Curable resin composition, cured product thereof, and semiconductor device

Abstract

To provide a curable resin composition which is curable by light such as ultraviolet light, as needed, by heat, and imparts its cured product with low dielectric characteristics.SOLUTION: A curable resin composition contains (A) a compound having at least two or more styrene structures in the molecule, and (B) a photopolymerization initiator.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition having excellent dielectric properties and a cured product thereof, which can be used as a protective film for semiconductor elements, an interlayer insulating film, an insulating film for rewiring layers, and the like.

[0002] Conventionally, curable resin compositions containing polyimide precursors or polybenzoxazole precursors, which have excellent heat resistance, electrical properties, and mechanical properties, have been used for protective films for semiconductor elements, interlayer insulating films formed on semiconductor surface layers, and insulating films for redistribution layers. As an example of a curable resin composition containing the polyimide precursor, JP 54-109828 A (Patent Document 1) describes a resin composition containing a polyamic acid, a compound having a polymerizable unsaturated bond, and a photopolymerization initiator. Furthermore, JP 2008-83468 A (Patent Document 2) describes a resin composition containing a polyamic acid ester composition and a photopolymerization initiator. The curable polyimide precursor obtained from such a resin composition is a negative-type curable material that can obtain a pattern by photocrosslinking the unsaturated bonds with the photopolymerization initiator. Furthermore, as curable resin compositions containing the polybenzoxazole precursor, for example, Japanese Patent Laid-Open No. 56-27140 (Patent Document 3) and Japanese Patent Laid-Open No. 11-237736 (Patent Document 4) describe resin compositions containing a polybenzoxazole precursor and a quinone diazide compound. Such resin compositions are positive curable materials in which, upon irradiation with light, the quinone diazide is converted to indene carboxylic acid, and the irradiated portions (exposed portions) are dissolved in an alkaline developer, thereby forming a pattern.

[0003] The polyimide precursors and polybenzoxazole precursors described in Patent Documents 1 to 4 require a dehydration ring-closing reaction during the curing reaction, and therefore must be heated to at least 230°C or higher to be cured. However, such high heating temperatures may cause damage to semiconductor elements. Furthermore, if the ring-closing reaction is insufficient, there is a concern that the dielectric properties may be deteriorated due to residual polar groups such as carboxyl groups, phenolic hydroxyl groups, and amide bonds. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 54-109828 [Patent Document 2] Japanese Patent Application Publication No. 2008-83468 [Patent Document 3] Japanese Patent Publication No. 56-27140 [Patent Document 4] Japanese Patent Publication No. 11-237736 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above points, and aims to provide a curable resin composition that can be cured by light such as ultraviolet light and, if necessary, heat, and that produces a cured product having low dielectric properties. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the present inventors have found that a cured product of a curable resin composition containing a compound having at least two styrene structures in the molecule and a photopolymerization initiator has excellent low dielectric properties, and have thus completed the present invention.

[0007] That is, the present invention relates to the following [1] to [8]. In the present invention, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limit values ​​are included. [1] A curable resin composition comprising: (A) a compound having at least two styrene structures in the molecule; and (B) a photopolymerization initiator. [2] The curable resin composition according to the above item [1], wherein the component (A) is a compound represented by the following formula (1):

[0008] [ka]

[0009] (In formula (1), multiple R's each independently represent a hydrocarbon group or a halogenated alkyl group having 1 to 10 carbon atoms; p and r each represent an integer of 0 to 4; q represents an integer of 0 to 3; and n is 1≦n≦20.) [3] The curable resin composition according to item [1] or [2] above, wherein the component (B) is a cationic photopolymerization initiator. [4] The curable resin composition according to item [1] or [2] above, wherein the component (B) is a photoradical polymerization initiator. [5] The curable resin composition according to the above item [1] or [2], wherein the component (B) is an oxime ester-based photoradical polymerization initiator. [6] The curable resin composition according to any one of the above items [1] to [5], further comprising an inorganic filler. [7] A cured product obtained by photocuring or photothermal curing the curable resin composition according to any one of the preceding items [1] to [6]. [8] A semiconductor device comprising the cured product according to the above item [7] as at least one selected from the group consisting of a surface protection film, an interlayer insulating film, and an insulating film for a rewiring layer. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin composition having excellent low dielectric properties and a cured product thereof, as well as a semiconductor device having an insulating film for an interlayer insulating layer, a surface protective film, and a redistribution layer formed from the cured product. [Brief explanation of the drawings]

[0011] [Figure 1] 1 shows a GPC chart of Synthesis Example 1. [Figure 2] 1 shows a GPC chart of Synthesis Example 2. [Figure 3] 1H-NMR chart of Synthesis Example 2 is shown. DETAILED DESCRIPTION OF THE INVENTION

[0012] The curable resin composition of the present invention contains (A) a compound having at least two styrene structures in the molecule (hereinafter also referred to as component (A)), and (B) a photopolymerization initiator (hereinafter also referred to as component (B)).

[0013] Component (A) may be any known compound having at least two styrene structures in the molecule. Examples include OPE-2St (manufactured by Mitsubishi Gas Chemical Co., Inc.), ODV (oligodivinyl copolymer, manufactured by Nippon Steel Chemical & Materials Co., Ltd.), 1,2-bis(vinylphenyl)ethane (BVPE: a group of compounds such as 4,4'-ethylenebisstyrene, 3,4'-ethylenebisstyrene, and 3,3'-ethylenebisstyrene), divinylfluorene, divinylbiphenyl, divinylnaphthalene, divinylbenzene, and compounds represented by the following formula (1). Component (A) may be used alone or in combination. Among these, compounds represented by the following formula (1) are preferred as component (A) from the viewpoints of heat resistance, dielectric properties, compatibility with other curable resins (such as epoxy resins and active ester resins), circuit embedding properties, and the like.

[0014] [ka]

[0015] (In formula (1), each R independently represents a hydrocarbon group or a halogenated alkyl group having 1 to 10 carbon atoms. p and r represent integers of 0 to 4, q represents an integer of 0 to 3, and n represents the average number of repetitions, and 1≦n≦20.)

[0016] In the formula (1), p and r are 0 to 4, preferably 0 to 2, and more preferably 0. q is 0 to 3, preferably 0 to 2, and more preferably 0. n is 1≦n≦20, preferably 1.1≦n≦20, more preferably 1.1≦n≦10, and particularly preferably 1.1≦n≦5. The value of n can be calculated from the number average molecular weight (Mn) of the compound of formula (1) determined by gel permeation chromatography (GPC). The number average molecular weight is preferably 200 or more and less than 5000, more preferably 300 or more and less than 3000, and particularly preferably 400 or more and less than 2000. A weight average molecular weight of less than 5000 facilitates purification by washing with water, while a weight average molecular weight of 200 or more prevents the target compound from volatilizing during the solvent distillation step.

