleimide group equivalent of the specific maleimide compound (A-1) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the specific maleimide compound (A-1) in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When the amount of the specific maleimide compound (A-1) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the (A-1) specific maleimide compound in the resin composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. The resin components in the resin composition refer to the non-volatile components in the resin composition excluding the (D) inorganic filler. When the amount of the (A-1) specific maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The amount of the specific maleimide compound (A-1) in the resin composition is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 100% by mass or more, relative to 100% by mass of the epoxy resin (B) in the resin composition, and is preferably 200% by mass or less, more preferably 180% by mass or less, and particularly preferably 160% by mass or less. When the amount of the specific maleimide compound (A-1) is within the above range, the effects of the present invention can be obtained significantly.

The ratio (maleimide group/epoxy group) of the total number of maleimide groups in the specific maleimide compound (A-1) to the total number of epoxy groups in the epoxy resin (B) is preferably within a specific range. The ratio (maleimide group/epoxy group) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. The "total number of maleimide groups in the specific maleimide compound (A-1)" refers to the total value of all values obtained by dividing the mass of the non-volatile components of the specific maleimide compound (A-1) present in the resin composition by the maleimide group equivalent. The "total number of epoxy groups in the epoxy resin (B)" refers to the total value of all values obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition by the epoxy equivalent. When the ratio (maleimide group/epoxy group) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the specific maleimide compound (A-1) in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, relative to 100% by mass of the active ester-based curing agent (C) in the resin composition, and is preferably 160% by mass or less, more preferably 130% by mass or less, and particularly preferably 110% by mass or less. When the amount of the specific maleimide compound (A-1) is within the above range, the effects of the present invention can be obtained significantly.

The ratio (maleimide group/active ester group) of the total number of maleimide groups in the (A-1) specific maleimide compound to the total number of active ester groups in the (C) active ester curing agent is preferably within a specific range. The ratio (maleimide group/active ester group) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. The "total number of active ester groups in the (C) active ester curing agent" refers to the total value of the mass of the non-volatile components of the (C) active ester curing agent present in the resin composition divided by the active ester equivalent. When the ratio (maleimide group/active ester group) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the specific maleimide compound (A-1) in the resin composition is preferably 30% by mass to 100% by mass, more preferably 40% by mass to 100% by mass, and particularly preferably 50% by mass to 100% by mass, relative to 100% by mass of the total amount of the maleimide compound (A). When the amount of the specific maleimide compound (A-1) is within the above range, the effects of the present invention can be obtained significantly.

The method for producing the specific maleimide compound (A-1) is not particularly limited. The specific maleimide compound (A-1) can be produced, for example, by the method described in Japan Institute of Invention and Innovation's Technical Journal No. 2020-500211. According to the production method described in Japan Institute of Invention and Innovation's Technical Journal No. 2020-500211, it is possible to obtain a maleimide compound having a distribution in the number of repeating units of the trimethylindane skeleton. The maleimide compound obtained by this method contains a structure represented by the following formula (A1). Therefore, the maleimide compound (A) may contain a maleimide compound containing a structure represented by formula (A1).

(In formula (A1), R ¹ independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group; R ² independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group; n ₁ represents an average number of repeating units of 0.95 to 10.0; n Each of _{n 2} independently represents an integer of 0 to 4; each of n ₃ independently represents an integer of 0 to ^3. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of ^{R 1} may be substituted with a halogen atom. The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, and cycloalkyl group of R 2 may be substituted with a halogen atom. When n ₂ is 2 to 4, R ¹ may be the same or different in the same ring. When n ₃ is 2 to 3, R ² may be the same or different in the same ring.)

In formula (A1), R ¹ , R ² , n ₂ and n ₃ are the same as R ^a1 , R ^a2 , n _a2 and n _a3 in formula (A4), respectively.

In formula (A1), n ₁ represents the average number of repeating units, and its range is 0.95 to 10.0. According to the manufacturing method described in the Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211, a group of maleimide compounds containing a structure represented by formula (A1) can be obtained. As can be seen from the fact that the average number of repeating units n ₁ in formula (A1) can be smaller than 1.00, the maleimide compound containing the structure represented by formula (A1) thus obtained can contain a maleimide compound having a trimethylindane skeleton repeating unit number of 0. Therefore, the maleimide compound containing the structure represented by formula (A1) can be purified to obtain a specific maleimide compound (A-1) excluding a maleimide compound having a trimethylindane skeleton repeating unit number of 0, and the resin composition may contain only the specific maleimide compound (A-1) obtained. However, even if a maleimide compound having a trimethylindane skeleton repeating unit number of 0 is contained in the resin composition, the effect of the present invention can be obtained. In addition, when purification is omitted, it is possible to suppress costs. Therefore, it is preferable that the resin composition contains a maleimide compound containing a structure represented by formula (A1), without excluding any maleimide compound having a trimethylindane skeleton with zero repeating units.

In formula (A1), the average number of repeating units _n1 is preferably 0.95 or more, more preferably 0.98 or more, even more preferably 1.0 or more, particularly preferably 1.1 or more, and is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 7.0 or less, particularly preferably 6.0 or less. When the average number of repeating units _n1 is within the above range, the effects of the present invention can be significantly obtained. In particular, the glass transition temperature of the resin composition can be effectively increased.

Examples of the structure represented by formula (A1) include the following:

The maleimide compound containing the structure represented by formula (A1) may further contain the structure represented by formula (A6) above. For example, the maleimide compound containing the structure represented by formula (A1) may contain a structure represented by formula (A6) in combination with the structure represented by formula (A1) when _n2 is 3 or less and ^R1 is not bonded to two or more of the ortho-positions and para-positions relative to the maleimide group of the benzene ring to which the maleimide group is bonded in formula (A1).

The maleimide compound containing the structure represented by formula (A1) preferably has a molecular weight distribution Mw/Mn calculated from gel permeation chromatography (GPC) measurement within a specific range. The molecular weight distribution is a value obtained by dividing the weight average molecular weight Mw by the number average molecular weight Mn, and is expressed as "Mw/Mn". Specifically, the molecular weight distribution Mw/Mn of the maleimide compound containing the structure represented by formula (A1) is preferably 1.0 to 4.0, more preferably 1.1 to 3.8, even more preferably 1.2 to 3.6, and particularly preferably 1.3 to 3.4. When the molecular weight distribution Mw/Mn of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be significantly obtained.

Of the maleimide compounds containing a structure represented by formula (A1), the amount of the maleimide compound having an average repeating unit number _n1 of 0 is preferably in a specific range. When the GPC measurement of the maleimide compound containing a structure represented by formula (A1) is performed, the amount of the maleimide compound having an average repeating unit number _n1 of 0 can be expressed in area % based on the results of the GPC measurement. In detail, the amount of the maleimide compound having an average repeating unit number n1 of 0 can be expressed by the ratio (area %) of the area of the peak of the maleimide compound having an average repeating unit number _n1 of 0 to the total area of the peaks of the maleimide compound containing a structure represented by formula (A1) in the chromatogram obtained by the GPC measurement. Specifically, the amount of the maleimide compound having an average repeating unit number _n1 of 0 is preferably 32 area % or less, more preferably 30 area % or less, and even more preferably 28 area % or less, relative to the total amount of the maleimide compound containing a structure represented by formula ( _A1) (100 area %). When the amount of the maleimide compound in which the average number of repeating units _n1 is 0 is within the above range, the effects of the present invention can be significantly obtained.

