JP7480808B2 - Resin composition, resin sheet, printed wiring board and semiconductor device - Google Patents

Description

The present invention relates to a resin composition. It also relates to a resin sheet containing the resin composition; a printed wiring board containing a cured product of the resin composition; and a semiconductor device containing the printed wiring board.

A known manufacturing technique for printed wiring boards is the build-up method, in which insulating layers and conductor layers are stacked alternately. In the build-up method, the insulating layers are generally formed by curing a resin composition.

As a resin composition or resin film for forming the insulating layer, a resin composition or resin film containing a maleimide compound has been proposed (for example, Patent Documents 1 to 4).

Specifically, Patent Document 1 discloses a thermosetting resin composition containing a maleimide compound having a melting point of 40°C or less, an epoxy compound, a cyanate ester compound, and an inorganic filler.

Patent Document 2 also discloses a resin film for manufacturing printed wiring boards for millimeter wave radar, which is obtained by a manufacturing method including a step of mixing a compound having a maleimide group, a divalent group having at least two imide bonds, and a saturated or unsaturated divalent hydrocarbon group with a spherical inorganic filler.

Patent Document 3 discloses a liquid epoxy resin composition containing an epoxy resin, an imidazole curing accelerator, and a maleimide compound.

Patent Document 4 discloses that a maleimide compound can be used as a thermosetting resin. Patent Document 4 also discloses that a phosphorus-containing benzoxazine compound can be used as a flame retardant.

JP 2016-010964 A JP 2017-125128 A JP 2018-070668 A JP 2011-144361 A

In recent years, in order to further promote labor saving in printed wiring boards, the cured resin composition for forming an insulating layer is required to have a low dielectric tangent. However, as a result of the inventor's research, it was found that the low dielectric tangent required in recent years cannot be met depending on the type of maleimide compound contained in the resin composition.

Furthermore, as a result of the inventor's research, it was found that when a via hole is formed after curing a resin composition whose composition has been adjusted to have a low dielectric tangent, the smear removal may be poor. Here, smear refers to residue generated after processing. If the smear removal is poor, the electrical conductivity reliability around the via hole cannot be ensured, and as a result, the connection reliability of the printed wiring board obtained using the resin composition is also poor. Furthermore, if the smear removal is poor, it is not possible to accommodate recent circuit designs, particularly finer and more densely packed wiring, and this also results in poor connection reliability in the printed wiring board.

In addition, since the insulating layer made of the cured resin composition is in contact with a conductor layer, it is required to have good adhesive strength between the insulating layer and the conductor layer (e.g., copper foil as plating or base layer), and it is desirable to be able to achieve further improvement in adhesive strength. This is expected to make it possible to accommodate a variety of circuit designs.

The object of the present invention is to provide a resin composition capable of forming a cured product having a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer; a resin sheet containing the resin composition; a printed wiring board containing a cured product of the resin composition; and a semiconductor device containing the printed wiring board.

In order to achieve the object of the present invention, the inventors conducted extensive research and discovered that a resin composition containing an epoxy resin can be provided that contains a specific maleimide compound and a specific component, and that is capable of forming a cured product that has a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer, and thus completed the present invention.

［３］ 一般式（Ｂ－Ｉ）中、Ｌは、酸素原子、置換基を有していてもよい炭素原子数６～２４のアリーレン基、置換基を有していてもよい炭素原子数が１～５０のアルキレン基、炭素原子数が５以上のアルキル基、フタルイミド由来の２価の基、ピロメリット酸ジイミド由来の２価の基、又はこれらの基の２以上の組み合わせからなる２価の基である、［２］に記載の樹脂組成物。
［４］ （Ｂ）成分が、下記一般式（Ｂ－ＩＩ）で表される、［１］に記載の樹脂組成物。

［５］ 一般式（Ｂ－ＩＩ）中、Ａはそれぞれ独立に、置換基を有していてもよい炭素原子数が５以上の環状のアルキレン基；置換基を有していてもよいベンゼン環を有する２価の基；置換基を有していてもよいフタルイミド環を有する２価の基；又は置換基を有していてもよいピロメリット酸ジイミド環を有する２価の基を表す、［４］に記載の樹脂組成物。
［６］ （Ｂ）成分の含有量が、樹脂組成物中の不揮発成分を１００質量％とした場合、０．１質量％以上２０質量％以下である、［１］～［５］のいずれかに記載の樹脂組成物。
［７］ （Ｃ）成分が、下記一般式（Ｃ－Ｉ）で表されるベンゾオキサジン化合物を含む、［１］～［６］のいずれかに記載の樹脂組成物。

［８］ 一般式（Ｃ－Ｉ）中、Ｒ^ａはアリーレン基、アルキレン基、酸素原子、又はこれらの２以上の組み合わせからなるｋ価の基である、［７］に記載の樹脂組成物。
［９］ 一般式（Ｃ－Ｉ）中、ｌは０を表す、［７］又は［８］に記載の樹脂組成物。
［１０］ （Ｃ）成分が、下記式（Ｃ－ＩＩ）で表される構造を含有するカルボジイミド化合物を含む、［１］～［９］のいずれかに記載の樹脂組成物。

［１１］ （Ｃ）成分の含有量が、樹脂組成物中の不揮発成分を１００質量％とした場合、０．１質量％以上３０質量％以下である、［１］～［１０］のいずれかに記載の樹脂組成物。
［１２］ （Ｄ）無機充填材を含む、［１］～［１１］のいずれかに記載の樹脂組成物。
［１３］ （Ｄ）成分が、アミノシランで表面処理されている、［１２］に記載の樹脂組成物。
［１４］ （Ｄ）成分の含有量が、樹脂組成物中の不揮発成分を１００質量％とした場合、４０質量％以上９５質量％以下である、［１２］又は［１３］に記載の樹脂組成物。
［１５］ プリント配線板の絶縁層形成用である、［１］～［１４］のいずれかに記載の樹脂組成物。
［１６］ 支持体と、該支持体上に設けられた［１］～［１５］のいずれかに記載の樹脂組成物を含む樹脂組成物層とを含む、樹脂シート。
［１７］ ［１］～［１５］のいずれかに記載の樹脂組成物の硬化物を含む、プリント配線板。
［１８］ ［１７］に記載のプリント配線板を含む、半導体装置。 That is, the present invention includes the following.
[1] A composition comprising (A) an epoxy resin, (B) a maleimide compound, and (C) a component, wherein the component (B) is a maleimide compound containing at least one hydrocarbon chain selected from the group consisting of an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms, and the component (C) is one or more compounds selected from the group consisting of (C-1) a benzoxazine compound and (C-2) a carbodiimide compound.
Resin composition.
[2] The resin composition according to [1], wherein the component (B) is represented by the following general formula (BI):

[3] In general formula (BI), L is an oxygen atom, an arylene group having 6 to 24 carbon atoms which may have a substituent, an alkylene group having 1 to 50 carbon atoms which may have a substituent, an alkyl group having 5 or more carbon atoms, a divalent group derived from phthalimide, a divalent group derived from pyromellitic diimide, or a divalent group consisting of a combination of two or more of these groups. The resin composition according to [2].
[4] The resin composition according to [1], wherein the component (B) is represented by the following general formula (B-II):

[5] In the general formula (B-II), each A independently represents a cyclic alkylene group having 5 or more carbon atoms which may have a substituent; a divalent group having a benzene ring which may have a substituent; a divalent group having a phthalimide ring which may have a substituent; or a divalent group having a pyromellitic diimide ring which may have a substituent, the resin composition according to [4].
[6] The resin composition according to any one of [1] to [5], wherein the content of the component (B) is 0.1 mass% or more and 20 mass% or less, when the non-volatile components in the resin composition are 100 mass%.
[7] The resin composition according to any one of [1] to [6], wherein the component (C) contains a benzoxazine compound represented by the following general formula (CI):

[8] The resin composition according to [7], wherein in general formula (CI), R ^a is an arylene group, an alkylene group, an oxygen atom, or a k-valent group consisting of a combination of two or more thereof.
[9] The resin composition according to [7] or [8], wherein in general formula (CI), l represents 0.
[10] The resin composition according to any one of [1] to [9], wherein the component (C) contains a carbodiimide compound having a structure represented by the following formula (C-II):

[11] The resin composition according to any one of [1] to [10], wherein the content of the component (C) is 0.1 mass% or more and 30 mass% or less, when the total amount of non-volatile components in the resin composition is 100 mass%.
[12] The resin composition according to any one of [1] to [11], further comprising (D) an inorganic filler.
[13] The resin composition according to [12], wherein the component (D) is surface-treated with aminosilane.
[14] The resin composition according to [12] or [13], wherein the content of the (D) component is 40% by mass or more and 95% by mass or less, when the total amount of non-volatile components in the resin composition is 100% by mass.
[15] The resin composition according to any one of [1] to [14], which is for forming an insulating layer of a printed wiring board.
[16] A resin sheet comprising a support and a resin composition layer provided on the support, the resin composition layer comprising the resin composition according to any one of [1] to [15].
[17] A printed wiring board comprising a cured product of the resin composition according to any one of [1] to [15].
[18] A semiconductor device comprising the printed wiring board according to [17].

The present invention provides a resin composition capable of forming a cured product having a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer; a resin sheet containing the resin composition; a printed wiring board containing a cured product of the resin composition; and a semiconductor device containing the printed wiring board.