[0017] In the formula (1), R is a hydrocarbon group or halogenated alkyl group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms, and particularly preferably a hydrocarbon group having 1 to 3 carbon atoms. Hydrocarbons having R of 3 or less carbon atoms are less likely to undergo molecular vibration when exposed to high frequency waves, and therefore have particularly excellent electrical properties.

[0018] The compound represented by the formula (1) is derived from a compound represented by the following formula (2).

[0019] [ka]

[0020] (In formula (2), multiple R's each independently represent a hydrocarbon group or a halogenated alkyl group having 1 to 10 carbon atoms. p and r represent integers of 0 to 4, q represents an integer of 0 to 3, n represents the average number of repetitions, and 1≦n≦20. X represents a halogen atom.)

[0021] The preferred ranges of R, p, r, q, and n in the formula (2) are the same as those in the formula (1). From the viewpoints of reactivity and the stability of the raw materials, X is preferably a bromine atom or a chlorine atom, and particularly preferably a bromine atom.

[0022] The compound represented by formula (1) can be obtained, for example, by subjecting the compound represented by formula (2) to a dehydrohalogenation reaction in a solvent in the presence of a basic catalyst. Examples of solvents that can be used include, but are not limited to, water-insoluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone. These solvents are not limited to these, and two or more of these solvents may be used in combination. Furthermore, aprotic polar solvents can also be used in combination with the water-insoluble solvents. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone, and two or more of these solvents may be used in combination. When using an aprotic polar solvent, it is preferable to use one with a higher boiling point than the water-insoluble solvent used in combination. The catalyst is not particularly limited, but examples include basic catalysts such as sodium hydroxide, potassium hydroxide, and potassium carbonate. Because it is difficult to completely complete the dehydrohalogenation reaction, a large excess of aprotic polar solvent relative to the substrate may be used, or the dehydrohalogenation reaction may be repeated two or more times. For example, the dehydrohalogenation reaction of the compound represented by formula (2) may be carried out in an organic solvent in the presence of a base catalyst, and the resulting solution may be washed with water and then returned to the reaction vessel, where the base catalyst is added and the reaction may be carried out again. This can increase the progress of the dehydrohalogenation reaction. This means that the amount of residual halogen in the target compound can be reduced. The amount of residual halogen is preferably 1 to 10,000 ppm, more preferably 1 to 1,000 ppm, and even more preferably 1 to 750 ppm. A high amount of residual halogen in the compound represented by formula (1) can cause molecular vibration when exposed to high frequency waves, adversely affecting electrical properties, particularly dielectric loss tangent. Furthermore, a high amount of residual halogen increases the risk of problems such as metal corrosion and ion migration in environmental tests such as HAST (High Accelerated Stress Test). Therefore, the above halogen content is preferred.

[0023] The method for producing the compound represented by formula (2) is not particularly limited. For example, a compound having a 2-bromoethylbenzene structure may be reacted with a bis(halogenated methylaryl) compound (or a bis(hydroxymethylaryl) compound, etc.) in the presence of an acid catalyst such as hydrochloric acid, sulfonic acid, or activated clay, or a compound having a 2-bromoethylbenzene structure may be reacted with a bis(hydroxymethylaryl) compound in the presence of an acid catalyst such as hydrochloric acid, sulfonic acid, or activated clay. When using a catalyst such as sulfonic acid, the reaction may be neutralized with an alkali metal such as sodium hydroxide or potassium hydroxide before proceeding to the extraction step. For the extraction step, an aromatic hydrocarbon solvent such as toluene or xylene may be used alone, or a non-aromatic hydrocarbon such as cyclohexane or toluene may be used in combination. After extraction, the organic layer is washed with water until the wastewater becomes neutral, and the solvent and excess compounds having a 2-bromoethylbenzene structure are distilled off using an evaporator or the like to obtain the target compound having at least two 2-bromoethylethylbenzene structures in the molecule.

[0024] Examples of compounds having a 2-bromoethylbenzene structure include, but are not limited to, 2-bromoethylbenzene, 1-(2-bromoethyl)-2-methylbenzene, 1-(2-bromoethyl)-3-methylbenzene, 1-(2-bromoethyl)-4-methylbenzene, 1-(2-bromoethyl)-2,3-dimethylbenzene, 1-(2-bromoethyl)-2,4-dimethylbenzene, 1-(2-bromoethyl)-2,5-dimethylbenzene, and 1-(2-bromoethyl)-2,6-dimethylbenzene. These may be used alone or in combination of two or more. A larger carbon number improves solvent solubility but reduces heat resistance. Therefore, the compound is preferably unsubstituted or substituted with an alkyl group having 1 to 3 carbon atoms, more preferably unsubstituted or substituted with an alkyl group having 1 to 2 carbon atoms, and most preferably unsubstituted or substituted with a methyl group.

[0025] Examples of bishalogenated methylaryl compounds include, but are not limited to, o-xylylene difluoride, m-xylylene difluoride, p-xylylene difluoride, o-xylylene dichloride, m-xylylene dichloride, p-xylylene dichloride, o-xylylene dibromide, m-xylylene dibromide, p-xylylene dibromide, o-xylylene diiodide, m-xylylene diiodide, and p-xylylene diiodide. These compounds may be used alone or in combination of two or more. From the viewpoint of the reactivity of the raw materials during synthesis, chloride-based compounds, bromide-based compounds, and iodide-based compounds are preferred, and chloride-based compounds and bromide-based compounds are more preferred.

[0026] Examples of bishydroxymethylaryl compounds include, but are not limited to, o-benzenedimethanol, m-benzenedimethanol, and p-benzenedimethanol. These compounds may be used alone or in combination of two or more. The amount of these compounds used is preferably 0.05 to 0.8 parts by mass, more preferably 0.1 to 0.6 parts by mass, per part by mass of the compound having a 2-bromoethylbenzene structure.

