Resin sheet for forming insulating layer of semiconductor package substrate

Abstract

To provide a resin sheet for forming an insulating layer of a semiconductor package substrate that is capable of forming a cured product exhibiting a low dielectric loss tangent, superior smear removal properties, and high adhesion strength with a conductor layer.SOLUTION: Provided is a resin sheet for forming an insulating layer of a semiconductor package substrate, the resin sheet including a support and a resin composition layer disposed on the support, the resin composition layer comprising (A) a carbodiimide resin containing an unsaturated bond, (B) a thermosetting resin, and (C) a constituent having a polystyrene skeleton, the constituent (C) comprising at least one selected from (C1) a resin having the polystyrene skeleton with a weight-average molecular weight of 100,000 or less, and (C2) particles having the polystyrene skeleton with an average particle diameter of less than 5 μm.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 semiconductor package substrate manufactured using the resin sheet and a semiconductor device including the semiconductor package substrate. [Background technology]

[0002] A known manufacturing technique for semiconductor package substrates is a build-up manufacturing method in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, the insulating layer is generally formed from a cured product of a resin composition. For example, Patent Documents 1 and 2 disclose techniques for forming an insulating layer by curing a resin composition containing a component having a polystyrene skeleton. Patent Document 3 also 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] Japanese Patent Publication No. 2022-1628 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-146019 [Patent Document 3] International Publication No. 2023 / 027013 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, semiconductor package substrates have been required to exhibit low transmission loss when operated in a high-frequency environment, and insulating layers used in semiconductor package substrates are required to exhibit a low dielectric dissipation factor. As disclosed in Patent Documents 1 and 2, resin compositions containing a component having a polystyrene skeleton are expected to be resin compositions that produce cured products with a low dielectric dissipation factor. However, when attempting to form an insulating layer for a semiconductor package substrate using a resin composition containing a component having a polystyrene skeleton, the present inventors found that the resin composition sometimes exhibited poor smear removability in a desmearing step, or poor adhesion strength with a conductor layer formed by dry plating.

[0005] Therefore, an object of the present invention is to provide a resin sheet for forming an insulating layer of a semiconductor package substrate, which is capable of forming a cured product that has a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength between the resin sheet and a conductor layer; a semiconductor package substrate including a cured product of a resin composition layer of the resin sheet; and a semiconductor device including the semiconductor package substrate. [Means for solving the problem]

[0006] As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by using a resin sheet for forming an insulating layer of a semiconductor package substrate, the resin sheet comprising a support and a resin composition layer provided on the support, wherein the resin composition layer contains (A) a carbodiimide resin having an unsaturated bond, (B) a thermosetting resin, and (C) a component having a polystyrene skeleton, and the component (C) contains at least one of (C1) a resin having a polystyrene skeleton and having a weight-average molecular weight of 100,000 or less, and (C2) particles having a polystyrene skeleton and having an average particle size of less than 5 μm, and have completed the present invention. That is, the present invention includes the following.