FIG. 1 is a partial cross-sectional view showing a schematic example of a printed wiring board.

The resin composition, resin sheet, printed wiring board, and semiconductor device of the present invention are described in detail below.

[1. Resin composition]
Hereinafter, the resin composition according to the embodiment of the present invention will be described in detail.

The resin composition according to this embodiment contains (A) an epoxy resin, (B) a maleimide compound, and (C) a component, where the (B) component contains at least one of an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms, and the (C) component is one or more compounds selected from the group consisting of (C-1) a benzoxazine compound and (C-2) a carbodiimide compound.

By including the epoxy resin in the resin composition, which contains the components (B) and (C), it is possible to provide a resin composition that has a low dielectric tangent, excellent smear removal properties, and is capable of forming a cured product that has excellent adhesive strength with the conductor layer.

In addition to the components (A) to (C), the resin composition may contain, as necessary, an inorganic filler (D), a curing agent (E), a curing accelerator (F), and any additives (G). Each component contained in the resin composition of the present invention will be described in detail below.

<(A) Epoxy Resin>
The resin composition includes an epoxy resin (A). Examples of the epoxy resin (A) include bixylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac 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, and tetraphenylethane type epoxy resin. The epoxy resins may be used alone or in combination of two or more.

(A) The epoxy resin preferably has two or more epoxy groups in one molecule. When the non-volatile components of the epoxy resin are taken as 100% by mass, it is preferable that at least 50% by mass of the epoxy resin has two or more epoxy groups in one molecule. In particular, the resin composition preferably contains a combination of an epoxy resin that is liquid at a temperature of 20°C (hereinafter also referred to as a "liquid epoxy resin") and an epoxy resin that is solid at a temperature of 20°C (hereinafter also referred to as a "solid epoxy resin"). As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferable, and an aromatic liquid epoxy resin having two or more epoxy groups in one molecule is more preferable. 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. In the present invention, an aromatic epoxy resin means an epoxy resin having an aromatic ring in its molecule.

Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, with bisphenol A type epoxy resins and bisphenol F type epoxy resins being more preferred. Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation, "828US", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins), "jER807", "1750" (bisphenol F type epoxy resins), "jER152" (phenol novolac type epoxy resins), "630", and "630LSD" (glycidylamine type epoxy resins) manufactured by Mitsubishi Chemical Corporation, and "ZX-1059" (bisphenol A type epoxy resins) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Examples include "EX-721" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nagase ChemteX Corporation (glycidyl ester type epoxy resin), "Celloxide 2021P" (alicyclic epoxy resin with an ester skeleton) and "PB-3600" (epoxy resin with a butadiene structure) manufactured by Daicel Corporation, "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and "630LSD" (glycidylamine type epoxy resin) manufactured by Mitsubishi Chemical Corporation. These may be used alone or in combination of two or more.

As solid epoxy resins, bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins are preferred, with naphthalene type epoxy resins being more preferred. Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), "N-690" (cresol novolac type epoxy resin), "N-695" (cresol novolac type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "HP-7200HH", "HP-7200H", "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin), and "EPPN-502H" (trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", and "NC Examples of epoxy resins include "ESN-475V" (naphthalene type epoxy resin) and "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), and "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., "YL7760" (bisphenol AF type epoxy resin) and "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (solid bisphenol A type epoxy resin), and "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation. These may be used alone or in combination of two or more.

When liquid epoxy resin and solid epoxy resin are used in combination as component (A), the ratio of the amounts (liquid epoxy resin:solid epoxy resin) is preferably in the range of 1:1 to 1:20 by mass. By setting the ratio of the liquid epoxy resin to the solid epoxy resin in this range, the following effects can be obtained: i) when used in the form of a resin sheet, appropriate adhesion is obtained; ii) when used in the form of a resin sheet, sufficient flexibility is obtained and handling is improved; and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects i) to iii) above, the ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin:solid epoxy resin) is more preferably in the range of 1:1 to 1:15 by mass, and even more preferably in the range of 1:1 to 1:10 by mass.

From the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulating reliability, the content of the (A) component in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. The upper limit of the epoxy resin content is not particularly limited as long as the effects of the present invention are exhibited, but is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.
In the present invention, the content of each component in the resin composition is a value when the non-volatile components in the resin composition are taken as 100 mass %, unless otherwise specified.

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

The weight average molecular weight of component (A) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

<(B) Maleimide Compound>
The resin composition contains, as component (B), a maleimide compound containing at least one hydrocarbon chain selected from an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms. The maleimide compound (B) is a compound containing a maleimide group represented by the following formula (1) in the molecule.

(B) The maleimide compound contains at least one of the following hydrocarbon groups: an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms. A maleimide compound containing at least one of the following hydrocarbon chains: an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms tends to be able to lower the dielectric tangent value of the cured product of the resin composition compared to a maleimide compound that does not contain such a hydrocarbon chain.

Furthermore, since compounds containing maleimide groups in the molecule are easily soluble in alkaline solutions, by including component (B) in the resin composition, it is usually possible to obtain a cured product with excellent smear removal properties.

Since an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms have a long carbon chain, they usually exhibit hydrophobicity. Therefore, the maleimide compound (B) is not easily deteriorated in a high humidity environment, and for example, even after a HAST test, delamination accompanied by destruction of the insulating layer can be suppressed. As a result, by containing the resin composition (B), it is possible to obtain an insulating layer having high adhesion with a conductor layer (particularly a conductor layer formed by plating). Here, adhesion refers to the adhesion strength between a first object and a second object adjacent to each other, and may be the adhesion strength when the second object is formed on the surface of the first object, or the adhesion strength when the first object is formed on the surface of the second object. The adhesion strength can be measured by the method described in the examples below.

Maleimide compounds containing at least one of the hydrocarbon chains, an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms, tend to have a flexible molecular structure due to the action of the long carbon chain. Therefore, it is possible to achieve a lower minimum melt viscosity than maleimide compounds not containing such a hydrocarbon chain and maleimide compounds containing an arylene group as a main component. The minimum melt viscosity can be determined by measuring the melt viscosity by a dynamic viscoelastic method. For example, a dynamic viscoelasticity measuring device ("Rheosol-G3000" manufactured by UBM) can be used to measure a 1 g sample taken from the resin composition layer of the resin composition using a parallel plate having a diameter of 18 mm. The measurement conditions are set as follows: starting temperature 60°C to 200°C, heating rate 5°C/min, measurement temperature interval 2.5°C, and vibration 1 Hz/deg, and the minimum melt viscosity can be determined from the measured melt viscosity value obtained.

The number of carbon atoms of the alkyl group having 5 or more carbon atoms is preferably 6 or more, more preferably 8 or more, preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. This alkyl group may be linear, branched, or cyclic, and linear is preferred. Examples of such alkyl groups include pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. In addition, the maleimide compound of component (B) may have an alkyl group having 5 or more carbon atoms as a substituent of an alkylene group having 5 or more carbon atoms.

The number of carbon atoms in the alkylene group having 5 or more carbon atoms is preferably 6 or more, more preferably 8 or more, preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The alkylene group may be linear, branched, or cyclic, with linear being preferred. Here, the concept of a cyclic alkylene group includes both a case consisting of only a cyclic alkylene group and a case consisting of a cyclic alkylene group to which a linear or branched alkylene group is bonded. Examples of such alkylene groups include 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, and a group having a propylene-cyclohexylene-octylene structure.

(B) In the maleimide compound, it is preferable that the alkyl group having 5 or more carbon atoms and the alkylene group having 5 or more carbon atoms are directly bonded to the nitrogen atom of the maleimide group. Here, "directly" means that there is no other group between the nitrogen atom of the maleimide group and the alkyl group or alkylene group. This can provide particularly good adhesion.

From the viewpoint of obtaining an insulating layer having high adhesion between the cured product and the conductor layer, it is preferable that the (B) maleimide compound contains both an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms.

Alkyl groups having 5 or more carbon atoms and alkylene groups having 5 or more carbon atoms may be bonded to each other to form a ring, and the ring structure also includes a spiro ring and a condensed ring. Examples of rings formed by bonding to each other include a cyclohexane ring.

An alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms may or may not have a substituent. The substituent is not particularly limited, and examples thereof include a halogen atom, -OH, -O-C _1-6 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 _p-q " (p and q are positive integers, and p<q is satisfied) indicates that the number of carbon atoms in the organic group described immediately after this term is p to q. For example, the expression "C _1-10 alkyl group" indicates an alkyl group having 1 to 10 carbon atoms. These substituents may be bonded to each other to form a ring, and the ring structure also includes a spiro ring and a fused ring.

The above-mentioned substituents may further have a substituent (hereinafter, sometimes referred to as a "secondary substituent"). Unless otherwise specified, the secondary substituent may be the same as the above-mentioned substituent.

The number of maleimide groups per molecule of (B) maleimide compound may be one, but is preferably two or more, and is preferably ten or less, more preferably six or less, and particularly preferably three or less. By using (B) maleimide compound having two or more maleimide groups per molecule, an insulating layer having higher adhesion with the conductor layer can be obtained.

(B) The maleimide compound may be used alone or in combination of two or more.