[0027] When reacting a compound having a 2-bromoethylbenzene structure with a halogenated methylaryl compound or the like, a catalyst such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, or methanesulfonic acid may be used, as needed. In addition, Lewis acids such as aluminum chloride and zinc chloride, activated clay, acid clay, white carbon, zeolite, and silica alumina may also be used, or acidic ion exchange resins may be used in combination. The amount of catalyst used is 0.05 to 0.8 mol, preferably 0.1 to 0.7 mol, per mol of the compound having a 2-bromoethylbenzene structure used. Using too much catalyst can result in a reaction solution with too high a viscosity, making stirring difficult; using too little can slow the reaction. The reaction can be carried out using an organic solvent such as hexane, cyclohexane, octane, toluene, or xylene, as needed, or it can be carried out solvent-free. For example, an acidic catalyst is added to a mixed solution of a compound having a 2-bromoethylbenzene structure, a halogenated methylaryl compound, and a solvent, and if the catalyst contains water, the water is removed from the system by azeotropy. The reaction is then carried out at 40 to 180°C, preferably 50 to 170°C, for 0.5 to 20 hours. After the reaction is complete, the acidic catalyst may be neutralized with an aqueous alkali solution, but the process can proceed to a water-washing step without neutralization. In the water-washing step, a water-insoluble organic solvent is added to the oil layer, and washing is repeated until the wastewater becomes neutral.

[0028] The softening point of the compound represented by formula (2) is preferably 80°C or lower, more preferably 70°C or lower. If the softening point is 80°C or lower, the viscosity when converted into the compound represented by formula (1) is low. This makes it easier to ensure fluidity, does not impair the impregnation ability into glass cloth, carbon fiber, etc., and facilitates B-stage formation, such as prepreg formation. If the viscosity is reduced by increasing the dilution solvent, there is a possibility that the resin will not adhere sufficiently to the fibrous material during the impregnation process.

[0029] The curable resin composition of the present invention contains a photopolymerization initiator as component (B). Component (B) is preferably a photoradical polymerization initiator or a photocationic polymerization initiator. The content of component (B) is 0.001 to 20 parts by mass, more preferably 0.002 to 15 parts by mass, per 100 parts by mass of component (A). If the content is less than 0.001 part by mass, photocuring may be insufficient, and if the content is more than 20 parts by mass, dielectric properties may deteriorate. Preferred examples of component (B) are shown below, but the present invention is not limited to these. These may be used alone or in combination of two or more types.

[0030] [Photoradical polymerization initiator] The photoradical polymerization initiator is not particularly limited as long as it is a compound that generates radicals and initiates a chain polymerization reaction when irradiated with ultraviolet or visible light, but examples thereof include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, and diphenyl disulfide. Specific examples include IRGACURE RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE RTM 1173, LUCIRIN RTM TPO (both manufactured by BASF), Seikuol RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.), etc. Among these, preferred are IRGACURER OXE01, OXE02, OXE03, and OXE04, which are oxime ester initiators.

[0031] [Cationic photopolymerization initiator] The photocationic polymerization initiator is not particularly limited as long as it is a radical polymerization initiator that generates cationic species such as Bronsted acids or Lewis acids upon irradiation with ultraviolet or visible light, but examples include aromatic iodonium complex salts and aromatic sulfonium complex salts. Specific examples of aromatic iodonium complex salts include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, tolylcumyliodonium tetrakis(pentafluorophenyl)borate (manufactured by Rhodia, trade name: Rhodosil PI2074), and di(4-tert-butyl)iodonium tris(trifluoromethanesulfonyl)methanide (manufactured by BASF, trade name: CGIBBI-C1). Specific examples of aromatic sulfonium complex salts include 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by San-Apro Co., Ltd., trade name: CPI-101A), thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate (manufactured by San-Apro Co., Ltd., trade name: CPI-210S), 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (manufactured by ADEKA Co., Ltd., trade name: SP-172), and aromatic sulfonium hexafluoroantimonate containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate. Examples thereof include a mixture of antimonates (manufactured by ACETO Corporation USA, trade name: CPI-6976), triphenylsulfonium tris(trifluoromethanesulfonyl)methanide (manufactured by BASF, trade name: CGITPS-C1), tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tris(trifluoromethylsulfonyl)methide (manufactured by BASF, trade name: GSID26-1), and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate (manufactured by BASF, trade name: Irgacure PAG290).Among these, aromatic sulfonium complex salts are preferred in the present invention because they have high vertical rectangular processability and high thermal stability in the photosensitive image formation process. Among these, 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate, and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate are particularly preferred.

[0032] [Inorganic filler] The curable resin composition of the present invention may contain an inorganic filler. Examples of inorganic fillers include, but are not limited to, powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide asbestos, and glass powder, as well as inorganic fillers obtained by making these into spherical or crushed shapes. These fillers may be used alone or in combination.

[0033] When a curable resin composition for semiconductor encapsulation is obtained, the amount of inorganic filler used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. When a curable resin composition for forming an interlayer insulating layer, or a substrate material such as a copper-clad laminate, prepreg, or RCC is obtained, the amount of inorganic filler used is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0034] [Thermal curing accelerator] The thermosetting property of the curable resin composition of the present invention can be improved by adding a thermosetting accelerator. The thermosetting accelerator is preferably an anionic thermosetting accelerator that generates an anionic species upon heating to accelerate thermosetting, or a cationic thermosetting accelerator that generates a cationic species upon heating to accelerate thermosetting.

[0035] Examples of thermal anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol; and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine; and quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide, but are not limited thereto. These may be used alone or in combination.

[0036] Examples of thermal cationic curing accelerators include, but are not limited to, quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counter ion of the quaternary salt may be a halogen, an organic acid ion, a hydroxide ion, or the like; there is no particular restriction, but organic acid ions and hydroxide ions are particularly preferred), and transition metal compounds (transition metal salts) such as tin octylate, zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate ester (zinc octylphosphate, zinc stearylphosphate). These may be used alone or in combination.

[0037] The amount of the heat curing accelerator to be added is 0.01 to 5.0 parts by mass, if necessary, based on 100 parts by mass of the nonvolatile content excluding the inorganic filler in the curable resin composition.

[0038] [Thermal radical polymerization initiator] The thermosetting properties of the curable resin composition of the present invention can be improved by adding a thermal radical polymerization initiator. A thermal radical polymerization initiator is a compound that generates radicals upon heating and initiates a chain polymerization reaction. Examples of thermal radical polymerization initiators that can be used include organic peroxides, azo compounds, and benzopinacols. Organic peroxides are preferred because they are effective in controlling the curing temperature, suppress outgassing, and have little effect on the electrical properties of decomposed products. Examples of the organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)-benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, t-butylperoxymethyl ... Examples of the peroxycarbonates include, but are not limited to, alkyl peresters such as di-2-ethylhexyl peroxydicarbonate, t-amylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-amylperoxybenzoate, peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, and lauroyl peroxide. These peroxycarbonates may be used alone or in combination. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, peroxycarbonates, etc. are preferred, with dialkyl peroxides being more preferred. Examples of the azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. These compounds may be used alone or in combination.

