Resin sheet for forming insulation layer of semiconductor package substrate

Abstract

To provide a resin sheet for forming an insulation layer of a semiconductor package substrate from which a cured product that has a high glass transition temperature, suppresses occurrence of a haloing phenomenon, and has good crack resistance and excellent flame retardancy can be obtained.SOLUTION: A resin sheet for forming an insulation layer of a semiconductor package substrate has a support, and a resin composition layer provided on the support, wherein the resin composition layer contains (A) a radical polymerizable group-containing compound having a carbodiimide structure, (B) a flame retardant having a crosslinkable functional group, and (C) a thermosetting resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin sheet for forming an insulating layer of a semiconductor package substrate, and further to a resin sheet, a printed wiring board, and a semiconductor device obtained by using the resin composition. [Background technology]

[0002] A known manufacturing technique for printed wiring boards is a build-up method in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, the insulating layer is generally formed by curing a resin composition. For example, Patent Document 1 discloses a technique for forming an insulating layer by curing a resin composition containing a carbodiimide compound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 027013 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, improvements in the functionality of electronic components have led to a demand for higher density wiring in circuit boards. To achieve even higher density wiring, further improvements in the mechanical strength, flame retardancy, and crack resistance of insulating layers are required. To improve mechanical strength, it is conceivable to increase the glass transition temperature of the insulating layer and suppress the occurrence of haloing.

[0005] Haloing refers to discoloration of the resin in the insulating layer around a via hole. This haloing is usually caused by deterioration of the resin around the via hole. Furthermore, if a roughening treatment is performed on an insulating layer where haloing has occurred, the resin in the part of the insulating layer where the haloing has occurred (hereinafter sometimes referred to as the "halo area") may be eroded during the roughening treatment, causing delamination between the insulating layer and the inner layer substrate, which may result in a decrease in mechanical strength.

[0006] An object of the present invention is to provide a resin sheet from which a cured product having a high glass transition temperature, suppressed occurrence of haloing, and good crack resistance can be obtained. [Means for solving the problem]

[0007] In order to achieve the objects of the present invention, the present inventors conducted extensive research and found that by using (A) a radically polymerizable group-containing compound having a carbodiimide structure, (B) a flame retardant having a crosslinkable functional group, and (C) a thermosetting resin, it is possible to obtain a cured product that has a high glass transition temperature, suppresses the occurrence of haloing, and has good crack resistance, and thus completed the present invention.

[0008] That is, the present invention includes the following. [1] A film having a support and a resin composition layer provided on the support, The resin composition layer comprises: (A) a radical polymerizable group-containing compound having a carbodiimide structure; (B) a flame retardant having a crosslinkable functional group, and (C) A resin sheet for forming an insulating layer of a semiconductor package substrate, comprising a thermosetting resin. [2] The resin sheet for forming an insulating layer of a semiconductor package substrate according to [1], further comprising (D) an inorganic filler. [3] The resin sheet for forming an insulating layer of a semiconductor package substrate according to [1] or [2], further comprising (E) a radically polymerizable group-containing compound that does not have a carbodiimide structure. [4] The resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [1] to [3], wherein the content of component (A) is 0.1% by mass or more and 15% by mass or less, when the non-volatile components of the resin composition layer are taken as 100% by mass. [5] The resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [1] to [4], wherein the content of component (B) is 0.01% by mass or more and 3% by mass or less, when the non-volatile components of the resin composition layer are taken as 100% by mass. [6] The resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [1] to [5], wherein the content of component (C) is 10% by mass or more and 40% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass. [7] The resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [2] to [6], wherein the content of component (D) is 45% by mass or more and 85% by mass or less, when the non-volatile components of the resin composition layer are taken as 100% by mass. [8] The resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [3] to [7], wherein the content of component (E) is 0.1% by mass or more and 20% by mass or less, when the non-volatile components of the resin composition layer are taken as 100% by mass. [9] A semiconductor chip package substrate comprising an insulating layer made of a cured product of the resin composition layer of the resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of [1] to [8].

[10] A semiconductor device comprising the semiconductor chip package substrate according to [9]. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain a resin sheet from which a cured product having a high glass transition temperature, suppressing the occurrence of haloing, and good crack resistance can be obtained. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an insulating layer obtained by curing a resin composition layer together with an inner layer substrate. [Figure 2]FIG. 2 is a plan view schematically showing the surface of the insulating layer obtained by curing the resin composition layer, opposite to the conductor layer. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an insulating layer obtained by curing a resin composition layer and having been subjected to a roughening treatment, together with an inner layer substrate. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to preferred embodiments thereof. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0012] [Resin sheet for forming insulating layers on semiconductor package substrates] The resin sheet for forming an insulating layer of a semiconductor package substrate of the present invention has a support and a resin composition layer provided on the support, the resin composition layer containing (A) a radically polymerizable group-containing compound having a carbodiimide structure, (B) a flame retardant having a crosslinkable functional group, (C) a thermosetting resin, and (D) an inorganic filler. Such a resin sheet has a high glass transition temperature, suppresses the occurrence of haloing, and enables the production of a cured product with good crack resistance. Furthermore, it is usually possible to produce a cured product with excellent flame retardancy.

[0013] The resin sheet for forming an insulating layer of a semiconductor chip package substrate of the present invention is useful for use as an insulating layer in semiconductor package substrates. Examples of semiconductor package substrates 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. Hereinafter, the "resin sheet for forming an insulating layer of a semiconductor package substrate" may be simply referred to as the "resin sheet."

[0014] <Support> The resin sheet has a support, and the support is bonded to one surface of the resin composition layer. Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferred.

[0015] When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0016] 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.).

[0017] The surface of the support that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

[0018] The support may also be a support with a release layer, which has a release layer on the surface that bonds to 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 resins, polyolefin resins, urethane resins, and silicone resins. Commercially available products may also be used as the support with a release layer, including, for example, "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, which are PET films having a release layer primarily composed of an alkyd resin-based release agent.

[0019] 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.

[0020] <Resin composition layer> The resin sheet has a resin composition layer and is provided on a support. The insulating layer can be formed by thermally curing the resin composition layer. Typically, the insulating layer contains a cured product of the resin composition layer, and preferably contains only the cured product of the resin composition layer. The resin composition layer contains (A) a radically polymerizable group-containing compound having a carbodiimide structure, (B) a flame retardant having a crosslinkable functional group, and (C) a thermosetting resin. The resin composition layer may further contain (D) an inorganic filler, (E) a radically polymerizable group-containing compound not having a carbodiimide structure, (F) a thermoplastic resin, (G) a stress relaxation material, (H) a radical polymerization initiator, (I) a curing accelerator, (J) other additives, and (K) a solvent, as needed.

[0021] In the present invention, unless otherwise specified, the content of each component in the resin composition layer is a value when the nonvolatile components in the resin composition layer are 100 mass %, and the nonvolatile components refer to all nonvolatile components in the resin composition layer excluding the solvent. Furthermore, in the present invention, the resin components in the resin composition layer refer to the nonvolatile components of the resin composition layer excluding the (D) inorganic filler.

[0022] -(A) Radical polymerizable group-containing compound having a carbodiimide structure- The resin composition layer contains a radical polymerizable group-containing compound having a carbodiimide structure as component (A). The component (A) may be used alone or in combination of two or more.

[0023] The (A) radically polymerizable group-containing compound having a carbodiimide structure is a compound having one or more carbodiimide structures (-N=C=N-) and one or more radically polymerizable groups in one molecule. The (A) component may further have one or more urethane bonds (-O-CO-NH-) in one molecule. Two or more carbodiimide structures, two or more radically polymerizable groups, and two or more urethane bonds may be present in one molecule. When an epoxy resin is included as the (C) thermosetting resin described below, the (A) component may react with the epoxy resin to cure it. The (A) component may be used alone or in combination of two or more.

[0024] The radical polymerizable group is a group having a radically polymerizable ethylenically unsaturated bond. Examples of the radical polymerizable 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 groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl). The radical polymerizable group is preferably present at the terminal of component (A).

[0025] The component (A) preferably contains a structural unit represented by the following formula (A-1) in addition to the radical polymerizable group. [ka] In formula (A-1), Y represents a divalent hydrocarbon group which may have a substituent.

[0026] In formula (A-1), Y represents a divalent hydrocarbon group which may have a substituent. The divalent hydrocarbon group represented by Y usually has 1 or more carbon atoms, preferably 2 or more carbon atoms, and usually 30 or less carbon atoms. The divalent hydrocarbon group may be a divalent saturated hydrocarbon group or a divalent unsaturated hydrocarbon group. Unless otherwise specified, a divalent unsaturated hydrocarbon group represents a hydrocarbon group having at least one carbon-carbon double bond, carbon-carbon triple bond, or aromatic hydrocarbon ring, and includes linear, branched, and cyclic groups.

[0027] Preferred divalent hydrocarbon groups for Y include, for example, alkylene groups, cycloalkylene groups, arylene groups, and groups formed by combining these groups.

[0028] The number of carbon atoms in the alkylene group for Y is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6, 1 to 4, or 1 to 3. The number of carbon atoms in the substituent is not included in this number of carbon atoms. Suitable examples of the alkylene group include a methylene group, an ethylene group, a propylene group, and a butylene group.

[0029] The number of carbon atoms in the cycloalkylene group for Y is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. The number of carbon atoms in the substituent is not included in this number of carbon atoms. Suitable examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.

[0030] The arylene group for Y represents a group obtained by removing two hydrogen atoms on an aromatic ring from an aromatic hydrocarbon. The number of carbon atoms in the arylene group is preferably 6 to 24, more preferably 6 to 18, and even more preferably 6 to 14 or 6 to 10. The number of carbon atoms does not include the number of carbon atoms of substituents. Suitable examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenylene group.

[0031] The substituent for Y is not particularly limited, and examples thereof include a halogen atom, an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, an alkyl-oxy-carbonyl group, an alkenyl-oxy-carbonyl group, an aryl-oxy-carbonyl group, an alkyl-carbonyl-oxy group, an alkenyl-carbonyl-oxy group, an aryl-carbonyl-oxy group, etc. Among these, it is preferable that the divalent hydrocarbon group for Y has no substituent.

[0032] More preferably, Y represents a divalent saturated hydrocarbon group of 2 to 30 carbon atoms which may have a substituent, or a divalent unsaturated hydrocarbon group of 2 to 30 carbon atoms which may have a substituent. Even more preferably, Y represents a divalent saturated hydrocarbon group of 2 to 30 carbon atoms which may have a substituent and has a ring structure (for example, a ring structure selected from a cycloalkane ring, a benzene ring, and a naphthalene ring), or a divalent unsaturated hydrocarbon group of 2 to 30 carbon atoms which may have a substituent and has a ring structure (for example, a ring structure selected from a cycloalkane ring, a benzene ring, and a naphthalene ring).

[0033] Y in formula (A-1) preferably represents a divalent group represented by the following formula (A-2). [ka] In formula (A-2), Y a , Y b and Y c are each independently a single bond or C(R y )2;R y each independently represents a hydrogen atom or a methyl group; ring Y1 and ring Y 2 each independently represents an optionally substituted cycloalkane ring having 4 to 10 carbon atoms, an optionally substituted benzene ring, or an optionally substituted naphthalene ring; y represents 0 or 1; * represents a binding site.

[0034] In formula (A-2), Y a , Y b and Y c are each independently a single bond or C(R y )2. Preferably, Y a and Y c is a single bond and Y b is C(R y )2. R y are each independently a hydrogen atom or a methyl group, and are preferably a hydrogen atom.

[0035] In formula (A-2), ring Y 1 and ring Y 2 each independently represents a cycloalkane ring having 4 to 10 carbon atoms which may have a substituent, a benzene ring which may have a substituent, or a naphthalene ring which may have a substituent. 1 and ring Y 2 each independently represents a cycloalkane ring having 4 to 10 carbon atoms, which may have a substituent. Examples of the cycloalkane ring having 4 to 10 carbon atoms include monocyclic saturated hydrocarbon rings such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclononane ring, and a cyclodecane ring; bicyclic saturated hydrocarbon rings such as a bicyclo[2.2.1]heptane ring (norbornane ring), a bicyclo[4.4.0]decane ring (decalin ring), a bicyclo[5.3.0]decane ring, a bicyclo[4.3.0]nonane ring (hydrindane ring), a bicyclo[3.3.0]octane ring, and a bicyclo[3.3.1]nonane ring; 2,6 ] Decane ring (tetrahydrodicyclopentadiene ring), tricyclo[3.3.1.1 3,7] A tricyclic saturated hydrocarbon ring such as a decane ring (adamantane ring) is preferred. 1 and ring Y 2 each independently represents a cyclohexane ring which may have a substituent. The substituents on the cycloalkane ring, benzene ring and naphthalene ring are not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aryl-alkyl group (an alkyl group substituted with an aryl group), an alkyl-aryl group (an aryl group substituted with an alkyl group), an alkyl-oxy group, an alkenyl-oxy group, an aryl-oxy group, an alkyl-oxy-carbonyl group, an alkenyl-oxy-carbonyl group, an aryl-oxy-carbonyl group, an alkyl-carbonyl-oxy group, an alkenyl-carbonyl-oxy group, and an aryl-carbonyl-oxy group. Among these, the ring Y 1 and ring Y 2 is particularly preferably an unsubstituted cyclohexane ring.

[0036] Specific examples of Y include divalent groups represented by formulae (Y1) to (Y14), and the divalent group represented by formula (Y1) is particularly preferred. In formulae (Y1) to (Y14), * indicates a bonding site. [ka]

[0037] In a preferred example, the proportion of the structural unit represented by formula (A-1) contained in component (A) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and may even be 90% by mass or more, relative to 100% by mass of the total molecular mass of component (A).

[0038] The component (A) is preferably a compound represented by formula (A-3). [ka] In formula (A-3), each R independently represents a hydrogen atom or a methyl group; X1 each independently represents a carbonyl group, a methylene group, a phenylene group, or a phenylene-methylene group; X 2 each independently represents a divalent saturated hydrocarbon group having 2 to 4 carbon atoms; each Z independently represents a divalent saturated hydrocarbon group having 2 to 300 carbon atoms which may have a substituent, or a divalent unsaturated hydrocarbon group having 2 to 300 carbon atoms which may have a substituent; each a independently represents 0 or an integer of 1 or more; each b independently represents b≦1; each c independently represents c≦1 or more; d independently represents 0 or d≦1 or more; and each Y independently represents the above-mentioned group. The a units, b units, c units, and d units may be the same or different for each unit.

[0039] In formula (A-3), each R independently represents a hydrogen atom or a methyl group.

[0040] In formula (A-3), X 1 are each independently a carbonyl group, a methylene group, a phenylene group, or a phenylene-methylene group (the bonding direction is not particularly limited, but it is preferable that the phenylene side is bonded to C in "RC"). Preferably, X 1 are each independently a methylene group or a carbonyl group. The phenylene-methylene group includes a 1,2-phenylene-methylene group, a 1,3-phenylene-methylene group, and a 1,4-phenylene-methylene group.

[0041] In formula (A-3), X 2 are each independently a divalent saturated hydrocarbon group having 2 to 4 carbon atoms. The divalent saturated hydrocarbon group may be linear, branched, or cyclic. Specific examples of the divalent saturated hydrocarbon group having 2 to 4 carbon atoms include linear alkylene groups having 2 to 4 carbon atoms, such as an ethylene group, a trimethylene group, and a tetramethylene group; and branched alkylene groups having 2 to 4 carbon atoms, such as an ethylidene group, a propylidene group, an isopropylidene group, and an ethylmethylmethylene group. X 2In one embodiment, each independently represents preferably a divalent saturated hydrocarbon group having 2 or 3 carbon atoms, and more preferably an ethylene group (—CH 2 —CH 2 —).