The (B) maleimide compound may contain at least any one of a hydrocarbon group, an alkyl group having 5 or more carbon atoms, and an alkylene group having 5 or more carbon atoms. From the viewpoint of improving the performance of the cured product, particularly from the viewpoint of obtaining an insulating layer having higher adhesion to a conductor layer, it is preferable that the (B) maleimide compound is a maleimide compound represented by the following general formula (B-I):

Each R independently represents an alkylene group having 5 or more carbon atoms, which may have a substituent. R has the same meaning as the alkylene group having 5 or more carbon atoms described above, and the preferred range is also the same.

L represents a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, -C(=O)-, -C(=O)-O-, -NR ⁰ - (R ⁰ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), an oxygen atom, a sulfur atom, C(=O)NR ⁰ -, a divalent group derived from phthalimide, a divalent group derived from pyromellitic diimide, and a divalent group consisting of a combination of two or more of these groups. The divalent group derived from phthalimide represents a divalent group derived from phthalimide, specifically a group represented by the general formula (2). The divalent group derived from pyromellitic diimide represents a divalent group derived from pyromellitic diimide, specifically a group represented by the general formula (3). In the formula, "*" represents a bond.

As the alkylene group, an alkylene group having 1 to 50 carbon atoms is preferable, an alkylene group having 1 to 45 carbon atoms is more preferable, and an alkylene group having 1 to 40 carbon atoms is particularly preferable. This alkylene group may be linear, branched, or cyclic. Examples of such alkylene groups include 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, and a group having a propylene-cyclohexylene-octylene structure.

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

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

As the arylene group, an arylene group having 6 to 24 carbon atoms is preferable, an arylene group having 6 to 18 carbon atoms is more preferable, an arylene group having 6 to 14 carbon atoms is even more preferable, and an arylene group having 6 to 10 carbon atoms is even more preferable. Examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenylene group.

The divalent linking groups, alkylene, alkenylene, alkynylene, and arylene, may have a substituent. The substituent is the same as the substituent that may be possessed by the alkyl group having 5 or more carbon atoms represented by R in general formula (B-I), and is preferably an alkyl group having 5 or more carbon atoms.

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

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

The maleimide compound (B) may contain at least one of the hydrocarbon groups, an alkyl group having 5 or more carbon atoms and an alkylene group having 5 or more carbon atoms. From the viewpoint of improving the performance of the cured product, particularly from the viewpoint of obtaining an insulating layer having higher adhesion with the conductor layer, it is preferable that the maleimide compound is represented by the following general formula (B-II). The maleimide compound represented by the general formula (B-II) may be a maleimide compound that replaces the maleimide compound represented by the above general formula (B-I), or may be a maleimide compound included in the maleimide compound represented by the above general formula (B-I).

Each R' independently represents an alkylene group having 5 or more carbon atoms, which may have a substituent. R' may be the same as R in general formula (B-I).

Each A independently represents an alkylene group having 5 or more carbon atoms which may have a substituent, or a divalent group having an aromatic ring which may have a substituent. However, this does not include cases where A is an alkylene group consisting of only linear alkylene groups. When A represents an alkylene group, it may be either branched or cyclic, and among these, a cyclic alkylene group having 5 or more carbon atoms which may have a substituent is preferred. The number of carbon atoms is preferably 6 or more, more preferably 8 or more, preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. Examples of such alkylene groups include groups having an octylene-cyclohexylene structure, groups having an octylene-cyclohexylene-octylene structure, and groups having a propylene-cyclohexylene-octylene structure.

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

The alkylene group and the divalent group having an aromatic ring represented by A may have a substituent. The substituent is the same as the substituent that may be possessed by the alkyl group having 5 or more carbon atoms represented by R in the general formula (B-I).

Specific examples of the group represented by A include the following groups (4) to (6), in which "*" represents a bond.

n represents an integer from 1 to 15, preferably an integer from 1 to 10.

The maleimide compound represented by general formula (BI) or (B-II) is preferably a maleimide compound represented by general formula (B-III). Alternatively, the maleimide compound represented by general formula (B-II) is preferably a maleimide compound represented by general formula (B-IV).

^R1 each independently represents an alkylene group having 5 or more carbon atoms which may have a substituent. ^R1 is the same as the alkylene group having 5 or more carbon atoms represented by R in general formula (BI), and is preferably a hexatriacontylene group.

^R2 each independently represents 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 arylene group and the alkylene group are the same as the arylene group and the alkylene group in the divalent linking group represented by L in the general formula (B-I), and the preferred ranges are also the same. ^R2 is preferably a divalent group consisting of a combination of two or more of these groups or an oxygen atom.

Examples of divalent groups formed by combining two or more of these groups include combinations of oxygen atoms, arylene groups, and alkylene groups. Specific examples of divalent groups formed by combining two or more of these groups include the following group (7). In the formula, "*" represents a bond.

^R3 each independently represents an alkylene group having 5 or more carbon atoms which may have a substituent. ^R3 is the same as the alkylene group having 5 or more carbon atoms represented by R in general formula (BI), and is preferably a hexylene group, a heptylene group, an octylene group, a nonylene group, or a decylene group, more preferably an octylene group.

R ⁴ represents a divalent group having an aromatic ring which may have a substituent, each independently. R ⁴ is the same as the divalent group having an aromatic ring represented by A in the general formula (B-II), and is preferably a group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide; a group consisting of a combination of a divalent group derived from phthalimide and an alkylene group, and more preferably a group consisting of a combination of an alkylene group and a divalent group derived from pyromellitic diimide. The arylene group and alkylene group are the same as the arylene group and alkylene group in the divalent linking group represented by L in the general formula (B-I), and the preferred range is also the same.

Specific examples of the group represented by ^R4 include the following group (8): In the formula, "*" represents a bond.

Each ^R5 independently represents an alkyl group having 5 or more carbon atoms. ^R5 is the same as the above-mentioned alkyl group having 5 or more carbon atoms, and is preferably a hexyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group, more preferably a hexyl group or an octyl group.

n1 represents an integer from 1 to 15, preferably an integer from 1 to 10. n2 represents an integer from 0 to 10, preferably an integer from 1 to 8. n3 each independently represents an integer from 0 to 4, preferably an integer from 1 to 3, more preferably 2.

Specific examples of the maleimide compound (B) include the following compounds (9) to (12). However, the maleimide compound (B) is not limited to these specific examples. In the formulas (9), (10), and (11), n9, n10, and n11 each represent an integer of 1 to 10.

(B) Specific examples of maleimide compounds include "BMI-1500" (compound of formula (9)), "BMI-1700" (compound of formula (10)), "BMI-3000", "BMI-3000J" (compound of formula (11)), and "BMI-689" (compound of formula (12)), all manufactured by Designer Molecules.

The molecular weight of the (B) maleimide compound is preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more, from the viewpoint of improving adhesion to the conductor layer, and is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 60,000 or less.

The content of the maleimide compound (B) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. By setting the lower limit of the content of the (B) component within this range, it is possible to obtain a cured product with better adhesion between the insulating layer and the conductor layer and better smear removal properties. The upper limit is preferably less than the content of the (A) component in terms of non-volatile components, and may be, for example, 20% by mass or less, 16% by mass or less, 10% by mass or less, or 6% by mass or less. By setting the upper limit of the content of the (B) component within this range, the dielectric tangent value can be sufficiently low, and the adhesive strength with the plating, particularly the copper plating, can be sufficiently ensured.

<Component (C)>
In this embodiment, the component (C) is one or more compounds selected from the group consisting of a benzoxazine compound (C-1) and a carbodiimide compound (C-2). The benzoxazine compound (C-1) and the carbodiimide compound (C-2) may be used in combination.

By including the (C) component, the performance of the cured product of the resin composition can be improved. Here, the performance of the cured product is preferably one or more performances selected from the performance group of good smear removal, low dielectric tangent, and high adhesion strength with the conductor layer, and more preferably, two performances of good smear removal and high adhesion strength with the conductor layer. More preferably, the conductor layer includes at least both plating (e.g., copper plating) formed by plating on the cured product and a thin film (e.g., copper as a base layer) laminated on the cured product by pressure bonding. Usually, a thin film laminated by pressure bonding has a lower adhesion strength to the substrate than a plating, so that the (C) component particularly preferably improves the adhesion strength between the cured product and the thin film laminated on the cured product by pressure bonding. In addition, the (C) component may be considered as a component capable of forming a cured product having improved performance in a resin composition containing the (A) and (B) components by including the (C) component, compared to a case in which the (C) component is not included, or a component capable of forming a cured product having improved performance in a resin composition containing the (A) and (C) components by including the (B) component, compared to a case in which the (B) component is not included, or a component capable of forming a cured product having better performance in a resin composition containing the (A) component by including the (B) component and the (C) component (i.e., a component that improves the performance of the cured product together with the (B) component). In addition, the (C) component can improve the performance of the resin composition. For example, the (C) component has the ability to maintain the pot life of the resin composition for a sufficient time (for example, one day or more), and specifically, even if the (C) component is present in the resin composition together with the (B) component, gelation of the resin composition is not observed for a sufficient time.

<(C-1) Benzoxazine Compound>
The resin composition contains a benzoxazine compound (C-1). As illustrated in the examples described below, the benzoxazine compound (C-1) is one of the components that have been confirmed to improve the performance of the cured product of the resin composition and the performance of the resin composition by including the component (C) in a resin composition containing the component (A) and the component (B) compared to the case where the component (C) is not included. Specifically, the benzoxazine compound (C-1) can maintain a sufficient pot life (for example, one day or more) compared to the case where the component (C-1) is not used by using it in combination with the component (B) in a resin composition containing the component (A), and the cured product can maintain a low value of the dielectric tangent, can maintain good smear removability, can further improve plating adhesion, and can significantly improve the adhesion to the base.