[0039] The amount of the thermal radical polymerization initiator added is preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the curable resin composition. If the amount of the thermal radical polymerization initiator used is less than 0.01 part by mass, there is a risk that the molecular weight will not be sufficiently elongated during the polymerization reaction, and if it is more than 5 parts by mass, there is a risk that the dielectric properties such as the dielectric constant and the dielectric loss tangent will be impaired.

[0040] [Polymerization inhibitor] The curable resin composition of the present invention may contain a polymerization inhibitor. The inclusion of a polymerization inhibitor improves storage stability and enables control of the reaction initiation temperature. Controlling the reaction initiation temperature makes it easier to ensure fluidity, prevents impregnation into glass cloth and the like, and facilitates B-staging, such as prepreg formation. If the polymerization reaction proceeds too much during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

[0041] The polymerization inhibitor may be added during or after the synthesis of component (A). The amount of the polymerization inhibitor used is 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of component (A).

[0042] Examples of the polymerization inhibitor include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors. One type of polymerization inhibitor may be used alone, or multiple types may be used in combination. Among these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors are preferred in the present invention.

[0043] Examples of the phenolic polymerization inhibitor include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, 2,4-bis[(octylthio)methyl]-o ...butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyani Monophenols such as resol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] N,N'-Hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t-butyl Bisphenols such as calcium ethyl-4-hydroxybenzylsulfonate, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,Examples of the phenolic compound include, but are not limited to, polymeric phenols such as 5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0044] Examples of the sulfur-based polymerization inhibitor include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0045] Examples of the phosphorus-based polymerization inhibitor include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bis(octadecyl) phosphite, cyclic neopentane tetrayl bi(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bi(2,4-di-t-butyl-4-methylphenyl) phosphite, bis[2-t 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the like, but are not limited to these.

[0046] Examples of the hindered amine polymerization inhibitor include, but are not limited to, ADK STAB LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, DECASTAB LA-82, DECASTAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, ADK STAB LA-52, Chimassorb 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, and Tinuvin 791FB.

[0047] Examples of the nitroso-based polymerization inhibitor include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salt of N-nitrosophenylhydroxyamine, (cupferron), etc. Among these, the ammonium salt of N-nitrosophenylhydroxyamine (cupferron) is preferred.

[0048] Examples of the nitroxyl radical polymerization inhibitor include di-tert-butyl nitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, but are not limited to these.

[0049] [Flame retardant] The curable resin composition of the present invention may contain a flame retardant. Examples of the flame retardant include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants. From the viewpoint of achieving halogen-free flame retardancy, phosphorus-based flame retardants are preferred. The phosphorus-based flame retardant may be either a reactive type or an additive type. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylenyl phosphate, 1,3-phenylenebis(dixylenyl phosphate), 1,4-phenylenebis(dixylenyl phosphate), and 4,4'-biphenyl(dixylenyl phosphate); phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resins with the active hydrogen of the phosphanes; and red phosphorus. These may be used alone or in combination. Of the above-mentioned exemplified substances, phosphate esters, phosphanes, and phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixylenyl phosphate), 1,4-phenylenebis(dixylenyl phosphate), 4,4'-biphenyl(dixylenyl phosphate), and phosphorus-containing epoxy compounds are particularly preferred. The content of the flame retardant is preferably in the range of 0.1 to 0.6 parts by mass, assuming that the total mass of nonvolatile matters in the curable resin composition excluding inorganic fillers is 100 parts by mass. If the content is less than 0.1 part by mass, the flame retardancy may be insufficient, and if the content is more than 0.6 part by mass, the moisture absorption and dielectric properties of the cured product may be adversely affected.

[0050] [Light stabilizer] The curable resin composition of the present invention may contain a light stabilizer, and as the light stabilizer, a hindered amine light stabilizer, particularly HALS, etc., is preferred. Examples of HALS include reaction products of dibutylamine, 1,3,5-triazine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, reaction products of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], bis(1,2 ,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate, etc., but are not limited thereto. These may be used alone or in combination.

[0051] The content of the light stabilizer is preferably in the range of 0.001 to 10 parts by mass, assuming that the nonvolatile content excluding inorganic fillers in the curable resin composition is 100 parts by mass. If it is less than 0.001, it may be insufficient to exhibit a light stabilizing effect, and if it is more than 10, it may have an adverse effect on the moisture absorption and dielectric properties of the cured product.

[0052] [Binder resin] The curable resin composition of the present invention may contain a binder resin. Examples of binder resins include, but are not limited to, butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, and silicone resins. These may be used alone or in combination.

[0053] The amount of binder resin to be added is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, and is preferably 0.05 to 50 parts by mass, and more preferably 0.05 to 20 parts by mass, based on 100 parts by mass of the nonvolatile content excluding inorganic fillers in the curable resin composition, as needed.

[0054] [Additives] The curable resin composition of the present invention may contain additives, such as modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0055] The amount of the additive to be added is preferably 1,000 parts by mass or less, more preferably 700 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0056] [Organic solvents] The curable resin composition of the present invention may contain an organic solvent, such as an aromatic solvent, a ketone solvent, a cyclic ether solvent, or an ester solvent. Examples of aromatic solvents include toluene, xylene, and tetralin. Examples of ketone solvents include methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Examples of cyclic ether solvents include tetrahydroxyfuran and dioxane. Examples of ester solvents include ethyl lactate, ethyl acetate, butyl acetate, methyl benzoate, and propylene glycol methyl ether acetate. Other high-boiling point solvents such as DMF, NMP, and γ-butyrolactone may also be used. These organic solvents may be used alone or in combination of two or more.

[0057] The curable resin composition of the present invention may further contain epoxy resins, active ester compounds, phenolic resins, polyphenylene ether compounds, amine resins, maleimide compounds, compounds having an ethylenically unsaturated bond, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, polybutadiene and its modified products, polystyrene and its modified products, etc., and these may be used alone or in combination. Among these compounds, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, cyanate ester resins, polybutadiene and its modified products, and polystyrene and its modified products are preferred in terms of the balance of heat resistance, adhesion, and dielectric properties. The inclusion of these compounds can improve the brittleness of the cured product and adhesion to metals, thereby suppressing package cracking during solder reflow and reliability tests such as thermal cycling.

