Resin composition

Abstract

To provide a resin composition enabling formation of an insulating layer having low dielectric tangent at elevated temperature and high frequency and having excellent smear removability.SOLUTION: A resin composition comprising (A) an epoxy resin, (B-1) an active ester resin containing a butadiene skeleton, and (B-2) an active ester resin not containing a butadiene skeleton.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a cured product thereof, a resin sheet, a circuit board, and a semiconductor device. [Background technology]

[0002] Circuit boards such as printed wiring boards are widely used in various electronic devices. A known method for manufacturing circuit boards is a build-up method in which insulating layers and conductor layers are alternately stacked on an inner layer substrate. The insulating layer is formed, for example, from a cured product of a resin composition (Patent Documents 1 and 2). To give a specific example, a resin composition layer containing a resin composition is formed, and then the resin composition layer is cured to form an insulating layer containing a cured product of the resin composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-100697 [Patent Document 2] Japanese Patent Publication No. 2023-037522 Summary of the Invention [Problem to be solved by the invention]

[0004] High-speed communications such as fifth-generation mobile communications systems (5G) require suppression of transmission loss when operating in high-frequency environments. Furthermore, circuit boards can become very hot due to heat generated by semiconductor chips. Therefore, the inventors attempted to develop an insulating layer that can reduce the dielectric loss tangent at high temperatures and high frequencies.

[0005] However, it has been found that cured products of resin compositions having such low dielectric dissipation factors have poor smear removal properties. Specifically, the reasons are as follows. Generally, when an insulating layer is formed using a cured product, holes such as via holes and through holes may be formed in the insulating layer. When holes are formed in this way, resin residue called "smear" may be formed in the holes. Therefore, a desmearing treatment is usually performed to remove this smear after the holes are formed. However, when an insulating layer is formed using a cured product having a low dielectric dissipation factor, the smear may not be sufficiently removed even by the desmearing treatment.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide: a resin composition capable of forming an insulating layer having a low dielectric tangent at high temperatures and high frequencies and excellent smear removal properties; a resin sheet containing the resin composition; a cured product of the resin composition; a circuit board containing the cured product of the resin composition; and a semiconductor device including the circuit board. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that a resin composition containing (A) an epoxy resin, (B-1) an active ester resin containing a butadiene skeleton, and (B-2) an active ester resin not containing a butadiene skeleton can solve the above-mentioned problems, thereby completing the present invention. That is, the present invention includes the following.

[0008] <1> A resin composition comprising: (A) an epoxy resin; (B-1) an active ester resin containing a butadiene skeleton; and (B-2) an active ester resin not containing a butadiene skeleton. <2> (A) The epoxy resin includes at least one selected from the group consisting of an epoxy resin containing a naphthalene skeleton and an epoxy resin containing a biphenyl skeleton; <1> The resin composition according to claim 1. <3> (B-1) The active ester resin containing a butadiene skeleton includes a structure represented by the following formula (B1): <1> or <2> The resin composition according to claim 1. [ka] (In formula (B1), R b each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms; * represents a bonding site.) <4> (C) containing an inorganic filler; <1> ~ <3> The resin composition according to any one of the above. <5> (C) The amount of the inorganic filler is 50% by mass or more relative to 100% by mass of the nonvolatile components of the resin composition; <4> The resin composition according to claim 1. <6> (D) a radical polymerizable resin, <1> ~ <5> The resin composition according to any one of the above. <7> (D) the radical polymerizable resin includes a maleimide resin; <6> The resin composition according to claim 1. <8> A support and a resin composition layer provided on the support, The resin composition layer is <1> ~ <7> A resin sheet comprising the resin composition according to any one of claims 1 to 11. <9> <1> ~ <7> A cured product of the resin composition according to any one of claims 1 to 11. <10> <1> ~ <7> A circuit board comprising a cured product of the resin composition according to any one of claims 1 to 4. <11> <10> A semiconductor device comprising the circuit board according to claim 1. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition capable of forming an insulating layer having a low dielectric tangent at high temperatures and high frequencies and excellent smear removal properties; a resin sheet including the resin composition; a cured product of the resin composition; a circuit board including the cured product of the resin composition; and a semiconductor device including the circuit board. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented within the scope of the claims and their equivalents.

[0011] As used herein, the term "optionally substituted" in reference to a compound or group means both a case where the hydrogen atoms of the compound or group are not substituted with substituents, and a case where some or all of the hydrogen atoms of the compound or group are substituted with substituents.

[0012] <Outline of Resin Composition> A resin composition according to one embodiment of the present invention comprises (A) an epoxy resin, (B-1) an activated ester resin containing a butadiene skeleton, and (B-2) an activated ester resin not containing a butadiene skeleton. In the following description, the "(B-1) activated ester resin containing a butadiene skeleton" may be referred to as the "first activated ester resin." Furthermore, the "(B-2) activated ester resin not containing a butadiene skeleton" may be referred to as the "(B-2) second activated ester resin." This resin composition can form an insulating layer that has a low dielectric loss tangent at high temperatures and high frequencies and excellent smear removal properties. Furthermore, this resin composition can typically reduce the linear thermal expansion coefficient of the insulating layer. Furthermore, this resin composition can typically improve the crack resistance of the insulating layer.

[0013] The inventors of the present invention speculate that the mechanism by which the above-described excellent effects are obtained is as follows: However, the technical scope of the present invention is not limited by the mechanism below.

[0014] In the resin composition according to this embodiment, the epoxy groups of the epoxy resin (A) react with the active ester groups of the first active ester resin (B-1) and the second active ester resin (B-2) to form bonds, resulting in curing of the resin composition. An insulating layer can then be formed as a layer containing the cured product of the resin composition. The reaction between the epoxy groups and the active ester groups generally does not produce polar groups such as hydroxyl groups, so the resulting cured product has low polarity. Therefore, the cured product can have a low dielectric loss tangent, and therefore the insulating layer can also have a low dielectric loss tangent.

[0015] Because the resin composition contains the first active ester resin (B-1) having a butadiene skeleton, the cured product may contain a butadiene skeleton. Furthermore, the carbon-carbon double bonds contained in the butadiene skeleton may undergo radical polymerization between the first active ester resin (B-1). Furthermore, when the resin composition contains a radically polymerizable resin (D), radical polymerization may occur between the first active ester resin (B-1) and the radically polymerizable resin (D). When such radical polymerization occurs, the cured product may contain carbon-carbon bonds formed by the radical polymerization. These butadiene skeletons and carbon-carbon bonds formed by radical polymerization are generally susceptible to oxidation by oxidizing agents. Therefore, even if the polarity of the cured product is low, the butadiene skeletons and carbon-carbon bonds formed by radical polymerization can be smoothly oxidized, allowing for smooth removal of smears by oxidation, thereby achieving high smear removability.

[0016] The resin composition contains a (B-2) second active ester resin in combination with a (B-1) first active ester resin. Because the (B-1) first active ester resin contains a butadiene skeleton, it tends to have a high active ester group equivalent, thereby lowering the density of crosslinking points in the cured product. Here, the active ester group equivalent refers to the mass of resin per equivalent of active ester groups. Furthermore, the butadiene skeleton contained in the (B-1) first active ester resin is flexible, and the bond formed by radical polymerization of the carbon-carbon double bond of the butadiene skeleton is also typically flexible. Therefore, combining only the (A) epoxy resin and the (B-1) first active ester resin tends to increase the thermal expansion of the cured product. However, in this embodiment, a (B-2) second active ester resin is also combined. Because the (B-2) second active ester resin does not contain a butadiene skeleton, it typically has a lower active ester equivalent than the (B-1) first active ester resin, thereby increasing the density of crosslinking points in the cured product. Furthermore, since the second active ester resin (B-2) does not contain a butadiene skeleton, it generally has higher molecular rigidity than the first active ester resin (B-1). Therefore, since the second active ester resin (B-2) is further contained in combination with the epoxy resin (A) and the first active ester resin (B-1), the resin composition according to this embodiment can obtain a cured product with a small degree of thermal expansion, and therefore can obtain an insulating layer with a small linear thermal expansion coefficient.

[0017] Furthermore, in the cured product of the resin composition, as described above, the butadiene skeleton contained in the first active ester resin (B-1) and the bond formed by radical polymerization of the carbon-carbon double bond of the butadiene skeleton are flexible. Therefore, the stress in the cured product is absorbed by these flexible skeletons and bonds, allowing the cured product to have high toughness. Therefore, an insulating layer containing the cured product can suppress the occurrence of cracks due to stress, thereby achieving high crack resistance.

[0018] <(A) Epoxy resin> The resin composition according to the present embodiment includes an epoxy resin (A) as component (A). The epoxy resin (A) may be a curable resin having an epoxy group. The epoxy resin (A) may be used alone or in combination of two or more types.

[0019] Examples of (A) epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, tetraphenylethane-type epoxy resins, isocyanurate-type epoxy resins, and phenolphthalimidine-type epoxy resins. Typically, these epoxy resins do not contain radically polymerizable non-aromatic carbon-carbon unsaturated bonds.

[0020] From the viewpoint of obtaining a cured product having excellent heat resistance, the (A) epoxy resin preferably contains an epoxy resin having an aromatic structure. The aromatic structure is a chemical structure generally defined as aromatic, and also includes polycyclic aromatic rings and aromatic heterocycles. Examples of epoxy resins containing an aromatic structure include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, bisxyleneol type epoxy resins, glycidylamine type epoxy resins having an aromatic structure, glycidyl ester type epoxy resins having an aromatic structure, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins having an aromatic structure, epoxy resins having a butadiene structure having an aromatic structure, alicyclic epoxy resins having an aromatic structure, heterocyclic epoxy resins, spiro ring-containing epoxy resins having an aromatic structure, cyclohexanedimethanol type epoxy resins having an aromatic structure, naphthylene ether type epoxy resins, trimethylol type epoxy resins having an aromatic structure, and tetraphenylethane type epoxy resins having an aromatic structure.

[0021] Among these, bisphenol A type epoxy resins, bisphenol F type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins are preferred, and naphthalene type epoxy resins and biphenyl type epoxy resins are more preferred. Naphthalene type epoxy resins refer to epoxy resins containing a naphthalene skeleton. Furthermore, biphenyl type epoxy resins refer to epoxy resins containing a biphenyl skeleton. When the epoxy resin (A) contains one or more epoxy resins selected from the group consisting of naphthalene type epoxy resins and biphenyl type epoxy resins, the dielectric loss tangent, smear removal ability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0022] The (A) epoxy resin preferably contains an epoxy resin having two or more epoxy groups per molecule, and the proportion of the epoxy resin having two or more epoxy groups per molecule relative to 100% by mass of the non-volatile components of the (A) epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0023] (A) Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). (A) Epoxy resins may contain only liquid epoxy resins, only solid epoxy resins, or a combination of liquid epoxy resins and solid epoxy resins.