The (C-1) benzoxazine compound is a compound having a benzoxazine ring represented by the following formula (13) in the molecule.

The number of benzoxazine rings per molecule of the (C-1) benzoxazine compound is preferably 1 or more, more preferably 2 or more, and is preferably 10 or less, more preferably 5 or less, from the viewpoint of improving the performance of the cured product, particularly the adhesion.

The (C-1) benzoxazine compound preferably has an aromatic ring in addition to the benzoxazine ring. By having an aromatic ring in addition to the benzoxazine ring, heat resistance is usually improved, so that high adhesion can be maintained even after environmental testing in a higher temperature environment. Examples of aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, and a biphenyl ring, with a benzene ring being preferred. In addition, from the viewpoint of improving the performance of the cured product, particularly the adhesion, the number of aromatic rings is preferably 1 or more, more preferably 2 or more, and is preferably 10 or less, more preferably 5 or less.

As the (C-1) benzoxazine compound, a benzoxazine compound represented by the following general formula (CI) is preferable.

R ^a represents a k-valent group. Such a group is preferably an arylene group, an alkylene group, an oxygen atom, or a k-valent group consisting of a combination of two or more of these, more preferably an arylene group or a k-valent group consisting of a combination of two or more, and even more preferably a k-valent group consisting of a combination of two or more.

As the arylene group, an arylene group having 6 to 20 carbon atoms is preferable, an arylene group having 6 to 15 carbon atoms is more preferable, and an arylene group having 6 to 12 carbon atoms is even more preferable. Specific examples of the arylene group include a phenylene group, a naphthylene group, an anthracenylene group, and a biphenylene group, and the phenylene group is preferable.

As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, an alkylene group having 1 to 6 carbon atoms is more preferable, and an alkylene group having 1 to 3 carbon atoms is even more preferable. Specific examples of the alkylene group include a methylene group, an ethylene group, and an n-propylene group, and a methylene group is preferable.

Examples of k-valent groups consisting of two or more combinations include groups in which one or more arylene groups are bonded to one or more oxygen atoms, groups in which one or more arylene groups are bonded to one or more alkylene groups, groups in which one or more alkylene groups are bonded to one or more oxygen atoms, groups in which one or more arylene groups are bonded to one or more alkylene groups, and groups in which one or more arylene groups are bonded to one or more oxygen atoms, and groups in which one or more arylene groups are bonded to one or more alkylene groups are bonded to one or more oxygen atoms, and the like. Of these, groups in which one or more arylene groups are bonded to one or more oxygen atoms and groups in which one or more arylene groups are bonded to one or more alkylene groups are preferred. Specific examples of k-valent groups consisting of two or more combinations include divalent groups represented by the following formulas (14) to (17). In formulas (14) to (17), "*" represents a bond.

The arylene group and the alkylene group may have a substituent. The substituent is not particularly limited and examples thereof include a halogen atom, -OH, -O-C _1-6 alkyl group, -N(C _1-6 alkyl group) ₂ , a C _1-6 alkyl group, a C _6-10 aryl group, -NH ₂ , -CN, -C(O)O-C _1-6 alkyl group, -COOH, -C(O)H, and -NO _2. The expression "C _1-6 alkyl group" refers to an alkyl group having 1 to 6 carbon atoms.

The above-mentioned substituents may further have a substituent (hereinafter, sometimes referred to as a "secondary substituent"). Unless otherwise specified, the secondary substituent may be the same as the above-mentioned substituent.

Each R ^b independently represents a halogen atom, an alkyl group, or an aryl group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms. The aryl group is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms. The halogen atom represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. The alkyl group and the aryl group may have a substituent. The substituent is the same as the substituent that the arylene group may have.

k represents an integer from 2 to 4, preferably an integer from 2 to 3, and more preferably 2. l represents an integer from 0 to 4, preferably an integer from 0 to 3, and more preferably 0.

From the viewpoint of achieving the desired effect of the present invention, the benzoxazine compound represented by general formula (C-I) is preferably at least one of the benzoxazine compounds represented by the following general formulas (18) and (19).

The benzoxazine compound represented by the general formula (18) is preferably at least one of the benzoxazine compounds represented by the formulas (20) and (21), and the benzoxazine compound represented by the formula (19) is preferably a benzoxazine compound represented by the formula (22).

As the (C-1) component, one type of compound belonging to the benzoxazine compound represented by the general formula (C-I) may be used alone, or a mixture of two or more types may be used. For example, when a mixture of a benzoxazine compound represented by the formula (20) and a benzoxazine compound represented by the formula (21) is used as the (C-1) component, the molar ratio (formula (20):formula (21)) is preferably 1:10 to 10:1, more preferably 2:8 to 8:2, and more preferably 5:5 to 7:3. The mass ratio (formula (20):formula (21)) is preferably 1:10 to 10:1, more preferably 2:8 to 8:2, and more preferably 5:5 to 7:3. By setting the molar ratio or mass ratio within such a range, the performance of the cured product, particularly the adhesion between the cured product and the conductor layer, can be improved.

Specific examples of (C-1) benzoxazine compounds include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "P-d" and "F-a" manufactured by Shikoku Chemical Industry Co., Ltd.; and "HFB2006M" manufactured by Showa Polymer Co., Ltd.

From the viewpoint of improving adhesion, the molecular weight of the (C-1) benzoxazine compound is preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more, and is preferably 1000 or less, more preferably 800 or less, and even more preferably 500 or less.

The content of the (C-1) benzoxazine compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. The upper limit is preferably less than the content of the (A) component in terms of non-volatile components, and is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less or 3% by mass or less. By setting the content of the (C-1) component within this range, the performance of the cured product, in particular the adhesion between the cured product and the conductor layer, can be improved. In this embodiment, the content of the (C) component is the content of the (C-1) component when the resin composition does not contain the (C-2) component, and is the sum of the content of the (C-1) component and the content of the (C-2) component when the resin composition contains the (C-2) component.

<(C-2) Carbodiimide Compound>
The resin composition contains a carbodiimide compound (C-2). As illustrated in the examples described below, the carbodiimide compound (C-2) is one of the components that have been confirmed to improve the performance of the cured product of the resin composition and the performance of the resin composition by including the component (C) in a resin composition containing the component (A) and the component (B) compared to the case where the component (C) is not included. Specifically, the carbodiimide compound (C-2) can maintain a sufficient pot life (for example, one day or more) compared to the case where the component (C-2) is not used by using the carbodiimide compound (C-2) in combination with the component (B) in a resin composition containing the component (A), and can maintain a low value of the dielectric tangent for the cured product, can maintain good smear removability, can further improve plating adhesion, and can significantly improve base adhesion.

The (C-2) carbodiimide compound is a compound having one or more carbodiimide groups (-N=C=N-) in one molecule. As the (C-2) carbodiimide compound, a compound having two or more carbodiimide groups in one molecule is preferable. The (C-2) carbodiimide compound may be used alone or in combination of two or more kinds.

Preferably, the carbodiimide compound (C-2) contains a structure represented by the following formula (C-II):

The number of carbon atoms in the alkylene group represented by X is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6, 1 to 4, or 1 to 3. The number of carbon atoms in the substituent is not included in the number of carbon atoms. Suitable examples of the alkylene group include a methylene group, an ethylene group, an n-propylene group, and an n-butylene group.

The number of carbon atoms in the cycloalkylene group represented by X is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. The number of carbon atoms does not include the number of carbon atoms of the substituent. Suitable examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.

The arylene group represented by X is a group in which two hydrogen atoms on an aromatic ring have been removed from an aromatic hydrocarbon. 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 even more preferably 6 to 10. The number of carbon atoms does not include the number of carbon atoms of the substituent. Suitable examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenylene group.

The alkylene group, cycloalkylene group or aryl group represented by X may have a substituent. The substituent is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkyloxy group, an aryl group, an aryloxy group, an acyl group and an acyloxy group. Examples of the halogen atom used as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The alkyl group and the alkoxy group used as a substituent may be either linear or branched, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6, 1 to 4, or 1 to 3. The number of carbon atoms of the cycloalkyl group and the cycloalkyloxy group used as a substituent is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. The aryl group used as a substituent is a group obtained by removing one hydrogen atom on the aromatic ring from an aromatic hydrocarbon, and the number of carbon atoms is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms of the aryloxy group used as a substituent is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10. The acyl group used as a substituent refers to a group represented by the formula: -C(=O)-R ^c (wherein R ^c represents an alkyl group or an aryl group). The alkyl group represented by R ^c may be either linear or branched, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 10, even more preferably 1 to 6, 1 to 4, or 1 to 3. The number of carbon atoms of the aryl group represented by R ^c is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10. The acyloxy group used as a substituent refers to a group represented by the formula: -O-C(=O)-R ^d (wherein R ^d represents the same meaning as R ^c above). Among them, as the substituent, an alkyl group, an alkoxy group, and an acyloxy group are preferable, and an alkyl group is more preferable.

In formula (C-II), m represents an integer of 1 to 5. From the viewpoint of improving the performance of the cured product, particularly the adhesion to the conductor layer, m is preferably 1 to 4, more preferably 2 to 4, and even more preferably 2 or 3.