[0058] Unless otherwise specified, the amount of the above compounds used is preferably 10 times by mass or less, more preferably 5 times by mass or less, and particularly preferably 3 times by mass or less, relative to the amount of component (A). The lower limit is preferably 0.1 times by mass or more, more preferably 0.25 times by mass or more, and even more preferably 0.5 times by mass or more. By keeping the amount within the above range, the effects of each compound added can be enhanced while utilizing the heat resistance and dielectric properties of component (A). The following examples of these components can be used.

[0059] [Epoxy resin] Preferred examples of epoxy resins include, but are not limited to, the following. The epoxy resin may be liquid or solid, and may be used alone or in combination.

[0060] Examples of liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure. Specific examples include "RE310S" and "RE410S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", and "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", and "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", and "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", and "1750" (all manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Novolac epoxy resin), "630", "630LSD" (all manufactured by Mitsubishi Chemical Corporation, glycidylamine epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester epoxy resin), "Celloxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin having an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin having a butadiene structure), "ZX1658", "ZX1658GS" (all manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane epoxy resin), etc. These may be used alone or in combination of two or more.

[0061] Preferred examples of solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins, and examples of such solid epoxy resins include naphthol-type epoxy resins, bisphenol AF-type epoxy resins, naphthalene-type epoxy resins, and biphenyl-type epoxy resins.Specific examples include "HP4032H" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (all manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200" (manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (all manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin). epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (all manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl ether type epoxy resin), raryl-type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene-type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol-type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol novolac-type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin) Examples of epoxy resins that can be used include "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100" and "CG-500" (manufactured by Osaka Gas Chemicals Co., Ltd., fluorene-based epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin).These may be used alone or in combination of two or more.

[0062] [Active ester compounds] An active ester compound refers to a compound containing at least one ester bond in its structure, with an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. Examples of active ester compounds include phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, which have two or more highly reactive ester groups per molecule. These compounds are obtained by a condensation reaction between at least one of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one of a hydroxy compound or a thiol compound. From the viewpoint of improving heat resistance, active ester compounds are preferably obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, with phenol compounds or naphthol compounds being preferred as the hydroxy compound. Active ester compounds may be used singly or in combination of two or more.

[0063] 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.

[0064] Examples of the acid chloride include acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0065] Examples of the phenol compound and naphthol compound 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, phloroglucinol, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolak, and the phenolic resins described below. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0066] Preferred specific examples of the active ester compound include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, active ester compounds containing a benzoylated product of phenol novolac, the compound described in Example 2 of WO 2020 / 095829, and the compounds disclosed in WO 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0067] Commercially available active ester compounds include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure, "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, and "EXB9416-70BK" (manufactured by DIC Corporation) as a phenolic compound. Examples of active ester compounds containing acetylated volac include "DC808" (manufactured by Mitsubishi Chemical Corporation); active ester compounds containing benzoylated phenol novolac include "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); an active ester curing agent that is an acetylated phenol novolac is "DC808" (manufactured by Mitsubishi Chemical Corporation); and an active ester curing agent containing a phosphorus atom is "EXB-9050L-62M" (manufactured by DIC Corporation).

[0068] [Phenol resin] A phenolic resin is a compound having two or more phenolic hydroxyl groups in the molecule. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. These may be used alone or in combination. Specific examples of the above raw materials are given below, but are not limited to these. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, and the like. <Diene compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, and the like. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substituted biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl and the like. <Substituted phenyls> 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene and the like.

[0069] [Polyphenylene ether compounds] From the viewpoints of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group) and OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure). The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, the heat resistance of the cured product tends to be insufficient. On the other hand, if the molecular weight is more than 5000, the melt viscosity increases and sufficient fluidity cannot be obtained, which tends to result in molding defects. In addition, the reactivity decreases, the curing reaction takes a long time, and the amount of unreacted material not incorporated into the curing system increases, which tends to lower the glass transition temperature of the cured product and reduce the heat resistance of the cured product. When the number average molecular weight of the polyphenylene ether compound is 500 to 5000, it is possible to exhibit excellent heat resistance, moldability, etc. while maintaining excellent dielectric properties. The number average molecular weight here can be specifically measured using gel permeation chromatography, etc.

[0070] The polyphenylene ether compound may be obtained by a polymerization reaction or by a redistribution reaction of a high-molecular-weight polyphenylene ether compound having a number-average molecular weight of approximately 10,000 to 30,000. Alternatively, these compounds may be used as raw materials and reacted with a compound having an ethylenically unsaturated bond, such as methacryl chloride, acrylic chloride, or chloromethylstyrene, to impart radical polymerizability. The polyphenylene ether compound obtained by the redistribution reaction may be obtained, for example, by heating a high-molecular-weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to cause a redistribution reaction. The polyphenylene ether compound obtained by the redistribution reaction thus has hydroxyl groups derived from the phenolic compound at both ends of the molecular chain that contribute to curing, thereby maintaining even higher heat resistance. Furthermore, functional groups can be introduced at both ends of the molecular chain even after modification with a compound having an ethylenically unsaturated bond. Furthermore, the polyphenylene ether compound obtained by the polymerization reaction is preferred because it exhibits excellent flowability.

[0071] In the case of polyphenylene ether compounds obtained by polymerization, the molecular weight of the polyphenylene ether compound can be adjusted by adjusting the polymerization conditions, etc. In the case of polyphenylene ether compounds obtained by redistribution, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions, etc. of the redistribution reaction. More specifically, adjusting the amount of the phenolic compound used in the redistribution reaction can be considered. That is, the greater the amount of the phenolic compound, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) or the like can be used as the high-molecular-weight polyphenylene ether compound that undergoes the redistribution reaction. The phenolic compound used in the redistribution reaction is not particularly limited, but preferred are, for example, polyfunctional phenolic compounds having two or more phenolic hydroxyl groups per molecule, such as bisphenol A, phenol novolac, and cresol novolac. These compounds may be used alone or in combination of two or more.

[0072] The content of the polyphenylene ether compound is not particularly limited, but is preferably 5 to 1,000 parts by mass, and more preferably 10 to 750 parts by mass, relative to 100 parts by mass of the nonvolatile content excluding inorganic fillers in the curable resin composition. A content of the polyphenylene ether compound within the above range is preferable in that it not only has excellent heat resistance, etc., but also allows a cured product to fully exhibit the excellent dielectric properties of the polyphenylene ether compound.