[0024] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule, such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AF epoxy resin, naphthalene epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, phenol novolac epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane epoxy resin, cyclohexanedimethanol epoxy resin, or epoxy resin having a butadiene structure.

[0025] Specific examples of liquid epoxy resins include "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US," "828EL," "jER828EL," "825," and "Epikote 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630," "630LSD," and "604" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycirol-type epoxy resin) manufactured by ADEKA Corporation; and "EP-3950L" and "EP-398" manufactured by ADEKA Corporation. 0S" (glycidylamine type epoxy resin); ADEKA's "EP-4088S" (dicyclopentadiene type epoxy resin); Nippon Steel Chemical & Material's "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase ChemteX's "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celloxide 2021P" (alicyclic epoxy resin with an ester skeleton); Daicel's "PB-3600," Nippon Soda's "JP-100" and "JP-200" (epoxy resins with a butadiene structure); and Nippon Steel Chemical & Material's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin).

[0026] The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups per molecule, and more preferably an aromatic solid epoxy resin having three or more epoxy groups per molecule.The solid epoxy resin is preferably a bixylenol type epoxy resin, a naphthalene type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a naphthol novolac type epoxy resin, a cresol novolac type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthylene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol AF type epoxy resin, a phenol aralkyl type epoxy resin, a tetraphenylethane type epoxy resin, or a phenolphthalimidine type epoxy resin.

[0027] Specific examples of solid epoxy resins include DIC Corporation's "HP4032H" (naphthalene-type epoxy resin); DIC Corporation's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC Corporation's "N-690" (cresol novolac-type epoxy resin); DIC Corporation's "N-695" (cresol novolac-type epoxy resin); DIC Corporation's "HP-7200," "HP-7200HH," "HP-7200H," and "HP-7200L" (dicyclopentadiene-type epoxy resins); and DIC Corporation's "EXA-7311." "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V", "ESN4" manufactured by Nippon Steel Chemical & Material Co., Ltd. 100V" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "Y" manufactured by Mitsubishi Chemical Corporation Examples include "X7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.

[0028] When the (A) epoxy resin contains a combination of a liquid epoxy resin and a solid epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

[0029] The epoxy equivalent of the (A) epoxy resin is preferably in the range of 50 g / eq to 5,000 g / eq, more preferably 60 g / eq to 3,000 g / eq, even more preferably 80 g / eq to 2,000 g / eq, and particularly preferably 110 g / eq to 1,000 g / eq. The epoxy equivalent represents the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0030] The weight average molecular weight (Mw) of the (A) epoxy resin is preferably in the range of 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0031] The amount of (A) epoxy resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition. The nonvolatile components in the resin composition refer to all components in the resin composition excluding (I) the solvent, unless otherwise specified. When the amount of (A) epoxy resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0032] The amount of (A) epoxy resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. Unless otherwise specified, the resin components in the resin composition refer to the non-volatile components in the resin composition excluding the (C) inorganic filler. When the amount of (A) epoxy resin is within the above range, the dielectric loss tangent, smear removal ability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0033] <(B-1) First activated ester resin> The resin composition according to this embodiment includes a (B-1) first active ester resin as a (B-1) component. The (B-1) first active ester resin is an active ester resin containing a butadiene skeleton. Therefore, the (B-1) first active ester resin can be a curable resin having a combination of an active ester group and a butadiene skeleton. The (B-1) first active ester resin may be used alone or in combination of two or more.

[0034] The activated ester group refers to a group formed by an ester bond directly bonded to an aromatic ring. This activated ester group encompasses not only ester bonds contained in an aromatic carbon-C(═O)-O-aromatic carbon structure, but also ester bonds contained in an aliphatic carbon-C(═O)-O-aromatic carbon structure, as long as they can react with an epoxy group to form a bond. The term "aromatic ring" refers to a ring conforming to the Hückel rule, in which the number of electrons contained in the π electron system of the ring is 4p+2 (p is a natural number), and includes monocyclic aromatic rings and fused polycyclic aromatic rings in which two or more monocyclic aromatic rings are fused. The aromatic ring may be an aromatic carbocycle containing only carbon atoms as ring-constituting atoms, or an aromatic heterocycle containing heteroatoms such as oxygen, nitrogen, or sulfur atoms as ring-constituting atoms in addition to carbon atoms. Aromatic rings include benzene, naphthalene, and anthracene rings, with benzene and naphthalene rings being particularly preferred. The term "aromatic carbon" refers to the carbon atoms constituting the aromatic ring.

[0035] The number of active ester groups contained in one molecule of the first active ester resin (B-1) is usually one or more, and preferably two or more.

[0036] The butadiene skeleton represents a carbon skeleton contained in a butenediyl group. Here, the butenediyl group includes a 2-butene-1,4-diyl group and a 3-butene-1,2-diyl group (i.e., a vinylethylene group). The 2-butene-1,4-diyl group may be either a cis or trans isomer. In the (B-1) first activated ester resin, the structure containing the butadiene skeleton may be referred to as a "butadiene structure" as appropriate. This butadiene structure includes the 2-butene-1,4-diyl group and the 3-butene-1,2-diyl group, as well as groups in which the hydrogen atoms contained in these groups are substituted with substituents. Examples of the substituent include halogen atoms; saturated aliphatic hydrocarbon groups such as alkyl groups and cycloalkyl groups; aromatic hydrocarbon groups such as aryl groups; and hydrocarbon oxy groups such as alkoxy groups, cycloalkyloxy groups, and aryloxy groups.

[0037] Preferred examples of the butadiene structure include structures represented by the following formulas (B1) and (B2).

[0038] [ka]

[0039] In formula (B1) and formula (B2), R b are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom or a halogen atom, more preferably a hydrogen atom. Also, * represents a bonding site.

[0040] Among the above, the butadiene structure is preferably a structure represented by formula (B1). Therefore, the first active ester resin (B-1) preferably contains the butadiene structure represented by formula (B1) as a structure having a butadiene skeleton, and may contain only the butadiene structure represented by formula (B1).

[0041] The number of butadiene structures contained in one molecule of the (B-1) first active ester resin is usually at least 1, and preferably at least 2. In particular, the (B-1) first active ester resin more preferably contains a polybutadiene structure in which two or more butadiene structures are bonded to each other.

[0042] The first active ester resin (B-1) typically has a larger active ester group equivalent weight than the second active ester resin (B-2). The active ester group equivalent weight of the first active ester resin (B-1) is preferably 200 g / eq or more, more preferably 300 g / eq or more, even more preferably 400 g / eq or more, and is preferably 3,000 g / eq or less, more preferably 2,000 g / eq or less, even more preferably 1,500 g / eq or less. As mentioned above, the active ester group equivalent weight refers to the mass of the resin per equivalent of active ester groups.

[0043] The weight average molecular weight (Mw) of the first active ester resin (B-1) is preferably in the range of 500 or more, more preferably 1,000 or more, and preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less.

[0044] Examples of the (B-1) first activated ester resin include resins represented by the following formula (b-1). In formula (b-1), each R independently represents an aryl group which may have a substituent, and preferably represents a phenyl group which may have a substituent or a naphthyl group which may have a substituent. The substituent is preferably a hydrocarbon group, more preferably a saturated aliphatic hydrocarbon group, and even more preferably an alkyl group having 1 to 6 carbon atoms. In formula (b-1), a and m each represent the number of repetitions, and specifically, are greater than 0. The (B-1) first activated ester resin is available, for example, as "EXB-LE-P01" manufactured by DIC Corporation.

[0045] [ka]

[0046] The number of active ester groups in the (B-1) first active ester resin is preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.05 or more, and preferably 1 or less, more preferably 0.5 or less, even more preferably 0.1 or less, relative to the number of epoxy groups in the (A) epoxy resin, where 1 is the number of epoxy groups in the (A) epoxy resin. The "number of epoxy groups in the (A) epoxy resin" in the resin composition refers to the sum of all values ​​obtained by dividing the mass of the non-volatile components of the (A) epoxy resins present in the resin composition by their epoxy equivalents. Furthermore, the "number of active ester groups in the (B-1) first active ester resin" in the resin composition refers to the sum of all values ​​obtained by dividing the mass of the non-volatile components of the (B-1) first active ester resins present in the resin composition by their active ester group equivalents. When the number of active ester groups in the (B-1) first active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly favorable.

[0047] The amount of the (B-1) first active ester resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. When the amount of the (B-1) first active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0048] The amount of the (B-1) first active ester resin is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to 100% by mass of the resin components in the resin composition, 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 amount of the (B-1) first active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0049] <(B-2) Second activated ester resin> The resin composition according to this embodiment includes a (B-2) second active ester resin as a (B-2) component. The (B-2) second active ester resin is an active ester resin that does not contain a butadiene skeleton. Therefore, the (B-2) second active ester resin can be a curable resin that has an active ester group but does not have a butadiene skeleton. The (B-2) second active ester resin may be used alone or in combination of two or more.

[0050] The second activated ester resin (B-2) is preferably a compound having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds.

[0051] The second activated ester resin (B-2) 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. From the viewpoint of improving heat resistance in particular, an activated ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an activated ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, 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 dicyclopentadiene molecule with two phenol molecules.

[0052] Specifically, the second active ester resin (B-2) is preferably a dicyclopentadiene-type active ester resin, a naphthalene-type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolac, or an active ester resin containing a benzoylated product of phenol novolac, and among these, a naphthalene-type active ester resin is more preferred. As the dicyclopentadiene-type active ester resin, an active ester resin containing a dicyclopentadiene-type diphenol structure is preferred.

[0053] Commercially available products of the (B-2) second active ester resin include, for example, active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", "HPC-8000H-65TM", and "NE-V-1100-70T" (manufactured by DIC Corporation); active ester resins containing a naphthalene structure such as "HP-B-8151-62T", "EXB-8100L-65T", and "EXB-8150-60T", Examples of such active ester resins include "EXB-8150-62T," "EXB-9416-70BK," "HPC-8150-60T," "HPC-8150-62T," and "HPC-8151-62T" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester resin; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin which is an acetylated product of phenol novolac; "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins which are benzoylated products of phenol novolac; and "PC1300-02-65MA" (manufactured by Air Water Inc.) as an active ester resin containing a styryl group and a naphthalene structure.