The maleimide group equivalent of the maleimide compound containing the structure represented by formula (A1) is preferably in the same range as the maleimide group equivalent of the specific maleimide compound (A-1) described above. When the maleimide group equivalent of the maleimide compound containing the structure represented by formula (A1) is in the above range, the effects of the present invention can be significantly obtained.

The amount of the maleimide compound containing the structure represented by formula (A1) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When the amount of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the maleimide compound containing the structure represented by formula (A1) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When the amount of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the maleimide compound containing the structure represented by formula (A1) is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 100% by mass or more, relative to 100% by mass of the epoxy resin (B) in the resin composition, and is preferably 200% by mass or less, more preferably 180% by mass or less, and particularly preferably 160% by mass or less. When the amount of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be obtained significantly.

The ratio (maleimide group/epoxy group) of the total number of maleimide groups in the maleimide compound containing the structure represented by formula (A1) to the total number of epoxy groups in the epoxy resin (B) is preferably within a specific range. The ratio (maleimide group/epoxy group) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. The "total number of maleimide groups in the maleimide compound containing the structure represented by formula (A1)" refers to the total value of the mass of the non-volatile components of the maleimide compound containing the structure represented by formula (A1) present in the resin composition divided by the maleimide group equivalent. When the ratio (maleimide group/epoxy group) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the maleimide compound containing the structure represented by formula (A1) is preferably 10% by mass or more, more preferably 20% by mass or more, particularly preferably 30% by mass or more, and is preferably 160% by mass or less, more preferably 130% by mass or less, particularly preferably 110% by mass or less, relative to 100% by mass of the active ester-based curing agent (C) in the resin composition. When the amount of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be obtained significantly.

It is preferable that the ratio (maleimide group/active ester group) of the total number of maleimide groups in the maleimide compound containing the structure represented by formula (A1) to the total number of active ester groups in the active ester curing agent (C) is within a specific range. The ratio (maleimide group/active ester group) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. When the ratio (maleimide group/active ester group) is within the above range, the effects of the present invention can be obtained significantly.

The amount of the maleimide compound containing the structure represented by formula (A1) is preferably 30% by mass to 100% by mass, more preferably 40% by mass to 100% by mass, and particularly preferably 50% by mass to 100% by mass, relative to 100% by mass of the total amount of the maleimide compound (A). When the amount of the maleimide compound containing the structure represented by formula (A1) is within the above range, the effects of the present invention can be significantly obtained.

The maleimide compound (A) may further contain an optional maleimide compound that does not contain a trimethylindane skeleton in combination with the specific maleimide compound (A-1) described above. Examples of the optional maleimide compound include a biphenyl-type maleimide compound (A-2) and an aliphatic maleimide compound (A-3). The optional maleimide compound may be used alone or in combination of two or more types in any ratio.

(A-2) Biphenyl-type maleimide compound refers to a maleimide compound containing a biphenyl skeleton. When (A-2) biphenyl-type maleimide compound is used in combination with (A-1) specific maleimide compound, plating peel strength can be effectively increased.

The benzene ring of the biphenyl skeleton contained in the biphenyl-type maleimide compound (A-2) may have one or more substituents bonded thereto. Examples of the substituent include a halogen atom, -OH, -O-C _1-10 alkyl group, -N(C _1-10 alkyl group) ₂ , C _1-10 alkyl group, 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 _x-y " (x and y are positive integers, and x<y) indicates that the number of carbon atoms in the organic group described immediately after this term is x to y. 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. The ring also includes a spiro ring and a condensed ring. The above-mentioned substituent may further have a substituent (hereinafter, sometimes referred to as a "secondary substituent"). The secondary substituent may be the same as the above-mentioned substituent. Among them, it is preferable that no substituent is bonded to the benzene ring of the biphenyl skeleton contained in the biphenyl-type maleimide compound (A-2).

The (A-2) biphenyl-type maleimide compound preferably contains either an aliphatic hydrocarbon group or an aromatic hydrocarbon group in combination with the biphenyl skeleton, and more preferably contains both an aliphatic hydrocarbon group and an aromatic hydrocarbon group. A preferred (A-2) biphenyl-type maleimide compound is the maleimide compound represented by the following formula (A7).

(In formula (A7), each R ^d1 independently represents an alkylene group; each R ^d2 independently represents an alkyl group which may have a substituent, or an aryl group which may have a substituent; each R ^d3 independently represents a substituent; n _d1 independently represents an integer of 1 to 100; each n _d2 independently represents an integer of 0 to 2; and each n _d3 independently represents an integer of 0 to 4.)

In formula (A7), each R ^d1 independently represents an alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3. The alkylene group is preferably a linear alkylene group, and more preferably a methylene group.

In formula (A7), each R ^d2 independently represents an alkyl group which may have a substituent, or an aryl group which may have a substituent.
The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 3. The alkyl group may be linear, branched, or cyclic. Examples of the substituent that the alkyl group may have include the same examples as those mentioned above as the substituent that may be bonded to the benzene ring of the biphenyl skeleton.
The number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 15, and particularly preferably 6 to 10. Examples of the substituent that the aryl group may have include the same examples as those mentioned above as the substituent that may be bonded to the benzene ring of the biphenyl skeleton.

In formula (A7), each R ^d3 independently represents a substituent. Examples of the substituent include the same examples as those mentioned above as the substituent that can be bonded to the benzene ring of the biphenyl skeleton.

In formula (A7), n _d1 represents an integer of 1 to 100, preferably 1 to 50, more preferably 1 to 20, and further preferably 1 to 5.

In formula (A7), n _{and d2} each independently represent an integer of 0 to 2, and are preferably 0.

In formula (A7), n _d3 each independently represents an integer of 0 to 4, preferably 0 to 3, more preferably 0 or 1, and particularly preferably 0.

An example of the biphenyl-type maleimide compound (A-2) represented by formula (A7) is "MIR-3000-70MT" (main component: compound represented by formula (A8) below) manufactured by Nippon Kayaku Co., Ltd. In formula (A8) below, n _d4 represents 1 or 2.

The amount of the (A-2) biphenyl-type maleimide compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 10.0% by mass or less, more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less. When the amount of the (A-2) biphenyl-type maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The amount of the (A-2) biphenyl-type maleimide compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. When the amount of the (A-2) biphenyl-type maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

(A-3) Aliphatic maleimide compound refers to a maleimide compound containing an aliphatic hydrocarbon group having 5 or more carbon atoms. When (A-3) aliphatic maleimide compound is used in combination with (A-1) specific maleimide compound, plating peel strength can be effectively increased.

The number of carbon atoms in the aliphatic hydrocarbon group contained in the aliphatic maleimide compound (A-3) is usually 5 or more, preferably 6 or more, more preferably 8 or more, and preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less.