[0073] [Amine resin] Amine resins are compounds having two or more amino groups in the molecule. Examples of amine resins include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolak (a reaction product of aniline and formalin), N-methylaniline novolak (a reaction product of N-methylaniline and formalin), orthoethylaniline novolak (a reaction product of orthoethylaniline and formalin), a reaction product of 2-methylaniline and formalin, a reaction product of 2,6-diisopropylaniline and formalin, a reaction product of 2,6-diethylaniline and formalin, a reaction product of 2-ethyl-6-ethylaniline and formalin, a reaction product of 2,6-dimethylaniline and formalin, and a reaction product obtained by the reaction of aniline and xylylene chloride. Examples of suitable aniline resins include, but are not limited to, aniline resins disclosed in Japanese Patent No. 6429862, reaction products of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl), reaction products of aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, reaction products of aniline and diisopropenylbenzene, and dimer diamine. These may be used singly or in combination.

[0074] [Maleimide compounds] A maleimide compound is a compound having one or more maleimide groups in the molecule. Examples of maleimide compounds include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), and Xyloc-type maleimide compounds (anilix). Maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide compounds described in WO 2020 / 054601 A), maleimide compounds having an indane structure described in Japanese Patent No. 6629692 or WO 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Story of Epoxy Resin CAS Numbers - Hardener CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019 "Continued Story of Epoxy Resin CAS Numbers - Hardener CAS Number Memorandum No. 32" Examples of suitable maleimide compounds include, but are not limited to, the maleimide compounds described in "Bismaleimide (2)." These compounds may be used alone or in combination.

[0075] The amount of the maleimide compound added is preferably 10 times by mass or less, more preferably 5 times by mass or less, and particularly preferably 3 times by mass or less, relative to the amount of component (A). The lower limit is preferably 0.01 times by mass or more, more preferably 0.1 times by mass or more. Within this range, the effects of heat resistance, dielectric properties, and low water absorption of component (A) can be utilized.

[0076] [Compounds containing ethylenically unsaturated bonds] A compound containing an ethylenically unsaturated bond is a compound that has one or more ethylenically unsaturated bonds in the molecule that can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. Examples of compounds containing ethylenically unsaturated bonds include, but are not limited to, reaction products of the phenolic resins with ethylenically unsaturated bond-containing halogenated compounds (e.g., chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride), reaction products of ethylenically unsaturated bond-containing phenols (e.g., 2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol) with halogenated compounds (e.g., 1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride), reaction products of epoxy resins or alcohols with (meth)acrylic acids (e.g., acrylic acid, methacrylic acid), and acid-modified products thereof. These compounds may be used singly or in combination.

[0077] The polybasic acid anhydride used to produce the acid-modified product is not particularly limited, and any polybasic acid anhydride having one or more acid anhydride structures in the molecule can be used.Specific examples include succinic anhydride, phthalic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, ethylene glycol-bis(anhydrotrimellitate), glycerin-bis(anhydrotrimellitate) monoacetate, 1,2,3,4,-butanetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3' Particularly preferred are polybasic acid anhydrides selected from among 2,4,4'-diphenylethertetracarboxylic acid dianhydride, 2,2-bis(3,4-anhydrodicarboxyphenyl)propane, 2,2-bis(3,4-anhydrodicarboxyphenyl)hexafluoropropane, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methylcyclohexene-1,2-dicarboxylic acid anhydride, and 3a,4,5,9b-tetrahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione.

[0078] [Isocyanate resin] An isocyanate resin is a compound that has two or more isocyanate groups in its molecule. Examples of the isocyanate resin include, but are not limited to, aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as one or more biuret forms of isocyanate monomers or isocyanate forms obtained by trimerizing the above-mentioned diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction between the above-mentioned isocyanate compounds and polyol compounds. These may be used alone or in combination.

[0079] [Polyamide resin] Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, and oxazolines with dicarboxylic acids, reaction products of diamines with acid chlorides, and ring-opening polymerization products of lactam compounds. These may be used alone or in combination. Specific examples of the above raw materials are given below, but are not limited to these. <Diamine> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimer diamine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane , 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenyl sulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, and the like. <Diisocyanate> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, and the like. <Dicarboxylic acid> Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid chloride> Acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride and the like. <Lactam> ε-caprolactam, ω-undecanelactam, ω-laurolactam, and the like.

[0080] [Polyimide resin] Examples of polyimide resins include, but are not limited to, reaction products of the above diamines with the following tetracarboxylic dianhydrides. These may be used alone or in combination. <Tetracarboxylic acid dianhydride> 4,4'-(Hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2',3, 3'-Biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2'-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic acid Dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]meth 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-Perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, 2,2-propylidene -4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R,6R]-3-oxabicyclo[3,2 ,1]Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenyl bis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.,

[0081] [Cyanate ester resin] Cyanate ester resins are cyanate ester compounds obtained by reacting phenolic resins with cyanogen halides. Specific examples include, but are not limited to, dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2'-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2'-bis(4-cyanatophenyl)ethane, 2,2'-bis(4-cyanatophenyl)hexafluoropropane, bis(4-cyanatophenyl)sulfone, bis(4-cyanatophenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene co-condensates in which the hydroxyl groups have been converted to cyanate groups. These compounds may be used alone or in combination. Furthermore, the cyanate ester compound, the synthesis method of which is described in JP-A-2005-264154, is particularly preferred as the cyanate ester compound because it has low moisture absorption, flame retardancy, and excellent dielectric properties. The cyanate ester resin may optionally contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate to trimerize the cyanate group to form a sym-triazine ring.

[0082] The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, and more preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the cyanate ester resin.

[0083] [Polybutadiene and its modified products] Polybutadiene and its modified products are polybutadiene or compounds having a structure derived from polybutadiene in the molecule. The unsaturated bonds in the polybutadiene-derived structure may be partially or entirely converted to single bonds by hydrogenation. Examples of polybutadiene and its modified products include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, (meth)acrylate-terminated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. These may be used alone or in combination. Among these, polybutadiene or styrene-butadiene rubber is preferred from the viewpoint of dielectric properties. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, and RICON-184 (all manufactured by Cray Valley Corporation), and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.). Examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda Co., Ltd.). The molecular weight of polybutadiene and styrene-butadiene rubber is preferably a weight-average molecular weight of 500 to 10,000, more preferably 750 to 7,500, and even more preferably 1,000 to 5,000. Below the lower limit of the above range, the amount of evaporation is high, making it difficult to adjust the solids content during prepreg production, while above the upper limit of the above range, compatibility with other curable resins deteriorates. Generally, in the case of compounds containing heteroatoms such as oxygen or nitrogen, such as bismaleimides and polymaleimides, it is difficult to ensure compatibility with low-polarity compounds, such as compounds composed mainly of hydrocarbons or compounds composed only of hydrocarbons, due to their polarity. On the other hand, component (A) of the present invention has a skeletal design that does not actively incorporate heteroatoms such as oxygen or nitrogen, and therefore has excellent compatibility with materials with low polarity and low dielectric properties, as well as compounds composed only of hydrocarbons.