[0007] <1> A resin sheet comprising a support and a resin composition layer provided on the support, the resin composition layer contains (A) a carbodiimide resin containing an unsaturated bond, (B) a thermosetting resin, and (C) a component having a polystyrene skeleton; A resin sheet for forming an insulating layer of a semiconductor package substrate, wherein the component (C) includes at least one of (C1) a resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less, and (C2) particles having a polystyrene skeleton and an average particle size of less than 5 μm. <2> The resin composition layer further contains (D) an inorganic filler. <1> 2. A resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1. <3> The content of the (A) component is 0.1% by mass or more and 5.0% by mass or less, when the nonvolatile components in the resin composition layer are taken as 100% by mass. <1> or <2> 2. A resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1. <4> the total content of the (C1) component and the (C2) component is 0.1% by mass or more and 10.0% by mass or less, when the total amount of nonvolatile components in the resin composition layer is 100% by mass; <1> ~ <3> 10. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 9. <5> the mass ratio of the (C1) component and the (C2) component to the (A) component contained in the resin composition layer (total content of the (C1) component and the (C2) component / content of the (A) component) is 0.1 or more and 10.0 or less; <1> ~ <4> 10. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 9. <6> The component (A) contains a carbodiimide resin represented by the following formula (1): <1> ~ <5> 10. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 9. [ka] (In formula (1), R each independently represents a hydrogen atom or a methyl group; X 1 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; Y's each independently represent a divalent saturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent, or a divalent unsaturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent; Z's each independently represent 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; b's each independently represent an integer of 1 or greater; c's each independently represent an integer of 1 or greater; d represents an integer of 0 or 1 or more. <7> The component (B) contains one or more thermosetting resins selected from epoxy resins, active ester resins, phenolic resins, naphthol resins, cyanate ester resins, and radical polymerizable resins. <1> ~ <6> 10. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 9. <8> <1> ~ <7> 10. A semiconductor package substrate comprising a cured product of the resin composition layer of the resin sheet according to any one of claims 1 to 9. <9> <8> A semiconductor device comprising the semiconductor package substrate according to claim 1. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin sheet for forming an insulating layer of a semiconductor package substrate, which is capable of forming a cured product that has a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength between the resin sheet and a conductor layer; a semiconductor package substrate including a cured product of a resin composition layer of the resin sheet; and a semiconductor device including the semiconductor package substrate. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below with reference to embodiments and examples. 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.

[0010] [Terminology] As used herein, the term "optionally substituted" in reference to a compound or group means both a case where the hydrogen atoms of the compound or group are not substituted with substituents, and a case where some or all of the hydrogen atoms of the compound or group are substituted with substituents.

[0011] In this specification, a substituent may further have a substituent (sometimes referred to as a "secondary substituent").

[0012] In this specification, examples of the "halogen atom" include a fluorine atom, a chlorine atom, and a bromine atom.

[0013] As used herein, the term "alkyl group" refers to a linear, branched, or cyclic monovalent aliphatic saturated hydrocarbon group. The alkyl group preferably has 1 to 14 carbon atoms, more preferably 1 to 10, even more preferably 1 to 6, and particularly preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an isohexyl group, a heptyl group, an isoheptyl group, an octyl group, an isooctyl group, a tert-octyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexylmethyl group.

[0014] As used herein, the term "alkyl group" refers to a linear, branched, or cyclic monovalent aliphatic saturated hydrocarbon group. The alkyl group preferably has 1 to 14 carbon atoms, more preferably 1 to 10, even more preferably 1 to 6, and particularly preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an isohexyl group, a heptyl group, an isoheptyl group, an octyl group, an isooctyl group, a tert-octyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexylmethyl group.

[0015] As used herein, the term "alkenyl group" refers to a linear, branched, or cyclic monovalent unsaturated hydrocarbon group having at least one carbon-carbon double bond. The alkenyl group preferably has 2 to 14 carbon atoms, more preferably 2 to 10 carbon atoms, even more preferably 2 to 6 carbon atoms, and particularly preferably 2 to 3 carbon atoms. Examples of alkenyl groups include vinyl groups, propenyl groups (allyl, 1-propenyl, isopropenyl), butenyl groups (1-butenyl, crotyl, methallyl, isocrotyl, etc.), pentenyl groups (1-pentenyl, etc.), hexenyl groups (1-hexenyl, etc.), heptenyl groups (1-heptenyl, etc.), octenyl groups (1-octenyl, etc.), cyclopentenyl groups (2-cyclopentenyl, etc.), and cyclohexenyl groups (3-cyclohexenyl).