[0054] The second active ester resin (B-2) usually has a smaller active ester group equivalent weight than the first active ester resin (B-1). The active ester group equivalent weight of the second active ester resin (B-2) is preferably 50 g / eq or more, more preferably 100 g / eq or more, and is preferably 3,000 g / eq or less, more preferably 1,000 g / eq or less, even more preferably 500 g / eq or less, and particularly preferably 300 g / eq or less.

[0055] The weight average molecular weight (Mw) range of the second active ester resin (B-2) may be the same as the weight average molecular weight (Mw) range of the epoxy resin (A).

[0056] The number of active ester groups in the (B-2) second active ester resin is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more, and is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less, relative to the number of epoxy groups in the (A) epoxy resin, taken as 1. The "number of active ester groups in the (B-2) second active ester resin" in the resin composition refers to the total value obtained by dividing the mass of the non-volatile components of the (B-2) second active ester resin present in the resin composition by its active ester group equivalent. When the number of active ester groups in the (B-2) second active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0057] The amount of the (B-2) second active ester resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, 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 amount of the (B-2) second active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0058] The amount of the (B-2) second active ester resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of the (B-2) second active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0059] Typically, the second active ester resin (B-2) is used in an amount greater than the first active ester resin (B-1). The ratio of the first active ester resin (B-1) to the second active ester resin (B-2) (second active ester resin (B-2) / first active ester resin (B-1)) is preferably 1.0 or more, more preferably 1.5 or more, even more preferably 2.0 or more, and even more preferably 2.5 or more, by mass, and is preferably 30 or less, more preferably 15.0 or less, more preferably 10.0 or less, more preferably 7.0 or less, and even more preferably 5.0 or less. When the ratio (second active ester resin (B-2) / first active ester resin (B-1)) is within the above range, the dielectric loss tangent, smear removal ability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0060] <Total amount of active ester resin> The total amount of active ester resins, including the (B-1) first active ester resin and the (B-2) second active ester resin, can be expressed as the sum of the (B-1) first active ester resin and the (B-2) second active ester resin. The total amount of active ester resins is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 20% by mass or less. When the total amount of active ester resins is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0061] The range of the total amount of the active ester resin is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, based on 100% by mass of the resin components in the resin composition. When the total amount of the (B) active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0062] The number of active ester groups in the active ester resin is preferably 0.1 or more, more preferably 0.5 or more, even more preferably 0.8 or more, and preferably 5 or less, more preferably 3 or less, even more preferably 2 or less, assuming that the number of epoxy groups in the (A) epoxy resin is 1. The "number of active ester groups in the active ester resin" in the resin composition refers to the total value obtained by dividing the mass of the non-volatile components of the active ester resin present in the resin composition by its active ester group equivalent. When the number of active ester groups in the active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0063] The range of the total amount of the (A) epoxy resin, (B-1) first active ester resin, and (B-2) second active ester resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and is preferably 98% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, based on 100% by mass of the resin components in the resin composition. When the total amount of the (A) epoxy resin, (B-1) first active ester resin, and (B-2) second active ester resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0064] <(C) Inorganic filler> The resin composition according to the present embodiment may contain an inorganic filler (C) as an optional component. The inorganic filler (C) as component (C) is in the form of particles of an inorganic material. Therefore, the inorganic filler (C) is contained in the resin composition in the form of particles, and is usually contained in the cured product while maintaining this particulate state.

[0065] Inorganic compounds are typically used as the inorganic material forming the (C) inorganic filler. Examples of materials for the (C) inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, with silica being particularly preferred. Therefore, the (C) inorganic filler preferably contains silica, or may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Moreover, the silica is preferably spherical silica.The inorganic filler (C) may be used alone or in combination of two or more kinds.

[0066] (C) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-03," and "FB-105FD" manufactured by Denka Company, Limited; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "CellSpheres" and "MGH-005" manufactured by Taiheiyo Cement Corporation; and "Sferique" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0067] The average particle size of the (C) inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, even more preferably 1 μm or less.

[0068] (C) The average particle size of an inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a volumetric particle size distribution of the inorganic filler is created using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The volumetric particle size distribution of the inorganic filler is measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths using a flow cell system, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. Examples of laser diffraction particle size distribution analyzers include the LA-960 manufactured by Horiba, Ltd.

[0069] (C) The specific surface area of ​​the inorganic filler is preferably 0.1 m 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 / g or more, preferably 100m 2 / g or less, more preferably 70m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 (C) The specific surface area of ​​the inorganic filler can be measured in accordance with the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0070] The (C) inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. One type of surface treatment agent may be used alone, or two or more types may be used in any combination.

[0071] 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).

[0072] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0073] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition layer, it is more preferable that the amount of the resin composition layer is 1.0 mg / m 2 Preferably less than 0.8 mg / m 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0074] (C) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. An "EMIA-320V" manufactured by Horiba, Ltd., or the like can be used as the carbon analyzer.

[0075] The amount of (C) inorganic filler is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. When the amount of (C) inorganic filler is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0076] The total amount of the (A) epoxy resin, (B-1) first active ester resin, (B-2) second active ester resin, and (C) inorganic filler is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and is preferably 100% by mass or less, more preferably 99% by mass or less, and even more preferably 97% by mass or less, based on 100% by mass of the non-volatile components of the resin composition. When the total amount of the (A) epoxy resin, (B-1) first active ester resin, (B-2) second active ester resin, and (C) inorganic filler is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0077] <(D) Radical polymerizable resin> The resin composition according to the present embodiment may contain a (D) radical polymerizable resin as an optional component. The (D) radical polymerizable resin as component (D) does not include those corresponding to the above-mentioned components (A) to (C). The (D) radical polymerizable resin may be used alone or in combination of two or more.

[0078] The (D) radical polymerizable resin may be a resin containing a non-aromatic carbon-carbon unsaturated bond. Therefore, the (D) radical polymerizable resin may typically have a polymerizable unsaturated group containing a non-aromatic carbon-carbon unsaturated bond. Examples of the polymerizable unsaturated group include unsaturated hydrocarbon groups such as vinyl, allyl, 1-propenyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl; and α,β-unsaturated carbonyl groups such as acryloyl, methacryloyl, and maleimide (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl) groups. The (D) radical polymerizable resins containing these polymerizable unsaturated groups can typically react with each other or with a carbon-carbon unsaturated bond that may be contained in the butadiene skeleton of the (B-1) first active ester resin through radical polymerization. The (D) radically polymerizable resin preferably has two or more polymerizable unsaturated groups.

[0079] A preferred example of the (D) radical polymerizable resin is a maleimide resin. Therefore, the (D) radical polymerizable resin preferably contains a maleimide resin, or may contain only a maleimide resin. The maleimide resin refers to a resin containing one or more, preferably two or more, maleimide groups in one molecule.

[0080] Examples of maleimide resins include aromatic maleimide resins having a maleimide group directly bonded to an aromatic ring, and aliphatic maleimide resins having a maleimide group directly bonded to an aliphatic group. The maleimide resin may contain only aromatic maleimide resin, only aliphatic maleimide resin, or a combination of aromatic maleimide resin and aliphatic maleimide resin. Among these, from the viewpoint of obtaining an insulating layer with a small linear thermal expansion coefficient, it is preferable to contain an aromatic maleimide resin. Furthermore, from the viewpoint of obtaining an insulating layer with a low dielectric loss tangent, it is preferable to contain an aliphatic maleimide resin.

[0081] Furthermore, the maleimide resin preferably contains a specific molecular skeleton. Examples of preferred molecular skeletons include a biphenyl skeleton and an alicyclic skeleton. Maleimide resins containing these molecular skeletons can particularly improve properties such as dielectric loss tangent, smear removal, crack resistance, and linear thermal expansion coefficient. Furthermore, among alicyclic skeletons, maleimide resins containing an indane skeleton have excellent compatibility and can particularly improve the above properties.

[0082] A preferred example of the maleimide resin is a maleimide resin containing a partial structure represented by the following formula (D1). Typically, the maleimide resin containing the partial structure represented by formula (D1) is an aliphatic maleimide resin. The number of maleimide groups in one molecule of the maleimide resin containing the partial structure represented by formula (D1) is preferably 2 or more, and more preferably 2.

[0083] [ka]

[0084] (In formula (D1), ring B d represents an aliphatic hydrocarbon ring which may have a substituent; i d and j d each independently represents an integer of 0 or 1 or more, and i d and j dThe sum of is 6 or more; * indicates a binding site.)

[0085] In formula (D1), ring B d represents an aliphatic hydrocarbon ring which may have a substituent. The aliphatic hydrocarbon ring may be a saturated aliphatic hydrocarbon ring or an unsaturated aliphatic hydrocarbon ring. Furthermore, the aliphatic hydrocarbon ring may be a monocyclic aliphatic hydrocarbon ring having one ring or a polycyclic aliphatic hydrocarbon ring having multiple rings. The number of carbon atoms in the aliphatic hydrocarbon ring is preferably 4 or more, more preferably 5 or more, and preferably 14 or less, more preferably 10 or less, and even more preferably 6 or less.

[0086] Ring B d Among the above, the aliphatic hydrocarbon ring is preferably a monocyclic aliphatic hydrocarbon ring, more preferably a monocyclic saturated aliphatic hydrocarbon ring. Examples of the monocyclic saturated aliphatic hydrocarbon ring include monocycloalkane rings such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring, and a cyclohexane ring is preferred.

[0087] Ring B d Examples of the substituent that the aliphatic hydrocarbon ring may have include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, an aralkyl-oxy group, etc. Among these, an alkyl group and an alkenyl group are preferred, and an alkyl group is more preferred.

[0088] Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0089] The alkyl group may be a linear, branched, or cyclic monovalent aliphatic saturated hydrocarbon group. The alkyl group preferably has 1 to 14 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an isohexyl group, a heptyl group, an isoheptyl group, an octyl group, an isooctyl group, a tert-octyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexylmethyl group.

[0090] The alkenyl group may be a linear, branched, or cyclic monovalent aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond. The number of carbon atoms in the alkenyl group is preferably 2 to 14, more preferably 2 to 6, and even more preferably 2 or 3. Examples of the alkenyl group include vinyl, propenyl (allyl, 1-propenyl, isopropenyl), butenyl (1-butenyl, crotyl, methallyl, isocrotyl, etc.), pentenyl (1-pentenyl, etc.), hexenyl (1-hexenyl, etc.), heptenyl (1-heptenyl, etc.), octenyl (1-octenyl, etc.), cyclopentenyl (2-cyclopentenyl, etc.), and cyclohexenyl (3-cyclohexenyl).