The aliphatic hydrocarbon group contained in the aliphatic maleimide compound (A-3) may be saturated or unsaturated, with saturated aliphatic hydrocarbon groups being preferred. The aliphatic hydrocarbon group may be a chain group or a cyclic group. Furthermore, the aliphatic hydrocarbon group may be a monovalent group or a divalent group.

(A-3) Examples of the aliphatic hydrocarbon group contained in the aliphatic maleimide compound include alkyl groups such as pentyl, hexyl, heptyl, octyl, nonyl, and decyl; and alkylene groups such as 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 aliphatic hydrocarbon group contained in the aliphatic maleimide compound (A-3) may have a substituent bonded thereto. Examples of the substituent include the same examples as those mentioned above as the substituents that can be bonded to the benzene ring of the biphenyl skeleton in the explanation of the biphenyl-type maleimide compound (A-2). In particular, it is preferable that the aliphatic hydrocarbon group contained in the aliphatic maleimide compound (A-3) does not have a substituent bonded thereto.

The (A-3) aliphatic maleimide compound preferably contains a polyimide structure. A preferred (A-3) aliphatic maleimide compound is a maleimide-terminated polyimide compound represented by the following formula (A9).

(In formula (A9), R ^e1 each independently represents an alkylene group having 5 or more carbon atoms which may have a substituent; R ^e2 each independently represents a divalent linking group; and n _e1 represents an integer from 1 to 10.)

In formula (A9), R ^e1 each independently represents an alkylene group having 5 or more carbon atoms which may have a substituent. The number of carbon atoms of R ^e1 is, in detail, usually 5 or more, preferably 6 or more, more preferably 8 or more, and preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. Examples of the substituent that the alkylene group may have include the same examples as those mentioned above as the substituent that may be bonded to the benzene ring of the biphenyl skeleton in the explanation of the biphenyl-type maleimide compound (A-2). Among them, R ^e1 is preferably an alkylene group having no substituent.

In formula (A9), R ^e2 each independently represents a divalent linking group. The divalent linking group is preferably an oxygen atom, an arylene group, an alkylene group, or a divalent group consisting of a combination of two or more of these groups. The number of carbon atoms in the arylene group is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and particularly preferably 6 to 10. Preferred arylene groups include, for example, a phenylene group, a naphthylene group, and an anthracenylene group. The number of carbon atoms in the alkylene group is preferably 1 to 50, more preferably 1 to 45, and even more preferably 1 to 40. The alkylene group may be linear, branched, or cyclic. Preferred alkylene groups include, for example, a methylethylene group, a cyclohexylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tridecylene group, a heptadecylene group, a hexatriacontylene group, a group having an octylene-cyclohexylene structure, a group having an octylene-cyclohexylene-octylene structure, a group having a propylene-cyclohexylene-octylene structure, etc. Among these, an oxygen atom is preferred as R ^e2 .

In formula (A9), n _e1 represents an integer of 1 to 10.

Examples of the aliphatic maleimide compound (A-3) represented by formula (A9) include "BMI-1500" (compound of formula (A10)) and "BMI-1700" (compound of formula (A11)) manufactured by Designer Molecules, Inc. In the following formulas (A10) and (A11), n _e2 and n _e3 each independently represent an integer of 1 to 10.

The amount of the (A-3) aliphatic maleimide compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 10.0% by mass or less, more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less. When the amount of the (A-3) aliphatic maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The amount of the aliphatic maleimide compound (A-3) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. When the amount of the aliphatic maleimide compound (A-3) is within the above range, the effects of the present invention can be obtained significantly.

The maleimide group equivalent of any maleimide compound, such as (A-2) biphenyl-type maleimide compound or (A-3) aliphatic maleimide compound, is preferably in the same range as the maleimide group equivalent of the above-mentioned (A-1) specific maleimide compound. When the maleimide group equivalent of any maleimide compound is in the above range, the effects of the present invention can be significantly obtained.

The amount of (A) maleimide compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When the amount of (A) maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The amount of (A) maleimide compound is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When the amount of (A) maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The amount of the (A) maleimide compound is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 100% by mass or more, relative to 100% by mass of the (B) epoxy resin in the resin composition, and is preferably 200% by mass or less, more preferably 180% by mass or less, and particularly preferably 160% by mass or less. When the amount of the (A) maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The ratio (maleimide group/epoxy group) of the total number of maleimide groups in the (A) maleimide compound to the total number of epoxy groups in the (B) epoxy resin is preferably within a specific range. The ratio (maleimide group/epoxy group) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. The "total number of maleimide groups in the (A) maleimide compound" refers to the total value of the mass of the non-volatile components of the (A) maleimide compound present in the resin composition divided by the maleimide group equivalent. When the ratio (maleimide group/epoxy group) is within the above range, the effects of the present invention can be obtained significantly.

The amount of (A) maleimide compound is preferably 10% by mass or more, more preferably 20% by mass or more, particularly preferably 30% by mass or more, and is preferably 160% by mass or less, more preferably 130% by mass or less, particularly preferably 110% by mass or less, relative to 100% by mass of (C) active ester-based curing agent in the resin composition. When the amount of (A) maleimide compound is within the above range, the effects of the present invention can be obtained significantly.

The ratio (maleimide groups/active ester groups) of the total number of maleimide groups in (A) the maleimide compound to the total number of active ester groups in (C) the active ester curing agent is preferably within a specific range. The ratio (maleimide groups/active ester groups) is preferably 0.01 or more, more preferably 0.3 or more, particularly preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. When the ratio (maleimide groups/active ester groups) is within the above range, the effects of the present invention can be significantly obtained.

[3. (B) Epoxy resin]
The epoxy resin as component (B) contained in the resin composition is a curable resin having an epoxy group, and examples thereof 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, glyceryl ... Examples of the epoxy resin include ricidyl ester type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexane dimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthalimidine type epoxy resin, phenolphthalein type epoxy resin, etc. The epoxy resin (B) may be used alone or in combination of two or more kinds in any ratio.

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

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain only liquid epoxy resins as the epoxy resin (B), may contain only solid epoxy resins, or may contain a combination of liquid epoxy resins and solid epoxy resins. Of these, it is more preferable to use only liquid epoxy resins as the epoxy resin (B).

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

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

Specific examples of liquid epoxy resins include DIC's "HP-4032", "HP-4032-D", and "HP-4032-SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "828EL", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F type epoxy resins); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630", "630LSD", and "604" (glycidylamine type epoxy resins); ADEKA's "ED-523T" (glycilol type epoxy resin); ADEKA's "EP-3950L" and "EP EP-3980S (glycidylamine type epoxy resin); ADEKA's "EP-4088S" (dicyclopentadiene type epoxy resin); Nippon Steel & Sumikin Chemical's "ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase ChemteX's "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton); Daicel's "PB-3600", Nippon Soda's "JP-100" and "JP-200" (epoxy resin having a butadiene structure); Nippon Steel & Sumikin Chemical's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin). These may be used alone or in combination of two or more types.

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

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

Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin); DIC's "N-690" (cresol novolac type epoxy resin); DIC's "N-695" (cresol novolac type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resin); DIC's "EXA-73 11", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN475V" manufactured by Nippon Steel Chemical & Material Co., Ltd. (naphthalene type epoxy resin); "ESN485" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX77" manufactured by Mitsubishi Chemical Co., Ltd. 00" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical; "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more types.