[0016] As used herein, the term "aryl group" refers to a monovalent aromatic hydrocarbon group. The number of carbon atoms in the aryl group is preferably 6 to 14, and more preferably 6 to 10. Examples of the aryl group include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0017] The term "aromatic ring" means a ring that conforms to Hückel's rule, in which the number of electrons in the π-electron system of the ring is 4n+2 (n is a natural number), and includes monocyclic aromatic rings and fused aromatic rings in which two or more monocyclic aromatic rings are fused together. The aromatic rings may be carbocyclic or heterocyclic.

[0018] As used herein, the term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and combinations thereof. The term "(meth)acryloyl group" includes acryloyl group, methacryloyl group, and combinations thereof. The term "(meth)acrylate" includes acrylate, methacrylate, and combinations thereof.

[0019] In this specification, the term "non-volatile components" in relation to the resin composition layer refers to the components constituting the resin composition layer excluding (G) the organic solvent, which will be described later. Also, the term "resin components" in relation to the resin composition layer refers to the components constituting the resin composition layer excluding (D) the inorganic filler, which will be described later.

[0020] [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 (hereinafter simply referred to as "the resin sheet of the present invention" or "resin sheet") is a resin sheet comprising a support and a resin composition layer provided on the support, the resin composition layer comprising (A) a carbodiimide resin having an unsaturated bond, (B) a thermosetting resin, and (C) a component having a polystyrene skeleton, the component (C) comprising at least one of (C1) a resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less, and (C2) particles having a polystyrene skeleton and an average particle size of less than 5 μm. The resin sheet can form a cured product that has a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer.

[0021] <Support> The resin sheet for forming an insulating layer of a semiconductor package substrate of the present invention includes a support, such as a film made of a plastic material, a metal foil, or a release paper, and a film made of a plastic material is preferred.

[0022] 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"); acrylic polymers such as polymethyl methacrylate (hereinafter sometimes abbreviated as "PMMA"); cyclic polyolefins; triacetyl cellulose (hereinafter sometimes abbreviated as "TAC"); polyether sulfide (hereinafter sometimes abbreviated as "PES"); polyether ketone; polyimide; etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0023] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil. Of these, copper foil is preferred. The copper foil may be a foil made of a single metal, copper, or a foil made of an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0024] 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, an antistatic treatment or the like.

[0025] 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 release agents include alkyd resin-based release agents such as "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation. Commercially available support with a release layer includes PET films having a release layer primarily composed of an alkyd resin-based release agent, such as "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.

[0026] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably 10 μm to 60 μm. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is in the above range.

[0027] <Resin composition layer> The resin sheet for forming an insulating layer of a semiconductor package substrate of the present invention includes a resin composition layer provided on the support, the resin composition layer including (A) a carbodiimide resin having an unsaturated bond, (B) a thermosetting resin, and (C) a component having a polystyrene skeleton, the component (C) including at least one of (C1) a resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less, and (C2) particles having a polystyrene skeleton and an average particle size of less than 5 μm.

[0028] The resin composition layer may further contain optional components in combination with the components (A) to (C). Examples of optional components include (A') other carbodiimide resins, (D) inorganic fillers, (E) curing accelerators, (F) other additives, and (G) organic solvents. Each component contained in the resin composition layer will be described in detail below.

[0029] <(A) Carbodiimide Resin Containing Unsaturated Bond> The resin composition layer contains a carbodiimide resin containing an unsaturated bond as component (A). Component (A) is a resin containing one or more unsaturated bonds and one or more carbodiimide structures (-N=C=N-) in the molecule. Component (A) may be used singly or in combination of two or more.

[0030] As used herein, the term "unsaturated bond" refers to a carbon-carbon unsaturated bond such as a carbon-carbon double bond or a carbon-carbon triple bond. The group containing an unsaturated bond may be a monovalent group. Examples of the group containing an unsaturated bond include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a fumaroyl group, a maleoyl group, a nadimide group, and a (meth)acryloyl group.

[0031] The component (A) preferably contains, as the group containing an unsaturated bond, one or more groups selected from a vinyl group, an allyl group, and a (meth)acryloyl group.