[0091] The aryl group may be a monovalent aromatic hydrocarbon group formed by removing one hydrogen atom from an aromatic carbon ring. The number of carbon atoms in the aryl group is preferably 6 to 14, more preferably 6 to 10. Examples of the aryl group include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0092] The aralkyl group may be an alkyl group substituted with one or more (preferably one) aryl groups. The number of carbon atoms in the aralkyl group is preferably 7 to 15, more preferably 7 to 11. Examples of the aralkyl group include a benzyl group, a phenethyl group, a hydrocinnamyl group, an α-methylbenzyl group, an α-cumyl group, a 1-naphthylmethyl group, and a 2-naphthylmethyl group.

[0093] In formula (D1), i d and j d are each independently an integer of 0 or 1 or more. d and j d The sum of is usually 6 or more, preferably 8 or more, and more preferably 10 or more. d and j d is preferably an integer of 0 to 20, more preferably an integer of 1 to 20, and even more preferably an integer of 5 to 10. d and j d may be the same or different. d and j d is particularly preferably 8.

[0094] An example of a maleimide resin containing a partial structure represented by formula (D1) is a maleimide resin represented by the following formula (D2).

[0095] [ka]

[0096] (In formula (D2), R d10 each independently represents a substituent; Ring C d each independently represents an aromatic ring which may have a substituent; D d1 and D d2 are each independently a single bond, -C(R x )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-; R xeach independently represents a hydrogen atom or an alkyl group; d each independently represents 0 or 1; d d each independently represents an integer of 0 or 1 or more; e d each independently represents 0, 1, or 2; n d represents an integer of 0 or 1 or more; other symbols are as described above. d Unit, d d Units and n d The units may be the same for each unit or may be different.

[0097] In formula (D2), R d10 R each independently represents a substituent. d10 Examples of the substituent represented by the group include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group.

[0098] In formula (D2), ring C d each independently represents an aromatic ring which may have a substituent. The aromatic ring is preferably an aromatic carbon ring. The aromatic ring is preferably a 5- to 14-membered aromatic ring, more preferably a 6- to 14-membered aromatic ring, and even more preferably a 6- to 10-membered aromatic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and more preferably a benzene ring or a naphthalene ring, and even more preferably a benzene ring.

[0099] Ring C d Examples of the substituent that the aromatic ring may have include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, an aralkyl-oxy group, etc. Among these, an alkyl group is preferred.

[0100] In formula (D2), D d1 and D d2 are each independently a single bond, -C(R x)2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-, and preferably represents a single bond, -C(R x )2- or -O-, more preferably -O-. x each independently represents a hydrogen atom or an alkyl group, and is preferably a hydrogen atom or a methyl group.

[0101] In formula (D2), c d are each independently 0 or 1, preferably 1.

[0102] In formula (D2), d d are each independently an integer of 0 or 1 or more, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and even more preferably 0.

[0103] In formula (D2), e d are each independently 0, 1 or 2, preferably 0.

[0104] In formula (D2), n d represents an integer of 0 or 1 or more, and is preferably 0.

[0105] Examples of the partial structure represented by the following formula (D3) contained in formula (D2) include partial structures represented by formulas (d-1) to (d-3) described below.

[0106] [ka]

[0107] [ka]

[0108] (In the formula, * indicates a binding site.)

[0109] Commercially available maleimide resins containing the partial structure represented by formula (D1) include, for example, "BMI-689," "BMI-1500," "BMI-1700," and "BMI-3000J" manufactured by Designer Molecules, Inc.; and "SLK-1500" (a compound represented by formula (d-4) below) and "SLK-6895" (a compound represented by formula (d-5)) manufactured by Shin-Etsu Chemical Co., Ltd.

[0110] [ka]

[0111] Another preferred example of the maleimide resin is a maleimide resin represented by formula (D4).

[0112] [ka]

[0113] (In formula (D4), R d20 each independently represents a hydrogen atom or an alkyl group; ring E d , ring F d and ring G d each independently represents an aromatic ring which may have a substituent; Z d1 are each independently a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-; R z each independently represents a hydrogen atom or an alkyl group; d indicates an integer greater than or equal to 1; g d h each independently represents 0 or 1; d f each independently represents 0, 1, 2 or 3. d Units and h d The units may be the same for each unit or may be different.

[0114] In formula (D4), R d20are each independently a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0115] In formula (D4), ring E d , ring F d and ring G d each independently represents an aromatic ring which may have a substituent. d , ring F d and ring G d Examples of the substituent in the ring E include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group. d , ring F d and ring G d is preferably a benzene ring which may have a substituent, more preferably a benzene ring which may be substituted with a group selected from an alkyl group and an aryl group, and even more preferably an unsubstituted benzene ring.

[0116] In formula (D4), Z d1 are each independently a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-, and preferably a single bond. z are each independently a hydrogen atom or an alkyl group, and are preferably a hydrogen atom or a methyl group.

[0117] In formula (D4), f d represents an integer of 1 or more, and is preferably an integer of 1 to 10.

[0118] In formula (D4), g d are each independently 0 or 1, preferably 1.

[0119] In formula (D4), h d each independently represents 0, 1, 2, or 3, preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 1.

[0120] Commercially available maleimide resins represented by formula (D4) include, for example, "MIR-3000-70MT" and "MIR-5000-60T" manufactured by Nippon Kayaku Co., Ltd.

[0121] Still another preferred example of the maleimide resin is a maleimide resin represented by formula (D5).

[0122] [ka]

[0123] (In formula (D5), R d30 each independently represents an alkyl group; d and Ring I d each independently represents an aromatic ring which may have a substituent; m d indicates an integer of 1 or greater. d The units may be the same for each unit or may be different.

[0124] In formula (D5), R d30 each independently represents an alkyl group, preferably a methyl group.

[0125] In formula (D5), ring H d each independently represents an aromatic ring which may have a substituent. d Examples of the substituent in the ring H include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group. d is preferably a benzene ring which may have a substituent, more preferably a benzene ring which may be substituted with an alkyl group, and even more preferably a benzene ring substituted with an alkyl group.

[0126] In formula (D5), ring I deach independently represents an aromatic ring which may have a substituent. d Examples of the substituent in Ring I include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, and an aralkyl-oxy group. d is preferably a benzene ring which may have a substituent, more preferably a benzene ring which may be substituted with an alkyl group, and even more preferably an unsubstituted benzene ring.

[0127] In formula (D5), m d represents an integer of 1 or more, preferably an integer of 1 to 20.

[0128] The maleimide resin represented by formula (D5) can be produced, for example, by the method described in the Japan Institute of Invention and Innovation's Disclosure Technical Bulletin No. 2020-500211 or a method equivalent thereto.

[0129] The maleimide group equivalent of the maleimide resin is preferably 30 g / eq or more, more preferably 75 g / eq or more, even more preferably 150 g / eq or more, even more preferably 200 g / eq or more, even more preferably 250 g / eq or more, even more preferably 300 g / eq or more, and is preferably 2,500 g / eq or less, more preferably 2,000 g / eq or less, even more preferably 1,500 g / eq or less, even more preferably 1,000 g / eq or less, even more preferably 500 g / eq or less. The maleimide group equivalent represents the mass of the resin per equivalent of maleimide group.

[0130] The weight average molecular weight of the maleimide resin is preferably 100 or more, more preferably 150 or more, even more preferably 200 or more, even more preferably 400 or more, even more preferably 500 or more, even more preferably 600 or more, and is preferably 10,000 or less, more preferably 7,000 or less, even more preferably 5,000 or less, even more preferably 3,000 or less.

[0131] The amount of maleimide resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.9% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, relative to 100% by mass of nonvolatile components in the resin composition. When the amount of maleimide resin is within the above range, the dielectric loss tangent, smear removal ability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0132] The amount of maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the resin components in the resin composition, 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 amount of maleimide resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0133] The range of the quantitative ratio of the maleimide resin to the (B-1) first activated ester resin (maleimide resin / (B-1) first activated ester resin) is, on a mass basis, preferably 0.01 or more, more preferably 0.1 or more, even more preferably 0.2 or more, and preferably 5 or less, more preferably 3 or less, even more preferably 2 or less. When the quantitative ratio (maleimide resin / (B-1) first activated ester resin) is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0134] Further examples of the (D) polymerizable unsaturated resin include (meth)acrylic polymerizable unsaturated resins, styrene polymerizable unsaturated resins, and allyl polymerizable unsaturated resins.

[0135] As the (meth)acrylic polymerizable unsaturated resin, a resin having one or more, preferably two or more, acryloyl groups and / or methacryloyl groups in one molecule can be used. Examples of the (meth)acrylic polymerizable unsaturated resin include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonane diol di(meth)acrylate, and the like. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester compounds such as diol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxane glycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, ) acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, and other low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins.Commercially available (meth)acrylic polymerizable unsaturated resins include, for example, "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), and "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether) manufactured by SABIC.

[0136] Styrenic polymerizable unsaturated resins may be those having one or more, preferably two or more, vinyl groups directly bonded to aromatic carbon atoms per molecule. Examples of styrenic polymerizable unsaturated resins include low-molecular-weight (molecular weight less than 1000) styrenic compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether; and high-molecular-weight (molecular weight greater than 1000) styrenic compounds such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers. Among these styrenic polymerizable unsaturated resins, resins containing a combination of monovinyl aromatic compound units and divinyl aromatic compound units are preferred. A monovinyl aromatic compound unit refers to a structural unit formed by polymerizing a monovinyl compound, such as styrene, having an aromatic ring to which a single vinyl group is directly bonded. The term "divinyl aromatic compound unit" refers to a structural unit formed by polymerizing a divinyl aromatic compound, such as divinylbenzene, having an aromatic ring to which two vinyl groups are directly bonded. Examples of suitable styrene-based polymerizable unsaturated resins include those described in International Publication No. 2017 / 115813. Commercially available styrene-based polymerizable unsaturated resins include "ODV-XET(X03)," "ODV-XET(X04)," and "ODV-XET(X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0137] As the allylic polymerizable unsaturated resin, a resin having one or more, preferably two or more, allyl groups in one molecule can be used. Examples of allyl-based polymerizable unsaturated resins include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, and diallyl 2,3-naphthalenecarboxylate; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyldiphenylsilane. Among these, resins having terminal allyl groups are preferred. Commercially available allyl polymerizable unsaturated resins include, for example, "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., "DAND" (2,3-diallyl naphthalenecarboxylate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., and " Examples include "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane), "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemicals Corporation, and "NE-V-1100-70T" manufactured by DIC Corporation.

[0138] The (D) polymerizable unsaturated resin may include a resin containing a polyphenylene ether skeleton in its molecular skeleton.