[0084] [Polystyrene and its modified products] Polystyrene and its modified products are polystyrene or compounds having a structure derived from polystyrene in the molecule. Examples of polystyrene and modified products thereof include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), SEBS (styrene-ethylene-butylene-styrene copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), Examples of suitable block copolymers include Septon 8004, Septon 8006, and Septon 8007L (all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a styrene-ethylene / ethylene-propylene-styrene block copolymer having a terminal hydroxyl group: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125 and Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybrar 7125F and Hybrar 7311F, both manufactured by Kuraray Co., Ltd.), and SIBS (styrene-isobutylene-styrene block copolymer: SIBSTAR 073T, SIBSTAR 102T, and SIBSTAR 103T (all manufactured by Kaneka Corporation), and Septon V9827 (manufactured by Kuraray Co., Ltd.)), but are not limited to these. These may be used alone or in combination. Polystyrene and its modified products are preferably free of unsaturated bonds, since they have higher heat resistance and are less susceptible to oxidative degradation. The weight-average molecular weight of polystyrene and its modified products is not particularly limited as long as it is 10,000 or more, but if it is too large, compatibility with not only polyphenylene ether compounds but also low-molecular-weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, the weight-average molecular weight is preferably about 10,000 to 300,000.

[0085] The curable resin composition of the present invention can be used by known methods. For example, the curable resin composition of the present invention, the viscosity of which has been adjusted with the organic solvent, can be applied to a support, and then dried at 50 to 180°C, preferably 80 to 140°C, for 5 to 30 minutes to form a film-like curable resin composition. Examples of the support include silicon wafers, ceramic substrates, rigid substrates, flexible substrates, and silicon wafers on which inorganic surface protection films such as SiN films and SiO2 films have been formed.

[0086] The coating method is not particularly limited, but examples include coating using a spin coater, slit coater, roll coater, etc., and screen printing. Among these, for example, when coating a silicon wafer, a coating method using a spin coater is preferably employed. Furthermore, the film thickness of the film-like curable resin composition can be adjusted as desired by adjusting the concentration of the curable resin composition and the coating thickness, and is not particularly limited. For example, when used as a protective film for semiconductor elements or an interlayer insulating film, the film thickness after drying is preferably 3 to 50 μm, more preferably 5 to 30 μm, and even more preferably 5 to 20 μm. If the film thickness is less than 3 μm, the underlying elements and circuits tend to be insufficiently protected, while if it exceeds 50 μm, fine pattern formation tends to be difficult. In the present invention, even if the film thickness is 10 μm or more (preferably 10 to 20 μm), it is possible to form a fine pattern, and it is possible to form a pattern in which the aspect ratio of the opening diameter (Via diameter) of the through-hole formed by exposure and development described below is 0.3 or more (more preferably 0.5 or more).

[0087] Next, the film-like curable resin composition thus obtained is exposed to light through a mask having a predetermined pattern, thereby photopolymerizing the curable resin composition of the present invention. Examples of the exposure method include contact exposure and reduced projection exposure. The exposure wavelength is preferably ultraviolet to visible light of 200 to 500 nm, and a standard reduced projection exposure machine (stepper) can be used. Furthermore, from the viewpoint of enabling the formation of a fine pattern, the exposure wavelength is more preferably 256 to 436 nm, and even more preferably 256 to 365 nm. The exposure dose is not particularly limited, but is preferably 100 to 5,000 mJ / cm. 2 is preferably 300 to 3000 mJ / cm 2 It is more preferable that:

[0088] Next, development is performed to dissolve and remove the unexposed portions of the film-like curable resin composition after exposure, thereby obtaining a polymerized film (polymer) having a predetermined pattern. Specifically, in the exposed portions, radicals or cationic species generated from the photopolymerization initiator upon irradiation with light cause crosslinking of component (A) and other compounds, rendering them insoluble in the developer. In contrast, the unexposed portions dissolve in the developer, and by utilizing the difference in solubility between the exposed and unexposed portions in the developer, a polymerized film having a pattern of through-holes with a predetermined opening diameter (Via diameter) can be obtained. In addition to using the above-mentioned solvents, the developer may further contain an alcoholic solvent such as methanol, ethanol, or propanol to adjust solubility during development. Examples of the development method include spraying, puddling, and dipping.

[0089] It is also preferable to further rinse the polymer film having the predetermined pattern obtained by the development with an organic solvent such as cyclopentanone or a mixed solvent of cyclopentanone and ethanol. From the viewpoints of suppressing the occurrence of surface roughness and facilitating dimensional design, it is preferable that the polymer film after the development has a residual film ratio of 90% or more. In the present invention, the residual film ratio refers to the ratio of the film thickness of the polymer film after development to the film thickness of the film-like curable resin composition after drying (before exposure) (film thickness of the polymer film after development / film thickness of the film-like curable resin composition after drying (before exposure)).

[0090] Next, the polymer film having the desired pattern obtained by the development is heated and cured as necessary to obtain a cured film (cured product) having the desired pattern. The heating temperature (curing temperature) is preferably 60 to 230°C, more preferably 150 to 230°C. The heating time is preferably 30 to 120 minutes. In the present invention, the curing temperature refers to the temperature required to thermally cure functional groups remaining unreacted during the exposure. This thermal curing reaction crosslinks functional groups that were unreacted during the photopolymerization described above. However, when the curable resin composition of the present invention is used, it is not necessary to raise the curing temperature as with conventional polyimide precursors or polybenzoxazole precursors. This is because the curable resin composition of the present invention does not require a dehydration ring-closing reaction.

[0091] Thus, by using the curable resin composition of the present invention, a cured film having a fine pattern can be obtained. The pattern preferably has an aspect ratio of the opening diameter (Via diameter) of the formed through-holes of 0.3 or more, more preferably 0.5 or more. In the present invention, the opening diameter can be determined by measurement using an optical microscope or a scanning electron microscope (SEM).

[0092] The cured product obtained by photocuring or photothermal curing (curing using a combination of photocuring and thermal curing) using the curable resin composition of the present invention can be suitably used for at least one film selected from the group consisting of a surface protection film for a semiconductor element, an interlayer insulating film, and an insulating film for a redistribution layer. Furthermore, the curable resin composition of the present invention is particularly effective when such a film requires a thickness of 10 μm or more and patterning is required so that the aspect ratio of the opening diameter (Via diameter) of the through-hole is 0.3 or more (more preferably 0.5 or more).