The epoxy equivalent of the (B) epoxy resin 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. The epoxy equivalent represents the mass of the epoxy resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

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

The amount of (B) epoxy resin in the resin composition is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and particularly preferably 5% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. When the amount of (B) epoxy resin is within the above range, the effects of the present invention can be obtained significantly.

The amount of (B) epoxy resin in the resin composition is not particularly limited, but is preferably 3% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more, based on 100% by mass of the resin components in the resin composition, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. When the amount of (B) epoxy resin is within the above range, the effects of the present invention can be obtained significantly.

[4. (C) Active ester curing agent]
The active ester curing agent as component (C) contained in the resin composition is a compound having one or more active ester groups in the molecule and capable of reacting with the epoxy resin (B). The active ester curing agent (C) may be used alone or in combination of two or more kinds in any ratio.

(C) As the active ester curing agent, a compound 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, is preferred. The active ester compound is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester compound obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester compound obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred.

Examples of 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. "Dicyclopentadiene-type diphenol compounds" refer to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, the active ester curing agent (C) is preferably a dicyclopentadiene type active ester compound, a naphthalene type active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, or an active ester compound containing a benzoylated product of phenol novolac. Among them, at least one selected from a dicyclopentadiene type active ester compound and a naphthalene type active ester compound is more preferable, and a dicyclopentadiene type active ester compound is even more preferable. As the dicyclopentadiene type active ester compound, an active ester compound containing a dicyclopentadiene type diphenol structure is preferable. The "dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

(C) Commercially available active ester curing agents include active ester compounds containing a dicyclopentadiene-type diphenol structure, such as "EXB-9451", "EXB-9460", "EXB-9460S", "HPC-8000", "HPC-8000-65T", "HPC-8000H", "HPC-8000H-65TM", "EXB-8000L", "EXB-8000L-65M", "HPC-8000L-65TM", and "EXB-8000L-65TM" manufactured by DIC Corporation; and active ester compounds containing a naphthalene structure, such as "EXB-8100L-65T", "HPC-8150-60T", "HPC-8150-62T", and "EXB-81 50-60T, "EXB-9416-70BK" (manufactured by DIC Corporation), "PC1300-02" (manufactured by Air Water Corporation); a phosphorus-containing active ester compound is "EXB9401" (manufactured by DIC Corporation); an active ester compound which is an acetylated product of phenol novolac is "DC808" (manufactured by Mitsubishi Chemical Corporation); active ester compounds which are benzoylated products of phenol novolac are "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); an active ester compound containing a styryl group is "PC1300-02-65MA" (manufactured by Air Water Corporation); and the like.

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

The amount of (C) active ester curing agent in the resin composition is not particularly limited, but is preferably 3% by mass or more, more preferably 6% by mass or more, and particularly preferably 10% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of (C) active ester curing agent is within the above range, the effects of the present invention can be obtained significantly.

The amount of (C) active ester curing agent in the resin composition is not particularly limited, but is preferably 6% by mass or more, more preferably 20% by mass or more, particularly preferably 30% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on 100% by mass of the resin components in the resin composition. When the amount of (C) active ester curing agent is within the above range, the effects of the present invention can be obtained significantly.

The ratio (active ester groups/epoxy groups) of the total number of active ester groups in (C) the active ester curing agent to the total number of epoxy groups in (B) the epoxy resin is preferably within a specific range. The ratio (active ester groups/epoxy groups) is preferably 0.1 or more, more preferably 0.5 or more, particularly preferably 0.8 or more, and is preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less. When the ratio (active ester groups/epoxy groups) is within the above range, the effects of the present invention can be significantly obtained.

[5. (D) Inorganic filler]
The resin composition may further contain an inorganic filler (D) as an optional component in addition to the above-mentioned components. The inorganic filler as component (D) is usually added to the resin composition in the form of particles. is included.

(D) Inorganic compounds can be used as the material for the inorganic filler. (D) Examples of the material for the inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica 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. (D) The inorganic filler may be used alone or in any combination of two or more kinds in any ratio.

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

(D) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less, from the viewpoint of obtaining the effects of the present invention significantly. (D) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering type particle size distribution measuring device, and the median diameter is used as the average particle size. The measurement sample can be obtained by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing it by ultrasonic waves for 10 minutes. The measurement sample can be measured using a laser diffraction type particle size distribution measuring device, with the wavelengths of the light source used being blue and red, and the volume-based particle size distribution of the inorganic filler is measured using a flow cell method, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction particle size distribution measuring device is the LA-960 manufactured by Horiba, Ltd.

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

(D) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. 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's "KBM-1003" and "KBE-1003" (vinyl silane coupling agents); "KBM-303", "KBM-402", "KBM-403", "KBE-402", and "KBE-403" (epoxy silane coupling agents); "KBM-1403" (styryl silane coupling agents); "KBM-502", "KBM-503", "KBE-502", and "KBE-503" (methacrylic silane coupling agents); "KBM-5103" (acrylic silane coupling agents); "KBM-602", "KBM-603", "KBM-903", "KBE-903", "KBE-9103P", "KBM-573", and "KBM-575" (amino silane coupling agents); Examples include "KBM-9659" (isocyanurate-based silane coupling agent); "KBE-585" (ureido-based silane coupling agent); "KBM-802" and "KBM-803" (mercapto-based silane coupling agent); "KBE-9007N" (isocyanate-based silane coupling agent); "X-12-967C" (acid anhydride-based silane coupling agent); "KBM-13", "KBM-22", "KBM-103", "KBE-13", "KBE-22", "KBE-103", "KBM-3033", "KBE-3033", "KBM-3063", "KBE-3063", "KBE-3083", "KBM-3103C", "KBM-3066", and "KBM-7103" (non-silane coupling - alkoxysilane compound).

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

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler (D). 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 preventing an increase in the melt viscosity of the resin composition or the melt viscosity in the form of a sheet, it is preferably 1.0 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

(D) 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 non-volatile components, 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.

From the viewpoint of obtaining a significant effect of the present invention, the amount of (D) inorganic filler in the resin composition is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and particularly preferably 50% by mass or more, based on 100% by mass of non-volatile components in the resin composition, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

The amount of the specific maleimide compound (A-1) relative to 100% by mass of the inorganic filler (D) is preferably 2% by mass or more, more preferably 5% by mass or more, particularly preferably 8% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less. When an amount of the inorganic filler (D) that satisfies this relationship is used, the effects of the present invention can be obtained significantly.

The amount of the maleimide compound containing the structure represented by formula (A1) relative to 100% by mass of the (D) inorganic filler is preferably 2% by mass or more, more preferably 5% by mass or more, particularly preferably 8% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less. When an amount of the (D) inorganic filler that satisfies this relationship is used, the effects of the present invention can be obtained significantly.

The amount of the (A) maleimide compound relative to 100% by mass of the (D) inorganic filler is preferably 2% by mass or more, more preferably 5% by mass or more, particularly preferably 10% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less. When an amount of the (D) inorganic filler that satisfies this relationship is used, the effects of the present invention can be obtained significantly.