[0032] The component (A) preferably further contains one or more urethane bonds (—O—CO—NH—) in the molecule.

[0033] In a preferred embodiment, the component (A) includes a carbodiimide resin represented by the following formula (1):

[0034] [ka]

[0035] (In formula (1), R each independently represents a hydrogen atom or a methyl group; X 1 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; Y's each independently represent a divalent saturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent, or a divalent unsaturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent; Z's each independently represent 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; b's each independently represent an integer of 1 or greater; c's each independently represent an integer of 1 or greater; d represents an integer of 0 or 1 or more.

[0036] In formula (1), each R independently represents a hydrogen atom or a methyl group.

[0037] In formula (1), X 1 are each independently a carbonyl group, a methylene group, a phenylene group, or a phenylene-methylene 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. X 1 is preferably a carbonyl group or a methylene group.

[0038] In formula (1), X 2 are each independently a divalent saturated hydrocarbon group having 2 to 4 carbon atoms. The divalent saturated hydrocarbon group refers to a linear, branched, and / or cyclic divalent saturated hydrocarbon group. 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 2 is preferably a divalent saturated hydrocarbon group having 2 or 3 carbon atoms, and more preferably an ethylene group (-CH2-CH2-).

[0039] In formula (1), each Y independently 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. The divalent unsaturated hydrocarbon group refers to a straight-chain, branched-chain, and / or cyclic divalent unsaturated hydrocarbon group which has at least one carbon-carbon double bond or aromatic hydrocarbon ring.

[0040] The substituent that Y may have 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, and an aryl-carbonyl-oxy group.

[0041] Each Y is preferably a divalent saturated hydrocarbon group having 2 to 30 carbon atoms and having a ring structure (for example, a ring structure selected from a cycloalkane ring, a benzene ring, and a naphthalene ring) which may have a substituent, or a divalent unsaturated hydrocarbon group having 2 to 30 carbon atoms and having a ring structure (for example, a ring structure selected from a cycloalkane ring, a benzene ring, and a naphthalene ring) which may have a substituent, and more preferably a divalent group represented by the following formula (Y):

[0042] [ka]

[0043] (In formula (Y), Y a , Y b and Y c are each independently a single bond or C(R y )2 indicates; R y each independently represents a hydrogen atom or a methyl group; Ring Y 1 and ring Y 2each independently represents an optionally substituted cycloalkane ring having 4 to 10 carbon atoms, an optionally substituted benzene ring, or an optionally substituted naphthalene ring; n y indicates 0 or 1; * indicates the binding site.)

[0044] In formula (Y), Y a , Y b and Y c are each independently a single bond or C(R y In one preferred embodiment, 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.

[0045] In formula (Y), 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 are each independently preferably a cycloalkane ring having 4 to 10 carbon atoms which may have a substituent, more preferably a cyclohexane ring which may have a substituent, and further preferably an unsubstituted cyclohexane ring.

[0046] Ring Y 1 and ring Y 2Examples of the cycloalkane ring having 4 to 10 carbon atoms represented by the formula (I) 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; and tricyclo[5.2.1.0 2,6 ] Decane ring (tetrahydrodicyclopentadiene ring), tricyclo[3.3.1.1 3,7 ] Examples include tricyclic saturated hydrocarbon rings such as a decane ring (adamantane ring).

[0047] The divalent group represented by Y is not particularly limited, but examples thereof include divalent groups represented by the following formulae (Y1) to (Y14).

[0048] [ka]

[0049] (In formulas (Y1) to (Y14), * indicates a bonding site.)

[0050] Among these, Y is more preferably a divalent group represented by formula (Y1).

[0051] In formula (Y), n y indicates 0 or 1.