[0042] In formula (A-3), each Z independently represents a divalent saturated hydrocarbon group of 2 to 300 carbon atoms, which may have a substituent, or a divalent unsaturated hydrocarbon group of 2 to 300 carbon atoms, which may have a substituent. Preferably, each Z independently represents a divalent saturated hydrocarbon group of 2 to 300 carbon atoms, or a divalent unsaturated hydrocarbon group of 2 to 300 carbon atoms. More preferably, each Z independently represents a divalent hydrocarbon group of 300 or less carbon atoms, which has a structural unit selected from the group consisting of formulae (Z1) to (Z8) below. Even more preferably, each Z independently represents a divalent hydrocarbon group of 300 or less carbon atoms, which is composed of a structural unit selected from the group consisting of formulae (Z1) to (Z8). [ka]

[0043] It is more preferable that Z each independently represent a divalent hydrocarbon group having 300 or less carbon atoms and having a structural unit represented by formula (Z1); it is even more preferable that Z represent a divalent hydrocarbon group having 300 or less carbon atoms and consisting of a structural unit selected from formulas (Z1) to (Z8) and having at least a structural unit represented by formula (Z1). Of these, it is particularly preferable that Z represent a divalent hydrocarbon group having 300 or less carbon atoms and represented by the following formula (Z-1). [ka] (In formula (Z-1), n z indicates an integer of 1 or more; * indicates a binding site.)

[0044] In formula (A-3), each a independently represents 0 or an integer of 1 or more, preferably 0 or an integer of 1 to 10, and more preferably 0 or 1.

[0045] In formula (A-3), b represents the average degree of polymerization of the carbodiimide group. Each b independently represents b≦1 or more, preferably an integer of 1 or more, more preferably an integer of 1 to 100, and even more preferably an integer of 1 to 100, 1 to 10, or an integer of 1 to 10.

[0046] In formula (A-3), c represents the average degree of polymerization of the divalent saturated hydrocarbon group of 2 to 300 carbon atoms, which may have a substituent, represented by Z. Each c independently represents c≦1 or more, and is preferably an integer of 1 or more, more preferably 1 to 100, still more preferably an integer of 1 to 100, 1 to 10, an integer of 1 to 10, or 1.

[0047] In formula (A-3), d represents the average degree of polymerization of the group represented by Z with the polycarbodiimide. Each d is independently 0 or d≦1 or greater, preferably 0 or an integer of 1 to 100, more preferably 0 or an integer of 1 to 100, and even more preferably 0 or an integer of 1 to 10.

[0048] Due to its manufacturing method, component (A) may contain isocyanate groups (-N=C=O) in the molecule. The content of isocyanate groups in component (A) (also referred to as the "NCO content") is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, still more preferably 2% by mass or less, and particularly preferably 1% by mass or less or 0.5% by mass or less.

[0049] Specific examples of the component (A) include compounds represented by the following formulas (S1) to (S5). However, the component (A) is not limited to these specific examples. In the formulas, b' is the same as b in formula (A-3), d' is the same as d in formula (A-3), and e' is the same as c in formula (A-3). Note that in formula (S5), only 1,2-addition structural units are shown as e' units, but 1,4-addition structural units (cis, trans) are also included. [ka]

[0050] Component (A) can be prepared by a conventionally known method. One known method involves, for example, mixing and stirring a diisocyanate compound such as dicyclohexylmethane-4,4'-diisocyanate with a carbodiimidization catalyst such as 3-methyl-1-phenyl-2-phospholene-1-oxide to carry out a carbodiimidization reaction to obtain an isocyanate-terminated polycarbodiimide. The resulting isocyanate-terminated polycarbodiimide is then reacted with a compound having a radical polymerizable group such as a (meth)acryloyl group, and, if necessary, with other polymerizable compounds such as polybutadiene having hydroxyl groups at both ends. The reaction temperature, reaction time, and other parameters can be appropriately determined by those skilled in the art.

[0051] The weight average molecular weight of component (A) is preferably 500 or more, more preferably 600 or more, even more preferably 700 or more, even more preferably 800 or more, even more preferably 900 or more, and even more preferably 1000 or more, and is preferably 10,000 or less, more preferably 8,000 or less, even more preferably 7,000 or less, and even more preferably 6,000 or less. The weight average molecular weight of component (A) can be measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0052] From the viewpoint of increasing the glass transition temperature, the carbodiimide equivalent of component (A) is preferably 150 g / eq. or more, more preferably 200 g / eq. or more, even more preferably 250 g / eq. or more, and is preferably 1,000 g / eq. or less, more preferably 800 g / eq. or less, even more preferably 600 g / eq. or less. The carbodiimide equivalent represents the mass of resin per equivalent of carbodiimide groups.

[0053] The content of component (A) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0054] The content of component (A) is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, when the resin component in the resin composition layer is taken as 100% by mass.

[0055] -(B) Flame retardant having a crosslinkable functional group- The resin composition layer contains a flame retardant (B) having a crosslinkable functional group as component (B). This flame retardant (B) having a crosslinkable functional group as component (B) excludes those that fall under component (A). By incorporating a flame retardant (B) having a crosslinkable functional group into the resin composition layer, flame retardancy is improved, a decrease in the glass transition temperature of the cured product of the resin composition layer is suppressed, and the occurrence of haloing can be suppressed. The flame retardants (B) having a crosslinkable functional group may be used alone or in combination of two or more.

[0056] A crosslinkable functional group is a functional group that can form a crosslinked structure by heat, irradiation with light such as ultraviolet light, etc., and component (B) has a crosslinkable functional group. Therefore, the crosslink density of a resin composition layer containing component (B) increases when cured. It is believed that an increase in the crosslink density of the cured product makes it more difficult for oxygen to penetrate into the cured product, thereby suppressing oxidation of metals such as copper foil underlying the insulating layer and preventing the occurrence of haloing. It is also believed that an increase in the crosslink density of the cured product also increases the glass transition temperature.

[0057] (B) As the flame retardant having a crosslinkable functional group, a flame retardant having one or more crosslinkable functional groups in one molecule can be used. The number of crosslinkable functional groups in one molecule may be one or more, and may be two or more. There is no particular lower limit to the number of crosslinkable functional groups that may be contained in one molecule, but it may be 10 or less, for example.

[0058] The crosslinkable functional group may be any functional group capable of crosslinking with a curable component such as an epoxy resin, and examples thereof include hydroxyl groups, 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, acryloyloxy, methacryloyloxy, and maleimide (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl) groups. Hydroxy, vinyl, acryloyl, and methacryloyl groups are preferred, hydroxyl and vinyl groups are more preferred, and hydroxyl groups are even more preferred. The crosslinkable functional group is preferably present at the terminal of component (B).

[0059] Examples of the component (B) include phosphorus-based flame retardants having a crosslinkable functional group, such as phosphazene compounds having a crosslinkable functional group, phosphates having a crosslinkable functional group, phosphoric esters having a crosslinkable functional group, polyphosphates having a crosslinkable functional group, phosphinates having a crosslinkable functional group, phosphinates having a crosslinkable functional group, phosphonates having a crosslinkable functional group, and phosphonates having a crosslinkable functional group; aliphatic amine compounds having a crosslinkable functional group, aromatic amine compounds having a crosslinkable functional group, nitrogen-containing heterocyclic compounds having a crosslinkable functional group, and crosslinkable functional groups. nitrogen-based flame retardants having a crosslinkable functional group, such as urea compounds having a crosslinkable functional group; and halogen-based flame retardants having a crosslinkable functional group, such as hexabromobenzene having a crosslinkable functional group, chlorinated paraffin having a crosslinkable functional group, brominated polycarbonate resin having a crosslinkable functional group, brominated epoxy resin having a crosslinkable functional group, brominated phenoxy resin having a crosslinkable functional group, brominated polyphenylene ether resin having a crosslinkable functional group, brominated polystyrene resin having a crosslinkable functional group, and brominated benzyl polyacrylate resin having a crosslinkable functional group.

[0060] Among these, from the viewpoint of significantly achieving the effects of the present invention, the component (B) is preferably a phosphorus-based flame retardant having a crosslinkable functional group, more preferably a phosphazene compound having a crosslinkable functional group or a phosphate ester having a crosslinkable functional group, and even more preferably a phosphate ester having a crosslinkable functional group.

[0061] The component (B) is preferably either a compound represented by the following formula (B-1) or a compound represented by the following formula (B-2). [ka] In formula (B-1), R 1b and R 2b each independently represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, or a crosslinkable functional group; R 3b represents a crosslinkable functional group, a divalent hydrocarbon group, a monovalent hydrocarbon group, or a monovalent group consisting of a combination thereof; R 1 and R2 may be bonded to each other to form a ring. In formula (B-2), R 11b each independently represents a crosslinkable functional group, R 12b each independently represents a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 6 carbon atoms, n1 represents an integer of 3 to 25, m1 represents an integer of 1 to 5, and m2 represents an integer of 0 to 5.

[0062] In formula (B-1), R 1 and R 2 each independently represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, or a crosslinkable functional group. The crosslinkable functional group is as described above.

[0063] The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. This number of carbon atoms does not include the number of carbon atoms of the substituents described below. The alkyl group may be linear, branched, or cyclic. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an isopropyl group, a s-butyl group, and a t-butyl group. Of these, the alkyl group is preferably a methyl group or an ethyl group, and more preferably an ethyl group.

[0064] The alkoxy group is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 15 carbon atoms, and even more preferably an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. This number of carbon atoms does not include the number of carbon atoms of the substituents described below. The alkoxy group may be linear, branched, or cyclic. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a 2-butoxy group, a t-butoxy group, a 1-pentoxy group, a 2-pentoxy group, a 3-pentoxy group, a 2,2-dimethylpropoxy group, a 2-ethylpropoxy group, a 3,3-dimethylpropoxy group, a 1,1-dimethylpropoxy group, a cyclopentoxy group, a 1-hexoxy group, a 2-hexoxy group, a 3-hexoxy group, and a 4-methylpentoxy group. Of these, the alkoxy group is preferably a methoxy group or an ethoxy group, and more preferably an ethoxy group.

[0065] The aryl group is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms. This number of carbon atoms does not include the number of carbon atoms of the substituents described below. Examples of the aryl group include a phenyl group and a naphthyl group. Of these, the phenyl group is preferred as the aryl group.

[0066] As the aryloxy group, an aryloxy group having 6 to 20 carbon atoms is preferable, an aryloxy group having 6 to 15 carbon atoms is more preferable, and an aryloxy group having 6 to 10 carbon atoms is even more preferable. The number of carbon atoms here does not include the number of carbon atoms of the substituents described later. Examples of the aryloxy group include a phenoxy group, 4-methylphenoxy group, 3-methylphenoxy group, 2-methylphenoxy group, 2,6-dimethylphenoxy group, 2,4-dimethylphenoxy group, 2,3-dimethylphenoxy group, 2,4,6-trimethylphenoxy group, 4-isopropylphenoxy group, 2-isopropylphenoxy group, 3-isopropylphenoxy group, 4-isobutylphenoxy group, 2-isobutylphenoxy group, 3-isobutylphenoxy group, 4-t-butylphenoxy group, 2-t-butylphenoxy group, 3-t-butylphenoxy group, 2,6-di-t-butylphenoxy group, 2,4-di-t-butylphenoxy group, 2,3-di-t-butylphenoxy group, 2-methyl-4-t-butylphenoxy group, 2-methyl-6-t-butylphenoxy group, 4-methyl-2-t-butylphenoxy group, etc. Among them, as the aryloxy group, a phenoxy group is preferable.

[0067] R 1 and R 2 The alkyl group, alkoxy group, aryl group, and aryloxy group represented by may have a substituent. The substituent is not particularly limited, and examples thereof include a halogen atom, -O-C 1-6 alkyl group, -N(C 1-10 alkyl group)2, C 1-10 alkyl group, C 6-10 aryl group, -NH2, -CN, -C(O)O-C 1-10 alkyl group, -COOH, -C(O)H, -NO2, etc. Further, the substituent may be a crosslinkable functional group. Here, the term "C p-q "(p and q are positive integers and satisfy p < q.) represents that the number of carbon atoms of the organic group described immediately after this term is p to q. For example, "C 1-10The expression "alkyl group" refers to an alkyl group having 1 to 10 carbon atoms. These substituents may be bonded to each other to form a ring, and the ring structure also includes a spiro ring and a fused ring.

[0068] The above-mentioned substituents may further have a substituent (hereinafter, sometimes referred to as a "secondary substituent"). Unless otherwise specified, the secondary substituent may be the same as the above-mentioned substituent.

[0069] R 1 and R 2 may be bonded to each other to form a ring. 1 and R 2 The ring structure that may be formed by includes a spiro ring and a fused ring. Examples of the ring structure include a group represented by the following formula (B-1a): In formula (B-1a), * represents the bonding site to the phosphorus atom. [ka]

[0070] In formula (B-1), R 3 represents a crosslinkable functional group, a divalent hydrocarbon group, a monovalent hydrocarbon group, or a monovalent group consisting of a combination thereof.

[0071] The monovalent hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and even more preferably 1 to 10 or 1 to 6 carbon atoms. The number of carbon atoms does not include the number of carbon atoms of the substituent. The monovalent hydrocarbon group may be linear, branched, or cyclic. Examples of the monovalent hydrocarbon group include a monovalent aliphatic hydrocarbon group and a monovalent aromatic hydrocarbon group, with a monovalent aromatic hydrocarbon group being preferred. The monovalent hydrocarbon group may be either a monovalent saturated hydrocarbon group or a monovalent unsaturated hydrocarbon group, with a monovalent unsaturated hydrocarbon group being preferred. Specific examples of the monovalent hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, etc., and the alkyl group and aryl group are represented by R in formula (B-1). 1 is the same as the alkyl group or aryl group represented by

[0072] Examples of the alkenyl group include an ethynyl group, a propynyl group, a butynyl group, and a pentynyl group.

[0073] The monovalent hydrocarbon group may have a substituent. The substituent is represented by R 1 Among these, the substituent that the monovalent hydrocarbon group may have is preferably a crosslinkable functional group, more preferably a hydroxy group.

[0074] The divalent hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and even more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. The divalent hydrocarbon group may be linear, branched, or cyclic. Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group and a divalent aromatic hydrocarbon group, with a divalent aliphatic hydrocarbon group being preferred. The divalent hydrocarbon group may be either a divalent saturated hydrocarbon group or a divalent unsaturated hydrocarbon group, with a divalent saturated hydrocarbon group being preferred. Specific examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group, and an arylene group.

[0075] Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, and a decylene group, and a methylene group is preferred.

[0076] Examples of the alkenylene group include an ethenylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, a nonenylene group, and a decenylene group.

[0077] Examples of the arylene group include a phenylene group and a naphthylene group.

[0078] The divalent hydrocarbon group may have a substituent. The substituent is represented by R 1Among these, the substituent that the divalent hydrocarbon group may have is preferably a crosslinkable functional group, more preferably a hydroxy group.

[0079] As the monovalent group formed from these combinations, a monovalent group formed from a combination of a monovalent hydrocarbon group and a crosslinkable functional group; a monovalent group formed from a combination of a crosslinkable functional group, a monovalent hydrocarbon group, and an oxygen atom; and a monovalent group formed from a combination of a divalent hydrocarbon group and a crosslinkable functional group are preferred, and a monovalent group formed from a combination of a monovalent hydrocarbon group and a crosslinkable functional group; and a monovalent group formed from a combination of a divalent hydrocarbon group and a crosslinkable functional group are more preferred.

[0080] Specific examples of monovalent groups formed from these combinations include groups represented by the following formulae (Ba) to (Bb), in which * indicates the bonding site to the phosphorus atom. [ka]

[0081] The compound represented by formula (B-1) is preferably a compound represented by formula (B-1-1). [ka] In formula (B-1-1), R 21b represents a crosslinkable functional group, a divalent hydrocarbon group, a monovalent hydrocarbon group, or a monovalent group consisting of a combination thereof.

[0082] In formula (B-1-1), R 31 represents a crosslinkable functional group, a divalent hydrocarbon group, a monovalent hydrocarbon group, or a monovalent group consisting of a combination thereof, and R in formula (B-1) 3b is the same as

[0083] Examples of the compound represented by formula (B-1) include, but are not limited to, the following compounds (B1) to (B6): In the formula, Et represents an ethyl group. [ka]

[0084] In formula (B-2), R 11b each independently represents a crosslinkable functional group, and the crosslinkable functional group is as described above.

[0085] In formula (B-2), R 12b Each of R independently represents a hydrogen atom, a hydroxy group, or an alkyl group. 1b is the same as the alkyl group represented by

[0086] In formula (B-2), n1 represents an integer of 3 to 25, preferably an integer of 3 to 15, more preferably an integer of 3 to 10, and even more preferably 3.

[0087] In formula (B-2), m1 represents an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 1.

[0088] In formula (B-2), m2 represents an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 0 or 1.