[0139] The polymerizable unsaturated group equivalent of (D) the polymerizable unsaturated resin is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., even more preferably 70 g / eq. to 2,000 g / eq., and particularly preferably 90 g / eq. to 1,500 g / eq. The polymerizable unsaturated group equivalent represents the mass of the resin per equivalent of the polymerizable unsaturated group.

[0140] The weight average molecular weight (Mw) of the (D) polymerizable unsaturated resin is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. The lower limit is not particularly limited, but may be, for example, 150 or more.

[0141] The amount of (D) polymerizable unsaturated resin 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 nonvolatile components in the resin composition, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the amount of (D) polymerizable unsaturated resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0142] The amount of (D) polymerizable unsaturated resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the resin components in the resin composition, 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 amount of (D) polymerizable unsaturated resin is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0143] The range of the quantitative ratio of the (D) polymerizable unsaturated resin to the (B-1) first active ester resin ((D) polymerizable unsaturated resin / (B-1) first active ester resin) is, on a mass basis, preferably 0.01 or more, more preferably 0.1 or more, even more preferably 0.2 or more, and preferably 5 or more, more preferably 3 or less, even more preferably 2 or less. When the quantitative ratio ((D) polymerizable unsaturated resin / (B-1) first active ester resin) is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0144] <(E) Optional Hardener> The resin composition according to this embodiment may contain, as an optional component, an optional curing agent (E) other than the first active ester resin (B-1) and the second active ester resin (B-2). The optional curing agent (E) as the component (E) refers to a resin that can react with an epoxy resin to cure the resin composition. The optional curing agent (E) does not include those corresponding to the above-mentioned components (A) to (D). For example, although a maleimide resin may react with an epoxy resin (A) under an appropriate catalyst, the maleimide resin is not classified as an optional curing agent (E). The optional curing agent (E) may be used alone or in combination of two or more.

[0145] Preferred examples of the optional curing agent (E) include phenolic resins, benzoxazine resins, cyanate ester resins, carbodiimide resins, acid anhydride resins, and amine resins.

[0146] As the phenolic resin, a resin having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule can be used. From the viewpoint of heat resistance and water resistance, a phenolic resin having a novolac structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a triazine skeleton-containing phenolic resin is more preferred. Among these, a triazine skeleton-containing phenolic novolac resin is preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion.

[0147] Specific examples of phenolic resins include "MEH-7700," "MEH-7810," "MEH-7851," and "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; and "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-495V," and "SN-3" manufactured by Nippon Steel Chemical & Material Co., Ltd. 75" and "SN-395" manufactured by DIC Corporation; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by Gun-ei Chemical Co., Ltd.; and "GDP-6115L", "GDP-6115H", and "ELPC75" manufactured by Gun-ei Chemical Co., Ltd.

[0148] The benzoxazine resin may be a resin having one or more, preferably two or more, benzoxazine rings in one molecule. Specific examples of the benzoxazine resin include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation, "HFB2006M" manufactured by Showa Polymer Co., Ltd., and "Pd", "Fa", and "ALP-d" manufactured by Shikoku Chemicals Corporation.

[0149] As the cyanate ester resin, a resin having one or more, preferably two or more, cyanate groups in one molecule can be used. Examples of cyanate ester resins include bifunctional cyanate ester 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-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; multifunctional cyanate ester resins derived from phenol novolac, cresol novolac, and the like; and prepolymers in which these cyanate ester resins are partially triazine converted. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type multifunctional cyanate ester resins) manufactured by Arxada, "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine converted to a trimer).

[0150] As the carbodiimide resin, a resin having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of the carbodiimide resin include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly(naphthalenecarbodiimide); Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(methylenediphenylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide resins include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-05," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510" manufactured by Lanxess AG.

[0151] As the acid anhydride resin, a resin having one or more, preferably two or more, acid anhydride groups in one molecule can be used. Specific examples of the acid anhydride resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride. Examples of suitable anhydrides include hydrates, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resin, which is a copolymer of styrene and maleic acid. Commercially available acid anhydride resins include, for example, "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" manufactured by Resonac Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Cray Valley Chemical Industries, Ltd.

[0152] The amine resin may be a resin having one or more, preferably two or more, amino groups in one molecule. Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, with aromatic amines being preferred. The amine resin is preferably a primary amine or secondary amine, with primary amines being more preferred. Specific examples of the amine resin include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propanol. Examples of suitable bis(4-aminophenoxy)benzene include bis(4-aminophenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, and bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine resins include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0153] The active group equivalent of the (E) optional curing agent is preferably 50 g / eq. to 3,000 g / eq., more preferably 100 g / eq. to 1,000 g / eq., even more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent represents the mass of the resin per equivalent of the active group. The active group of the (E) optional curing agent represents a group capable of reacting with the epoxy group of the (A) epoxy resin, such as a phenolic hydroxyl group. For example, the active group equivalent of a phenolic resin represents the phenolic hydroxyl group equivalent, which represents the mass of the resin per equivalent of the phenolic hydroxyl group.

[0154] The weight average molecular weight (Mw) range of the (E) optional curing agent may be the same as the weight average molecular weight (Mw) range of the (A) epoxy resin.

[0155] The amount of (E) optional curing agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less.

[0156] The amount of (E) optional curing agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, relative to 100% by mass of the resin component in the resin composition.

[0157] The total number of active ester groups in the (B-1) first active ester resin, the (B-2) second active ester resin, and the (E) optional curing agent is preferably 0.1 or more, more preferably 0.5 or more, even more preferably 1.0 or more, and is preferably 10 or less, more preferably 5.0 or less, even more preferably 3.0 or less, and even more preferably 2.0 or less, relative to the number of epoxy groups in the (A) epoxy resin. The "number of active groups in the (E) optional curing agent" in the resin composition refers to the sum of all values ​​obtained by dividing the mass of the non-volatile components of the (E) optional curing agent present in the resin composition by its active group equivalent. When the total number of active ester groups in the (B-1) first active ester resin, the (B-2) second active ester resin, and the (E) optional curing agent is within the above range, the dielectric loss tangent, smear removability, linear thermal expansion coefficient, and crack resistance at high temperatures and high frequencies can be particularly improved.

[0158] <(F)Organic filler> The resin composition according to this embodiment may contain an organic filler (F) as an optional component. The organic filler (F) as component (F) does not include those corresponding to the above-mentioned components (A) to (E). The organic filler (F) is usually incompatible with resin components other than the organic filler (F), is contained in the resin composition in the form of particles, and is contained in the cured product while maintaining this particle state. Furthermore, one type of organic filler (F) may be used alone, or two or more types may be used in combination.

[0159] The (F) organic filler may be particles of an organic material. A rubber component is preferred as the organic material contained in the (F) organic filler. Examples of rubber components include silicone-based elastomers such as polydimethylsiloxane; olefin-based thermoplastic elastomers such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, and ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic thermoplastic elastomers such as polypropyl(meth)acrylate, polybutyl(meth)acrylate, polycyclohexyl(meth)acrylate, and polyoctyl(meth)acrylate. Furthermore, silicone-based rubbers such as polyorganosiloxane rubber may be mixed into the rubber component. The rubber component contained in the rubber particles has a glass transition temperature of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0160] The (F) organic filler may be a core-shell type rubber particle consisting of a core particle containing the above-mentioned rubber component and a shell portion formed by graft copolymerization of a monomer component copolymerizable with the rubber component contained in the core particle. Here, the term "core-shell type" does not necessarily refer only to those in which the core particle and the shell portion are clearly distinguishable, but also includes those in which the boundary between the core particle and the shell portion is unclear, and the core particle does not necessarily have to be completely covered with the shell portion.

[0161] Specific examples of (F) organic fillers include "CHT" manufactured by Samsung SDI; "B602" manufactured by Techno UMG; "Paraloid EXL-2602", "Paraloid EXL-2603", "Paraloid EXL-2655", "Paraloid EXL-2311", "Paraloid-EXL2313", "Paraloid EXL-2315", "Paraloid KM-330", "Paraloid KM-336P", and "Paraloid KCZ-201" manufactured by Dow; and "Metabrene C-223A" and "Metabrene E- 901," "Metabrene S-2001," "Metabrene W-450A," "Metabrene SRK-200," "Kane Ace M-511," "Kane Ace M-600," "Kane Ace M-400," "Kane Ace M-580," and "Kane Ace MR-01" manufactured by Kaneka Corporation, and "Staphyloid AC3355," "Staphyloid AC3816," "Staphyloid AC3816N," "Staphyloid AC3832," "Staphyloid AC4030," and "Staphyloid AC3364" manufactured by Aica Kogyo Co., Ltd.

[0162] The amount of (F) organic filler is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less.

[0163] The amount of (F) organic filler is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

[0164] <(G) Curing accelerator> The resin composition according to the present embodiment may contain a (G) curing accelerator as an optional component. The (G) curing accelerator as component (G) does not include components (A) to (F) described above. The (G) curing accelerator acts as a catalyst for the reaction of the (A) epoxy resin, thereby accelerating the curing of the resin composition.

[0165] Examples of the (G) curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. One type of (G) curing accelerator may be used alone, or two or more types may be used in combination.

[0166] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0167] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0168] 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.

[0169] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. 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-phenylimidazolium 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 Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0170] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0171] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0172] The amount of (G) curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, relative to 100% by mass of non-volatile components in the resin composition, and is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less.

[0173] The amount of (G) curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 10% by mass or less, more preferably 6% by mass or less, even more preferably 3% by mass or less.

[0174] <(H) Optional Additives> The resin composition according to this embodiment may further contain an optional additive (H) as an optional component. The optional additive (H) as component (H) does not include those corresponding to the above-mentioned components (A) to (G). Examples of the optional additive (H) include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silanes; triazole-based adhesion promoters, tetrazole-based adhesion promoters, and triazine-based adhesion promoters. Examples of the additives include adhesion promoters such as adhesives, antioxidants such as hindered phenol antioxidants, fluorescent brighteners such as stilbene derivatives, surfactants such as fluorine-based surfactants and silicone-based surfactants, flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide), dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants, and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (H) Optional additives may be used singly or in combination of two or more.

[0175] The resin composition may contain a photopolymerization initiator such as a photoacid generator and a photoradical generator. The resin composition according to this embodiment is preferably thermosetting, and therefore preferably contains substantially no photopolymerization initiator. Specifically, when the resin component in the resin composition is taken as 100% by mass, the amount of the photopolymerization initiator is preferably less than 0.1% by mass, 0.05% by mass or less, 0.04% by mass or less, 0.02% by mass or less, 0.01% by mass or less, less than 0.01% by mass, 0.005% by mass or less, 0.001% by mass or less, or less than 0.001% by mass. The amount of the photopolymerization initiator may even be 0% by mass.