[0052] In formula (1), 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. Z is preferably a divalent saturated hydrocarbon group of 2 to 300 carbon atoms or a divalent unsaturated hydrocarbon group of 2 to 300 carbon atoms, and more preferably a divalent hydrocarbon group of 300 or less carbon atoms which is composed of one or more structural units (preferably repeating structural units) selected from the structural units represented by the following formulae (Z1) to (Z8):

[0053] [ka]

[0054] Among these, Z is more preferably a divalent hydrocarbon group having 300 or less carbon atoms and containing at least a structural unit represented by formula (Z1), and even more preferably a divalent hydrocarbon group having 300 or less carbon atoms and represented by the following formula (Z1'):

[0055] [ka]

[0056] (In formula (Z1'), n z represents an integer of 1 to 74; * represents a binding site.

[0057] In formula (Z1'), n z represents an integer from 1 to 74.

[0058] In formula (1), each a is independently 0 or an integer of 1 or more, preferably 0 or an integer of 1 to 10, and more preferably 0 or 1.

[0059] In formula (1), each b independently represents an integer of 1 or more, preferably an integer of 1 to 100, and more preferably an integer of 1 to 10.

[0060] In formula (1), each c independently represents an integer of 1 or more, preferably an integer of 1 to 100, more preferably an integer of 1 to 10, and even more preferably 1.

[0061] In formula (1), d represents 0 or an integer of 1 or more, preferably 0 or an integer of 1-100, and more preferably 0 or an integer of 1-10.

[0062] In formula (1), the a units, b units, and c units may be the same or different for each unit.

[0063] The weight average molecular weight (Mw) of component (A) is not particularly limited, but is preferably 500 to 10,000, more preferably 1,000 to 8,000, even more preferably 2,000 to 7,000, and still more preferably 3,000 to 6,000. The Mw of component (A) can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0064] The component (A) may be a commercially available product or may be synthesized using a known method.

[0065] The content of component (A) contained in the resin composition layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more, and is preferably 10.0% by mass or less, more preferably 7.5% by mass or less, and even more preferably 5.0% by mass or less, based on 100% by mass of the non-volatile components in the resin composition layer.

[0066] The content of component (A) contained in the resin composition layer is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and even more preferably 3.0% by mass or more, and is preferably 30.0% by mass or less, more preferably 20.0% by mass or less, and even more preferably 15.0% by mass or less, assuming that the resin component in the resin composition layer is 100% by mass.

[0067] <(A') Other carbodiimide resins> The resin composition layer may contain (A') other carbodiimide resin as an optional component. (A') other carbodiimide resin is a resin that contains one or more carbodiimide structures (-N=C=N-) in the molecule but does not contain unsaturated bonds. (A') other carbodiimide resin as component (A') may be used alone or in combination of two or more.

[0068] (A') Other carbodiimide resins include, for example, 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); Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(naphthylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide].

[0069] (A') Other 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.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510," manufactured by Lanxess AG.

[0070] The content of component (A') in the resin composition layer is, when the nonvolatile components in the resin composition layer are taken as 100% by mass, for example, 0.01% by mass or more, preferably 0.10% by mass or more, more preferably 0.30% by mass or more, and even more preferably 0.40% by mass or more. The upper limit of the content is not particularly limited, but is, for example, 10.0% by mass or less, preferably 5.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.8% by mass or less.

[0071] The content of component (A') in the resin composition layer is, when the resin component in the resin composition layer is taken as 100% by mass, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more. The upper limit of the content is not particularly limited, but is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0072] <(B) Thermosetting resin> The resin composition layer contains a thermosetting resin as component (B). The thermosetting resin is a resin that reacts with heat to form bonds and represents a component other than components (A) and (A'). Examples of this thermosetting resin include epoxy resins, active ester resins, phenolic resins, naphthol resins, cyanate ester resins, benzoxazine resins, acid anhydride resins, amine resins, and radical polymerizable resins. In particular, the resin composition layer preferably contains one or more thermosetting resins selected from epoxy resins, active ester resins, phenolic resins, naphthol resins, cyanate ester resins, and radical polymerizable resins. The component (B) may be used singly or in combination of two or more.