[0089] Examples of the compound represented by formula (B-2) include, but are not limited to, the compound (B7) shown below. [ka]

[0090] Component (B) may be a commercially available product, such as "HCA-HQ-HST" manufactured by Sankosha, "FP700-TP" manufactured by Fushimi Pharmaceutical Industry Co., Ltd., or "V5," "V7," "API-09," "MC-2," or "MC-4" manufactured by Katayama Chemical Industry Co., Ltd.

[0091] From the viewpoint of improving flame retardancy, the content of phosphorus atoms is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, when the resin component in the resin composition layer is taken as 100% by mass. The upper limit is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, and even more preferably 0.3% by mass or less. Here, the "content of phosphorus atoms" is a concept that includes not only the phosphorus atoms contained in component (B) but also the content of phosphorus atoms contained in components (A) to (H) excluding component (B).

[0092] The content of component (B) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, when the non-volatile components of the resin composition layer are taken as 100% by mass, and is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0093] The content of component (B) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, when the resin component of the resin composition layer is taken as 100% by mass, and is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0094] When the content of the (A) component when the resin component of the resin composition layer is 100% by mass is a, and the content of the (B) component when the resin component of the resin composition layer is 100% by mass is b, a / b is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more, and is preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less.

[0095] -(C)Thermosetting resin- The resin composition layer contains a (C) thermosetting resin as the (C) component. The (C) thermosetting resin as the (C) component excludes those corresponding to the (A) and (B) components. The (C) thermosetting resin is not particularly limited in type as long as it can be cured by heat. One type of (C) thermosetting resin may be used alone, or two or more types may be used in combination.

[0096] Examples of the (C) thermosetting resin include epoxy resins, phenolic resins, cyanate resins, active ester resins, carbodiimide resins (excluding those corresponding to component (A)), acid anhydride resins, amine resins, benzoxazine resins, and thiol resins. One type of thermosetting resin may be used alone, or two or more types may be used in combination.

[0097] From the viewpoint of significantly achieving the effects of the present invention, it is preferable to use the (C) thermosetting resin in combination with an epoxy resin and a resin capable of reacting with the epoxy resin to cure the resin composition layer. Hereinafter, a resin capable of reacting with an epoxy resin to cure the resin composition layer may be referred to as a "curing agent." Examples of curing agents include phenolic resins, cyanate resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, and thiol resins. Among these, phenolic resins and active ester resins are preferred as curing agents. One type of curing agent may be used alone, or two or more types may be used in combination. In one embodiment, the thermosetting resin includes an epoxy resin, an active ester resin, and a phenolic resin.

[0098] Epoxy resins are thermosetting resins having epoxy groups. Examples of epoxy resins include tetramethylbisphenol type epoxy resins (bixylenol type epoxy resins), biphenyl type epoxy resins, naphthalene 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, naphthol type epoxy resins, anthracene type epoxy resins, Examples of the epoxy resin include glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, phenol aralkyl-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. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0099] The thermosetting resin (C) 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 is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, based on 100% by mass of the non-volatile components of the epoxy resin.

[0100] Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition layer may contain only a liquid epoxy resin as the epoxy resin, or may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin.

[0101] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0102] Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, and epoxy resins having a butadiene structure, more preferred are glycidyl amine type epoxy resins, bisphenol A type epoxy resins, and bisphenol F type epoxy resins, and even more preferred are naphthalene type epoxy resins, bisphenol A type epoxy resins, and bisphenol F type epoxy resins.

[0103] Specific examples of liquid epoxy resins include "HP4032," "HP4032D," and "HP4032SS" (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-3980S" (glycidylamine-type epoxy resins) manufactured by ADEKA Corporation. epoxy resins); "EP-4088S" (dicyclopentadiene-type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation; "PB-3600" manufactured by Daicel Corporation; "JP-100" and "JP-200" (epoxy resins having a butadiene structure (epoxidized polybutadiene resin) manufactured by Nippon Soda Co., Ltd.); and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. These may be used alone or in combination of two or more.

[0104] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0105] Preferred solid epoxy resins include tetramethylbisphenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, naphthol novolac-type epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, phenol aralkyl-type epoxy resins, tetraphenylethane-type epoxy resins, and phenolphthalimidine-type epoxy resins, with biphenyl-type epoxy resins being more preferred.

[0106] 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.These may be used alone or in combination of two or more.

[0107] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably 1:0.01 to 1:20, more preferably 1:0.05 to 1:10, and particularly preferably 1:0.1 to 1:7.

[0108] The epoxy equivalent of the epoxy resin is preferably 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.

[0109] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0110] The content of the epoxy resin as the (C) thermosetting resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 15% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0111] The content of the epoxy resin as the (C) thermosetting resin is, when the resin component in the resin composition layer is taken as 100% by mass, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more, and is preferably 65% ​​by mass or less, more preferably 60% by mass or less, and particularly preferably 55% by mass or less.

[0112] The phenolic resin may be a compound having one or more, preferably two or more, hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule. When combined with an epoxy resin, the phenolic resin may react with the epoxy resin to harden the resin composition layer, and is therefore sometimes referred to as a "phenolic curing agent." From the viewpoint of achieving the remarkable effects of the present invention, the phenolic resin is preferably a phenolic resin having a novolac structure. Furthermore, from the viewpoint of adhesion, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Of these, triazine skeleton-containing phenolic novolac resins are preferred from the viewpoint of achieving the remarkable effects of the present invention. Specific examples of phenolic resins include "MEH-7700," "MEH-7810," and "MEH-7851" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-375," and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "LA-7052," "LA-7054," "LA-3018," "LA-3018-50P," "LA-1356," "TD2090," "TD-2090-60M," and "KA-1163" manufactured by DIC Corporation.

[0113] As the active ester resin, compounds 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, are generally preferred. When combined with an epoxy resin, active ester resins can react with the epoxy resin to cure the resin composition layer, and are therefore sometimes referred to as "active ester curing agents." The active ester resin is preferably one obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving resistance to high-temperature reflow blistering, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, 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.

[0114] Specifically, the active ester resin 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, at least one selected from a dicyclopentadiene-type active ester resin and 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.

[0115] Commercially available active ester resins include, for example, activated 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-8000L-65T", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation); activated 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 "EXB-8" (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.

[0116] The cyanate resin may be a compound having one or more, preferably two or more, cyanate groups in one molecule. When combined with an epoxy resin, the cyanate resin reacts with the epoxy resin to harden the resin composition layer, and therefore is sometimes called a "cyanate-based curing agent." Examples of cyanate resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-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 resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Specific examples of cyanate resins include "PT30" and "PT60" manufactured by Lonza (both of which are phenol novolac-type multifunctional cyanate resins), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine-converted to form a trimer).

[0117] The carbodiimide resin (excluding those corresponding to component (A)) may be a compound having one or more, preferably two or more, carbodiimide structures in one molecule and having no radical polymerizable group. When combined with an epoxy resin, the carbodiimide resin reacts with the epoxy resin to harden the resin composition layer, and therefore is sometimes called a "carbodiimide-based curing agent."

[0118] Specific examples of carbodiimide resins 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].

[0119] Commercially available carbodiimide resins include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09," manufactured by Nisshinbo Chemical Inc.

[0120] As the acid anhydride resin, a compound having one or more, preferably two or more, acid anhydride groups in one molecule can be used. When combined with an epoxy group, the acid anhydride resin can react with the epoxy resin to harden the resin composition layer, and therefore is sometimes called an "acid anhydride curing agent." Specific examples of acid anhydride resins 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" and "HN-5500" manufactured by Resonac Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Cray Valley Chemical Industries, Ltd.

[0121] The amine resin may be a compound having one or more, preferably two or more, amino groups in one molecule. When combined with an epoxy group, the amine resin may react with the epoxy resin to harden the resin composition layer, and is therefore sometimes referred to as an "amine-based curing agent." 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 amine resins 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)propionate. 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.

[0122] Benzoxazine resins, when combined with epoxy resins, can react with the epoxy resin to cure the resin composition layer, and are therefore sometimes referred to as "benzoxazine-based curing agents." Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd" and "Fa" manufactured by Shikoku Chemicals Corporation.

[0123] Thiol resins, when combined with epoxy resins, can react with the epoxy resin to harden the resin composition layer, and are therefore sometimes referred to as "thiol-based curing agents." Examples of thiol resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0124] The active group equivalent of the curing agent is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., still more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent is the mass of the curing agent per equivalent of the active group.

[0125] The weight average molecular weight (Mw) of the curing agent is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0126] When the number of epoxy groups in the epoxy resin is taken as 1, the number of active groups in the curing agent is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, and preferably 5 or less, more preferably 3 or less, and particularly preferably 2 or less. The "number of epoxy groups in the epoxy resin" refers to the total value obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition layer by the epoxy equivalent. Furthermore, the "number of active groups in the curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition layer by the active group equivalent.

[0127] The content of the curing agent as the (C) thermosetting resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0128] The content of the curing agent as (C) thermosetting resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, when the resin component in the resin composition layer is taken as 100% by mass.

[0129] The content of (C) thermosetting resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, assuming that the non-volatile components in the resin composition layer are 100% by mass.

[0130] The content of (C) thermosetting resin is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, and is preferably 98% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less, assuming that the resin component in the resin composition layer is 100% by mass.

[0131] The total content of the (A), (B), and (C) components is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more, and is preferably 100% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, assuming that the non-volatile components in the resin composition layer are 100% by mass.

[0132] -(D) Inorganic filler- The resin composition layer may contain an inorganic filler (D) as component (D). The inorganic filler (D) may be used alone or in combination of two or more kinds in any ratio.

[0133] The (D) inorganic filler is contained in the resin composition layer in the form of particles. An inorganic compound is used as the (D) inorganic filler material. Examples of (D) inorganic filler materials 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 is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Furthermore, spherical silica is preferred.

[0134] (D) 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 "Sfereek" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0135] The average particle size of the (D) inorganic filler is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, still more preferably 2 μm or less, and particularly preferably 1.5 μm or less. The lower limit of the average particle size of the (D) inorganic filler is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more.

[0136] (D) The average particle size of inorganic fillers 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 was measured using a laser diffraction particle size distribution analyzer with blue and red wavelength light sources using a flow cell system, and the average particle size was 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.

[0137] The specific surface area of ​​the (D) inorganic filler is not particularly limited, but is preferably 0.1 m2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 The upper limit of the specific surface area of ​​the (D) inorganic filler is not particularly limited, but is preferably 100 m 2 / g or less, more preferably 70m 2 / g or less, more preferably 50m 2 / g or less, and even more preferably 30m 2 / g or less, particularly preferably 10m 2 The specific surface area of ​​the inorganic filler is obtained 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.) according to the BET method, and then calculating the specific surface area using the BET multipoint method.

[0138] (D) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. The surface treatment agent may be used alone or in any combination of two or more.

[0139] 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).

[0140] The degree of surface treatment with the surface treatment agent is preferably within a predetermined 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 0.2% to 3% by mass, and even more preferably 0.3% to 2% by mass.

[0141] 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. 2 More 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 or the melt viscosity in the form of a sheet, it is more preferable that the melt viscosity 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:

[0142] (D) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the 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.

[0143] The content of the (D) inorganic filler is preferably 45% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, 60% by mass or more, or 65% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer, and the upper limit is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0144] -(E) Radical polymerizable group-containing compound having no carbodiimide structure- The resin composition layer may contain, as component (E), a (E) radical polymerizable group-containing compound that does not have a carbodiimide structure. The (E) radical polymerizable group-containing compound that does not have a carbodiimide structure as component (E) does not include compounds that fall under the above-mentioned components (A) to (D). The (E) radical polymerizable group-containing compound that does not have a carbodiimide structure is a compound that contains one or more radical polymerizable groups in one molecule but does not have a carbodiimide structure (-N=C=N-). One type of (E) component may be used alone, or two or more types may be used in combination. From the viewpoint of improving flame retardancy, it is preferable that the resin composition contains component (E).

[0145] The component (E) may have two or more radically polymerizable groups in one molecule. The radically polymerizable groups are as described above.

[0146] In the first embodiment, the component (E) preferably contains a thermoplastic resin having two or more radically polymerizable groups (for example, a number average molecular weight of 800 or more). The thermoplastic resin is not particularly limited, but examples include phenoxy resin, polyvinyl acetal resin, polystyrene resin, polyethylene resin, polypropylene resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polyetheretherketone resin, and polyester resin. In this embodiment, the component (E) contains a modified resin of these resins having two or more radically polymerizable groups.

[0147] In the first embodiment, the component (E) more preferably includes a resin selected from a modified polyphenylene ether resin having two or more radically polymerizable groups and a modified polystyrene resin having two or more radically polymerizable groups, even more preferably includes a modified polyphenylene ether resin having two or more radically polymerizable groups, and more preferably includes a resin represented by formula (E-1). [ka] In formula (E-1), R b each independently represents a hydrogen atom or a methyl group; X b are each independently a carbonyl group, a methylene group, a phenylene group, or a phenylene-methylene group (the bonding direction is not particularly limited, but the phenylene side is "R b -C"); R 11 and R 12 each independently represents an alkyl group; R 13 , R 14 , R 21 , R 22 , R 23 and R 24 each independently represents a hydrogen atom or an alkyl group; A represents a single bond, -C(R c )2-, -O-, -CO-, -S-, -SO-, or -SO2-; R ceach independently represents a hydrogen atom or an alkyl group; p represents 0 or 1; and q and r each independently represent an integer of 1 or greater. The q units and r units may be the same or different for each unit.

[0148] R b X each independently represents a hydrogen atom or a methyl group. b are each independently a carbonyl group, a methylene group, a phenylene group, or a phenylene-methylene group (the bonding direction is not particularly limited, but the phenylene side is "R b It is preferably bonded to C in "-C"), and is preferably a carbonyl group or a phenylene-methylene group.

[0149] R 11 and R 12 R each independently represents an alkyl group, preferably a methyl group. 13 and R 14 R each independently represents a hydrogen atom or an alkyl group, and is preferably a hydrogen atom. 21 and R 22 R each independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, and more preferably a methyl group. 23 and R 24 are each independently a hydrogen atom or an alkyl group, and are preferably a hydrogen atom or a methyl group.

[0150] A is a single bond, -C(R c )2-, -O-, -CO-, -S-, -SO-, or -SO2-, and preferably represents a single bond, -C(R c )2- or -O-. c each independently represents a hydrogen atom or an alkyl group, and preferably a hydrogen atom or a methyl group. p represents 0 or 1, and preferably 1. q and r each independently represent an integer of 1 or more, and preferably an integer of 1 to 200, and more preferably an integer of 1 to 100.

[0151] The radical polymerizable group equivalent of the component (E) in the first embodiment is preferably 300 g / eq. to 2500 g / eq., and more preferably 400 g / eq. to 2000 g / eq. The radical polymerizable group equivalent represents the mass of the resin (compound) per equivalent of the radical polymerizable group.

[0152] The number average molecular weight of the component (E) in the first embodiment is preferably 800 to 10000, and more preferably 900 to 5000. The number average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0153] Examples of commercially available products of the component (E) in the first embodiment include "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Company, Inc.; and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether resins) manufactured by SABIC.

[0154] In the second embodiment, the component (E) contains a low-molecular-weight compound (e.g., a molecular weight of less than 800) having two or more radically polymerizable groups. Examples of such compounds include polyfunctional (meth)acryloyl group-containing compounds having a molecular weight of less than 800, polyfunctional vinylaryl group-containing compounds having a molecular weight of less than 800, and polyfunctional allyl group-containing compounds having a molecular weight of less than 800.

[0155] A polyfunctional (meth)acryloyl group-containing compound having a molecular weight of less than 800 is a compound having two or more (meth)acryloyl groups. Examples of polyfunctional (meth)acryloyl group-containing compounds having a molecular weight of less than 800 include aliphatic (meth)acrylic acid ester compounds such as 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-nonanediol 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 Examples of the ether-containing (meth)acrylic acid ester compounds include ricol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)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, and propoxylated bisphenol A di(meth)acrylate; and 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.Examples of commercially available polyfunctional (meth)acryloyl group-containing compounds having a molecular weight of less than 800 include "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate) and "DCP" (tricyclodecane dimethanol dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., and "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd.