In formula (C-II), when there are multiple X's, they may be the same or different. In a preferred embodiment, at least one X is an alkylene group or a cycloalkylene group, which may have a substituent.

From the viewpoint of improving the performance of the cured product, particularly the adhesion to the conductor layer, the weight average molecular weight of the (C-2) carbodiimide compound is preferably 500 or more, more preferably 600 or more, even more preferably 700 or more, even more preferably 800 or more, and particularly preferably 900 or more or 1000 or more. In addition, from the viewpoint of obtaining good compatibility, the upper limit of the weight average molecular weight of the (C-2) carbodiimide compound is preferably 5000 or less, more preferably 4500 or less, even more preferably 4000 or less, even more preferably 3500 or less, and particularly preferably 3000 or less. The weight average molecular weight of the (C-2) carbodiimide compound can be measured, for example, by gel permeation chromatography (GPC) method (polystyrene equivalent). When the (C-2) carbodiimide compound is produced by polymerization using a compound containing an isocyanate group as a material, the number average molecular weight is preferably 500 or more, more preferably 1000 or more, and even more preferably 1500 or more, from the viewpoint of improving adhesion, and is preferably 30000 or less, more preferably 25000 or less. The number average molecular weight of the (C-2) carbodiimide compound is, for example, a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). When measuring the weight average molecular weight and the number average molecular weight, it is preferable to cap the terminal isocyanate group of the (C-2) carbodiimide compound with a specified compound.

The (C-2) carbodiimide compound may contain an isocyanate group (-N=C=O) in the molecule due to its manufacturing method. From the viewpoint of obtaining a resin composition exhibiting good storage stability, and thus from the viewpoint of realizing an insulating layer exhibiting the desired characteristics, the content of isocyanate groups in the (C-2) carbodiimide compound (also referred to as the "NCO content") is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, even more preferably 2% by mass or less, and particularly preferably 1% by mass or less or 0.5% by mass or less.

(C-2) Commercially available carbodiimide compounds may be used. Examples of commercially available carbodiimide compounds include Carbodilite (registered trademark) V-02B, V-03, V-04K, V-07, and V-09 manufactured by Nisshinbo Chemical Co., Ltd., and Stavaxol (registered trademark) P, P400, and Hi-Kasil 510 manufactured by Rhein Chemie.

The content of the (C-2) carbodiimide compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. The upper limit is preferably less than the content of the (A) component in terms of non-volatile components, and is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less or 3% by mass or less. By setting the content of the (C-2) component within this range, the performance of the cured product, in particular the adhesion between the cured product and the conductor layer, can be improved. In this embodiment, the content of the (C) component is the content of the (C-2) component when the resin composition does not contain the (C-1) component, and is the sum of the content of the (C-1) component and the content of the (C-2) component when the resin composition contains the (C-1) component.

<(D) Inorganic filler>
In this embodiment, the resin composition may contain (D) an inorganic filler. The material of (D) the inorganic filler is not particularly limited as long as it is an inorganic compound, but examples thereof 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. Moreover, spherical silica is preferable as the silica. The inorganic filler may be used alone or in combination of two or more.

(D) Commercially available inorganic fillers include, for example, "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 Co., Ltd.; "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.

Usually, the inorganic filler (D) is contained in the resin composition in the form of particles. From the viewpoint of significantly obtaining the intended effect of the present invention, the average particle size of the inorganic filler (D) is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and is preferably 5.0 μm or less, more preferably 2.0 μm or less, and even more preferably 1.0 μm or less. In addition, by having the average particle size of the inorganic filler (D) within the above range, it is usually possible to improve the circuit embedding property of the resin composition layer and reduce the surface roughness of the insulating layer.

The average particle size of the inorganic filler (D) can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler (D) is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is taken as the average particle size. The measurement sample is preferably one in which the inorganic filler (D) is dispersed in methyl ethyl ketone using ultrasonic waves. Examples of laser diffraction/scattering particle size distribution measuring devices that can be used include the LA-500 manufactured by Horiba, Ltd. and the SALD-2200 manufactured by Shimadzu Corporation.

From the viewpoint of significantly obtaining the intended effect of the present invention, the specific surface area of the (D) inorganic filler is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, and particularly preferably 3 m ² /g or more. There is no particular upper limit, but it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area can be measured according to the BET method by adsorbing nitrogen gas to the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and using the BET multipoint method.

(D) In order to improve moisture resistance and dispersibility, it is preferable that the inorganic filler is surface-treated with a surface treatment agent. Examples of the surface treatment agent include aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, etc. Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane). Surface treatment agents may be used alone or in combination of two or more.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler (D). The amount of carbon per unit surface area of the inorganic filler (D) 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, from the viewpoint of improving the dispersibility of the inorganic filler (D). On the other hand, from the viewpoint of suppressing the increase in the melt viscosity of the resin varnish and the melt viscosity in the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

The amount of carbon per unit surface area of the (D) inorganic filler can be measured after the surface-treated (D) 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 (D) inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the (D) 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 reducing the thermal expansion coefficient, the content of the inorganic filler (D) is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and even more preferably 60% by mass or more or 65% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass. The upper limit is not particularly limited, but may be, for example, 95% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less. It is known that the adhesion between the cured product and the conductor layer decreases when a large amount of inorganic filler (D) is blended, but in the present invention, the decrease in adhesion can be effectively suppressed even when a large amount of inorganic filler (D) is blended.

<(E) Curing Agent>
In addition to the above-mentioned components, the resin composition may contain a curing agent (E) as an optional component. The curing agent (E) is generally available under the name of a curing agent for resin compositions. However, the resin composition according to this embodiment contains the components (A), (B), and (C), and the component (B) can react with the component (A) by heat regardless of the presence or absence of a radical reaction initiator, and as a result, the resin composition is thermally cured even without a curing agent, so the resin composition according to this embodiment does not necessarily need to contain the curing agent (E). Therefore, the component (E) is an optional component and is clearly distinguished from the component (C), which is the essential component described above. The curing agent as the component (E) usually has the function of reacting with the epoxy resin (A) to cure the resin composition. Examples of such a curing agent (E) include an active ester curing agent (E-1), a phenol curing agent (E-2), a naphthol curing agent (E-3), and a cyanate ester curing agent (E-4). The curing agent may be used alone or in combination of two or more kinds.

(E-1) As the active ester curing agent, a compound having one or more active ester groups in one molecule can be used. Among them, 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 preferable. The active ester curing agent is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferable.

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

Examples of phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

(E-1) Preferred specific examples of the active ester curing agent include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, and active ester compounds containing a benzoylated product of phenol novolac. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The term "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

(E-1) Commercially available active ester curing agents include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-60T" (manufactured by DIC Corporation); active ester compounds containing a naphthalene structure such as "EXB9416-70BK" (manufactured by DIC Corporation); and active esters containing an acetylated product of phenol novolac. Examples of terephthalate compounds include "DC808" (manufactured by Mitsubishi Chemical Corporation); active ester compounds containing benzoyl phenol novolac include "YLH1026" (manufactured by Mitsubishi Chemical Corporation); active ester curing agents that are acetylated phenol novolac include "DC808" (manufactured by Mitsubishi Chemical Corporation); and active ester curing agents that are benzoyl phenol novolac include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation).

From the viewpoint of heat resistance and water resistance, it is preferable that the (E-2) phenol-based curing agent and (E-3) naphthol-based curing agent have a novolac structure. From the viewpoint of adhesion between the insulating layer and the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent is more preferable.

Specific examples of (E-2) phenol-based curing agents and (E-3) naphthol-based curing agents include, for example, "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd.; "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", and "SN375" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

(E-4) Examples of cyanate ester-based 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 are partially converted to triazine. (E-4) Specific examples of cyanate ester-based curing agents include "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), all manufactured by Lonza Japan.

Among the above, from the viewpoint of obtaining the intended effect of the present invention remarkably, it is preferable to use one or more curing agents selected from (E-1) active ester curing agent and (E-2) phenolic curing agent as the (E) curing agent. When (E-1) active ester curing agent is used, the amount of (E-1) active ester curing agent relative to 100% by mass of (E) curing agent is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 100% by mass or less. By the amount of (E-1) active ester curing agent being within the above range, the intended effect of the present invention can be obtained remarkably, and in particular the dielectric constant of the cured product of the resin composition can be effectively reduced. When (E-2) phenolic curing agent is used, the amount of (E-2) phenolic curing agent relative to 100% by mass of (E) curing agent is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and preferably 100% by mass or less. (E-2) By using a phenol-based curing agent in an amount within the above range, the desired effects of the present invention can be significantly achieved, and in particular, the dielectric constant of the cured resin composition can be effectively reduced.

The amount of (E) curing agent in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, from the viewpoint of significantly obtaining the intended effect of the present invention, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

When the number of epoxy groups in the (A) epoxy resin is taken as 1, the number of active groups in the (E) curing agent is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 1.5 or less, more preferably 1.2 or less, even more preferably 1 or less. Here, the "number of epoxy groups in the (A) epoxy resin" refers to the total value obtained by dividing the mass of the non-volatile components of the (A) epoxy resin present in the resin composition by the epoxy equivalent. Also, the "number of active groups in the (E) curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the (E) curing agent present in the resin composition by the active group equivalent. When the number of epoxy groups in the (A) epoxy resin is taken as 1, the number of active groups in the (E) curing agent is within the above range, so that the desired effect of the present invention can be obtained significantly, and moreover, usually, the heat resistance of the cured product of the resin composition is further improved.