[0073] Examples of epoxy resins include bisphenol-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, and tetraphenylethane-type epoxy resins. Bisphenol-type epoxy resins refer to epoxy resins having a bisphenol structure, such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and bisphenol AF-type epoxy resins. Biphenyl-type epoxy resin refers to an epoxy resin having a biphenyl structure, where the biphenyl structure may have a substituent such as an alkyl group, an alkoxy group, or an aryl group. Therefore, bixylenol-type epoxy resins and biphenylaralkyl-type epoxy resins are also included in the biphenyl-type epoxy resin. The epoxy resins may be used alone or in combination of two or more.

[0074] The epoxy resin is preferably an aromatic epoxy resin, which means an epoxy resin having an aromatic ring in its molecule.

[0075] The epoxy resin preferably has two or more epoxy groups in one molecule. When the non-volatile components of the epoxy resin are taken as 100% by mass, the proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0076] Epoxy resins include those that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins") and those that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins").

[0077] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0078] Preferred liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins such as alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, and epoxy resins having a butadiene structure.

[0079] Specific examples of liquid epoxy resins include "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene type epoxy resins) manufactured by DIC Corporation; "828US," "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; and "630" and "630LSD" (glycidylamine type epoxy resins) manufactured by Mitsubishi Chemical Corporation. Examples include "ZX1059" manufactured by Nippon Steel Chemical & Material Co., Ltd. (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); "EX-721" manufactured by Nagase ChemteX Corporation (glycidyl ester type epoxy resin); "Celloxide 2021P" manufactured by Daicel Corporation (alicyclic epoxy resin with an ester skeleton); "PB-3600" manufactured by Daicel Corporation (epoxy resin with a butadiene structure); and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.

[0080] 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.

[0081] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins.

[0082] Specific examples of solid epoxy resins include "HP-4032H" (naphthalene type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC Corporation; "N-690" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "HP-7200HH", "HP-7200H", and "HP-7200" (dicyclopentadiene epoxy resins) manufactured by DIC Corporation. DIC Corporation's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether type epoxy resin); Nippon Kayaku Corporation's "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Corporation's "NC-7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Corporation's "NC-3000H", "NC-3000", and "NC-3000" L, "NC-3100" (biphenyl-type epoxy resin); "ESN-475V" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN-485" (naphthol novolac-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation. Examples of epoxy resins include "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YL7760" (bisphenol AF-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (solid bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "jER1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

[0083] The resin composition layer may contain only a liquid epoxy resin as the epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. When a liquid epoxy resin and a solid epoxy resin are used in combination, the ratio by mass between them (liquid epoxy resin:solid epoxy resin) is preferably 1:0.01 to 1:50, more preferably 1:0.05 to 1:20, and even more preferably 1:0.1 to 1:10.

[0084] The epoxy equivalent of the epoxy resin is preferably 50 g / eq to 5000 g / eq, more preferably 50 g / eq to 3000 g / eq, even more preferably 80 g / eq to 2000 g / eq, and even more preferably 110 g / eq to 1000 g / eq. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0085] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. The Mw of the epoxy resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0086] The content of the epoxy resin contained in the resin composition layer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, 6% by mass or more, or 7% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, when the non-volatile components in the resin composition layer are taken as 100% by mass.

[0087] The content of the epoxy resin contained in the resin composition layer 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 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, assuming that the resin component in the resin composition layer is 100% by mass.

[0088] The active ester resin may be a compound having one or more active ester groups per molecule. Among these, preferred active ester resins are 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. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance, an active ester resin derived from a carboxylic acid compound is preferred, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is more preferred, and an active ester resin obtained from a carboxylic acid compound and an aromatic hydroxy compound is even more preferred. The active ester resin may be used alone or in combination of two or more.