[0156] A polyfunctional vinylaryl group-containing compound having a molecular weight of less than 800 is a compound having two or more vinylaryl groups. Examples of polyfunctional vinylaryl group-containing compounds having a molecular weight of less than 800 include 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether.

[0157] A polyfunctional allyl group-containing compound having a molecular weight of less than 800 is a compound having two or more allyl groups. Examples of polyfunctional allyl group-containing compounds having a molecular weight of less than 800 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. Commercially available polyfunctional allyl group-containing compounds with a molecular weight of less than 800 include "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry 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., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) manufactured by Shikoku Chemical Industry Co., Ltd., "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd.

[0158] The radical polymerizable group equivalent of the component (E) in the second embodiment is preferably 30 g / eq. to 400 g / eq., more preferably 50 g / eq. to 300 g / eq., and even more preferably 75 g / eq. to 200 g / eq.

[0159] The molecular weight of the component (E) in the second embodiment is preferably 100-700, more preferably 200-400, and even more preferably 250-500.

[0160] In the third embodiment, the component (E) preferably includes a maleimide compound having a partial structure represented by formula (E-2). The maleimide compound refers to a compound containing at least one maleimide group (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl group) in one molecule. In the third embodiment, the number of maleimide groups in one molecule of the maleimide compound is preferably two or more, and particularly preferably two. [ka] In the formula, ring E represents a monocycloalkane ring which may have a substituent, or a monocycloalkene ring which may have a substituent; i and j each independently represent an integer of 0 or 1 or greater, and the sum of i and j is 6 or greater; and * represents a bonding site.

[0161] The monocycloalkane ring refers to a monocyclic aliphatic saturated hydrocarbon ring. The monocycloalkane ring is preferably a monocycloalkane ring having 4 to 14 carbon atoms, more preferably a monocycloalkane ring having 4 to 10 carbon atoms, and particularly preferably a monocycloalkane ring having 5 or 6 carbon atoms. Examples of the monocycloalkane ring include a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring. The monocycloalkene ring refers to a monocyclic aliphatic unsaturated hydrocarbon ring having at least one carbon-carbon double bond. The monocycloalkene ring is preferably a monocycloalkene ring having 4 to 14 carbon atoms, more preferably a monocycloalkene ring having 4 to 10 carbon atoms, and particularly preferably a monocycloalkene ring having 5 or 6 carbon atoms. Examples of the monocycloalkene ring include a cyclobutene ring, a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a cyclooctene ring, a cyclopentadiene ring, and a cyclohexadiene ring.

[0162] Examples of the substituents on the monocycloalkane ring and the monocycloalkene ring include the same as the substituents that may be carried on Y in formula (A-1).

[0163] Ring E represents a monocycloalkane ring which may have a substituent, or a monocycloalkene ring which may have a substituent. Ring E is preferably a monocycloalkane ring which may have a substituent selected from an alkyl group and an alkenyl group; or a monocycloalkene ring which may have a substituent selected from an alkyl group and an alkenyl group. Ring E is more preferably a monocycloalkane ring which may have a substituent selected from an alkyl group having 1 to 14 carbon atoms and an alkenyl group having 2 to 14 carbon atoms; or a monocycloalkene ring which may have a substituent selected from an alkyl group having 1 to 14 carbon atoms and an alkenyl group having 2 to 14 carbon atoms.

[0164] i and j each independently represent an integer of 0 or 1 or more, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are preferably each independently an integer of 0 to 20, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are more preferably each independently an integer of 1 to 20, and the sum of i and j is 6 or more (preferably 8 or more, more preferably 10 or more). i and j are further preferably each independently an integer of 5 to 10. i and j are particularly preferably 8.

[0165] In the third embodiment, the component (B) particularly preferably includes a maleimide compound represented by formula (E-3). [ka] In the formula, R 1 each independently represents a substituent; each ring F independently represents an aromatic ring which may have a substituent; D 1 and D 2 are each independently a single bond, -C(R x)2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-; R x each independently represents a hydrogen atom or an alkyl group; each e independently represents 0 or 1; each f independently represents an integer of 0 or 1 or greater; each g independently represents 0, 1, or 2; and m independently represents an integer of 0 or 1 or greater; and other symbols are as defined above. The f units, g units, and m units may be the same or different for each unit.

[0166] The aromatic ring refers to a ring that conforms to Hückel's rule, in which the number of electrons contained in the π-electron system on the ring is 4p+2 (p is a natural number). The aromatic ring may be an aromatic carbocyclic ring containing only carbon atoms as ring-constituting atoms, or an aromatic heterocyclic ring containing heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms in addition to carbon atoms as ring-constituting atoms. In one embodiment, the aromatic ring is preferably an aromatic carbocyclic ring. In one embodiment, 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. Specific examples of suitable aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. A benzene ring or a naphthalene ring is more preferred, and a benzene ring is particularly preferred.

[0167] R 1 The substituents in and the aromatic ring are the same as the substituents that Y in formula (A-1) may have.

[0168] Each ring F independently represents an aromatic ring which may have a substituent, and is preferably a benzene ring which may have a substituent selected from alkyl groups. 1 and D 2 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-. xare each independently a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group. e are each independently 0 or 1, preferably 0. f are each independently an integer of 0 or 1 or more, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2. g are each independently 0, 1 or 2, preferably 0. m are each independently an integer of 0 or 1 or more, preferably 0.

[0169] The partial structure represented by formula (E-4) contained in formula (E-3) is not particularly limited, and examples thereof include partial structures represented by formulas (Ea) to (Ec). [ka] In the formula, * represents a binding site, and other symbols are the same as above. [ka] In the formula, * represents a binding site.

[0170] The radical polymerizable group equivalent of the component (E) in the third embodiment is preferably 200 g / eq. to 2500 g / eq., more preferably 250 g / eq. to 2000 g / eq., and even more preferably 300 g / eq. to 1500 g / eq. The radical polymerizable group equivalent of the component (E) represents the mass of the resin per equivalent of the radical polymerizable group.

[0171] The weight average molecular weight of the component (E) in the third embodiment is preferably 400 to 100,000, more preferably 500 to 7,000, and particularly preferably 600 to 5,000.

[0172] Examples of commercially available products of the component (E) in the third embodiment include "BMI-689," "BMI-1500," "BMI-1700," and "BMI-3000J" manufactured by Designer Molecules Inc., and "SLK-6895-T90" manufactured by Shin-Etsu Chemical Co., Ltd.

[0173] In the fourth embodiment, the component (E) preferably includes a maleimide compound represented by formula (E-5). [ka] In the formula, R 2 each independently represents a hydrogen atom or an alkyl group; ring L, ring M, and ring N each independently represents an aromatic ring which may have a substituent; Z 1 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; s represents an integer of 1 or greater; each independently represents 0 or 1; and each independently represents 0, 1, 2, or 3. The s units and u units may be the same or different for each unit.

[0174] R 2 are each independently a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0175] Ring L, ring M, and ring N each independently represent an aromatic ring which may have a substituent, 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 particularly preferably an (unsubstituted) benzene ring.

[0176] Z 1 are each independently a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-, and preferably a single bond, -C(R z )2- or -O-, and more preferably a single bond or -C(R z )2-, and particularly preferably a single bond. zeach independently represents a hydrogen atom or an alkyl group, and is preferably a hydrogen atom or a methyl group.

[0177] s represents an integer of 1 or more, preferably an integer of 1 to 10. Each t independently represents 0 or 1, preferably 1. Each u independently represents 0, 1, 2, or 3, preferably 0, 1, or 2, more preferably 0 or 1, and particularly preferably 1.

[0178] The radical polymerizable group equivalent of the component (E) in the fourth embodiment is preferably 150 g / eq. to 1000 g / eq., and more preferably 200 g / eq. to 500 g / eq.

[0179] The weight average molecular weight of the component (E) in the fourth embodiment is preferably 100 to 10,000, more preferably 150 to 5,000, and particularly preferably 200 to 3,000.

[0180] Commercially available products of the component (E) in the fourth embodiment include, for example, "MIR-3000-70MT" and "MIR-5000-60T" manufactured by Nippon Kayaku Co., Ltd.

[0181] The component (E) may contain any one of the suitable thermoplastic resins in the first embodiment, the suitable compounds in the second embodiment, the suitable maleimide compounds in the third embodiment, and the suitable maleimide compounds in the fourth embodiment, alone, or may contain a combination of two or more of these in any ratio.

[0182] The radical polymerizable group equivalent of the component (E) is preferably 30 g / eq. to 2500 g / eq., and particularly preferably 75 g / eq. to 2000 g / eq.

[0183] The content of component (E) 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, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0184] The content of component (E), when the resin component in the resin composition layer is taken as 100% by mass, is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less.

[0185] When the content of the (E) component when the resin component in the resin composition layer is 100% by mass is e, and the content of the (A) component when the resin component in the resin composition layer is 100% by mass is a, e / a is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 0.8 or more, and is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less, 3 or less.

[0186] -(F)Thermoplastic resin- The resin composition layer may contain a thermoplastic resin (F) as the component (F). The thermoplastic resin (F) as the component (F) does not include those corresponding to the above-mentioned components (A) to (E). The component (F) may be used alone or in combination of two or more.

[0187] (F) Examples of thermoplastic resins include polyimide resins, phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins.

[0188] Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd.

[0189] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

[0190] Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "YX7200B35," "YL7500BH30," "YX6954BH30," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," and "YL7482" manufactured by Mitsubishi Chemical Corporation.

[0191] Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins being preferred. Specific examples of polyvinyl acetal resins include S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemical Co., Ltd.

[0192] Examples of polyolefin resins include ethylene copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0193] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxy group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0194] Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imides) manufactured by Resonac Corporation.

[0195] A specific example of the polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0196] Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers. A specific example of the polyphenylene ether resin is NORYL SA90 manufactured by SABIC, etc. A specific example of the polyetherimide resin is ULTEM manufactured by GE, etc.

[0197] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, Inc., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd. Specific examples of polyether ether ketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

[0198] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

[0199] The weight average molecular weight (Mw) of the (F) thermoplastic resin is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and particularly preferably 50,000 or less.

[0200] The content of the (F) thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1.5% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0201] The content of the (F) thermoplastic resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less, when the resin component in the resin composition layer is taken as 100% by mass.

[0202] -(G) Stress relief material- The resin composition layer may contain a (G) stress relaxation material as the (G) component. The (G) stress relaxation material as the (G) component does not include those corresponding to the above-mentioned (A) to (F). The (G) component may be used alone or in combination of two or more.

[0203] The (G) stress relief material refers to a flexible resin, and may be a particulate resin component (particulate stress relief material) that maintains a particle shape in the resin composition layer, or a non-particulate resin component (non-particulate stress relief material) that tends to be mixed or dissolved in the resin composition layer. Only one or both of these may be included, and the resin components that form them may be resins that themselves exhibit rubber elasticity, or resins that exhibit rubber elasticity by reacting with other components. Examples of resins that exhibit rubber elasticity include resins that exhibit an elastic modulus of 1 GPa or less when subjected to a tensile test in accordance with Japanese Industrial Standards (JIS K7161) at a temperature of 25°C and a humidity of 40% RH.

[0204] The particulate stress relief material is preferably spherical. The particulate stress relief material may be hollow particles having voids inside the particles, or may be non-hollow particles having no voids inside the particles. The hollow particles may be monohollow particles having only one void inside the particles, or polyhollow particles having multiple voids inside the particles.

[0205] The particulate stress relief material is, for example, rubber particles containing a rubber component, and is preferably a rubber particle containing, as the rubber component, a silicone-based elastomer such as polydimethylsiloxane; an olefin-based thermoplastic elastomer 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-butadiene terpolymer, or ethylene-propylene-butene terpolymer; or an acrylic-based thermoplastic elastomer such as polypropyl(meth)acrylate, polybutyl(meth)acrylate, polycyclohexyl(meth)acrylate, or polyoctyl(meth)acrylate. Furthermore, a silicone-based rubber such as polyorganosiloxane rubber may be mixed with 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.

[0206] The particulate stress relief material preferably comprises core-shell rubber particles. The core-shell rubber particles are particulate stress relief materials consisting of a core particle containing a rubber component as described above and one or more shell layers covering the core particle. Furthermore, the core-shell rubber particles are preferably core-shell graft copolymer rubber particles consisting of a core particle containing a rubber component as described above and a shell formed by graft copolymerization of a monomer component copolymerizable with the rubber component contained in the core particle. The term "core-shell" as used herein does not necessarily refer only to particles in which the core particle and the shell portion are clearly distinguishable, but also includes particles 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 by the shell portion.

[0207] The rubber component is preferably contained in the core-shell rubber particles in an amount of 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. The upper limit of the rubber component content in the core-shell rubber particles is not particularly limited, but from the viewpoint of sufficiently covering the core particles with the shell portion, it is preferably 95% by mass or less, for example, 90% by mass or less.

[0208] The monomer components forming the shell of the core-shell rubber particles include, for example, (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, and glycidyl (meth)acrylate; (meth)acrylic acid; N-substituted maleimides such as N-methylmaleimide and N-phenylmaleimide; maleimide; α,β-unsaturated carboxylic acids such as maleic acid and itaconic acid; aromatic vinyl compounds such as styrene, 4-vinyltoluene, and α-methylstyrene; and (meth)acrylonitrile. Among these, (meth)acrylic acid esters are preferred, and methyl (meth)acrylate is more preferred. Note that "(meth)acrylic acid" refers to methacrylic acid or acrylic acid.

[0209] Commercially available core-shell type rubber particles include, for example, "CHT" manufactured by Samsung SDI; "B602" manufactured by Techno UMG; and "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 KM-336P" manufactured by Dow Chemical Japan. Examples include "Laroid KCZ-201", "Metablen C-223A", "Metablen E-901", "Metablen S-2001", "Metablen W-450A", and "Metablen SRK-200" manufactured by Mitsubishi Rayon Co., Ltd., "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 "AC3401N" and "AC3816N" manufactured by Ganz Chemical Co., Ltd.

[0210] The average particle size (average primary particle size) of the particulate stress relief material is not particularly limited, but is preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more. The upper limit of the average particle size (average primary particle size) of the particulate stress relief material is not particularly limited, but is preferably 10,000 nm or less, more preferably 5,000 nm or less, and even more preferably 1,000 nm or less. The average particle size (average primary particle size) of the particulate stress relief material can be measured using a zeta potential particle size distribution measuring device or the like.

[0211] The non-particulate stress relief material preferably contains a resin having one or more structures selected from a polybutadiene structure, a polysiloxane structure, a poly(meth)acrylate structure, a polyalkylene structure, a polyalkyleneoxy structure, a polyisoprene structure, a polyisobutylene structure, and a polycarbonate structure in its molecule, more preferably a resin having one or more structures selected from a polybutadiene structure and a polycarbonate structure, and particularly preferably a resin having a polybutadiene structure and a phenolic hydroxyl group (phenolic hydroxyl group-containing polybutadiene resin) or a resin having a polycarbonate structure (polycarbonate resin). Note that "(meth)acrylate" refers to methacrylate and acrylate.

[0212] The polybutadiene structure includes not only a structure formed by polymerizing butadiene but also a structure formed by hydrogenating the structure. The polybutadiene structure may be partially or entirely hydrogenated. Furthermore, the polybutadiene structure may be contained in the main chain or side chain of the stress relaxation material molecule.

[0213] Preferred examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, and urethane group-containing polybutadiene resins. Among these, phenolic hydroxyl group-containing polybutadiene resins and epoxy group-containing polybutadiene resins are more preferred, and phenolic hydroxyl group-containing polybutadiene resins are particularly preferred. Here, "hydrogenated polybutadiene skeleton-containing resin" refers to a resin in which at least a portion of the polybutadiene skeleton is hydrogenated, and does not necessarily have to be a resin in which the polybutadiene skeleton is completely hydrogenated. Examples of hydrogenated polybutadiene skeleton-containing resins include hydrogenated polybutadiene skeleton-containing epoxy resins. Examples of preferred phenolic hydroxyl group-containing polybutadiene resins include those made from hydroxyl group-terminated polybutadiene, diisocyanate compounds, and phenolic hydroxyl group-containing resins. Here, the hydroxyl group-terminated polybutadiene and diisocyanate compounds are the same as those exemplified below. Examples of phenolic hydroxyl group-containing resins include cresol novolac resins.