6. (E) Optional Hardener
In addition to the above-mentioned components, the resin composition may further contain an optional curing agent (E) as an optional component. However, the optional curing agent (E) does not include the active ester curing agent (C). Examples of the optional curing agent as the component (E) include a phenolic curing agent, a naphthol curing agent, a benzoxazine curing agent, a cyanate ester curing agent, a carbodiimide curing agent, and an acid anhydride curing agent. Among them, from the viewpoint of obtaining the effects of the present invention remarkably, the optional curing agent (E) is preferably one or more of a phenolic curing agent, a naphthol curing agent, a cyanate ester curing agent, and a carbodiimide curing agent, more preferably one or more of a phenolic curing agent and a naphthol curing agent, and particularly preferably a phenolic curing agent. The optional curing agent (E) may be used alone or in combination of two or more in any ratio.

As the phenol-based hardener and naphthol-based hardener, from the viewpoint of heat resistance and water resistance, a phenol-based hardener having a novolac structure or a naphthol-based hardener having a novolac structure is preferred. Also, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based hardener is preferred, and a triazine skeleton-containing phenol-based hardener is more preferred.

Specific examples of phenol-based and naphthol-based curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", "SN-375", and "SN-395" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA3018-50P", and "EXB-9500" manufactured by DIC Corporation.

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

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

Specific examples of carbodiimide-based curing agents include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

Examples of acid anhydride curing agents include curing agents having one or more acid anhydride groups in one molecule, and curing agents having two or more acid anhydride groups in one molecule are preferred. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Examples of acid anhydrides include polymeric acid anhydrides such as 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 styrene-maleic acid resins in which styrene and maleic acid are copolymerized. Examples of commercially available acid anhydride-based hardeners include "HNA-100" and "MH-700" manufactured by New Japan Chemical Co., Ltd.

The amount of optional curing agent (E) in the resin composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 8% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. When the amount of optional curing agent (E) is within the above range, the effects of the present invention can be obtained significantly.

The amount of optional curing agent (E) in the resin composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 6% by mass or less. When the amount of optional curing agent (E) is within the above range, the effects of the present invention can be obtained significantly.

The ratio (active group/epoxy group) of the total number of active groups of the optional curing agent (E) to the total number of epoxy groups of the epoxy resin (B) is preferably within a specific range. The ratio (active group/epoxy group) is preferably 0.01 or more, more preferably 0.05 or more, particularly preferably 0.1 or more, and is preferably 3 or less, more preferably 1 or less, particularly preferably 0.5 or less. The "total number of active groups of the optional curing agent (E)" is the total value of all values obtained by dividing the mass of the non-volatile components of the optional curing agent (E) present in the resin composition by the active group equivalent. When the ratio (active group/epoxy group) is within the above range, the effect of the present invention can be obtained significantly.

[7. (F) Curing Accelerator]
In addition to the above-mentioned components, the resin composition may further contain (F) a curing accelerator as an optional component. Examples of the curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. The (F) curing accelerator may be used alone or in combination of two or more types in any ratio.

Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butylmethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, and tetraphenylphosphine. aromatic phosphonium salts such as sulfonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; tributylphosphine, tri-t Aliphatic phosphines such as tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine; dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, ) phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenyl ether and other aromatic phosphines.

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

Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

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

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, organozinc complexes such as zinc (II) acetylacetonate, organoiron complexes such as iron (III) acetylacetonate, organonickel complexes such as nickel (II) acetylacetonate, and organomanganese complexes such as manganese (II) acetylacetonate. Organometallic salts include, for example, zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

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

The amount of (F) curing accelerator in the resin composition is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0.05% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the amount of (F) curing accelerator is within the above range, the effects of the present invention can be obtained significantly.

The amount of (F) curing accelerator in the resin composition is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0.1% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the amount of (F) curing accelerator is within the above range, the effects of the present invention can be obtained significantly.

[8. (G) Solvent]
In addition to the above-mentioned components, the resin composition may further contain a (G) solvent as an optional component. The solvent is usually a volatile component, and an organic solvent may be used. Examples of the (G) solvent include ketone-based solvents such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetate-based solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitol-based solvents such as cellosolve and butyl carbitol; aromatic hydrocarbon-based solvents such as toluene and xylene; amide-based solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone; and the like. The (G) solvent may be used alone or in combination of two or more types in any ratio.

The amount of (G) solvent is not particularly limited. The amount of (G) solvent can be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, etc., relative to 100% by mass of all components in the resin composition.

[9. Other Ingredients]
The resin composition may further contain any additives as optional components other than the above-mentioned components. Examples of such additives include thermoplastic resins, organic fillers, thickeners, defoamers, leveling agents, adhesion promoters, flame retardants, etc. These may be used alone or in combination of two or more in any ratio.

[10. Method for producing resin composition]
The resin composition can be produced, for example, by mixing the above-mentioned components in any order. In addition, heating and/or cooling may be performed by appropriately adjusting the temperature during the process of mixing each component. In addition, each component may be uniformly dispersed by stirring using a stirring device such as a mixer during or after mixing. Furthermore, the resin composition may be subjected to a degassing treatment as necessary.

[11. Characteristics of resin composition]
According to the above-mentioned resin composition, it is possible to obtain a cured product having a low dielectric tangent and a high glass transition temperature.

For example, the dielectric loss tangent Df of the cured product obtained by curing the resin composition under the conditions described in the Examples below is preferably 0.010 or less, more preferably 0.005 or less, and particularly preferably 0.004 or less. The lower limit of the dielectric loss tangent Df of the cured product is not particularly limited, but may be 0.001 or more. The dielectric loss tangent of the cured product can be measured by the method described in the Examples.

For example, the glass transition temperature Tg of the cured product obtained by curing the resin composition under the conditions described in the examples below is preferably 130°C or higher, more preferably 140°C or higher, and particularly preferably 150°C or higher. The upper limit of the glass transition temperature Tg of the cured product is not particularly limited, but may be 260°C or lower.

The cured product of the resin composition can usually have a small dielectric constant. For example, the dielectric constant Dk of the cured product obtained by curing the resin composition under the conditions described in the Examples below is preferably 3.5 or less, more preferably 3.2 or less, and particularly preferably 3.0 or less. The lower limit of the dielectric constant of the cured product is not particularly limited, but can be, for example, 2.0 or more. The dielectric constant of the cured product can be measured by the method described in the Examples.

When an insulating layer is formed from a cured product of a resin composition, the surface roughness of the insulating layer after roughening treatment can be reduced. For example, when an insulating layer is formed and roughened by the method described in the Examples below, the arithmetic mean roughness Ra of the surface of the insulating layer is preferably 200 nm or less, more preferably 100 nm or less, and particularly preferably 70 nm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but can be, for example, 10 nm or more. The arithmetic mean roughness Ra of the surface of the insulating layer can be measured by the method described in the Examples.

When an insulating layer is formed from a cured resin composition and a conductor layer is formed on the insulating layer by plating, the plating peel strength as the adhesive strength between the insulating layer and the conductor layer can be increased. For example, when the insulating layer and the conductor layer are formed by the method described in the Examples below, the plating peel strength between the insulating layer and the conductor layer can be preferably 0.3 kgf/cm or more, more preferably 0.4 kgf/cm or more, and particularly preferably 0.5 kgf/cm or more. The upper limit of the plating peel strength is not particularly limited, but can be, for example, 2.0 kgf/cm or less. The plating peel strength between the insulating layer and the conductor layer can be measured by the method described in the Examples.