[0176] <(I) Solvent> The resin composition according to this embodiment may further contain (I) a solvent as an optional volatile component in addition to the non-volatile components (A) to (H) described above. The (I) solvent is typically an organic solvent. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (I) The solvents may be used singly or in combination of two or more.

[0177] The amount of (I) solvent, relative to 100% by mass of all components in the resin composition, can be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, or may be 0% by mass.

[0178] <Method of manufacturing resin composition> The resin composition according to the present embodiment can be produced, for example, by mixing components that can be contained in the resin composition. The above-mentioned components may be mixed in part or all at the same time, or may be mixed sequentially. In the process of mixing each component, the temperature may be appropriately set, and thus heating and / or cooling may be performed temporarily or throughout. Furthermore, stirring or shaking may be performed in the process of mixing each component.

[0179] <Characteristics of the cured resin composition> By curing the resin composition according to this embodiment, a cured product of the resin composition can be obtained. An insulating layer can be formed from this cured product. Since heat is typically applied during curing of the resin composition, volatile components, such as (I) the solvent, contained in the resin composition can volatilize due to the heat during curing. Therefore, the cured product obtained by curing the resin composition can contain non-volatile components, such as components (A) to (H), or reaction products thereof.

[0180] The cured product of the resin composition according to this embodiment can have excellent dielectric properties, specifically, a low dielectric loss tangent Df. In one example, the dielectric loss tangent Df of the cured product is preferably 0.0030 or less, more preferably 0.0027 or less, and even more preferably 0.0025 or less. There is no particular lower limit to the dielectric loss tangent Df, and it can be, for example, 0.0010 or more.

[0181] The dielectric loss tangent Df of the cured product can be measured by the split cylinder method at a measurement frequency of 10 GHz and a measurement temperature of 90°C. When the sample is a resin composition before curing, the resin composition may be cured at 190°C for 90 minutes to obtain a cured product, and the dielectric loss tangent Df of the cured product may be measured. A specific measurement method may be the method described in <Test 1. Measurement of Dielectric Loss Tangent> in the Examples below.

[0182] The cured product of the resin composition according to this embodiment can usually have excellent smear removability. For example, when an insulating layer is formed using the cured product by the method described in <Test 3. Evaluation test of smear removability> in the Examples below and the smear removability is evaluated, the maximum smear length can be reduced to less than 5 μm.

[0183] The cured product of the resin composition according to this embodiment can usually have excellent crack resistance. For example, when an insulating layer is formed from the cured product by the method described in <Test 4. Evaluation test for crack resistance after desmear treatment> in the Examples below and the crack resistance is evaluated, the number of cracks can be 10 or less.

[0184] The cured product of the resin composition according to this embodiment can have a small coefficient of linear thermal expansion. In one example, the average coefficient of linear thermal expansion of the cured product is preferably 25 ppm / °C or less, more preferably 20 ppm / °C or less, and even more preferably 16 ppm / °C or less. There is no particular lower limit to the average coefficient of linear thermal expansion of the cured product, and it can be, for example, 5 ppm / °C or more.

[0185] The average linear thermal expansion coefficient of the cured product can be measured using a thermomechanical analyzer under measurement conditions of a measurement temperature range of 25°C to 250°C and a heating rate of 5°C / min. When the sample is a resin composition before curing, the resin composition may be cured under curing conditions of 190°C for 90 minutes to obtain a cured product, and the average linear thermal expansion coefficient of the cured product may be measured. A specific measurement method may be the method described in <Test 2. Measurement of Linear Thermal Expansion Coefficient (CTE)> in the Examples below.

[0186] <Applications of resin composition> The resin composition according to this embodiment can be used to form an insulating layer, and is particularly preferably used to form an insulating layer for a circuit board. The resin composition may also be used to manufacture a resin sheet. Typically, an insulating layer is formed using this resin sheet. The resin composition may also be used for other purposes, such as solder resist, underfill material, die bonding material, hole filling resin, sealing resin, and component embedding resin.

[0187] <Resin sheet> A resin sheet according to one embodiment of the present invention includes a support and a resin composition layer formed on the support. The resin composition layer contains the resin composition described above, and preferably contains only the resin composition described above.

[0188] From the viewpoint of thinning, the thickness of the resin composition layer provided in the resin sheet is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The lower limit of the thickness of the resin composition layer can be, for example, 1 μm or more, 3 μm or more, 5 μm or more, etc.

[0189] Examples of the support include plastic film, metal foil, and release paper, with plastic film and metal foil being preferred.

[0190] When a film of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0191] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be 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.).

[0192] The surface of the support that is to be bonded to the resin composition layer may be subjected to a surface treatment such as matte treatment, corona treatment, or antistatic treatment.

[0193] The support may be a support with a release layer, which has a release layer on the surface that bonds with the resin composition layer. 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-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, including PET films having a release layer primarily composed of a silicone-based release agent or an alkyd resin-based release agent, such as "PET501010," "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; and "Uni-Peel" manufactured by Unitika Limited.

[0194] The thickness of the support is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and is preferably 75 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is within the above range.

[0195] The resin sheet may include any optional member as needed. For example, the resin sheet may include a protective film for protecting the resin composition layer. The protective film is usually provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film is provided, adhesion of dust and scratches to the surface of the resin composition layer can be suppressed.

[0196] The resin sheet can be produced, for example, by a method including forming a resin composition layer on a support. Specifically, the resin sheet can be produced by applying a liquid (varnish-like) resin composition directly or by mixing a solvent and the resin composition to prepare a liquid (varnish-like) resin composition, applying the liquid (varnish-like) resin composition to a support, and then drying it as necessary to form a resin composition layer. The solvent may be the same as the (I) solvent described as a component of the resin composition.

[0197] The resin composition can be applied using a coating device such as a die coater. Drying can be performed by a drying method such as heating or hot air blowing. The drying conditions are not particularly limited, but drying is typically performed so that the solvent content in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although this may vary depending on the boiling point of the solvent, for example, when a resin composition containing 30% by mass to 60% by mass of solvent is used, a resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0198] The produced resin sheet can be stored by being wound up in a roll. When the resin sheet has a protective film, the resin sheet can usually be used by peeling off the protective film.

[0199] <Circuit board> A circuit board according to one embodiment of the present invention includes a cured product of the resin composition described above. Typically, the circuit board includes an insulating layer, and this insulating layer includes a cured product of the resin composition. The insulating layer may include only a cured product of the resin composition. The thickness of the insulating layer is not particularly limited and may be, for example, in the same range as the thickness of the resin composition layer included in the resin sheet. Furthermore, the insulating layer may typically have properties similar to those of the cured product of the resin composition described above.

[0200] Preferably, the circuit board includes an inner layer substrate and the insulating layer is provided on the inner layer substrate. The circuit board may also include a conductor layer. For example, the conductor layer may be provided on an insulating layer. An example of a preferred method for manufacturing a circuit board will be described below.

[0201] A preferred example of a method for manufacturing a circuit board includes the steps of: Step (I) of forming a resin composition layer on an inner layer substrate; a step (II) of curing the resin composition layer; Includes.

[0202] An "inner layer substrate" is a member that serves as the base material of a circuit board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate may have a conductor layer on one or both sides. The conductor layer of the inner layer substrate may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate is sometimes called an "inner layer circuit board." The term "inner layer substrate" also includes intermediate products on which insulating layers and / or conductor layers are to be further formed during the production of a circuit board. In addition, inner layer substrates with built-in components may also be used.

[0203] The resin composition layer may be formed on the inner layer substrate by, for example, a method including applying a resin composition to the inner layer substrate and drying it as necessary, but is preferably formed using a resin sheet. The method for forming a resin composition layer using a resin sheet typically includes laminating the resin sheet and the inner layer substrate. The resin sheet and the inner layer substrate are laminated so that the resin composition layer of the resin sheet and the inner layer substrate are bonded. This lamination may be performed, for example, by thermocompression bonding the resin sheet to the inner layer substrate from the support side. Examples of a member for thermocompression bonding the resin sheet to the inner layer substrate (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS panel) or a metal roll (such as a SUS roll). It is preferable to press the thermocompression bonding member not directly against the resin sheet but through an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the inner layer substrate.

[0204] The lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 26.7hPa or less.

[0205] The lamination may be performed using a commercially available vacuum laminator, such as a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., or a batch-type vacuum pressure laminator.

[0206] The method for manufacturing a circuit board may include smoothing the resin sheet after lamination under normal pressure (atmospheric pressure), for example, by pressing the resin sheet from the support side with a thermocompression member. The pressing conditions for the smoothing may be the same as those for the thermocompression bonding of the lamination. The smoothing may be performed using a commercially available laminator. The lamination and smoothing may be performed consecutively using the commercially available vacuum laminator.

[0207] The method for producing a circuit board according to this example includes a step (II) of curing the resin composition layer after the step (I). By curing the resin composition layer in the step (II), an insulating layer containing a cured product of the resin composition can be formed.

[0208] The resin composition layer is usually cured by thermal curing. The thermal curing conditions for the resin composition layer may vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0209] The method for producing a circuit board may include preheating the resin composition layer at a temperature lower than the curing temperature before thermally curing the resin composition layer. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated for typically 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 typically 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C. Preheating is typically carried out after step (I). Furthermore, when a smoothing treatment is carried out after laminating the inner layer substrate and the resin sheet, preheating can typically be carried out after the smoothing treatment.

[0210] When a resin sheet is used, the method for producing a circuit board may include a step of peeling off the support of the resin sheet after laminating the inner layer substrate and the resin sheet. The peeling off of the support may be performed between steps (I) and (II), or after step (II). Furthermore, when the method for producing a circuit board includes step (III) of forming holes in the insulating layer, step (IV) of roughening the insulating layer, and step (V) of forming a conductor layer, as described below, the peeling off of the support may be performed between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V).

[0211] The method for producing a circuit board may include, after step (II), step (III) of forming holes such as via holes or through holes in the insulating layer. The method for forming the holes may be selected depending on factors such as the composition of the resin composition used to form the insulating layer. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. For example, holes may be formed by irradiating the insulating layer with laser light after peeling off the support, or by irradiating the insulating layer with laser light through the support. The dimensions and shape of the holes may be determined appropriately depending on the design of the circuit board.

[0212] The method for manufacturing a circuit board may include a step (IV) of roughening the insulating layer. The roughening treatment can roughen the surface of the insulating layer. The roughening treatment can also remove smears (resin residues) from the insulating layer. Therefore, this roughening treatment is sometimes called a "desmear treatment." For example, when holes are formed in step (III), smears may form in the holes. Therefore, it is preferable to perform the roughening treatment of step (IV) after step (III) to remove the smears.