[0214] Specific examples of polybutadiene resins include "PB-3600" (epoxy group-containing polybutadiene) manufactured by Daicel Corporation, "JP-100" and "JP-200" (epoxy group-containing polybutadiene) manufactured by Nippon Soda Co., Ltd., and "Ricon 657" (epoxy group-containing polybutadiene), "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", and "Ricon Examples include "184MA6" (polybutadiene containing an acid anhydride group), "GQ-1000" (polybutadiene with introduced hydroxyl and carboxyl groups), "G-1000", "G-2000", and "G-3000" (polybutadiene with hydroxyl groups at both ends) manufactured by Nippon Soda Co., Ltd., "GI-1000", "GI-2000", and "GI-3000" (hydrogenated polybutadiene with hydroxyl groups at both ends) manufactured by Daicel Corporation, "PB3600" and "PB4700" (polybutadiene-based epoxy compounds), "Epofriend A1005", "Epofriend A1010", and "Epofriend A1020" (epoxy compounds of styrene, butadiene, and styrene block copolymers), and "FCA-061L" (hydrogenated polybutadiene-based epoxy compound) and "R-45EPT" (polybutadiene-based epoxy compound) manufactured by Nagase ChemteX Corporation.

[0215] Further, examples of preferred polybutadiene resins include linear polyimides (such as those described in JP 2006-37083 A and WO 2008 / 153208 A) made from hydroxyl-terminated polybutadiene, diisocyanate compounds, and polybasic acids or their anhydrides. The polyimide resin preferably has a polybutadiene structure content of 60% to 95% by mass, more preferably 75% to 85% by mass. For details of the polyimide resin, please refer to the descriptions in JP 2006-37083 A and WO 2008 / 153208 A, the contents of which are incorporated herein by reference.

[0216] The number average molecular weight of the hydroxyl group-terminated polybutadiene is preferably 500 to 5,000, more preferably 800 to 3,500. The hydroxyl group equivalent of the hydroxyl group-terminated polybutadiene is preferably 250 to 5,000 g / eq., more preferably 1,000 to 3,000 g / eq.

[0217] Examples of diisocyanate compounds include aromatic diisocyanates such as toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylylene diisocyanate, and diphenylmethane diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate; and alicyclic diisocyanates such as isophorone diisocyanate. Among these, aromatic diisocyanates are preferred, and toluene-2,4-diisocyanate is more preferred.

[0218] Examples of polybasic acids or anhydrides thereof include tetrabasic acids such as ethylene glycol bistrimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, biphenyl tetracarboxylic acid, naphthalene tetracarboxylic acid, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-cyclohexene-1,2-dicarboxylic acid, and 3,3'-4,4'-diphenylsulfone tetracarboxylic acid, and their anhydrides; tribasic acids such as trimellitic acid and cyclohexane tricarboxylic acid, and their anhydrides; and 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho(1,2-C)furan-1,3-dione.

[0219] The polybutadiene resin may also contain a polystyrene structure obtained by polymerizing styrene.

[0220] Specific examples of polystyrene resins, which are resins having a polystyrene structure in the molecule, include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butylene-styrene block copolymer (SBBS), styrene-butadiene diblock copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer, and hydrogenated styrene-butadiene random copolymer.

[0221] Commercially available polystyrene resins may be used, including hydrogenated styrene-based thermoplastic elastomers "H1041," "Tuftec H1043," "Tuftec P2000," and "Tuftec MP10" (manufactured by Asahi Kasei Corporation); epoxidized styrene-butadiene thermoplastic elastomers "Epofriend AT501" and "CT310" (manufactured by Daicel Corporation); modified styrene-based elastomer having hydroxyl groups "Septon HG252" (manufactured by Kuraray Co., Ltd.); modified styrene-based elastomer having carboxyl groups "Tuftec N503M," modified styrene-based elastomer having amino groups "Tuftec N501," modified styrene-based elastomer having acid anhydride groups "Tuftec M1913" (manufactured by Asahi Kasei Corporation); and unmodified styrene-based elastomer "Septon S8104" (manufactured by Kuraray Co., Ltd.). Component (C) may be used alone or in combination of two or more.

[0222] The polysiloxane structure is a structure containing a siloxane bond, and is contained in, for example, silicone rubber. The polysiloxane structure may be contained in the main chain or the side chain of the stress relaxation material molecule.

[0223] Specific examples of polysiloxane resins, which are resins having a polysiloxane structure in the molecule, include "SMP-2006," "SMP-2003PGMEA," and "SMP-5005PGMEA" manufactured by Shin-Etsu Silicones Co., Ltd., amine-terminated polysiloxanes, and linear polyimides made from tetrabasic acid anhydrides (WO 2010 / 053185).

[0224] The poly(meth)acrylate structure is a structure formed by polymerizing acrylic acid or an acrylic acid ester, and also includes a structure formed by polymerizing methacrylic acid or a methacrylic acid ester. The (meth)acrylate structure may be contained in the main chain or in the side chain of the stress relaxation material molecule.

[0225] Preferred examples of poly(meth)acrylate resins, which are resins having a poly(meth)acrylate structure in the molecule, include hydroxy group-containing poly(meth)acrylate resins, phenolic hydroxy group-containing poly(meth)acrylate resins, carboxy group-containing poly(meth)acrylate resins, acid anhydride group-containing poly(meth)acrylate resins, epoxy group-containing poly(meth)acrylate resins, isocyanate group-containing poly(meth)acrylate resins, and urethane group-containing poly(meth)acrylate resins.

[0226] Specific examples of poly(meth)acrylate resins include Nagase ChemteX's Teisan Resin "SG-70L," "SG-708-6," "WS-023," "SG-700AS," and "SG-280TEA" (carboxyl group-containing acrylic ester copolymer resin, acid value 5 to 34 mgKOH / g, weight average molecular weight 400,000 to 900,000, Tg -30°C to 5°C), "SG-80H," "SG-80H-3," and "SG-P3" (epoxy group-containing acrylic ester copolymer resin, epoxy equivalent 4761 to 14285 g / eq, weight average molecular weight 350,000). Examples include "SG-600TEA" and "SG-790" (hydroxy group-containing acrylic ester copolymer resin, hydroxyl value 20-40 mgKOH / g, weight average molecular weight 500,000-1,200,000, Tg -37°C to -32°C) manufactured by Negami Chemical Industrial Co., Ltd., as well as "ME-2000" and "W-116.3" (carboxy group-containing acrylic ester copolymer resin), "W-197C" (hydroxy group-containing acrylic ester copolymer resin), "KG-25" and "KG-3000" (epoxy group-containing acrylic ester copolymer resin).

[0227] The polyalkylene structure preferably has a predetermined number of carbon atoms. The specific number of carbon atoms in the polyalkylene structure is preferably 2 or more, more preferably 3 or more, particularly preferably 5 or more, and preferably 15 or less, more preferably 10 or less, particularly preferably 6 or less. The polyalkylene structure may be contained in the main chain or side chain of the stress relaxation material molecule.

[0228] The polyalkyleneoxy structure preferably has a predetermined number of carbon atoms. The specific number of carbon atoms in the polyalkyleneoxy structure is preferably 2 or more, preferably 3 or more, more preferably 5 or more, and preferably 15 or less, more preferably 10 or less, and particularly preferably 6 or less. The polyalkyleneoxy structure may be contained in the main chain or side chain of the stress relaxation material molecule.

[0229] Specific examples of polyalkylene resins, which are resins having a polyalkylene structure in the molecule, and polyalkyleneoxy resins, which are resins having a polyalkyleneoxy structure in the molecule, include "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers Corporation, "YX-7180" (a resin containing an alkylene structure with an ether bond) manufactured by Mitsubishi Chemical Corporation, "EXA-4850-150," "EXA-4816," and "EXA-4822" manufactured by DIC Corporation, "EP-4000," "EP-4003," "EP-4010," and "EP-4011" manufactured by ADEKA Corporation, "BEO-60E" and "BPO-20E" manufactured by New Japan Chemical Co., Ltd., and "YL7175" and "YL7410" manufactured by Mitsubishi Chemical Corporation.

[0230] The polyisoprene structure may be contained in the main chain or side chain of the stress relaxation material molecule. Specific examples of polyisoprene resins that have a polyisoprene structure in the molecule include "KL-610" and "KL-613" manufactured by Kuraray Co., Ltd.

[0231] The polyisobutylene structure may be contained in the main chain or in a side chain of the stress relaxation material molecule. Specific examples of polyisobutylene resins, which are resins having a polyisobutylene structure in the molecule, include "SIBSTAR-073T" (styrene-isobutylene-styrene triblock copolymer) and "SIBSTAR-042D" (styrene-isobutylene diblock copolymer), both manufactured by Kaneka Corporation.

[0232] The polycarbonate structure may be contained in the main chain or in the side chain of the molecule of the stress relaxation material.

[0233] Preferred examples of polycarbonate resins, which are resins having a polycarbonate structure in the molecule, include hydroxy group-containing polycarbonate resins, phenolic hydroxy group-containing polycarbonate resins, carboxy group-containing polycarbonate resins, acid anhydride group-containing polycarbonate resins, epoxy group-containing polycarbonate resins, isocyanate group-containing polycarbonate resins, and urethane group-containing polycarbonate resins.

[0234] Specific examples of polycarbonate resins include "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Corporation, and "C-1090", "C-2090", and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd.

[0235] Preferred examples of polycarbonate resins include linear polyimides made from hydroxyl-terminated polycarbonates, diisocyanate compounds, and polybasic acids or their anhydrides. The linear polyimides have a urethane structure and a polycarbonate structure. The polycarbonate structure content of the polyimide resin is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. For details of the polyimide resin, please refer to the description in International Publication No. 2016 / 129541, the contents of which are incorporated herein by reference.

[0236] The number average molecular weight of the hydroxyl group-terminated polycarbonate is preferably 500 to 5,000, more preferably 1,000 to 3,000. The hydroxyl group equivalent of the hydroxyl group-terminated polycarbonate is preferably 250 to 1,250.

[0237] The non-particulate stress relief material preferably further has an imide structure, which can increase the heat resistance of the non-particulate stress relief material and effectively increase the crack resistance.

[0238] The chemical structure of the non-particulate stress relaxation material may be any of a linear, branched, and cyclic structure, but is preferably a linear structure.

[0239] The non-particulate stress relief material preferably further has a functional group capable of reacting with the epoxy resin. This functional group includes a reactive group that appears upon heating. The non-particulate stress relief material having the functional group can improve the mechanical strength of the cured resin composition.

[0240] Examples of the functional group include a carboxy group, a hydroxy group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group. Among these, from the viewpoint of significantly achieving the effects of the present invention, the functional group preferably has one or more functional groups selected from a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group, and a phenolic hydroxyl group is particularly preferred.

[0241] The non-particulate stress relaxation material may be used alone or in combination of two or more kinds.

[0242] The specific number average molecular weight Mn of the non-particulate stress relief material is preferably 500 or more, more preferably 800 or more, even more preferably 1,000 or more, particularly preferably 1,200 or more, and is preferably 100,000 or less, more preferably 50,000 or less, particularly preferably 10,000 or less. The number average molecular weight Mn of the non-particulate stress relief material is the number average molecular weight in terms of polystyrene measured using GPC (gel permeation chromatography).

[0243] When the non-particulate stress relief material has functional groups, the functional group equivalent of the non-particulate stress relief material is preferably 100 g / eq. or more, more preferably 200 g / eq. or more, even more preferably 1,000 g / eq. or more, particularly preferably 2,500 g / eq. or more, and preferably 50,000 g / eq. or less, more preferably 30,000 g / eq. or less, even more preferably 10,000 g / eq. or less, particularly preferably 5,000 g / eq. or less. The functional group equivalent is the number of grams of resin containing 1 gram equivalent of functional groups. For example, the epoxy group equivalent can be measured according to JIS K7236. Furthermore, for example, the hydroxyl group equivalent can be calculated by dividing the molecular weight of KOH by the hydroxyl value measured according to JIS K1557-1.

[0244] The glass transition temperature (Tg) of the (G) stress relaxation material is preferably 20°C or lower, more preferably 10°C or lower, and even more preferably 0°C or lower.

[0245] The content of the (G) stress relaxation material is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1.5% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0246] The content of the (G) stress relaxation material is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, and is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less, when the resin component in the resin composition layer is taken as 100% by mass.

[0247] -(H) Radical polymerization initiator- The resin composition layer may contain a (H) radical polymerization initiator as component (H). The (H) radical polymerization initiator as component (H) does not include those corresponding to the above-mentioned components (A) to (G). The (H) radical polymerization initiator may be, for example, a thermal polymerization initiator that generates free radicals upon heating. The (H) radical polymerization initiator may be a polymerization initiator for the radically polymerizable groups contained in components (A) and (E). One type of (H) radical polymerization initiator may be used alone, or two or more types may be used in any combination.

[0248] (H) Examples of the radical polymerization initiator include peroxide radical polymerization initiators, azo radical polymerization initiators, etc. Among these, peroxide radical polymerization initiators are preferred.

[0249] Examples of the peroxide radical polymerization initiator include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkyl peroxide compounds such as tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and diacyl peroxide compounds such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl)peroxydicarbonate. peroxyester compounds such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyneodecanoate, tert-hexylperoxyisopropyl monocarbonate, tert-butyl peroxylaurate, (1,1-dimethylpropyl) 2-ethylperhexanoate, tert-butyl 2-ethylperhexanoate, tert-butyl 3,5,5-trimethylperhexanoate, tert-butylperoxy-2-ethylhexyl monocarbonate, and tert-butylperoxymaleic acid; and the like.

[0250] Examples of the azo radical polymerization initiator include azonitrile compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, and 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile; 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], and 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide]. azoamide compounds such as 2,2'-azobis[2-methyl-N-[2-(1-hydroxybutyl)]-propionamide], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(2-methylpropionamide) dihydrate, 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide); alkyl azo compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 2,2'-azobis(2-methylpropane); and the like.

[0251] (H) Commercially available radical polymerization initiators include, for example, "Perbutyl C," "Perbutyl A," "Perbutyl P," "Perbutyl L," "Perbutyl O," "Perbutyl ND," "Perbutyl Z," "Perbutyl I," "Percumyl P," "Percumyl D," "Perhexyl D," "Perhexyl A," "Perhexyl I," "Perhexyl Z," "Perhexyl ND," "Perhexyl O," and "Perhexyl PV," all manufactured by NOF Corporation.

[0252] The content of the (H) radical polymerization initiator is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and is preferably 1.5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0253] The content of the (H) radical polymerization initiator is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, when the resin component in the resin composition layer is taken as 100% by mass, and is preferably 3% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less.

[0254] -(I) Curing accelerator- The resin composition layer may contain a curing accelerator (I) as component (I). This curing accelerator (I) as component (I) does not include those corresponding to the above-mentioned components (A) to (H). The curing accelerator (I) functions as a curing catalyst that accelerates the curing of the epoxy resin in component (C).

[0255] As the (I) curing accelerator, a compound that accelerates the curing of the epoxy resin can be used. Examples of such (I) curing accelerators include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. One type of (I) curing accelerator may be used alone, or two or more types may be used in combination.

[0256] 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;

[0257] 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].

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] The content of the (I) curing accelerator is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, or 0.05% by mass or more, and is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, 2% by mass or less, 1% by mass or less, or 0.5% by mass or less, based on 100% by mass of the non-volatile components in the resin composition layer.

[0263] The content of (I) the curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, and is preferably 10% by mass or less, more preferably 9% by mass or less, and even more preferably 5% by mass or less, 3% by mass or less, or 1% by mass or less, when the resin component in the resin composition layer is 100% by mass.

[0264] -(J) Other additives- The resin composition layer may contain (J) other additives as an optional non-volatile component. Examples of (J) other additives 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 silane; triazole-based adhesion promoters, tetrazole-based adhesion promoters, triazole-based adhesion promoters, and triazole-based adhesion promoters. Examples of the additives include adhesion promoters such as vinyl-based adhesion promoters; antioxidants such as hindered phenol-based antioxidants; fluorescent brighteners such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers; photopolymerization initiator aids such as tertiary amines; photosensitizers such as pyrarizones, anthracenes, coumarins, xanthones, and thioxanthones; antioxidants; and flame retardants (excluding those corresponding to component (B)). (J) Other additives may be used alone or in combination of two or more.