<(F) Curing Accelerator>
In addition to the above-mentioned components, the resin composition may contain an optional component, (F) a curing accelerator (catalyst). By using the (F) curing accelerator, curing can be accelerated when curing the resin composition.

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

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

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

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-furan. phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 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 1-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; and adducts of imidazole compounds and epoxy resins. Among these, 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferred.

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

Examples of guanidine 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. Among these, dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

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

Examples of peroxide-based curing accelerators include cyclohexanone peroxide, tert-butyl peroxybenzoate, methyl ethyl ketone peroxide, dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, and tert-butyl hydroperoxide.

Commercially available peroxide-based curing accelerators can be used, such as NOF Corp.'s "Percumyl D."

When a curing accelerator (F) is used, the amount of the curing accelerator (F) in the resin composition is, from the viewpoint of significantly obtaining the intended effect of the present invention, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and particularly preferably 0.03% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less.

<(G) Optional Additives>
In one embodiment, the resin composition may further contain other additives as necessary. Examples of such other additives include dispersion media such as solvents, flame retardants, organic fillers, organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds, thickeners, defoamers, leveling agents, adhesion imparting agents, colorants, and resin additives such as thermoplastic resins.

Examples of flame retardants include phosphazene compounds, organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, metal hydroxides, etc. Specific examples of phosphazene compounds include "SPH-100", "SPS-100", "SPB-100", and "SPE-100" manufactured by Otsuka Chemical Co., Ltd., and "FP-100", "FP-110", "FP-300", and "FP-400" manufactured by Fushimi Pharmaceutical Co., Ltd. Commercially available flame retardants other than phosphazene compounds may be used, such as "HCA-HQ" manufactured by Sankosha and "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd.

As the organic filler, any organic filler that can be used when forming an insulating layer of a printed wiring board may be used, such as rubber particles, polyamide fine particles, silicone particles, etc. As the rubber particles, commercially available products may be used, such as "EXL2655" manufactured by Dow Chemical Japan, and "AC3401N" and "AC3816N" manufactured by Aica Kogyo Co., Ltd.

<Production Method>
The above-mentioned resin composition can be produced by mixing the above-mentioned components. When mixing, the components may be kneaded or stirred by kneading means such as a triple roll mill, a ball mill, a bead mill, or a sand mill, or by stirring means such as a super mixer or a planetary mixer, if necessary. The resin composition can be obtained as a resin varnish by including, for example, an organic solvent (G).

<Physical properties and applications of resin composition>
The resin composition according to the present embodiment is thermally cured at 200° C. for 90 minutes to produce a cured product with a low dielectric loss tangent (Df). Specifically, the dielectric loss tangent is preferably less than 0.0040, more preferably 0.0035 or less, and more preferably 0.0031 or less. The dielectric loss tangent (Df) can be measured by the method described in the examples below.

The resin composition is thermally cured at 200°C for 90 minutes to produce a cured product that exhibits excellent smear removal properties. That is, even if a via hole is formed in the cured product, an insulating layer is formed in which the maximum smear length at the bottom of the via hole is 5 μm or less. Smear removal properties can be evaluated by the method described in the examples below.

The resin composition is thermally cured at 200°C for 90 minutes to obtain a cured product that exhibits excellent adhesion to a conductor layer (e.g., a thin film formed by plating and pressure bonding). Specifically, the adhesion strength between the resin composition and the plating (copper plating) is preferably 0.340 kgf/cm or more, more preferably 0.400 kgf/cm or more, and even more preferably more than 0.420 kgf/cm. The adhesion strength between the resin composition and the thin film (copper foil) formed by pressure bonding is preferably 0.510 kgf/cm or more, more preferably 0.650 kgf/cm or more, and even more preferably 0.680 kgf/cm or more. The plating adhesion and the substrate adhesion can be evaluated by the method described in the Examples below. The adhesion strength can be measured by the method described in the Examples below.

The resin composition of the present invention can provide a cured product having a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength between the resin composition and the conductor layer. Therefore, the resin composition of the present invention can be suitably used as a resin composition for forming an insulating layer of a printed wiring board (resin composition for insulating layer of printed wiring board), and can be more suitably used as a resin composition for forming an interlayer insulating layer of a printed wiring board (resin composition for insulating layer of printed wiring board). In addition, since the resin composition of the present invention provides an insulating layer with good component embedding properties, it can also be suitably used when the printed wiring board is a component-embedded circuit board.

[Resin sheet]
The resin sheet of the present invention includes a support and a resin composition layer provided on the support, the resin composition of the present invention being included.

The resin composition layer may contain any material other than the resin composition of the present invention, as long as the effect of the present invention is not significantly impaired, and may contain, for example, a sheet-like reinforcing member such as glass cloth. However, since the thickness of the resin composition layer tends to increase when the resin composition layer contains a sheet-like reinforcing member, from the viewpoint of reducing the thickness, it is preferable that the resin composition layer does not contain a sheet-like reinforcing member, and for example, the resin composition layer is composed only of the resin composition. Note that the characteristics of the cured product described above are the characteristics of a cured product obtained by curing a resin composition layer of a resin composition that does not contain a sheet-like reinforcing member.

From the viewpoint of providing a cured product with excellent insulating properties, the thickness of the resin composition layer is preferably 70 μm or less, more preferably 40 μm or less, and even more preferably 25 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 1 μm or more, 1.5 μm or more, 2 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, and inexpensive polyethylene terephthalate is particularly preferred.

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

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

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

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

In one embodiment, the resin sheet may further include other layers as necessary. Examples of such other layers include a protective film similar to the support provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress adhesion of dirt and the like and scratches on the surface of the resin composition layer.

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

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

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

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

[Printed wiring board]
The printed wiring board of the present invention includes a cured product of the resin composition of the present invention. The cured product functions as an insulating layer in the printed wiring board. The insulating layer is provided, for example, on a circuit board described later in the printed wiring board. The insulating layer is provided, for example, between a first conductor layer and a second conductor layer of the printed wiring board, and in this case, insulates the first conductor layer from the second conductor layer (the conductor layer may be referred to as a wiring layer).

The thickness of the insulating layer between the first and second conductor layers is preferably less than 70 μm, more preferably less than 40 μm, and from the viewpoint of thinning the printed wiring board, is preferably 6 μm or less, more preferably 5.5 μm or less, and even more preferably 5 μm or less. The lower limit is not particularly limited, but may be 0.1 μm or more. The distance between the first conductor layer and the second conductor layer (the thickness of the insulating layer between the first and second conductor layers) refers to the thickness t1 of the insulating layer 3 between the main surface 11 of the first conductor layer 1 and the main surface 21 of the second conductor layer 2, as shown in FIG. 1 as an example. The first and second conductor layers are adjacent conductor layers with an insulating layer interposed between them, and the main surface 11 and the main surface 21 face each other.

The thickness t2 of the entire insulating layer is determined according to the thickness of the resin composition layer and the wiring pattern, and is preferably 70 μm or less, more preferably 40 μm or less, and from the viewpoint of thinning the printed wiring board, is preferably 15 μm or less, more preferably 13 μm or less, and even more preferably 10 μm or less. There is no particular limit to the lower limit, but it can usually be 1 μm or more, 1.5 μm or more, 2 μm or more, etc.

The printed wiring board can be produced by using the above-mentioned resin sheet by a method including the following steps (I) and (II).
(I) a step of laminating the resin sheet on the inner layer substrate so that the resin composition layer of the resin sheet is bonded to the inner layer substrate; and (II) a step of thermally curing the resin composition layer to form an insulating layer.

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

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

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

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

After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example by pressing a 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 thermally cured to form an insulating layer.

The thermal curing conditions for the resin composition layer are not particularly limited, and conditions normally used for forming an insulating layer for a printed wiring board may be used.

For example, the thermal curing conditions for the resin composition layer vary depending on the type of resin composition, but the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 200°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 90 minutes.

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

When manufacturing a printed wiring board, the steps of (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming a conductor layer may be further carried out. These steps (III) to (V) may be carried out according to various methods known to those skilled in the art that are used in the manufacture of printed wiring boards. When the support is removed after step (II), the removal of the support may be carried out between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). If necessary, the formation of the insulating layer and the conductor layer in steps (II) to (V) may be repeated to form a multilayer wiring board. In this case, it is preferable that the thickness of the insulating layer between each conductor layer (t1 in FIG. 1) is within the above range.

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. The procedure and conditions of the roughening treatment are not particularly limited, and known procedures and conditions that are usually used when forming an insulating layer of a printed wiring board can be adopted. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order. The swelling liquid used for the roughening treatment is not particularly limited, but includes an alkaline solution, a surfactant solution, etc., and is preferably an alkaline solution, and as the alkaline solution, a sodium hydroxide solution or a potassium hydroxide solution is more preferable. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. The swelling treatment with a swelling liquid is not particularly limited, but can be performed by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40°C to 80°C for 5 to 15 minutes. The oxidizing agent used in the roughening treatment is not particularly limited, but examples thereof include an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. The concentration of the permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by Atotech Japan. The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and examples of commercially available products include "Reduction Solution Securiganth 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 400 nm or less, more preferably 350 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, but it may be preferably 0.5 nm or more, more preferably 1 nm or more, etc. In addition, the root mean square roughness (Rq) of the insulating layer surface after the roughening treatment is preferably 400 nm or less, more preferably 350 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, but it may be preferably 0.5 nm or more, more preferably 1 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. If no conductor layer is formed on the inner layer substrate, step (V) is a step of forming a first conductor layer. If a conductor layer is formed on the inner layer substrate, the conductor layer is the first conductor layer, and step (V) is a step of forming a second conductor 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 them, from the viewpoints of versatility, cost, ease of patterning, etc. of the conductor layer formation, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

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

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

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

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

The resin composition of the present invention or the resin composition layer of the resin sheet of the present invention tends to have good component embedding properties, and can therefore be suitably used when the printed wiring board is a circuit board with built-in components. Circuit boards with built-in components can be produced by known manufacturing methods.