[0213] The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions that are commonly used when forming an insulating layer for a circuit board can be adopted. For example, the roughening treatment may be performed by subjecting the insulating layer to a swelling treatment using a swelling liquid, an oxidation treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order.

[0214] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solutions and potassium hydroxide solutions are more preferred as alkaline solutions. Commercially available swelling liquids include "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Atotech Japan. Swelling treatment using a swelling liquid can be performed, for example, by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. To keep the swelling of the resin in 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.

[0215] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Oxidation treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0216] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan can be cited as an example. Neutralization treatment using a neutralizing solution can be carried out by immersing the surface that has been oxidized with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0217] The method for producing a circuit board may include step (V) of forming a conductor layer on the insulating layer. When the method for producing a circuit board includes step (III) or (IV), step (V) of forming a conductor layer is usually preferably carried out after steps (III) and (IV).

[0218] The conductive 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. Examples of alloy layers include layers formed from an alloy of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred. Single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single metal layers of copper are even more preferred.

[0219] The conductor layer may have a single layer structure or a multi-layer structure including two or more single metal or alloy layers made of different types of metals or alloys. 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.

[0220] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0221] The conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. An example of forming a conductor layer by a semi-additive method will be described below.

[0222] First, an electroless plated layer (plating seed layer) is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed electroless plated layer, exposing a portion of the electroless plated layer corresponding to the desired wiring pattern. After forming an electroless plated layer on the exposed electroless plated layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary electroless plated layer is removed by etching, thereby forming a conductor layer having the desired wiring pattern.

[0223] As another example, the conductor layer may be formed using a metal foil. When a metal foil is used to form the conductor layer, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed, and a metal foil is laminated on the exposed surface of the resin composition layer. The lamination of the resin composition layer and the metal foil may be performed by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having a desired wiring pattern can be formed using the metal foil on the insulating layer by a known technique such as a subtractive method or a modified semi-additive method. The metal foil can be manufactured by a known method such as an electrolytic method or a rolling method. Commercially available metal foils include, for example, HLP foil and JXUT-III foil manufactured by JX Nippon Mining & Smelting Co., Ltd., and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0224] When a conductor layer is formed on an insulating layer, the method for manufacturing a circuit board may include performing an annealing treatment after the formation of the conductor layer. The annealing treatment can improve the adhesion between the insulating layer and the conductor layer. The annealing treatment can be performed, for example, by heating at 150°C to 210°C for 20 to 180 minutes.

[0225] In the method for manufacturing a circuit board, each of the above steps may be performed only once or may be repeated two or more times. For example, steps (I) to (V) may be performed repeatedly to form a circuit board having a multilayer structure, such as a multilayer printed wiring board having a plurality of insulating layers and conductor layers.

[0226] The method for manufacturing a circuit board may include any additional steps in addition to the steps described above. For example, the method for manufacturing a circuit board may include a step of providing a semiconductor chip so that the semiconductor chip is bonded to the conductor layer. Specifically, when manufacturing a circuit board for a semiconductor chip package including a semiconductor chip, the method for manufacturing a circuit board may include a step of providing the semiconductor chip. The semiconductor chip may be bonded under appropriate conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the conductor layer formed on the insulating layer. For example, conditions used in flip-chip mounting may be used. The semiconductor chip may be bonded via an insulating adhesive or by reflow bonding. If necessary, the provided semiconductor chip may be filled with a mold underfill material. The method for manufacturing a circuit board may also include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, and a step of dicing the manufactured circuit board into individual pieces.

[0227] Examples of circuit boards include printed wiring boards and semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA package, ETS-BGA package, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. In these semiconductor chip packages, it is preferable to form a rewiring formation layer as an insulating layer using a cured product obtained by curing the above-mentioned resin composition. However, the circuit board is not limited to those exemplified here.

[0228] <Semiconductor device> The circuit board can be used to manufacture a semiconductor device. The semiconductor device includes the circuit board described above. Examples of the semiconductor device include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft). [Example]

[0229] The present invention will be specifically described below with reference to examples, although the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm). In the following description, unless otherwise specified, "Mw" represents the weight average molecular weight, and "Mn" represents the number average molecular weight.

[0230] <Synthesis Example 1: Synthesis of Active Ester Resin A-1> A flask equipped with a thermometer, dropping funnel, condenser, distillation column, and stirrer was charged with 320 g (2.0 mol) of 2,7-dihydroxynaphthalene, 184 g (1.7 mol) of benzyl alcohol, and 5.0 g of paratoluenesulfonic acid monohydrate. The mixture was stirred at room temperature while blowing in nitrogen. The temperature was then raised to 150 °C and the mixture was stirred for 4 hours while distilling off the resulting water. After the reaction was complete, 900 g of methyl isobutyl ketone and 5.4 g of 20% aqueous sodium hydroxide solution were added to neutralize the mixture. The aqueous layer was then removed by separation, washed three times with 280 g of water, and the methyl isobutyl ketone was removed under reduced pressure to obtain 460 g of benzyl-modified naphthalene compound (A'). The resulting benzyl-modified naphthalene compound (A') was a black solid with a hydroxyl equivalent of 180 g / eq.

[0231] A flask equipped with a thermometer, dropping funnel, condenser, distillation column, and stirrer was charged with 203.0 g of isophthalic acid chloride (molar number of acid chloride groups: 2.0 mol) and 1,400 g of toluene. The system was then purged with nitrogen under reduced pressure and dissolved. Next, 72.4 g (0.67 mol) of orthocresol and 240 g of benzyl-modified naphthalene compound (A') (molar number of phenolic hydroxyl groups: 1.33 mol) were charged and the system was then purged with nitrogen under reduced pressure and dissolved. Next, 0.70 g of tetrabutylammonium bromide was dissolved. While purging with nitrogen gas, the system was maintained at 60°C or below, and 400 g of 20% aqueous sodium hydroxide solution was added dropwise over 3 hours. The reaction was then allowed to proceed under these conditions with stirring for 1 hour.

[0232] After the reaction was completed, the mixture was allowed to stand for separation, and the aqueous layer was removed. Furthermore, water was added to the toluene layer in which the reactant was dissolved, and the mixture was stirred and mixed for 15 minutes. The mixture was then allowed to stand for separation, and the aqueous layer was removed. This procedure was repeated until the pH of the aqueous layer reached 7. The water was then removed by decanting, yielding an active ester resin A-1 in the form of a toluene solution with a non-volatile content of 65% by mass. The active ester group equivalent of the resulting active ester resin A-1 was 238 g / eq.

[0233] <Synthesis Example 2: Synthesis of Active Ester Resin A-2> A flask equipped with a thermometer, dropping funnel, condenser, distillation column, and stirrer was charged with 165 g of a polyaddition resin (hydroxyl equivalent: 165 g / eq., softening point: 85°C) of dicyclopentadiene and phenol, 134 g (1.0 mol) of ortho-allylphenol, and 1200 g of toluene. The system was then purged with nitrogen under reduced pressure. Next, 203 g (1.0 mol) of isophthalic acid chloride was added, and the system was purged with nitrogen under reduced pressure. 0.6 g of tetrabutylammonium bromide was added, and while purging with nitrogen gas, the system was maintained at 60°C or below. 412 g of 20% aqueous sodium hydroxide solution was added dropwise over 3 hours. After the addition, the mixture was stirred for 1.0 hour. After the reaction was complete, the aqueous layer was removed by static separation. Water was added to the resulting toluene layer and stirred for 15 minutes. The aqueous layer was then removed by static separation. This procedure was repeated until the pH of the aqueous layer reached 7. The non-volatile component was then adjusted to 70% by mass by heat drying, thereby obtaining an active ester resin A-2 represented by the following formula.

[0234] [ka]

[0235] <Synthesis Example 3: Synthesis of Maleimide Resin B> An MEK solution (62% by mass of non-volatile components) of maleimide resin B represented by the following formula (d-6) was prepared according to Synthesis Example 1 in Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211. The Mw / Mn of this maleimide resin B was 1.81, and t'' in formula (d-6) was 1.47 (mainly 1, 2, or 3).

[0236] [ka]

[0237] <Synthesis Example 4: Synthesis of vinyl resin C> According to Example 1 of WO 2017 / 115813, 3.0 moles (390.6 g) of divinylbenzene, 1.8 moles (229.4 g) of ethylvinylbenzene, 10.2 moles (1066.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were charged into a 5.0 L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70 °C. The reaction was allowed to proceed for 4 hours. The polymerization solution was terminated with aqueous sodium bicarbonate solution. The oil layer was then washed three times with pure water, and the polymer was recovered by devolatilization under reduced pressure at 60 °C. The resulting polymer was weighed, and it was confirmed that 896.7 g of vinyl resin C was obtained as the polymer. The weight-average molecular weight (Mw) of vinyl resin C was 41,300.

[0238] <Examples 1 to 15 and Comparative Examples 1 to 4> (1) Preparation of resin composition: Each component was weighed and mixed according to the formulation shown in Tables 1, 2, and 3, which will be described later, and then 10 parts of MEK and 10 parts of cyclohexanone were added and uniformly dispersed using a high-speed rotary mixer to obtain a resin composition (resin varnish). The formulations shown in Tables 1, 2, and 3 represent the amount (parts by mass) of nonvolatile components. Details of each component shown in Tables 1, 2, and 3 are as follows:

[0239] (A) Epoxy resin: ZX1059: Epoxy equivalent weight 170g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd., 1:1 mixture of bisphenol A and bisphenol F epoxy resins. HP-4032-SS: Epoxy equivalent weight 144g / eq., manufactured by DIC, naphthalene-type epoxy resin. NC-3000L: Epoxy equivalent 270g / eq., manufactured by Nippon Kayaku Co., Ltd., biphenyl type epoxy resin

[0240] (B-1) First active ester resin: EXB-LE-P01: Active ester resin with an active ester group equivalent of 990 g / eq., manufactured by DIC Corporation, represented by the following formula (b-2). [ka]

[0241] (B-2) Second activated ester resin: HPC-8150-62T: Active ester group equivalent weight 230 g / eq., toluene solution with 61.5% non-volatile content by mass, manufactured by DIC Corporation, active ester resin with a naphthalene structure. HPC-8000L-65MT: Active ester resin containing dicyclopentadiene-type diphenol structure, toluene / MEK solution with active ester group equivalent of 223 g / eq. and non-volatile content of 65% by mass, manufactured by DIC Corporation Active ester resin A-1: ​​Active ester group equivalent weight 238 g / eq., active ester resin synthesized in Synthesis Example 1. Active ester resin A-2: an active ester resin synthesized in Synthesis Example 2, with an active ester group equivalent of 214 g / eq., and a toluene solution containing 70% by mass of nonvolatile components. Active ester resin B: a compound having an active ester group equivalent of 250 g / eq. and represented by the following formula (b-3).