[0265] -(K) Solvent- The resin composition layer may further contain a (K) solvent as an optional volatile component in addition to the nonvolatile components (A) to (J) described above. An organic solvent is typically used as the (K) 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. The (K) solvent may be used singly or in combination of two or more.

[0266] The amount of (K) solvent is not particularly limited, but may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or even 0% by mass, relative to 100% by mass of all components of the resin composition layer.

[0267] The thickness of the resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 55 μm or less, from the viewpoint of reducing the thickness of the printed wiring board and providing a cured product with excellent insulating properties even when the cured product of the resin composition layer is thin. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 5 μm or more, 10 μm or more, etc.

[0268] <Protective film> The resin sheet may optionally include a protective film conforming to the support as another layer. The protective film is provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). By laminating the protective film on the resin sheet, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed.

[0269] Examples of the protective film include films made of plastic materials, metal foils, and release papers, with films made of plastic materials and metal foils being preferred.

[0270] When a film made of a plastic material is used as the protective film, 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.

[0271] When a metal foil is used as the protective film, 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.).

[0272] The surface of the protective film that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

[0273] The protective film may also be a protective film with a release layer, which has a release layer on the surface that bonds to the resin composition layer. Examples of the release agent used in the release layer of the protective film with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available protective films with a release layer may be used, including, for example, "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation, "Lumirror T60," "Lumirror R80," and "Lumirror" manufactured by Toray Industries, Inc., "Purex" manufactured by Teijin Limited, and "Uni-Peel" manufactured by Unitika Limited, which are PET films having a release layer primarily composed of an alkyd resin-based release agent.

[0274] The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film has a multi-layer structure such as a protective film with a release layer, it is preferable that the thickness of the entire protective film is in this range.

[0275] <Method of manufacturing resin sheet> The resin sheet can be produced, for example, by preparing a resin varnish by dissolving the components contained in the resin composition layer in a solvent, applying this resin varnish to a support using a die coater or the like, and then drying it to form a resin composition layer.

[0276] The solvent may be the same as the solvent explained as a component of the resin composition layer, and one type of solvent may be used alone, or two or more types may be used in combination.

[0277] Drying may be carried out by heating, blowing hot air, or the like. Drying conditions are not particularly limited, but drying is usually carried out so that the solvent content in the resin composition layer becomes 10% by mass or less, preferably 5% by mass or less. Although this varies depending on the boiling point of the solvent in the resin composition, 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.

[0278] The resin sheet can be stored in a rolled state. When the resin sheet has a protective film, it can usually be used by peeling off the protective film.

[0279] <Physical properties of resin sheet> By curing the resin composition layer, an insulating layer formed of the cured resin composition layer can be obtained. When via holes are formed in this insulating layer and the layer is subjected to a roughening treatment, the haloing phenomenon can be suppressed. These effects will be described below with reference to the drawings.

[0280] 1 is a cross-sectional view schematically showing an insulating layer 100 obtained by curing a resin composition layer of a resin sheet of the present invention, together with an inner layer substrate 200. In this Fig. 1, a cross section of the insulating layer 100 is shown cut along a plane that passes through the center 120C of the bottom 120 of the via hole 110 and is parallel to the thickness direction of the insulating layer 100.

[0281] As shown in FIG. 1 , the insulating layer 100 is a layer obtained by curing a resin composition layer formed on an inner layer substrate 200 including a conductor layer 210, and is made of a cured product of the resin composition layer. The insulating layer 100 also has a via hole 110 formed therein. The via hole 110 is generally formed in a forward tapered shape, with the diameter increasing toward the surface 100U of the insulating layer 100 opposite the conductor layer 210 and decreasing toward the conductor layer 210, and ideally formed in a columnar shape with a constant diameter in the thickness direction of the insulating layer 100. The via hole 110 is usually formed by irradiating the surface 100U of the insulating layer 100 opposite the conductor layer 210 with laser light to remove a portion of the insulating layer 100.

[0282] The bottom of the via hole 110 on the conductor layer 210 side is referred to as the "via bottom" as appropriate and is indicated by the reference numeral 120. The diameter of this via bottom 120 is referred to as the bottom diameter Lb. The opening formed on the opposite side of the via hole 110 from the conductor layer 210 is referred to as the "via top" as appropriate and is indicated by the reference numeral 130. The diameter of this via top 130 is referred to as the top diameter Lt. Usually, the via bottom 120 and the via top 130 are formed so that their planar shapes are circular when viewed from the thickness direction of the insulating layer 100, but they may also be elliptical. When the planar shapes of the via bottom 120 and the via top 130 are elliptical, the bottom diameter Lb and the top diameter Lt respectively represent the major axes of the elliptical shapes.

[0283] In this case, the closer to 100% the taper ratio Lb / Lt (%) obtained by dividing the bottom diameter Lb by the top diameter Lt is, the better the shape of the via hole 110. By using the resin composition layer of the present invention, it is possible to easily control the shape of the via hole 110, and therefore it is possible to realize a via hole 110 with a taper ratio Lb / Lt close to 100%.

[0284] For example, when an insulating layer 100 is obtained by heating a resin composition layer at 100°C for 30 minutes and then curing it at 180°C for 30 minutes, and then irradiating the insulating layer 100 with CO2 laser light under the conditions of a mask diameter of 2.0 mm, a pulse width of 6 μsec, an energy (output) of 4 W / shot, a shot count of 2, and burst mode (2 kHz), to form a via hole 110 with a top diameter Lt of approximately 50 μm, the taper ratio Lb / Lt of the via hole 110 can be preferably 75% to 100%, more preferably 80% to 100%, and particularly preferably 85% to 100%.

[0285] The taper ratio Lb / Lt of the via hole 110 can be calculated from the bottom diameter Lb and top diameter Lt of the via hole 110. The bottom diameter Lb and top diameter Lt of the via hole 110 can be measured by using a focused ion beam (FIB) to cut out the insulating layer 100 so as to reveal a cross section that is parallel to the thickness direction of the insulating layer 100 and passes through the center 120C of the via bottom 120, and then observing the cross section with an electron microscope.

[0286] Figure 2 is a plan view schematically showing the surface 100U of the insulating layer 100 obtained by curing the resin composition in the first embodiment of the present invention into a sheet form, opposite the conductor layer 210 (not shown in Figure 2).

[0287] 2, when observing an insulating layer 100 having a via hole 110 formed therein, a discolored area 140, where the insulating layer 100 has discolored, may be observed around the via hole 110. This discolored area 140 can be formed by resin deterioration during the formation of the via hole 110, and is usually formed continuously from the via hole 110. In many cases, the discolored area 140 is a whitened area.

[0288] 3 is a cross-sectional view schematically showing a roughening-treated insulating layer 100 obtained by curing the resin composition layer of the resin sheet of the present invention, together with an inner layer substrate 200. This Fig. 3 shows a cross section of the insulating layer 100 cut along a plane that passes through the center 120C of the via bottom 120 of the via hole 110 and is parallel to the thickness direction of the insulating layer 100.

[0289] 3, when a roughening treatment is performed on the insulating layer 100 in which the via hole 110 is formed, a haloing phenomenon occurs, and the insulating layer 100 in the discolored portion 140 peels off from the conductor layer 210, and a gap 160 may be formed that continues from the edge 150 of the via bottom 120. This gap 160 is usually formed by erosion of the discolored portion 140 during the roughening treatment.

[0290] In the present invention, the resin composition layer contains components (A) to (C), which can suppress the haloing phenomenon, thereby preventing the insulating layer 100 from peeling off from the conductor layer 210, thereby reducing the size of the gap 160.

[0291] The edge 150 of the via bottom 120 corresponds to the inner peripheral edge of the gap 160. Therefore, the distance Wb from the edge 150 of the via bottom 120 to the outer peripheral end 170 of the gap 160 (i.e., the end farther from the center 120C of the via bottom 120) corresponds to the in-plane size of the gap 160. Here, the in-plane direction refers to the direction perpendicular to the thickness direction of the insulating layer 100. In the following description, the distance Wb may be referred to as the halo distance Wb of the via hole 110 from the edge 150 of the via bottom 120. The halo distance Wb from the edge 150 of the via bottom 120 can be used to evaluate the degree of suppression of the halo phenomenon. Specifically, it can be evaluated that the smaller the halo distance Wb from the edge 150 of the via bottom 120, the more effectively the halo phenomenon can be suppressed.

[0292] For example, a resin composition layer is heated at 100°C for 30 minutes, then heated at 180°C for 30 minutes to harden, and the resulting insulating layer 100 is irradiated with CO2 laser light under the following conditions: mask diameter 2.0 mm, pulse width 6 μsec, energy 4 W / shot, shot count 2, burst mode (2 kHz) to form via holes 110 with a top diameter Lt of approximately 50 μm. The resulting insulating layer 100 is then immersed in a swelling solution at 60°C for 10 minutes, then immersed in an oxidizing agent solution at 80°C for 20 minutes, then immersed in a neutralizing solution at 40°C for 5 minutes, and then dried at 80°C for 15 minutes.

[0293] The halo distance Wb from the edge 150 of the via bottom 120 can be measured by using a FIB (focused ion beam) to remove the insulating layer 100 so as to reveal a cross section that is parallel to the thickness direction of the insulating layer 100 and passes through the center 120C of the via bottom 120, and then observing the cross section with an electron microscope.

[0294] Furthermore, by using the resin composition layer in the resin sheet of the present invention, the shape of the via hole 110 in the insulating layer 100 before the roughening treatment can be easily controlled, and therefore, it is usually possible to easily control the shape of the via hole 110 in the insulating layer 100 after the roughening treatment. Therefore, even after the roughening treatment, the shape of the via hole 110 can be made as good as before the roughening treatment. Therefore, by using the resin composition layer in the resin sheet of the present invention, it is possible to realize a via hole 110 with a taper ratio Lb / Lt of nearly 100% in the insulating layer after the roughening treatment.

[0295] For example, a resin composition layer is heated at 100°C for 30 minutes, then heated at 180°C for 30 minutes to cure the resulting insulating layer 100. The resulting insulating layer 100 is then irradiated with CO2 laser light under the following conditions: mask diameter 2.0 mm, pulse width 6 μsec, energy 4 W / shot, shot count 2, burst mode (2 kHz) to form a via hole 110 with a top diameter Lt of approximately 50 μm. The resulting insulating layer 100 is then immersed in a swelling solution at 60°C for 10 minutes, then immersed in an oxidizing agent solution at 80°C for 20 minutes, then immersed in a neutralizing solution at 40°C for 5 minutes, and then dried at 80°C for 15 minutes. By using the resin composition of the present invention, the taper ratio Lb / Lt of the via hole 110 formed in the insulating layer 100 thus obtained can be preferably 76% to 100%, more preferably 80% to 100%, and particularly preferably 85% to 100%.

[0296] The taper ratio Lb / Lt of the via hole 110 can be calculated from the bottom diameter Lb and top diameter Lt of the via hole 110. The bottom diameter Lb and top diameter Lt of the via hole 110 can be measured by using a focused ion beam (FIB) to cut out the insulating layer 100 so as to reveal a cross section that is parallel to the thickness direction of the insulating layer 100 and passes through the center 120C of the via bottom 120, and then observing the cross section with an electron microscope.

[0297] Furthermore, by using the resin sheet of the present invention, it is possible to suppress the formation of discolored portion 140 during the formation of via hole 110. Therefore, as shown in Fig. 2, the size of discolored portion 140 can be reduced, and ideally, discolored portion 140 can be eliminated. The size of discolored portion 140 can be evaluated by the halo distance Wt from edge 180 of via top 130 of via hole 110.

[0298] The edge 180 of the via top 130 corresponds to the inner peripheral edge of the discoloration portion 140. The halo distance Wt from the edge 180 of the via top 130 represents the distance from the edge 180 of the via top 130 to the outer peripheral edge 190 of the discoloration portion 140. It can be evaluated that the smaller the halo distance Wt from the edge 180 of the via top 130, the more effectively the formation of the discoloration portion 140 can be suppressed.

[0299] The halo distance Wt from the edge 180 of the via top 130 can be measured by observation with an optical microscope.

[0300] Furthermore, according to the inventor's research, it has been found that, in general, the larger the diameter of the via hole 110, the larger the size of the discolored portion 140 tends to be. Therefore, the degree of suppression of the formation of the discolored portion 140 can be evaluated by the ratio of the size of the discolored portion 140 to the diameter of the via hole 110. For example, the evaluation can be performed by the halo ratio Ht to the top radius Lt / 2 of the via hole 110. Here, the top radius Lt / 2 of the via hole 110 refers to the radius of the via top 130 of the via hole 110. The halo ratio Ht to the top radius Lt / 2 of the via hole 110 is the ratio obtained by dividing the halo distance Wt from the edge 180 of the via top 130 by the top radius Lt / 2 of the via hole 110. A smaller halo ratio Ht to the top radius Lt / 2 of the via hole 110 indicates that the formation of the discolored portion 140 is more effectively suppressed.

[0301] For example, when an insulating layer 100 is obtained by heating a resin composition layer at 100°C for 30 minutes and then curing it at 180°C for 30 minutes, and then irradiating the resulting insulating layer 100 with CO2 laser light under the conditions of a mask diameter of 2.0 mm, a pulse width of 6 μsec, an energy of 4 W / shot, 2 shots, and burst mode (2 kHz), to form a via hole 110 with a top diameter Lt of approximately 50 μm, the haloing ratio Ht of the via hole 110 to the top radius Lt / 2 can be preferably 70% or less, more preferably 50% or less, and even more preferably 35% or less.

[0302] The halo ratio Ht to the top radius Lt / 2 of the via hole 110 can be calculated from the top diameter Lt of the via hole 110 and the halo distance Wt from the edge 180 of the via top 130 of the via hole 110.

[0303] During the manufacturing process of a semiconductor chip package substrate, the via hole 110 is typically formed without another conductor layer (not shown) being provided on the surface 100U of the insulating layer 100 opposite the conductor layer 210. Therefore, if the manufacturing process of the semiconductor chip package substrate is understood, it is possible to clearly recognize the structure in which the via bottom 120 is located on the conductor layer 210 side and the via top 130 opens on the opposite side of the conductor layer 210. However, in a completed semiconductor chip package substrate, conductor layers may be provided on both sides of the insulating layer 100. In this case, it may be difficult to distinguish the via bottom 120 from the via top 130 due to their positional relationship with the conductor layers. However, typically, the top diameter Lt of the via top 130 is greater than or equal to the bottom diameter Lb of the via bottom 120. Therefore, in the above case, it is possible to distinguish the via bottom 120 from the via top 130 based on their diameters.

[0304] The resin composition layer in the resin sheet of the present invention contains a combination of components (A) to (C), and therefore exhibits the characteristic that the glass transition temperature (Tg) of the cured product of the resin composition layer is high. This results in an insulating layer with a high glass transition temperature. The glass transition temperature of the cured product of the resin composition layer is preferably 130°C or higher, more preferably 140°C or higher, and even more preferably 150°C or higher. There is no particular upper limit to the glass transition temperature of the cured product, but it can be 300°C or lower, for example. The glass transition temperature can be measured by the method described in the examples below.

[0305] A cured product obtained by curing a resin composition layer at 100°C for 30 minutes and then at 180°C for 30 minutes exhibits the property of being able to suppress the occurrence of cracks after desmear treatment (roughening treatment). Therefore, an insulating layer with excellent crack resistance is obtained. Specifically, after preparing a circuit board and performing a desmear treatment, the presence or absence of cracks on the circuit board is observed and evaluated according to JIS K 5600-5-6. As a result, the cracks are preferably less than 15%, more preferably less than 5%, and even more preferably less than 5%. Crack resistance can be evaluated by the method described in the examples below.

[0306] A cured product obtained by curing a resin composition layer at 200°C for 90 minutes typically exhibits excellent flame retardancy. Therefore, the cured product provides an insulating layer with excellent flame retardancy. The flame retardancy is measured by a flame retardancy test in accordance with the UL94 standard, and is preferably rated "V-1," more preferably "V-0" or better. The flame retardancy can be measured by the method described in the Examples below.

[0307] [Semiconductor package substrate and its manufacturing method] The semiconductor chip package of the present invention includes a circuit board and a semiconductor chip mounted on the circuit board, and the circuit board includes an insulating layer formed from a cured product of the resin composition layer in the resin sheet of the present invention. This semiconductor chip package can be produced by bonding the semiconductor chip to the circuit board. The circuit board will be described later.