The printed wiring board manufactured using the resin sheet of the present invention may have an insulating layer that is a cured product of the resin composition layer of the resin sheet, and an embedded wiring layer embedded in the insulating layer.

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

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

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

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

The present invention will be specifically explained below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[Example 1]
10 parts of a bisphenol type epoxy resin ("ZX-1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., a 1:1 mixture of bisphenol A type and bisphenol F type, epoxy equivalent 169) and 50 parts of a naphthol type epoxy resin ("ESN-475V" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent approximately 330) were heated and dissolved in 70 parts of solvent naphtha (product name "IP150") with stirring. This was cooled to room temperature to prepare an epoxy resin solution composition (A).

To this epoxy resin (A) solution composition, 10 parts of a phenol-based curing agent (E-2) (DIC Corporation's "LA-3018-50P", active group equivalent of about 151, 2-methoxypropanol solution with 50% nonvolatile content), 60 parts of an active ester-based curing agent (DIC Corporation's "EXB-8150-60T", active group equivalent of about 230, toluene solution with 60% nonvolatile content by mass), 10 parts of methyl ethyl ketone (MEK), and benzoxazole as component (C) were added. A benzoxazine compound solution A in which 10 parts of benzoxazine compound A ("ODA-BOZ" manufactured by JFE Chemical Corporation; active group equivalent: 310) were dissolved, a solution in which (F) curing accelerator (0.15 parts of 4-dimethylaminopyridine (DMAP) was dissolved in 1.35 parts of methyl ethyl ketone (MEK), 300 parts of spherical silica (average particle size: 0.77 μm, specific surface area: 5.9 m ² /g, manufactured by Admatechs "SO-C2") surface-treated with aminosilane ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) as an inorganic filler (D), and a maleimide compound solution A in which 10 parts of (B) maleimide compound A ("BMI-689" manufactured by Designer Molecules) were dissolved in 10 parts of MEK were mixed and uniformly dispersed using a high-speed rotating mixer to prepare 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 25 μm. The resin varnish was then dried at 80°C to 120°C (average 100°C) for 4 minutes to obtain a resin sheet including a support and a resin composition layer.

[Example 2]
In Example 1, the maleimide compound solution A was changed to a maleimide compound solution B prepared by dissolving 10 parts of (B) maleimide compound B ("BMI-1500" manufactured by Designer Molecules, Inc.) in 10 parts of MEK. A resin varnish and a resin sheet were produced in the same manner as in Example 1, except for the above.

[Example 3]
In Example 1, the maleimide compound solution A was changed to a maleimide compound solution C prepared by dissolving 10 parts of (B) maleimide compound C ("BMI-1700" manufactured by Designer Molecules, Inc.) in 10 parts of MEK. A resin varnish and a resin sheet were produced in the same manner as in Example 1, except for the above.

[Example 4]
In Example 1, the maleimide compound solution A was changed to a maleimide compound solution D prepared by dissolving 10 parts of (B) maleimide compound D ("BMI-3000J" manufactured by Designer Molecules, Inc.) in 10 parts of MEK. A resin varnish and a resin sheet were produced in the same manner as in Example 1, except for the above.

[Example 5]
In Example 1, the benzoxazine compound solution A was changed to 20 parts of a carbodiimide compound A ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., active group equivalent of about 216, toluene solution containing 50% by mass of non-volatile components) as component (C). A resin varnish and a resin sheet were produced in the same manner as in Example 1, except for the above.

[Example 6]
In Example 5, the maleimide compound solution A was changed to the maleimide compound solution B. Except for the above, a resin varnish and a resin sheet were produced in the same manner as in Example 5.

[Example 7]
In Example 5, the maleimide compound solution A was changed to the maleimide compound solution C. Except for the above, a resin varnish and a resin sheet were produced in the same manner as in Example 5.

[Example 8]
In Example 5, the maleimide compound solution A was changed to the maleimide compound solution D. Except for the above, a resin varnish and a resin sheet were produced in the same manner as in Example 5.

[Comparative Example 1]
In Example 1, the maleimide compound solution A was not used, and the amount of component (D) was changed to 280 parts. A resin varnish and a resin sheet were produced in the same manner as in Example 1 except for the above.

[Comparative Example 2]
In Example 1, the maleimide compound solution A was changed to a maleimide compound solution E prepared by dissolving 10 parts of maleimide compound E (bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, "BMI-70" manufactured by K.I. Chemical Industry Co., Ltd.) as a comparison component (B) in 20 parts of anone (1-cyclohexanone). A resin varnish and a resin sheet were produced in the same manner as in Example 1, except for the above-mentioned points.

[Comparative Example 3]
In Example 5, the maleimide compound solution A was not used, and the amount of component (D) was changed to 280 parts. A resin varnish and a resin sheet were produced in the same manner as in Example 5 except for the above.

[Comparative Example 4]
In Example 5, the maleimide compound solution A was changed to the maleimide compound solution E. Except for the above, a resin varnish and a resin sheet were produced in the same manner as in Example 5.

[Comparative Example 5]
In Example 5, the benzoxazine compound solution A was not used, and the amount of the component (D) was changed to 280 parts. A resin varnish and a resin sheet were produced in the same manner as in Example 5 except for the above.

[Comparative Example 6]
In Example 1, the maleimide compound solution A and the benzoxazine compound solution A were not used, and the amount of the (D) component was changed to 280 parts. A resin varnish and a resin sheet were produced in the same manner as in Example 1 except for the above.

[Evaluation method]
The cured products of the resin composition layers of the resin sheets obtained in the above-mentioned Examples and Comparative Examples were evaluated by the following methods.

<Measurement of dielectric tangent (Df)>
(Preparation of evaluation samples of cured products)
The resin composition layers of the resin sheets obtained in the Examples and Comparative Examples were cured by heat treatment at 200° C. for 90 minutes, and the support was peeled off to obtain a cured film formed of the cured product of the resin composition. This cured film was cut into a length of 80 mm and a width of 2 mm to obtain an evaluation sample.

(measurement)
The dielectric loss tangent (Df) of this evaluation sample was measured by a cavity resonance perturbation method using a measuring device ("HP8362B" manufactured by Agilent Technologies) at a measurement frequency of 10 GHz and a measurement temperature of 23° C. Measurements were performed on three test pieces, and the average value was calculated. The results are shown in Table 1.

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

(2) Lamination and curing of resin sheets:
The resin sheets obtained in the above-mentioned Examples and Comparative Examples were laminated on both sides of the inner layer substrate using a batch type vacuum pressure laminator (two-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.) so that the resin composition layer was bonded to the inner layer substrate. This lamination was performed by reducing the pressure for 30 seconds to 13 hPa or less, and then pressing at a temperature of 100°C and a pressure of 0.74 MPa for 30 seconds.
The laminated resin sheet was then heat-pressed at atmospheric pressure at 100° C. and a pressure of 0.5 MPa for 60 seconds to smooth it out. The sheet was then placed in an oven at 100° C. and heated for 30 minutes, and then transferred to an oven at 170° C. and heated for 30 minutes. This resulted in an insulating layer formed of a cured product of the resin composition.

(3) Via hole formation:
Using a _CO2 laser processing machine (LK-2K212/2C) manufactured by Via Mechanics, the insulating layer on one side of the inner layer substrate was processed under the conditions of a frequency of 2000 Hz, a pulse width of 3 μs, an output of 0.95 W, and a shot number of 3, to form a via hole with a top diameter (diameter) of 50 μm on the insulating layer surface and a diameter of 50 μm on the insulating layer bottom surface. After that, the support was peeled off to obtain a circuit board.

(4) Roughening Treatment The insulating layer surface of the circuit board was immersed in a swelling liquid, Swelling Dip Securigant P, manufactured by Atotech Japan, for 10 minutes at 60° C. Next, the insulating layer surface of the circuit board 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, for 25 minutes at 80° C. Finally, the insulating layer surface of the circuit board was immersed in a neutralizing liquid, Reduction Solution Securigant P, manufactured by Atotech Japan, for 5 minutes at 40° C.

(5) Evaluation of residue at bottom of via hole The periphery of the bottom of three via holes was observed with a scanning electron microscope (SEM), and the maximum smear length from the wall surface of the bottom of the via hole was measured from the obtained image and evaluated according to the following criteria. The results are shown in Table 1.
○: The maximum smear length is less than 5 μm (i.e., none of the three via holes has a smear length of 5 μm or more, and the smear removal is good).
×: The maximum smear length is 5 μm or more (i.e., at least one of the three via holes has a smear length of 5 μm or more, and the smear removal performance is poor)

<Evaluation of plating adhesion and substrate adhesion>
<<Preparation of evaluation board>>
(1) Undercoat treatment of inner layer circuit board Both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, Panasonic Corporation's "R1515A") on which an inner layer circuit was formed were immersed in a microetching agent (Mec Corporation's "CZ8101") and etched by 1 μm to roughen the copper surface.