[0242] [ka]

[0243] (C) Inorganic filler: SO-C2: Spherical silica surface-treated with an amino-silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573"), average particle size 0.5 μm, specific surface area 5.8 m 2 / g, manufactured by Admatechs Co., Ltd.

[0244] (D) Radical polymerizable resin: Maleimide resin B: Maleimide resin B synthesized in Synthesis Example 3. MIR-3000-70MT: toluene / MEK solution with 70% by mass of non-volatile components, manufactured by Nippon Kayaku Co., Ltd., maleimide resin having a structure represented by the following formula (d-7) (in formula (d-7), n represents 1 to 100).

[0245] [ka]

[0246] · SLK-6895: Aliphatic maleimide resin manufactured by Shin-Etsu Chemical Co., Ltd. SLK-1500: Aliphatic maleimide resin manufactured by Shin-Etsu Chemical Co., Ltd. OPE-2St-1200: Toluene solution with 65% non-volatile content, manufactured by Mitsubishi Gas Chemical Co., Ltd., a styrene-based radical polymerizable resin with a polyphenylene ether skeleton. Vinyl resin C: Resin C synthesized in Synthesis Example 4.

[0247] (E) Optional hardener: LA-3018-50P: 1-methoxy-2-propanol solution with a phenolic hydroxyl group equivalent of 151 g / eq. and 50% non-volatile content by mass, manufactured by DIC Corporation, phenolic resin.

[0248] (D) Organic filler: EXL-2655: Organic filler containing rubber components, manufactured by Dow. (H) Curing accelerator 1B2PZ: Imidazole-based curing accelerator manufactured by Shikoku Chemicals Corporation.

[0249] (2) Resin sheet manufacturing: A polyethylene terephthalate film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) with a release layer was prepared as a support. The obtained resin composition was uniformly applied onto the release layer of this support so that the thickness of the resin composition layer after drying would be 40 μm. The resin composition was then dried at 80°C to 100°C (average 90°C) for 4 minutes to obtain a resin sheet A having a layer structure of resin composition layer / support.

[0250] Resin sheet B was produced by the same production method as resin sheet A, except that the coating thickness of the resin composition was changed so that the thickness of the resin composition layer after drying would be 25 μm.

[0251] <Test 1. Dielectric loss tangent measurement test> Resin sheet A was heated in an oven at 190°C for 90 minutes to cure the resin composition layer. The support was then peeled off to obtain a cured resin composition layer. The cured product was cut into a length of 80 mm and a width of 2 mm to obtain a cured product sample for measuring dielectric loss tangent.

[0252] The dielectric loss tangent Df of the cured sample was measured by the split cylinder method using a measuring device ("HP8362B" manufactured by Agilent Technologies) at a measurement frequency of 10 GHz and a measurement temperature of 90° C. Measurement was performed on two test pieces, and the average was calculated.

[0253] <Test 2. Measurement test of coefficient of linear thermal expansion (CTE)> Resin sheet A was cured in an oven at 190°C for 90 minutes, and the support was then peeled off to obtain a cured film. This cured film was cut into a length of 20 mm and a width of 6 mm to obtain a cured sample for measuring the linear thermal expansion coefficient. The average linear thermal expansion coefficient (CTE) of this cured sample was measured using a TMA device (thermomechanical analyzer, manufactured by Rigaku Corporation) from 25°C to 250°C at a heating rate of 5°C / min. The same test piece was measured twice, and the second value was recorded.

[0254] <Test 3. Evaluation test of smear removal ability> (1) Preparation of inner layer 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 "R1515A") with an inner layer circuit formed thereon were etched by 1 μm with a microetching agent (MEC "CZ8101") to roughen the copper surface, thereby obtaining an inner layer substrate.

[0255] (2) Lamination of resin sheet A: Using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator "CVP700"), resin sheet A was laminated on both sides of the inner layer substrate so that the resin composition layer was in contact with the inner layer substrate. Lamination was performed by reducing the pressure for 30 seconds to adjust the air pressure to 13 hPa or less, followed by pressure bonding at 120°C and a pressure of 0.74 MPa for 30 seconds. The resin composition layer was then smoothed by heat pressing at 100°C and a pressure of 0.5 MPa for 60 seconds.

[0256] (3) Thermal curing of the resin composition layer: The inner layer substrate laminated with resin sheet A was then placed in an oven at 130°C and heated for 30 minutes, and then transferred to an oven at 170°C and heated for 30 minutes to thermally cure the resin composition layer and form an insulating layer. The support was then peeled off to obtain a cured substrate having a structure of insulating layer / inner layer substrate / insulating layer.

[0257] (4) Formation of via holes: The insulating layer of the obtained cured substrate was drilled using a CO2 laser processing machine ("LK-2K212 / 2C" manufactured by Via Mechanics) under the conditions of a frequency of 2000 Hz, a pulse width of 3 μs, an output of 0.95 W, and a shot count of 3 to form via holes. The opening diameter (diameter, top diameter) of the formed via hole on the surface of the insulating layer was 50 μm, and the diameter (bottom diameter) at the bottom of the insulating layer was 50 μm.

[0258] (5) Roughening treatment: The insulating layer of the cured substrate having the via holes formed therein was subjected to a desmear treatment as a roughening treatment, which was the following wet desmear treatment.

[0259] (wet desmear treatment) The cured substrate was immersed in a swelling solution (Atotech Japan's "Swelling Dip Securigant P," an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 10 minutes. The cured substrate was then immersed in an oxidizing solution (Atotech Japan's "Concentrate Compact P," an aqueous solution of approximately 6% potassium permanganate and 4% sodium hydroxide) at 80°C for 25 minutes. Finally, the cured substrate was immersed in a neutralizing solution (Atotech Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes. The cured substrate was then dried at 80°C for 15 minutes. The cured substrate after this desmearing process is hereinafter referred to as "Evaluation Substrate A."

[0260] (6) Evaluation of smear removal: The periphery of the bottom of the via hole of evaluation substrate A was observed with a scanning electron microscope (SEM). From the obtained image, the length of the longest smear (resin residue) extending from the wall surface of the bottom of the via hole (maximum smear length) was measured and evaluated according to the following criteria. "Good": Maximum smear length is less than 5 μm. "Poor": Maximum smear length is 5 μm or more.

[0261] <Test 4. Evaluation test of crack resistance after desmear treatment> (1) Preparation of inner layer board: As the inner layer substrate, a core material (Resonac's "E705GR", thickness 400 μm) was prepared, in which circular copper pads (copper thickness 35 μm) with a diameter of 350 μm were arranged in a grid pattern at intervals of 400 μm so that the remaining copper ratio was 60%.

[0262] (2) Lamination of resin sheet B: Using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator "CVP700"), resin sheet B was laminated on both sides of the inner layer substrate so that the resin composition layer was in contact with the inner layer substrate. Lamination was performed by reducing the pressure for 30 seconds to adjust the air pressure to 13 hPa or less, followed by pressure bonding at 100°C and a pressure of 0.74 MPa for 30 seconds. The resin composition layer was then smoothed by heat pressing at 100°C and a pressure of 0.5 MPa for 60 seconds.

[0263] (3) Thermal curing of the resin composition layer: The inner layer substrate laminated with resin sheet B was then placed in a 130°C oven and heated for 30 minutes, and then transferred to a 175°C oven and heated for 40 minutes to thermally cure the resin composition layer and form an insulating layer. The support was then peeled off to obtain a cured substrate having a structure of insulating layer / inner layer substrate / insulating layer.

[0264] (4) Desmearing: The resulting cured substrate was immersed in a swelling solution (Atotech Japan's "Swelling Dip Securigant P," an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 10 minutes. The cured substrate was then immersed in an oxidizing solution (Atotech Japan's "Concentrate Compact P," an aqueous solution of approximately 6% potassium permanganate and 4% sodium hydroxide) at 80°C for 30 minutes. Finally, the cured substrate was immersed in a neutralizing solution (Atotech Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes. The cured substrate was then dried at 80°C for 15 minutes. The cured substrate after this desmearing process is hereinafter referred to as "Evaluation Substrate B."

[0265] (5) Crack resistance evaluation: For the evaluation substrate B, 100 copper pad portions were observed to check for the presence or absence of cracks in the insulating layer, and the crack resistance was evaluated according to the following criteria. "Good": 10 or fewer cracks. "Poor": More than 10 cracks.

[0266] <Result> The results of the above-mentioned Examples and Comparative Examples are shown in Tables 1 to 3 below. In the tables below, the "amount of component (A)," "amount of component (B-1)," and "amount of component (B-2)" represent values ​​relative to 100% by mass of the resin components in the resin composition. The "amount of component (C)" represents a value relative to 100% by mass of the non-volatile components in the resin composition.

[0267] [Table 1]

[0268] [Table 2]

[0269] [Table 3]

Claims

1. A resin composition comprising: (A) an epoxy resin; (B-1) an active ester resin containing a butadiene skeleton; and (B-2) an active ester resin not containing a butadiene skeleton.

2. 2. The resin composition according to claim 1, wherein the epoxy resin (A) comprises at least one selected from the group consisting of epoxy resins containing a naphthalene skeleton and epoxy resins containing a biphenyl skeleton.

3. The resin composition according to claim 1, wherein the active ester resin (B-1) containing a butadiene skeleton includes a structure represented by the following formula (B1): 【Chemical 1】 (In formula (B1), R ｂ each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms; * represents a bonding site.

4. The resin composition according to claim 1 , further comprising (C) an inorganic filler.

5. The resin composition according to claim 4, wherein the amount of the inorganic filler (C) is 50% by mass or more relative to 100% by mass of the nonvolatile components of the resin composition.

6. The resin composition according to claim 1, further comprising (D) a radical polymerizable resin.

7. The resin composition according to claim 6 , wherein the radical polymerizable resin (D) comprises a maleimide resin.

8. A support and a resin composition layer provided on the support, A resin sheet, wherein the resin composition layer comprises the resin composition according to any one of claims 1 to 7.

9. A cured product of the resin composition according to any one of claims 1 to 7.

10. A circuit board comprising a cured product of the resin composition according to any one of claims 1 to 7.

11. A semiconductor device comprising the circuit board according to claim 10.

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