[0308] The bonding conditions are not particularly limited as long as the terminal electrodes of the semiconductor chip are conductively connected to the circuit wiring of the circuit board, and known conditions used in flip-chip mounting of semiconductor chips may be used. Alternatively, the semiconductor chip and the circuit board may be bonded via an insulating adhesive.

[0309] In a preferred embodiment, the semiconductor chip is pressure-bonded to the circuit board under pressure conditions such as a pressure-bonding temperature in the range of 120°C to 240°C (preferably 130°C to 200°C, more preferably 140°C to 180°C) and a pressure-bonding time in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

[0310] In another preferred embodiment, the semiconductor chip is bonded to the circuit board by reflow. The reflow conditions can be, for example, in the range of 120°C to 300°C.

[0311] After bonding the semiconductor chip to the circuit board, it is also possible to obtain a semiconductor chip package by, for example, filling the semiconductor chip with a mold underfill material. The method of filling with a mold underfill material can be carried out by a known method.

[0312] The circuit board includes an insulating layer formed from a cured product of the resin composition layer in the resin sheet of the present invention. This circuit board can be produced, for example, by a production method including the following steps (I) and (II). (I) A step of laminating a resin sheet on an inner layer substrate so that the resin composition layer of the resin sheet is bonded to the inner layer substrate. (II) A step of curing the resin composition layer to form an insulating layer.

[0313] The "inner layer substrate" used in step (I) is a member that will become the substrate 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 substrate may have a conductor layer on one or both sides, and this conductor layer may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate is sometimes referred to as an "inner layer circuit board." Furthermore, intermediate products on which an insulating layer and / or a conductor layer is to be further formed during the production of a circuit board are also included in the aforementioned "inner layer substrate." When the circuit board is a circuit board with built-in components, an inner layer substrate with built-in components may be used.

[0314] The inner layer substrate and the resin sheet can be laminated, 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 plate) or a metal roll (such as a SUS roll). Note that rather than pressing the thermocompression bonding member directly onto the resin sheet, it is preferable to press it via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the inner layer substrate.

[0315] 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.

[0316] The lamination can 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 vacuum pressure laminator.

[0317] After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

[0318] The support may be removed between step (I) and step (II), or may be removed after step (II).

[0319] In step (II), the resin composition layer is cured to form an insulating layer made of a cured product of the resin composition layer. The resin composition layer is usually cured by thermal curing. Specific curing conditions for the resin composition layer may be those typically used when forming an insulating layer for a printed wiring board.

[0320] For example, the thermal curing conditions for the resin composition layer vary depending on the types of components contained in the resin composition layer, but in one embodiment, the curing temperature is preferably 120° C. to 240° C., more preferably 150° C. to 220° C., and even more preferably 170° C. to 210° C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0321] Before thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0322] When manufacturing a circuit board, the following steps may be further performed: (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming a conductor layer. These steps (III) to (V) may be performed according to various methods known to those skilled in the art and used in manufacturing circuit boards. When the support is removed after step (II), the removal of the support may be performed between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, if necessary, the formation of the insulating layer and the conductor layer in steps (I) to (V) may be repeated to form a multilayer wiring board.

[0323] Step (III) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (III) may be performed using, for example, a drill, a laser, plasma, or the like, depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be determined appropriately depending on the design of the printed wiring board.

[0324] Step (IV) is a step of roughening the insulating layer. Typically, smear removal is also performed in this step (IV). The roughening treatment procedure and conditions are not particularly limited, and known procedures and conditions commonly used in forming insulating layers for printed wiring boards can be adopted. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

[0325] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Examples of the alkaline solution include sodium hydroxide solution and potassium hydroxide solution. Examples of commercially available swelling liquids include "Swelling Dip Securigance P" and "Swelling Dip Securigance SBU" manufactured by Atotech Japan. Swelling treatment using a swelling liquid can be performed by immersing the insulating layer in the swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in the swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0326] 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. Roughening 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.

[0327] 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. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0328] In one embodiment, the arithmetic mean roughness (Ra) of the insulating layer surface after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. There is no particular limitation on the lower limit and it can be, for example, 1 nm or more, 2 nm or more, etc. Furthermore, the root mean square roughness (Rq) of the insulating layer surface after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. There is no particular limitation on the lower limit and it can be, for example, 1 nm or more, 2 nm or more, etc. The arithmetic mean roughness (Ra) and root mean square roughness (Rq) of the insulating layer surface can be measured using a non-contact surface roughness meter.

[0329] Step (V) is a step of forming a conductor layer, and the conductor layer is formed on the insulating layer. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

[0330] The conductor layer may have a single layer structure, or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0331] The thickness of the conductor layer depends on the desired design of the printed wiring board, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

[0332] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. An example of forming a conductor layer using a semi-additive method will be described below.

[0333] First, a plating seed layer is formed on the surface of an insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After a metal layer is formed on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, thereby forming a conductor layer having the desired wiring pattern.

[0334] In another embodiment, 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 resin composition layer and the metal foil may be laminated 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 conventionally known technique such as a subtractive method or a modified semi-additive method.

[0335] The metal foil can be produced by a known method such as an electrolytic method, a rolling method, etc. Examples of commercially available metal foils include 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.

[0336] [Semiconductor Devices] Semiconductor devices that can be equipped with the semiconductor chip package of the present invention 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]

[0337] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature conditions are room temperature (23°C), and unless otherwise specified, the pressure conditions are atmospheric pressure (1 atm).

[0338] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature conditions are room temperature (23°C), and unless otherwise specified, the pressure conditions are atmospheric pressure (1 atm).

[0339] <Synthesis Example 1> 100 parts by mass of dicyclohexylmethane-4,4'-diisocyanate (HMDI) and 0.5 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst were placed in a reaction vessel equipped with a reflux condenser and a stirrer, and the mixture was stirred and mixed under a nitrogen stream at 185°C for 24 hours to carry out a carbodiimidization reaction, yielding an isocyanate-terminated polycarbodiimide. IR spectroscopy of the obtained isocyanate-terminated polycarbodiimide revealed a peak at a wavelength of 2150cm. -1 Absorption peaks due to carbodiimide groups were confirmed before and after the measurement. The terminal NCO content was 8.19 mass %, and the average degree of polymerization of the carbodiimide groups determined by the above measurement method was 3.5.

[0340] Next, 8.8 parts by mass of ethylene glycol monoacrylate was added to the isocyanate-terminated polycarbodiimide at 150°C under a nitrogen stream, and the mixture was heated to 180°C and stirred for 2 hours to react. -1After confirming that the absorption peak of the isocyanate group had disappeared, the reaction product was removed from the reaction vessel and cooled to room temperature to obtain a pale yellow, transparent, solid polycarbodiimide compound (a radically polymerizable group-containing compound having a carbodiimide structure; the main component is the compound of the above formula (S1); b' means the average degree of polymerization of the carbodiimide group). [ka]

[0341] <Synthesis Example 2> A solid polycarbodiimide compound (a radically polymerizable group-containing compound having a carbodiimide structure; the main component is the compound of the above formula (S2); b' is the same as above) was obtained in the same manner as in Synthesis Example 1, except that ethylene glycol monoallyl ether was used instead of ethylene glycol monoacrylate. [ka]

[0342] <Synthesis Example 3> A solid polycarbodiimide compound (a radically polymerizable group-containing compound having a carbodiimide structure; the main component is the compound of the above formula (S3); b' is the same as above) was obtained in the same manner as in Synthesis Example 1, except that ethylene glycol methacrylate was used instead of ethylene glycol monoacrylate. [ka]

[0343] <Synthesis Example 4> A solid polycarbodiimide compound (a radically polymerizable group-containing compound having a carbodiimide structure; the main component is the compound of the above formula (S4); b' is the same as above) was obtained in the same manner as in Synthesis Example 1, except that ethylene glycol monoacrylate was changed to allyl alcohol. [ka]

[0344] <Synthesis Example 5> To the isocyanate-terminated polycarbodiimide obtained in the same manner as in Synthesis Example 1, 8.8 parts by mass of ethylene glycol monoacrylate and 4 parts by mass of polybutadiene having hydroxyl groups at both ends ("G-1000" manufactured by Nippon Soda Co., Ltd., number average molecular weight 1400, 1,2-addition structural unit 85% or more, trans-1,4-addition structural unit 15% or less) were added, and the mixture was heated to 180°C and stirred for 2 hours to react. IR spectroscopy showed a wavelength of 2200 to 2300 cm. -1 After confirming that the absorption peak of the isocyanate group had disappeared, the reaction product was removed from the reaction vessel and cooled to room temperature to obtain a pale yellow, transparent, solid polycarbodiimide compound (a radically polymerizable group-containing compound having a carbodiimide structure; the main component is the compound of the above formula (S5); b' is the same as above. d' means the average degree of polymerization of combined units of polybutadiene and polycarbodiimide. e' means the average degree of polymerization of butadiene units corresponding to the above number average molecular weight. Although only 1,2-addition structural units are shown as e' units, 1,4-addition structural units (cis, trans) are also included). [ka]

[0345] Example 1 25 parts of bisphenol A type epoxy resin ("828US" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight: approximately 180 g / eq.) and 25 parts of biphenyl type epoxy resin ("NC3000H" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight: approximately 269 g / eq.) were heated and dissolved in 50 parts of solvent naphtha with stirring, and then cooled to room temperature. To this mixed solution, 270 parts of spherical silica (average particle size 0.5 μm, Admatechs "SO-C2") surface-treated with an aminosilane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573"), 3 parts of methacryl butadiene styrene rubber particles (Dow Chemical Japan "EXL-2655"), and 0.5 parts of a flame retardant with crosslinkable functional groups (Sankosha "HCA-HQ-HST", 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.) were added, and the mixture was kneaded using a three-roll mill to uniformly disperse the mixture. The roll dispersion was mixed with 14 parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-3018-50P," hydroxyl group equivalent of approximately 151 g / eq., 1-methoxy-2-propanol solution with a solid content of 50%), 40 parts of an active ester compound (DIC Corporation's "HPC-8000-65T," active group equivalent of approximately 223 g / eq., toluene solution with a non-volatile content of 65% by mass), 20 parts of a phenoxy resin (Mitsubishi Chemical Corporation's "YX6954BH30," a mixed solution of MEK and cyclohexanone with a solid content of 30%), and 20 parts of a styrene-modified polyphenylene ether resin (Mitsubishi Gas Chemical Company's "OPE-2St"). A varnish-like resin composition was prepared by mixing 15.4 parts of methylcellulose (1200) (number average molecular weight 1200), a toluene solution with a solids content of 65%, 12 parts of a radically polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solids content of 50%), 6 parts of a curing accelerator (DMAP, 4-dimethylaminopyridine, an MEK solution with a solids content of 5% by mass), and 5 parts of an organic peroxide (NOF Corporation's Perbutyl C, an MEK solution with a solids content of 20%) and dispersing the mixture uniformly using a high-speed rotary mixer.

[0346] The flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha) has the following structural formula: [ka]

[0347] A PET film (Toray Industries, Inc., "Lumirror R80," thickness 38 μm) that had been subjected to a release treatment with an alkyd resin-based release agent (Lintec Corporation, "AL-5") was prepared as a support. A varnish-like resin composition was uniformly applied onto the release layer of the support so that the thickness of the resin composition layer after drying would be 40 μm, and the resulting layer was dried at 80 to 120°C (average 100°C) for 5 minutes to produce a resin sheet with a resin composition layer thickness of 40 μm.

[0348] Furthermore, a resin sheet having a resin composition layer with a thickness of 80 μm after drying was produced by the same method as that for producing the resin sheet having a resin composition layer with a thickness of 40 μm.

[0349] <Example 2> In Example 1, 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was changed to 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 2, a toluene solution with a solid content of 50%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0350] Example 3 In Example 1, 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was changed to 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 3, a toluene solution with a solid content of 50%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0351] Example 4 In Example 1, 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was changed to 12 parts of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 4, a toluene solution with a solid content of 50%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0352] <Example 5> In Example 1, 12 parts of the radically polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was changed to 12 parts of the radically polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 5, a toluene solution with a solid content of 50%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0353] Example 6 In Example 1, 1) The amount of the radical polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 5, a toluene solution with a solid content of 50%) was changed from 12 parts to 6 parts. 2) Furthermore, 6 parts of a polycarbodiimide compound having no radical polymerizable group ("V-03" manufactured by Nisshinbo Chemical Inc., a toluene solution with a solid content of 50%) was used. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0354] Example 7 In Example 1, 1) 12 parts of a compound having a radical polymerizable group and a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was replaced with 12 parts of a compound having a radical polymerizable group and a carbodiimide structure (obtained in Synthesis Example 5, a toluene solution with a solid content of 50%), 2) 25 parts of biphenyl-type epoxy resin (Nippon Kayaku's "NC3000H", epoxy equivalent approximately 269 g / eq.) was replaced with 25 parts of naphthalene-type epoxy resin (DIC's "HP-4032SS", epoxy equivalent approximately 144 g / eq.). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0355] Example 8 In Example 5, 25 parts of biphenyl-type epoxy resin ("NC3000H" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approximately 269 g / eq.) was changed to 25 parts of bixylenol-type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 185 g / eq.). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0356] Example 9 In Example 5, 1) Without using 14 parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-3018-50P," hydroxyl group equivalent of approximately 151 g / eq., 1-methoxy-2-propanol solution with a solid content of 50%), 2) The amount of active ester compound (DIC Corporation's "HPC-8000-65T," active group equivalent weight approximately 223 g / eq., toluene solution with 65% nonvolatile content by mass) was changed from 40 parts to 20 parts. 3) The amount of hardening accelerator (DMAP, 4-dimethylaminopyridine, MEK solution with 5% solids by mass) was changed from 6 parts to 0.4 parts. 4) 12 parts of bisphenol A dicyanate prepolymer ("BA230S75" manufactured by Lonza, cyanate equivalent weight approximately 235 g / eq., MEK solution with a solid content of 75%) was used. 5) 5 parts of a phenol novolac type multifunctional cyanate ester resin ("PT30" manufactured by Lonza, cyanate equivalent weight approximately 124 g / eq., MEK solution with a solid content of 80%) was used. 6) 4 parts of an organometallic catalyst (Tokyo Chemical Industry Co., Ltd. "Cobalt (III) acetylacetonate", MEK solution with a solid content of 1%) was used. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0357] Example 10 In Example 5, 15.4 parts of a styrene-modified polyphenylene ether resin ("OPE-2St 1200 (number average molecular weight 1200)" manufactured by Mitsubishi Gas Chemical Co., Inc., a toluene solution with a solid content of 65%) was changed to 11.1 parts of a bismaleimide resin ("SLK-6895-T90" manufactured by Shin-Etsu Chemical Co., Ltd., a maleimide equivalent of approximately 345 g / eq., a toluene solution with a solid content of 90%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0358] Example 11 In Example 5, 15.4 parts of a styrene-modified polyphenylene ether resin ("OPE-2St 1200 (number average molecular weight 1200)" manufactured by Mitsubishi Gas Chemical Co., Inc., a toluene solution with a solid content of 65%) was changed to 14.3 parts of a biphenylaralkyl-type polyfunctional maleimide resin ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., a maleimide equivalent of approximately 393 g / eq., a mixed solution of MEK and toluene with a solid content of 70%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0359] Example 12 In Example 5, 0.5 parts of a flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.) was changed to 0.5 parts of a flame retardant having a crosslinkable functional group ("FP700-TP" manufactured by Fushimi Pharmaceutical Co., Ltd., a phosphorus-based flame retardant containing an ethylenically unsaturated bond, phosphorus content 0.127, ethylenically unsaturated bond equivalent 488 g / eq.). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0360] The flame retardant having a crosslinkable functional group ("FP700-TP" manufactured by Fushimi Pharmaceutical Industry Co., Ltd.) has the following structural formula: [ka]

[0361] Example 13 In Example 5, 0.5 parts of a flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.) was changed to 0.5 parts of a flame retardant having a crosslinkable functional group ("V5" manufactured by Katayama Chemical Co., Ltd., a phosphorus-based flame retardant containing an ethylenically unsaturated bond, phosphorus content 0.128, ethylenically unsaturated bond equivalent 242 g / eq.). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0362] The flame retardant having a crosslinkable functional group ("V5" manufactured by Katayama Chemical Industry Co., Ltd.) has the following structural formula: [ka]