(2) Lamination of Resin Sheets The resin sheets prepared in the Examples and Comparative Examples were laminated on both sides of the inner layer circuit board using a batch type vacuum pressure laminator ("MVLP-500" manufactured by Meiki Seisakusho Co., Ltd.) so that the resin composition layer was bonded to the inner layer circuit board. The lamination was performed by reducing the pressure for 30 seconds to 13 hPa or less, and then pressing at 100°C and a pressure of 0.74 MPa for 30 seconds.

(3) Curing of Resin Composition Layer The laminated adhesive film was thermally cured at 200° C. for 90 minutes to form a cured product (insulating layer) on both sides of the inner layer circuit board. Thereafter, the support was peeled off from the resin sheet.

(4) Roughening Treatment The inner layer circuit board on which the insulating layer was formed was immersed in a swelling liquid (Atotech Japan Ltd.'s "Swelling Dip Securigant P", an aqueous solution of sodium hydroxide containing diethylene glycol monobutyl ether) at 60°C for 10 minutes, then immersed in a roughening liquid (Atotech Japan Ltd.'s "Concentrate Compact P", an aqueous solution of potassium permanganate at a concentration of 60 g/L and sodium hydroxide at a concentration of 40 g/L) at 80°C for 20 minutes, and finally immersed in a neutralizing liquid (Atotech Japan Ltd.'s "Reduction Solution Securigant P", an aqueous solution of hydroxylamine sulfate) at 40°C for 5 minutes. The resulting substrate was called "evaluation substrate A".

(5) Formation of a plated conductor layer According to the semi-additive method, a plated conductor layer (second conductor layer) was formed on the surface of the evaluation substrate A. Specifically, the 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. The obtained evaluation substrate A was heated at 150°C for 30 minutes for annealing, and then subjected to copper sulfate electroplating to form a plated conductor layer with a thickness of 30 μm. The evaluation substrate A on which the plated conductor layer was formed was annealed at 190°C for 60 minutes. The obtained substrate is referred to as "evaluation substrate B".

<<Measurement of plating adhesion>>
A cut was made in the plated conductor layer (second conductor layer) of evaluation board B, measuring 10 mm wide and 100 mm long, and one end of the cut was peeled off and held with a gripper. The load [kgf/cm (N/cm)] when 35 mm was peeled off in the vertical direction at a speed of 50 mm/min at room temperature (25°C) was measured. A tensile tester ("AC-50C-SL" manufactured by TSE Corporation) was used for the measurement. The results are shown in Table 1.

<<Measurement of adhesion to substrate>>
(1) Copper foil preparation The shiny side of "3EC-III" (electrolytic copper foil, 35 μm) manufactured by Mitsui Mining & Smelting Co., Ltd. was immersed in a microetching agent ("CZ8101" manufactured by MEC Co., Ltd.) to roughen the copper surface (Ra value = 1 μm) and to apply anti-rust treatment (CL8300). This copper foil is called CZ copper foil. It was then heated in an oven at 130°C for 30 minutes.

(2) Lamination of copper foil and formation of insulating layer The same operation as in "(2) Lamination of resin sheet" in <Preparation of evaluation board> above was carried out to prepare a board in which a resin sheet was laminated on both sides of an inner layer circuit board. Then, the supports on both sides were peeled off from the board to expose both resin composition layers. The treated side of the CZ copper foil of "3EC-III" was laminated on these resin composition layers under the same conditions as in "(2) Lamination of resin sheet" in <Preparation of evaluation board> above. Then, the resin composition layer was cured under the curing conditions of 190°C and 90 minutes to form an insulating layer, thereby preparing a sample.

(3) Measurement of copper foil peel strength (substrate adhesion) The prepared sample was cut into small pieces of 150 x 30 mm. A cutter was used to make a 10 mm wide and 100 mm long cut in the copper foil part of the small piece, and one end of the copper foil was peeled off and held with a gripper ("AC-50C-SL" manufactured by TSE Co., Ltd.), and the load [kgf/cm (N/cm)] when 35 mm was peeled off in the vertical direction at room temperature at a speed of 50 mm/min was measured using an Instron universal testing machine in accordance with JIS C6481. The results are shown in Table 1.

<Pot life evaluation>
In producing the resin sheets of the Examples and Comparative Examples, 100 ml (milliliters) of the resin varnish prepared was left to stand at room temperature in a dark place for one day, and then the resin varnish was visually inspected to see whether gelation had occurred.
If gelation was observed as a result of the confirmation, the pot life was evaluated as "x" (bad), and if gelation was not observed, the pot life was evaluated as "○" (good).

[result]
The results of the above-mentioned Examples and Comparative Examples are shown in Table 1 below. In Table 1 below, the amount of each component is expressed as the amount converted into non-volatile components. In Table 1 below, the meanings of the abbreviations are as follows. In Table 1 below, the content of component (D) is shown as a percentage [mass %] when the non-volatile components in the resin composition are taken as 100 mass %.

<Consideration>
As can be seen from Table 1, by comparing the Examples and Comparative Examples, it was found that the Examples can provide a resin composition capable of forming a cured product having a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer. It was also found that the Examples have a good pot life. Furthermore, it was found that it is possible to provide a resin sheet containing the resin composition according to the Examples; a printed wiring board containing a cured product of the resin composition; and a semiconductor device containing the printed wiring board.

In addition, it has been confirmed that, even if any or all of the components (D), (E), and (F) are not contained in Examples 1 to 8, or even if the amount of the component (D) is changed, the results are similar to those of the above examples, although to a different extent.

In addition, it has been confirmed that, even when a carbodiimide compound is further included in Examples 1 to 4, and when a benzoxazine compound is further included in Examples 5 to 8, the results are similar to those of the above examples, although to a lesser extent.

Furthermore, in Examples 1 to 8, it has been confirmed that even if the component (B') is further contained, the effect of the present invention tends to be impaired, but the results are similar to those of the above examples. However, it is preferable that the content of the component (B') is less than the content of the component (B).

1 First conductor layer 11 Main surface of the first conductor layer 2 Second conductor layer 21 Main surface of the second conductor layer 3 Insulating layer t1 Distance between the first conductor layer and the second conductor layer (thickness of the insulating layer between the first and second conductor layers)
t2 Total thickness of the insulating layer

Claims (14)

(A) an epoxy resin, (B) a maleimide compound, (C) a component, and (E-1) an active ester-based curing agent,
The component (B) is represented by the following general formula (B-II):
The component (C) is one or more compounds selected from the group consisting of (C-1) benzoxazine compounds and (C-2) carbodiimide compounds,
The component (C-1) contains a benzoxazine compound having an aromatic ring in addition to a benzoxazine ring,
when the component (C) contains the component (C-1), the content of the component (C-1) is 0.5% by mass or more and 3% by mass or less, based on 100% by mass of the non-volatile components in the resin composition;
When the component (C) contains the component (C-2), the content of the component (C-2) is 1% by mass or more and 3 % by mass or less, when the total amount of non-volatile components in the resin composition is 100% by mass.
Resin composition.

In general formula (B-II), R' each independently represents an alkylene group having 5 or more carbon atoms which may have a substituent, A each independently represents a cyclic alkylene group having 5 or more carbon atoms which may have a substituent; a divalent group having a benzene ring which may have a substituent; a divalent group having a phthalimide ring which may have a substituent; or a divalent group having a pyromellitic diimide ring which may have a substituent. n represents an integer from 1 to 10. The resin composition according to claim 1, wherein the content of component (B) is 0.1% by mass or more and 20% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass. The resin composition according to claim 1 or 2, wherein the component (C) contains a benzoxazine compound represented by the following general formula (CI):

In formula (CI), R ^a represents a k-valent group containing an arylene group, and R ^b each independently represents a halogen atom, an alkyl group, or an aryl group, k represents an integer of 2 to 4, and l represents an integer of 0 to 4. The resin composition according to claim 3, wherein in general formula (CI), R ^a is an arylene group or a k-valent group consisting of a combination of an arylene group with an alkylene group and/or an oxygen atom. The resin composition according to claim 3 or 4, wherein in general formula (C-I), l represents 0. The resin composition according to any one of claims 1 to 5, wherein the component (C) comprises a carbodiimide compound having a structure represented by the following formula (C-II):

The resin composition according to any one of claims 1 to 6, wherein the content of the component (C) is 0.5 mass% or more and 3 mass% or less, when the non-volatile components in the resin composition are 100 mass%. The resin composition according to any one of claims 1 to 7, further comprising (D) an inorganic filler. The resin composition according to claim 8, wherein component (D) is surface-treated with aminosilane. The resin composition according to claim 8 or 9, wherein the content of component (D) is 40% by mass or more and 95% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass. The resin composition according to any one of claims 1 to 10, which is used to form an insulating layer for a printed wiring board. A resin sheet comprising a support and a resin composition layer containing the resin composition according to any one of claims 1 to 11 provided on the support. A printed wiring board comprising a cured product of the resin composition according to any one of claims 1 to 11. A semiconductor device including the printed wiring board according to claim 13.

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