[12. Uses of resin composition]
The resin composition according to one embodiment of the present invention is suitable as a resin composition for insulating purposes, and is particularly suitable as a resin composition for forming an insulating layer. Thus, for example, the resin composition is suitable as a resin composition for forming an insulating layer of a printed wiring board (a resin composition for forming an insulating layer of a printed wiring board). In addition, the resin composition is suitable as a resin composition for forming an insulating layer for forming a conductor layer (including a rewiring layer) formed on an insulating layer (a resin composition for forming an insulating layer for forming a conductor layer). The resin composition can also be used in a wide range of applications in which the resin composition can be used, such as a resin sheet, a sheet-like laminate material such as a prepreg, a solder resist, an underfill material, a die bonding material, a semiconductor encapsulant, a hole filling resin, and a component embedding resin.

Furthermore, for example, when a semiconductor chip package is manufactured through the following steps (1) to (6), the resin composition according to the present embodiment is also suitable as a resin composition for forming a rewiring formation layer 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.

The above-mentioned resin composition can also be used when the printed wiring board is a circuit board with built-in components.

[13. Sheet-like laminate material]
The resin composition according to one embodiment of the present invention can be used by coating in a varnish state, but is preferably used industrially in the form of a sheet-like laminate material containing the resin composition. As the sheet-like laminate material, the following resin sheets and prepregs are preferred.

The resin sheet includes a support and a resin composition layer formed on the support with the above-mentioned resin composition layer.

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 insulation 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 be, for example, 3 μm or more, 5 μm or more, etc.

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

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

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

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

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

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

In one embodiment, the resin sheet may further include an optional layer as necessary. For example, such an optional layer may be a protective film similar to the support provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress adhesion of dirt and 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 the resin composition in a solvent, applying the resin varnish to a support using a coating device such as a die coater, and then drying to form a resin composition layer. Examples of the solvent include the same ones as those described as component (G) that the resin composition may contain. The solvent may be used alone or in combination of two or more kinds in any ratio.

Drying may be performed by heating, blowing hot air, or other methods. 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 1 minute 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.

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

The sheet-like fiber substrate used for the prepreg is not particularly limited, and examples thereof include glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric. From the viewpoint of thinning the printed wiring board, the thickness of the sheet-like fiber substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. The lower limit of the thickness of the sheet-like fiber substrate is not particularly limited, but is usually 10 μm or more.

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

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

[14. Printed Wiring Board]
A printed wiring board according to one embodiment of the present invention includes an insulating layer formed of a cured product obtained by curing the above-described resin composition.

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 a resin sheet on an inner layer substrate so that a resin composition layer of the resin sheet is bonded to the inner layer substrate; and (II) a step of curing the resin composition layer to form an insulating layer.

The "inner layer substrate" used in step (I) is a member that will be the substrate of the printed wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may have a conductor layer on one or both sides, and the conductor layer may be patterned. An inner layer substrate having a conductor layer 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." When the printed wiring board is a circuit board with built-in components, an inner layer substrate with built-in components 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 (such as a 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 may be performed under reduced pressure conditions, preferably at 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 atmospheric pressure, for example by pressing a thermocompression member from the support side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for the lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

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

In step (II), the resin composition layer is cured to form an insulating layer made of a cured product of the resin composition. The curing conditions for the resin composition layer are not particularly limited, and the conditions employed for forming an insulating layer of a printed wiring board may be used. Typically, the curing of the resin composition layer proceeds as thermal curing.

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

Before the resin composition layer is thermally cured, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 120°C, preferably 60°C to 115°C, and more preferably 70°C to 110°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

The method for producing a printed wiring board may further include (III) a step of drilling holes in the insulating layer, (IV) a step of roughening the insulating layer, and (V) a step of forming a conductor layer. When the support is removed after step (II), the removal of the support may be performed between step (II) and step (III), between step (III) and step (IV), or between step (IV) and step (V). In addition, the formation of the insulating layer and the conductor layer in steps (I) to (V) may be repeated as necessary to form a multilayer wiring board.

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

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

Step (IV) is a step of roughening the insulating layer. Usually, smears are also removed in this step (IV). The procedure and conditions of the roughening treatment are not particularly limited. For example, the insulating layer can be roughened by carrying out a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order.

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

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

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

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

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

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

The conductor layer is preferably formed by plating. For example, the surface of the insulating layer can be plated by a semi-additive method, a full-additive method, or the like to form a conductor layer having a desired wiring pattern. 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 a conductor layer by a semi-additive method is shown.

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.

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

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

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the operations described below were carried out in an environment of normal temperature and pressure, unless otherwise specified.

[Preparation of maleimide compound]
An MEK solution (non-volatile content 70% by mass) of maleimide compound _A1 synthesized by the method described in Synthesis Example 1 of Japan Institute of Invention and Innovation Disclosure Technical Journal Publication No. 2020-500211 was prepared. This maleimide compound _A1 is represented by the following formula.

When the FD-MS spectrum of maleimide compound _A1 is measured, peaks at M+=560, 718 and 876 are confirmed. These peaks correspond to the cases where _n1 is 0, 1 and 2, respectively. Furthermore, when maleimide compound _A1 is analyzed by GPC and the value of the number of repeating units _n1 of the indane skeleton portion is calculated based on the number average molecular weight, _n1 =1.47, and the molecular weight distribution (Mw/Mn)=1.81. Furthermore, the content of maleimide compounds having an average number of repeating units _n1 of 0 is 26.5 area % in the total amount (100 area %) of maleimide compound _A1 .

The FD-MS spectrum of the maleimide compound _A1 was measured using the following measuring device and under the following measuring conditions.
(FD-MS spectrum measuring device and measuring conditions)
Measurement device: JMS-T100GC AccuTOF
Measurement conditions Measurement range: m/z = 4.00 to 2000.00
Rate of change: 51.2mA/min
Final current value: 45mA
Cathode voltage: -10 kV
Recording interval: 0.07 sec

The GPC of the maleimide compound _A1 was measured using the following measuring device and under the following measuring conditions.
Measuring device: Tosoh Corporation "HLC-8320 GPC"
Columns: Tosoh Corporation guard column "HXL-L", Tosoh Corporation "TSK-GEL G2000HXL", Tosoh Corporation "TSK-GEL G2000HXL", Tosoh Corporation "TSK-GEL G3000HXL", and Tosoh Corporation "TSK-GEL G4000HXL"
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation "GPC Workstation EcoSEC-WorkStation"
Measurement conditions: Column temperature 40°C
Developing solvent: Tetrahydrofuran
Flow rate: 1.0 ml/min. Standard: Monodisperse polystyrene with a known molecular weight is used in accordance with the measurement manual for the aforementioned "GPC Workstation EcoSEC-WorkStation."
Sample: A tetrahydrofuran solution of 1.0% by mass, calculated as the non-volatile component of the maleimide compound, filtered through a microfilter (50 μl).

The molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of the maleimide compound _A1 and the average number of repeating units "n ₁ " contributing to the indane skeleton in the maleimide compound are calculated from the GPC chart obtained by the above-mentioned GPC measurement. The average number of repeating units "n ₁ " is calculated based on the number average molecular weight (Mn). Specifically, for compounds in which n ₁ is 0 to 4, the theoretical molecular weight and the molecular weight measured by GPC are plotted on a scatter diagram, and an approximate straight line is drawn. Then, the number average molecular weight (Mn) is obtained from the point indicated by the measured value Mn(1) on this straight line, and the average repeating unit "n ₁ " is calculated. Furthermore, based on the results of the GPC measurement, the content ratio (area %) of the maleimide compound in which the average number of repeating units n ₁ is 0 in the total amount of the maleimide compound _A1 (100 area %) is calculated. For details, please refer to the Japan Institute of Invention and Innovation's Technical Journal Publication No. 2020-500211.

[Example 1]
The above-mentioned maleimide compound A ₁ (solution with 70% by mass of non-volatile components) was mixed with 20 parts, a liquid naphthalene skeleton-containing epoxy resin (DIC Corporation's "HP-4032-SS", epoxy equivalent 144 g/eq.) was mixed with 10 parts, a dicyclopentadiene-type diphenol structure-containing active ester curing agent (DIC Corporation's "HPC-8000-65T", a toluene solution with 65% by mass of non-volatile components, active ester group equivalent 223 g/eq.) was mixed with 30 parts, and an inorganic filler (spherical silica (Admatechs Corporation's "SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² ) surface-treated with an amine-based alkoxysilane compound (Shin-Etsu Chemical Co., Ltd.'s "KBM573") was mixed with 10 parts of the above-mentioned epoxy resin. 80 parts of the hydroxyethyl ether ester (1B2PZ/g) and 0.5 parts of a curing accelerator (imidazole compound "1B2PZ" manufactured by Shikoku Kasei Corporation) were mixed and uniformly dispersed using a high-speed rotating mixer to obtain a resin varnish.

A polyethylene terephthalate film with a release layer ("AL5" manufactured by Lintec Corporation, thickness 38 μm) was prepared as a support. The resin varnish was uniformly applied onto the release layer of this support so that the thickness of the resin composition layer after drying would be 40 μm. The resin varnish was then dried at 80°C to 100°C (average 90°C) for 4 minutes to obtain a resin sheet including a support and a resin composition layer.

[Example 2]
Instead of an active ester curing agent containing a dicyclopentadiene-type diphenol structure (DIC Corporation's "HPC-8000-65T"), 30 parts of an active ester compound containing a naphthalene structure (DIC Corporation's "HPC-8150-62T", a toluene solution containing 62% by mass of non-volatile components, active ester group equivalent of 229 g/eq.) was used. A resin sheet was produced in the same manner as in Example 1, except for the above points.

[Example 3]
The amount of maleimide compound A ₁ (solution with 70% by mass of non-volatile components) was changed from 20 parts to 15 parts. In addition, instead of an active ester curing agent containing a dicyclopentadiene-type diphenol structure (DIC Corporation's "HPC-8000-65T"), 30 parts of an active ester compound containing a naphthalene structure (DIC Corporation's "HPC-8150-62T", a toluene solution with 62% by mass of non-volatile components, active ester group equivalent of 229 g/eq.) was used. Furthermore, 5 parts of a biphenylaralkyl-type maleimide compound (Nippon Kayaku Co., Ltd.'s "MIR-3000-70MT", maleimide group equivalent: 275 g/eq., MEK/toluene mixed solution with 70% non-volatile components) were added to the resin composition. A resin sheet was produced in the same manner as in Example 1, except for the above items.

[Example 4]
The amount of maleimide compound A ₁ (solution of 70% by mass of non-volatile components) was changed from 20 parts to 18 parts. In addition, instead of an active ester curing agent containing a dicyclopentadiene-type diphenol structure (DIC Corporation's "HPC-8000-65T"), 30 parts of an active ester compound containing a naphthalene structure (DIC Corporation's "HPC-8150-62T", a toluene solution of 62% by mass of non-volatile components, active ester group equivalent of 229 g/eq.) was used. Furthermore, 2 parts of a liquid aliphatic maleimide compound (Designer Molecules'"BMI-1500", maleimide group equivalent of 750 g/eq.) were added to the resin composition. A resin sheet was produced in the same manner as in Example 1, except for the above items.

[Example 5]
Instead of the active ester curing agent containing a dicyclopentadiene type diphenol structure (DIC Corporation's "HPC-8000-65T"), 25 parts of an active ester compound containing a naphthalene structure (DIC Corporation's "HPC-8150-62T", a toluene solution containing 62% by mass of non-volatile components, active ester group equivalent of 229 g/eq.) was used. In addition, the amount of the curing accelerator (Shikoku Kasei Corporation's imidazole compound "1B2PZ") was changed from 0.5 parts to 0.1 parts. Furthermore, 5 parts of a triazine skeleton-containing cresol novolac-based curing agent (DIC Corporation's "LA-3018-50P", hydroxyl group equivalent: about 151, 2-methoxypropanol solution containing 50% non-volatile components) were added to the resin composition. A resin sheet was produced in the same manner as in Example 1, except for the above items.

[Comparative Example 1]
Maleimide compound _A1 was not used. In addition, instead of an active ester curing agent containing a dicyclopentadiene type diphenol structure (DIC Corporation's "HPC-8000-65T"), 30 parts of an active ester compound containing a naphthalene structure (DIC Corporation's "HPC-8150-62T", a toluene solution containing 62% by mass of non-volatile components, active ester group equivalent of 229 g/eq.) was used. Furthermore, the amount of inorganic filler was changed from 80 parts to 55 parts. A resin sheet was produced in the same manner as in Example 1, except for the above points.

[Comparative Example 2]
Instead of 20 parts of maleimide compound A ₁ (solution with 70% non-volatile content), 20 parts of a biphenylaralkyl type maleimide compound ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., maleimide group equivalent: 275 g/eq., MEK/toluene mixed solution with 70% non-volatile content) was used. In addition, instead of an active ester curing agent containing a dicyclopentadiene type diphenol structure ("HPC-8000-65T" manufactured by DIC Corporation), 30 parts of an active ester compound containing a naphthalene structure ("HPC-8150-62T" manufactured by DIC Corporation, toluene solution with 62% non-volatile content, active ester group equivalent 229 g/eq.) was used. A resin sheet was produced in the same manner as in Example 1, except for the above items.

[Comparative Example 3]
Instead of 20 parts of maleimide compound _A1 (solution containing 70% by mass of non-volatile components), 14 parts of a liquid aliphatic maleimide compound (Designer Molecules'"BMI-1500", maleimide group equivalent 750 g/eq.) was used. In addition, instead of an active ester curing agent containing a dicyclopentadiene-type diphenol structure (DIC's "HPC-8000-65T"), 30 parts of an active ester compound containing a naphthalene structure (DIC's "HPC-8150-62T", toluene solution containing 62% by mass of non-volatile components, active ester group equivalent 229 g/eq.) was used. A resin sheet was produced in the same manner as in Example 1, except for the above.