[0093] The cured product of the present invention is used, for example, as a resist film, an interlayer insulating material for build-up processes, or as an optical waveguide in printed circuit boards, or as an electrical, electronic, or optical substrate such as an optoelectronic board or optical board. Specific examples of these include computers, home appliances, and mobile devices. The film thickness of this cured product layer is usually about 0.5 to 160 μm, and preferably about 1 to 100 μm. [Example]

[0094] The present invention will now be described in more detail with reference to examples. Unless otherwise specified, all parts are by weight. However, the present invention is not limited to these examples.

[0095] The various analytical methods used in the examples are described below. <Weight average molecular weight (Mw), number average molecular weight (Mn)> Calculation was performed in terms of polystyrene using a polystyrene standard solution. GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-20A, CBM-20A (all manufactured by Shimadzu Corporation) Column: Shodex KF-603, KF-602x2, KF-601x2) Coupled eluent: tetrahydrofuran Flow rate: 0.5ml / min. Column temperature: 40℃ Detection: RI (differential refractive index detector)

[0096] [Synthesis Example 1] A flask equipped with a thermometer, condenser, and stirrer was equipped with an aspirator and a base trap. 370.1 parts of 2-bromoethylbenzene (Tokyo Chemical Industry Co., Ltd.), 175.1 parts of α,α'-dichloro-p-xylene (Tokyo Chemical Industry Co., Ltd.), and 27.3 parts of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.) were charged to the flask and reacted at 130°C for 6 hours while collecting the evolved hydrogen chloride with a base trap. 100 parts of toluene and 600 parts of cyclohexane were added for extraction, and the organic layer was washed five times with 100 parts of water. The solvent and excess 2-bromoethylbenzene were distilled off under reduced pressure with heating to obtain 380 parts of a compound (BEB-1) having a 2-bromoethylbenzene structure represented by formula (3) below as a liquid resin (Mn: 938, Mw: 1290). The GPC chart of the resulting compound is shown in Figure 1. The average repeating unit value (n), calculated from the area percentage of the GPC chart, was 2.2.

[0097] [ka]

[0098] [Synthesis Example 2] A flask equipped with a thermometer, condenser, and stirrer was charged with 300 parts of BEB-1 obtained in Synthesis Example 1, 245 parts of toluene, 735 parts of dimethyl sulfoxide, 0.15 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, and 146.4 parts of 50 wt% aqueous sodium hydroxide solution, and the reaction was continued at 40°C for 6 hours. 100 parts of water was added, and the organic layer was washed, and then returned to the reaction vessel. 735 parts of dimethyl sulfoxide and 9.8 parts of 50 wt% aqueous sodium hydroxide solution were added, and the reaction was continued for another hour at 40°C. 300 parts of toluene was added, and the organic layer was repeatedly washed with 100 parts of water until the wastewater became neutral. The mixture was concentrated under reduced pressure using an evaporator to obtain 180 parts of compound (O-1) having two or more styrene structures in the molecule, as represented by the following formula (4). The GPC chart of the obtained compound is shown in Figure 2. The obtained compound 1 The H-NMR data (deuterated chloroform) is shown in Figure 3. 1Signals derived from vinyl groups were observed at 5.10-5.30 ppm, 5.50-5.85 ppm, and 6.60-6.80 ppm in the H-NMR chart. The average value n of the repeating units calculated from the area % of the GPC chart was 2.2 (the molecular weight of the resin component was Mn: 797, Mw: 1187).

[0099] [ka]

[0100] [Examples 1 to 3, Comparative Examples 1 and 2] Each material was mixed in the proportions shown in Table 1 and coated onto a PET film to a thickness of 100 μm. A PET film was also attached to the side not in contact with the film, and the mixture was irradiated with a high-pressure mercury lamp (365 nm) at 3000 mJ / cm 2 The dielectric properties of the photocured film thus obtained were measured. Furthermore, a photocured film was obtained using the same procedure as above, and then thermally cured in an oven at 180° C. for 1 hour. The dielectric properties of the photocured film thus obtained were measured. In addition, for the evaluation, test pieces were cut out to a desired size using a laser cutter as necessary, and the evaluation was carried out.

[0101] <Dielectric constant test / dielectric loss tangent test> The test was performed using a cavity resonator perturbation method using a 10GHz cavity resonator manufactured by ATE Co., Ltd. The sample size was 1.7mm wide x 100mm long, and the thickness was 0.1mm.

[0102] [Table 1] R-684: Reaction product of tricyclodecane dimethanol and acrylic acid (Nippon Kayaku Co., Ltd.) RE-310S: Liquid bisphenol A epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) OXE-04: Oxime ester photo-radical polymerization initiator (BASF) Irgacure 290: Sulfonium salt-based cationic photopolymerization initiator (BASF)

[0103] From the results in Table 1, it was confirmed that Examples 1 and 2 were superior in low dielectric properties after photo- and photo-thermal curing compared to the conventionally used acrylate resin composition (Comparative Example 1).

[0104] From the results in Table 1, it was confirmed that Example 3 was superior in low dielectric properties after photo- and photothermal curing compared to the conventionally used epoxy resin composition (Comparative Example 2).

[0105] The curable resin composition, resin sheet, and cured product thereof of the present invention are used as resist films, interlayer insulating materials for build-up methods, and optical waveguides in substrates such as printed circuit boards, optoelectronic boards, and optical boards, and other electrical, electronic, and optical substrates.

Claims

1. A curable resin composition comprising: (A) a compound having at least two styrene structures in the molecule; and (B) a photopolymerization initiator, The curable resin composition, wherein the component (A) is a compound represented by the following formula (1): 【Chemical 1】 (In formula (1), each R independently represents a hydrocarbon group or a halogenated alkyl group having 1 to 10 carbon atoms; p and r each represent an integer of 0 to 4; q represents an integer of 0 to 3; and n satisfies 1≦n≦20.)

2. 2. The curable resin composition according to claim 1, wherein the component (B) is a cationic photopolymerization initiator.

3. The curable resin composition according to claim 1, wherein the component (B) is a photoradical polymerization initiator.

4. 2. The curable resin composition according to claim 1, wherein the component (B) is an oxime ester-based photoradical polymerization initiator.

5. The curable resin composition according to claim 1 , further comprising an inorganic filler.

6. A cured product obtained by photocuring or photothermal curing the curable resin composition according to any one of claims 1 to 5.

7. A semiconductor device comprising the cured product according to claim 6 as at least one selected from the group consisting of a surface protection film, an interlayer insulating film, and an insulating film for a rewiring layer.

Images