[0363] Example 14 In Example 5, 1) The amount of styrene-modified polyphenylene ether resin ("OPE-2St 1200 (number average molecular weight 1200)" manufactured by Mitsubishi Gas Chemical Co., Ltd., toluene solution with a solid content of 65%) was changed from 15.4 parts to 46.2 parts. 2) The amount of bisphenol A epoxy resin (Mitsubishi Chemical Corporation "828US", epoxy equivalent weight approximately 180g / eq.) was changed from 25 parts to 18 parts. 3) The amount of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000H", epoxy equivalent: approximately 269 g / eq.) was changed from 25 parts to 18 parts. 4) The amount of active ester compound (DIC Corporation's "HPC-8000-65T," active group equivalent weight approximately 223 g / eq., toluene solution with 65% by mass of nonvolatile components) was changed from 40 parts to 30 parts. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0364] Example 15 In Example 5, 1) The amount of styrene-modified polyphenylene ether resin (Mitsubishi Gas Chemical Company, Ltd. "OPE-2St 1200 (number average molecular weight 1200)", toluene solution with a solid content of 65%) was changed from 15.4 parts to 77.9 parts. 2) The amount of bisphenol A epoxy resin (Mitsubishi Chemical Corporation "828US", epoxy equivalent weight approximately 180g / eq.) was changed from 25 parts to 11 parts. 3) The amount of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000H", epoxy equivalent weight approximately 269 g / eq.) was changed from 25 parts to 11 parts. 4) The amount of active ester compound (DIC Corporation's "HPC-8000-65T," active group equivalent weight approximately 223 g / eq., toluene solution with 65% by mass of nonvolatile components) was changed from 40 parts to 20 parts. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0365] Example 16 In Example 5, 1) The amount of solvent naphtha was changed from 50 parts to 25 parts. 2) 270 parts of spherical silica (average particle size 0.5 μm, manufactured by Admatechs Co., Ltd., "SO-C2") surface-treated with an aminosilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573") was not used. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0366] Example 17 In Example 5, 1) Styrene-modified polyphenylene ether resin (Mitsubishi Gas Chemical Co., Ltd. "OPE-2St 1200 (number average molecular weight 1200)", toluene solution with a solid content of 65%) was not used, 15.4 parts. 2) The amount of spherical silica (average particle size 0.5 μm, Admatechs "SO-C2") surface-treated with an aminosilane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573") was changed from 270 parts to 250 parts. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0367] <Comparative Example 1> In Example 1, 12 parts of the radically polymerizable group-containing compound having a carbodiimide structure (obtained in Synthesis Example 1, a toluene solution with a solid content of 50%) was changed to 12 parts of a carbodiimide compound not having a radically polymerizable group ("V-03" manufactured by Nisshinbo Chemical Inc., a toluene solution with a solid content of 50%). A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 1 except for the above.

[0368] <Comparative Example 2> In Example 5, 0.5 parts of a flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent of approximately 162 g / eq.) was not used. A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above.

[0369] <Comparative Example 3> In Example 5, 0.5 parts of a flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.) was changed to 0.5 parts of a flame retardant not having a crosslinkable functional group ("FP-100" manufactured by Fushimi Pharmaceutical Industry Co., Ltd., phosphorus content 0.134, compound having the following structure): A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above. [ka]

[0370] <Comparative Example 4> In Example 5, 0.5 parts of a flame retardant having a crosslinkable functional group ("HCA-HQ-HST" manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.) was changed to 0.5 parts of a flame retardant not having a crosslinkable functional group ("PX-200" manufactured by Daihachi Chemical Industry Co., Ltd., phosphorus content 0.09, compound having the following structure): A varnish-like resin composition and a resin sheet were obtained in the same manner as in Example 5 except for the above. [ka]

[0371] <Comparative Example 5> 270 parts of spherical silica (average particle size 0.5 μm, Admatechs "SO-C2") surface-treated with an aminosilane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573"), 3 parts of methacrylic butadiene styrene rubber particles (Dow Chemical Japan "EXL-2655"), 0.5 parts of a flame retardant with a crosslinkable functional group (Sankosha "HCA-HQ-HST", 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.5 μm, phenolic hydroxyl group equivalent approximately 162 g / eq.), styrene-modified polyphenylene ether resin (Mitsubishi Gas Chemical Co., Ltd. "OPE-2St") 76.9 parts of "1200 (number average molecular weight 1200)" (65% solids in toluene solution) and 60 parts of solvent naphtha were added and uniformly dispersed by kneading with a three-roll mill. 20 parts of phenoxy resin (Mitsubishi Chemical Corporation "YX6954BH30" (30% solids in a mixed solution of MEK and cyclohexanone), 33.3 parts of bismaleimide resin (Shin-Etsu Chemical Co., Ltd. "SLK-6895-T90" (maleimide equivalent: approximately 345 g / eq., 90% solids in toluene solution), 33.3 parts of biphenylaralkyl-type multifunctional maleimide resin (Nippon Kayaku Co., Ltd. "MIR-3000-70MT" ( A varnish-like resin composition was prepared by mixing 14.3 parts (maleimide equivalent: approximately 393 g / eq.), 12 parts of a polycarbodiimide compound (obtained in Synthesis Example 5, a toluene solution with a 50% solids content), 6 parts of a curing accelerator (DMAP, 4-dimethylaminopyridine, a MEK solution with a 5% solids content by mass), and 5 parts of an organic peroxide (NOF Corporation's Perbutyl C, a MEK solution with a 20% solids content) and dispersing the mixture uniformly in a high-speed rotating mixer. A resin sheet was produced in the same manner as in Example 1.

[0372] <Test Example 1: Measurement of Glass Transition Temperature (Tg)> (1) Preparation of cured product for evaluation The resin sheets prepared in the Examples and Comparative Examples, each having a dried resin composition layer thickness of 40 μm, were heated at 200° C. for 90 minutes to thermally cure the resin composition layer, and then the support was peeled off. The resulting cured product is referred to as the “cured product for evaluation.”

[0373] (2) Measurement of glass transition temperature The cured product for evaluation was cut into test pieces approximately 5 mm wide and 15 mm long, and thermomechanical analysis was performed using a thermomechanical analyzer (Rigaku Corporation, "Thermo Plus TMA8310") using the tensile load method. After mounting the test pieces in the analyzer, measurements were performed twice consecutively under the conditions of a load of 1 g and a heating rate of 5°C / min. The glass transition temperature was obtained in the second measurement.

[0374] <Test Example 2: Flame Retardancy Measurement> (1) Preparation of a resin sheet having a resin composition layer thickness of 80 μm after drying Resin sheets each having a resin composition layer with a thickness of 80 μm after drying, produced in the examples and comparative examples, were prepared.

[0375] (2) Preparation of the substrate A copper foil etched-out copper-clad laminate (679FG, manufactured by Resonac Corporation) (substrate thickness: 0.2 mm, halogen-free core material) was heated in an oven at 190 °C for 30 minutes and then cooled to room temperature. An 80 μm resin sheet was laminated onto both sides of the copper foil etched-out substrate using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator, CVP700) so that the resin composition layer was in contact with the substrate. Lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, followed by pressure bonding at 100 °C and a pressure of 0.74 MPa for 30 seconds.

[0376] (3) Thermal curing of the resin composition layer After laminating the resin sheet, the PET film was peeled off, and the resin composition layer was thermally cured by heating at 200°C for 90 minutes to form an insulating layer. This resulted in a substrate having a layer structure of insulating layer / substrate / insulating layer. The resulting substrate having a layer structure of insulating layer / substrate / insulating layer is referred to as "Substrate A."

[0377] (4) Preparation of evaluation board The obtained substrate A was cut into a piece 12.7 mm wide and 127 mm long, and the cut surface was polished with sandpaper (#1200) and then with sandpaper (#2800). This gave a substrate for flame retardancy testing. The obtained substrate for flame retardancy testing is referred to as "evaluation substrate A."

[0378] (5) Flame retardancy evaluation The obtained evaluation substrate A was subjected to a flame retardancy test (flame resistance test) in accordance with the UL94 standard. If the evaluation substrate A continued to burn for 30 seconds or more after being exposed to a flame for 10 seconds as a result of the flame retardancy test, it was rated as "X", indicating poor flame resistance, and if the flame retardancy test substrate did not continue to burn for 30 seconds or more after being exposed to a flame for 10 seconds, it was rated as either "V-0" grade or "V-1" grade according to the UL94 standard rating criteria.

[0379] <Test Example 3: Evaluation of crack resistance> (1) Preparation of a resin sheet having a resin composition layer thickness of 40 μm after drying Resin sheets each having a resin composition layer with a thickness of 40 μm after drying were prepared in the examples and comparative examples.

[0380] (2) Surface treatment of inner layer circuit board Both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic "R1766") with an inner layer circuit formed on it were etched 1.0 μm deep using MEC "CZ8101" to roughen the copper surface.

[0381] (3) Lamination of resin sheets The resin sheet prepared in (1) above was laminated onto both sides of the inner layer circuit board prepared in (2) above using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator, CVP700) so that the resin composition layer bonded to the inner layer circuit board. The lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, followed by pressure bonding at 100°C and a pressure of 0.74 MPa for 30 seconds. Next, a heat press was performed at 100°C and a pressure of 0.5 MPa for 60 seconds.

[0382] (4) Curing of the resin composition After laminating the resin sheet, the resin composition layer was thermally cured at 100° C. for 30 minutes and then at 180° C. for 30 minutes to form an insulating layer. Thereafter, the support was peeled off to expose the insulating layer.

[0383] (5) Roughening treatment The inner layer circuit board with the exposed insulation layer was immersed in a swelling solution (Atotech Japan's "Swelling Dip Securigant P," a sodium hydroxide solution containing diethylene glycol monobutyl ether) at 60°C for 10 minutes, then in an oxidizing agent (Atotech Japan's "Concentrate Compact CP," a solution containing approximately 6% potassium permanganate and 4% sodium hydroxide) at 80°C for 20 minutes, and finally in a neutralizing solution (Atotech Japan's "Reduction Solution Securigant P," a hydroxylamine sulfate solution) at 40°C for 5 minutes. It was then dried at 80°C for 15 minutes. The resulting substrate is referred to as "Evaluation Substrate B."

[0384] (6) Evaluation of crack resistance According to JIS K 5600-5-6, evaluation substrate B was scored in a grid pattern, and the presence or absence of cracks on evaluation substrate B was evaluated by observing it with an optical microscope. Specifically, grid-like scores were scored at 1 mm intervals on the cured coating film of evaluation substrate B, forming 10 scores vertically and 10 scores horizontally, for a total of 100 coating film pieces. Here, a coating film piece refers to each portion of the cured coating film separated by the scores. These 100 coating film pieces were observed with an optical microscope, and the number of coating film pieces with cracks was counted. Based on the ratio of the number of coating film pieces with cracks to the total number of coating film pieces (100), crack resistance was evaluated according to the following evaluation criteria. ○: Almost no cracks on evaluation board B (less than 5%) △: Slight cracks on evaluation board B (5% to less than 15%) ×: Evaluation board B has many cracks (15% or more)

[0385] <Test Example 4: Evaluation of the Haloing Phenomenon> (1) Preparation of a resin sheet having a resin composition layer thickness of 40 μm after drying Resin sheets each having a resin composition layer with a thickness of 40 μm after drying were prepared in the examples and comparative examples.

[0386] (2) Surface treatment of inner layer circuit board Both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic "R1766") with an inner layer circuit formed on it were etched 0.5 μm deep using MEC "CZ8201" to roughen the copper surface.

[0387] (3) Lamination of resin sheets The resin sheets were laminated onto both sides of the inner layer circuit board prepared in (2) above using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator, CVP700) so that the resin composition layer bonded to the inner layer circuit board. The lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, followed by pressure bonding at 100°C and a pressure of 0.74 MPa for 30 seconds. The laminate was then heat-pressed at 100°C and a pressure of 0.5 MPa for 60 seconds.

[0388] (4) Curing of the resin composition layer After laminating the resin sheet, the resin composition layer was thermally cured at 100° C. for 30 minutes and then at 180° C. for 30 minutes to form an insulating layer.

[0389] (5) Formation of via holes Using a CO2 laser processing machine (Via Mechanics, "LC-2E21B / 1C"), openings were formed in the insulating layer with the support still attached under the following conditions: mask diameter 2.0 mm, frequency 2000 Hz, pulse width 6 μs, output 4 W, and 2 shots. The support was then peeled off to expose the insulating layer. The top diameter of the opening on the insulating layer surface was 50 μm. The depth of the opening was determined by measuring and calculating the difference in depth between the unprocessed and processed parts of the insulating layer from cross-sectional observation images.

[0390] (6) Roughening treatment The inner layer circuit board with the exposed insulating layer and via holes 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, then in an oxidizing solution (Atotech Japan's "Concentrate Compact CP," an aqueous solution of potassium permanganate approximately 6% and sodium hydroxide approximately 4%) at 80°C for 20 minutes, and finally in a neutralizing solution (Atotech Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes, and then dried at 80°C for 15 minutes. This is called "Evaluation Board C."

[0391] (7) Measurement of via diameter after desmearing The cross section of the evaluation substrate C was observed using a FIB-SEM composite device ("SMI3050SE" manufactured by SII Nano Technology Corporation). Specifically, a cross section perpendicular to the laser via was cut out using a FIB (focused ion beam), and the via hole diameter after desmearing was measured from the cross-sectional SEM image. For each sample, the via top diameter after desmearing was measured from the cross-sectional SEM image of five randomly selected points, and the average value was taken as the via top diameter Lt (μm).

[0392] (8) Measurement of halo distance after roughening treatment Evaluation substrate C was observed with an optical microscope (Hirox Corporation, "KH8700"). Specifically, the insulating layer around the via hole was observed from above evaluation substrate C using an optical microscope (CCD). This observation was performed by focusing the optical microscope on the via top. As a result of the observation, a doughnut-shaped halo was observed around the via hole, where the insulating layer had turned white, continuing from the edge of the via top of the via hole. From the observed image, the radius r1 of the via top of the via hole (corresponding to the inner radius of the halo) and the outer radius r2 of the halo were measured, and the difference r2 - r1 between these radii r1 and r2 was calculated as the halo distance from the edge of the via top at that measurement point.

[0393] The above measurement was performed on five randomly selected via holes, and the average of the measured halo distances of the five via holes was used as the halo distance Wt (μm) from the edge of the via top of that sample.

[0394] The haloing ratio Ht (the ratio (Wt / (Lt / 2)) of the haloing distance Wt from the edge of the via top after roughening treatment to the radius (Lt / 2) of the via top of the via hole after roughening treatment) was calculated, and if this haloing ratio Ht was 35% or less, it was judged as "◎", if the haloing ratio Ht was greater than 35% and less than 50%, it was judged as "◯", if the haloing ratio Ht was greater than 50% and less than 70%, it was judged as "△", and if the haloing ratio Ht was greater than 70%, it was judged as "X".

[0395] [Table 1] [Table 2] [Table 3] *In the table, the content of each component represents the content when the non-volatile components in the resin composition layer are taken as 100% by mass.

Claims

1. A support and a resin composition layer provided on the support, The resin composition layer comprises: (A) a radical polymerizable group-containing compound having a carbodiimide structure; (B) a flame retardant having a crosslinkable functional group, and (C) A resin sheet for forming an insulating layer of a semiconductor package substrate, comprising a thermosetting resin.

2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1 , further comprising (D) an inorganic filler.

3. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, further comprising (E) a radical polymerizable group-containing compound having no carbodiimide structure.

4. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the content of the component (A) is 0.1% by mass or more and 15% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass.

5. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the content of the component (B) is 0.01% by mass or more and 3% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass.

6. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the content of the component (C) is 10% by mass or more and 40% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass.

7. 3. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 2, wherein the content of the component (D) is 45% by mass or more and 85% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass.

8. 4. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 3, wherein the content of the component (E) is 0.1% by mass or more and 20% by mass or less, when the non-volatile components of the resin composition layer are 100% by mass.

9. A semiconductor chip package substrate comprising an insulating layer made of a cured product of the resin composition layer of the resin sheet for forming an insulating layer of a semiconductor package substrate according to any one of claims 1 to 8.

10. A semiconductor device comprising the semiconductor chip package substrate according to claim 9.

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