[Measurement of dielectric properties]
The resin sheets prepared in the examples and comparative examples were heated at 200°C for 90 minutes to thermally cure the resin composition layer. The support was then peeled off to obtain a cured product of the resin composition. The cured product was cut into test pieces having a width of 2 mm and a length of 80 mm. The dielectric constant Dk and dielectric loss tangent Df of the test pieces were measured at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C using an Agilent Technologies "HP8362B" by a cavity resonance perturbation method. Measurements were performed on three test pieces, and the average values are shown in the table below.

[Measurement of plating peel strength]
(1) Surface preparation of inner layer circuit board:
As an inner layer circuit board, a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, Panasonic "R1515A") having inner layer circuits (copper foil) on both sides was prepared. Both sides of this inner layer circuit board were etched by 1 μm using MEC's "CZ8101" to roughen the copper surface.

(2) Lamination of resin sheet:
The resin sheet was laminated on both sides of the inner layer circuit board using a batch type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator, CVP700). This lamination was performed so that the resin composition layer of the resin sheet was in contact with the inner layer circuit board. This lamination was also performed by reducing the pressure for 30 seconds to 13 hPa or less, and pressing at 130°C and a pressure of 0.74 MPa for 45 seconds. Next, a heat press was performed at 120°C and a pressure of 0.5 MPa for 75 seconds.

(3) Curing of resin composition:
The laminated resin sheet and the inner layer circuit board were heated at 130° C. for 30 minutes, and then heated at 170° C. for 30 minutes to harden the resin composition and form an insulating layer. Thereafter, the support was peeled off to obtain a laminated substrate having the insulating layer, the inner layer circuit board, and the insulating layer in this order.

(4) Roughening treatment:
The laminated substrate was immersed in a swelling liquid (Swelling Dip Securigant P (aqueous solution of glycol ethers and sodium hydroxide) containing diethylene glycol monobutyl ether, manufactured by Atotech Japan) at 60° C. for 10 minutes. Next, the laminated substrate was immersed in a roughening liquid (Concentrate Compact P (aqueous solution of KMnO ₄ : 60 g/L, NaOH: 40 g/L) manufactured by Atotech Japan) at 80° C. for 20 minutes. Thereafter, the laminated substrate was immersed in a neutralizing liquid (Reduction Showreusin Securigant P (aqueous solution of sulfuric acid) manufactured by Atotech Japan) at 40° C. for 5 minutes. The laminated substrate was then dried at 80° C. for 30 minutes to obtain "Evaluation Substrate A".

(5) Semi-additive plating:
Evaluation substrate A was immersed in an electroless plating solution containing _PdCl2 at 40°C for 5 minutes, and then immersed in an electroless copper plating solution at 25°C for 20 minutes. After that, it was heated at 150°C for 30 minutes and annealed. After that, an etching resist was formed, and a pattern was formed by etching. Then, copper sulfate electrolytic plating was performed to form a conductor layer with a thickness of 20 μm. Next, an annealing treatment was performed at 200°C for 60 minutes to obtain "evaluation substrate B".

(6) Measurement of plating peel strength:
A cut was made in the conductor layer of evaluation board B, surrounding a rectangular portion 10 mm wide and 100 mm long. One end of the rectangular portion was peeled off and held with a gripper (Autocom type testing machine "AC-50C-SL" manufactured by TSE Corporation). The rectangular portion was peeled off in the vertical direction at room temperature at a speed of 50 mm/min with the gripper, and the load (kgf/cm) when 35 mm was peeled off was measured as the plating peel strength.

[Measurement of surface roughness Ra]
The arithmetic mean roughness Ra of the surface of the insulating layer of the evaluation substrate A prepared in the above [Measurement of plating peel strength] was measured. The measurement was performed using a non-contact surface roughness meter (WYKO NT3300 manufactured by Veeco Instruments) in VSI mode with a 50x lens, with a measurement range of 121 μm x 92 μm. This measurement was performed at 10 measurement points, and the average values are shown in the table below.

[Measurement of glass transition temperature Tg]
The resin sheet was heated in an oven at 190° C. for 90 minutes to cure the resin composition layer. The support was then peeled off to obtain a cured product of the resin composition layer. This cured product was cut into a length of 20 mm and a width of 6 mm to obtain a cured product for evaluation.
For this cured product for evaluation, a first TMA curve was obtained using a thermomechanical analyzer (TMA) manufactured by Rigaku Corporation, with a temperature rise rate of 5°C/min from 25°C to 250°C by the tensile load method. The same measurements were then performed on the same cured product for evaluation to obtain a second TMA curve. The glass transition temperature Tg (°C) was calculated from the second TMA curve obtained.

[result]
The results of the examples and comparative examples are shown in Table 1 below.

Claims (7)

(A) a maleimide compound, (B) an epoxy resin, (C) an active ester curing agent, and (D) an inorganic filler,
(A) the maleimide compound includes (A-1) a maleimide compound having a trimethylindane skeleton,
The component (A-1) contains a structure represented by the following formula (A4):
The amount of the (A-1) component is 2% by mass or more and 50% by mass or less, based on 100% by mass of the resin component in the resin composition;
the amount of the component (A-1) is 60% by mass or more and 200% by mass or less, relative to 100% by mass of the epoxy resin (B) in the resin composition;
The amount of the (B) component is 20% by mass or more and 40 % by mass or less, based on 100% by mass of the resin component in the resin composition;
The amount of the (C) component is 30% by mass or more and 60 % by mass or less, based on 100% by mass of the resin component in the resin composition;
The amount of the (D) component is 50% by mass or more and 90% by mass or less based on 100% by mass of the non-volatile components in the resin composition,
A resin composition, wherein a cured product of the resin composition heated at 200°C for 90 minutes has a dielectric loss tangent Df of 0.004 or less, as measured by a cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C.

(In formula (A4),
Ar ^a1 represents a divalent aromatic hydrocarbon group which may have a substituent;
R ^a1 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group;
R ^a2 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group;
Each R ^a3 independently represents a divalent aliphatic hydrocarbon group;
n _a1 represents a positive integer;
Each n _a2 independently represents an integer of 0 to 4;
Each of n _{and a3} independently represents an integer of 0 to 3.
The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group and cycloalkyl group of R ^a1 may be substituted with a halogen atom.
The hydrogen atom of the alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group and cycloalkyl group of R ^a2 may be substituted with a halogen atom.
When n _a2 is 2 to 4, R ^a1 may be the same or different in the same ring.
When n _a3 is 2 to 3, R ^a2 may be the same or different in the same ring. The resin composition according to claim 1, wherein the amount of component (A) is 2% by mass or more and 50% by mass or less relative to 100% by mass of the resin components in the resin composition. The resin composition according to claim 1 or 2, which is for forming an insulating layer. A cured product of the resin composition according to any one of claims 1 to 3. A resin sheet comprising a support and a resin composition layer formed on the support from the resin composition according to any one of claims 1 to 3. A printed wiring board comprising an insulating layer formed from a cured product of the resin composition according to any one of claims 1 to 3. A semiconductor device including the printed wiring board according to claim 6.