[0089] The carboxylic acid compound may be either an aromatic carboxylic acid compound or an aliphatic carboxylic acid compound, and examples thereof include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and halides thereof.

[0090] Examples of the aromatic hydroxy compound include (i) polyaddition products of unsaturated aliphatic cyclic compounds containing two double bonds per molecule with phenols, (ii) various bisphenol compounds, (iii) aromatic polyols having two or more hydroxy groups bonded to a carbon atom on an aromatic ring, and (iv) aromatic monools having one hydroxy group bonded to a carbon atom on an aromatic ring. Examples of the polyaddition products of unsaturated aliphatic cyclic compounds with phenols include polyaddition products of unsaturated aliphatic cyclic compounds such as dicyclopentadiene, tetrahydroindene, norbornadiene, limonene, and vinylcyclohexene with phenols that may have a substituent (e.g., phenol, cresol, xylenol, ethylphenol, propylphenol, vinylphenol, allylphenol, phenylphenol, benzylphenol, and halophenols), and specific examples thereof include dicyclopentadiene-phenol polyaddition products. Examples of bisphenol compounds include bisphenol A, bisphenol F, bisphenol AF, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, and bisphenol M. Examples of aromatic polyols in which two or more hydroxy groups are bonded to carbon atoms on an aromatic ring include hydroquinone, resorcinol, catechol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, and phenol novolak. Examples of aromatic monools having one hydroxy group bonded to a carbon atom on an aromatic ring include phenol, cresol, xylenol, ethylphenol, propylphenol, vinylphenol, allylphenol, phenylphenol, benzylphenol, halophenols, naphthol, methylnaphthol, dimethylnaphthol, ethylnaphthol, propylnaphthol, vinylnaphthol, allylnaphthol, phenylnaphthol, benzylnaphthol, and halonaphthol.

[0091] Specific examples of preferred active ester resins from the viewpoint of further enjoying the effects of the present invention include active ester resins containing a dicyclopentadiene-type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated product of phenol novolac, and active ester resins containing a benzoylated product of phenol novolac. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene-type diphenol structure are more preferred from the viewpoint of realizing a cured product with a low dielectric tangent. The "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0092] Commercially available active ester resins may be used, and examples of such commercially available products include active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB-9451," "EXB-9460," "EXB-9460S," "HPC-8000-65T," "HPC-8000H-65MT," and "HPC-8000L-65MT" (manufactured by DIC Corporation); and active ester resins containing a naphthalene structure such as "EXB-8100L-65T," "EXB-8150-60T," "EXB-8150-62T," "EXB-9416-70BK," "HPC-8150H-65MT," and "HPC-8000L-65MT." Examples of such active ester resins include PC-8150-62T and HP-B-8151-62T (manufactured by DIC Corporation); an activated ester resin containing phosphorus, such as EXB9401 (manufactured by DIC Corporation); an activated ester resin which is an acetylated product of phenol novolac, such as DC808 (manufactured by Mitsubishi Chemical Corporation); activated ester resins which are benzoylated products of phenol novolac, such as YLH1026, YLH1030, and YLH1048 (manufactured by Mitsubishi Chemical Corporation); and an activated ester resin containing a styryl group and a naphthalene structure, such as PC1300-02-65MA (manufactured by Air Water Inc.).

[0093] The active ester group equivalent of the active ester resin is preferably 50 g / eq. to 500 g / eq., more preferably 50 g / eq. to 400 g / eq., and even more preferably 100 g / eq. to 300 g / eq. The active ester group equivalent is the mass of the active ester resin per equivalent of the active ester group.

[0094] The content of the active ester resin in the resin composition layer is, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, 6% by mass or more, or 7% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, or 13% by mass or less.

[0095] The content of the active ester resin in the resin composition layer is, for example, 1% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0096] From the viewpoint of heat resistance and water resistance, the phenolic resin and naphthol resin preferably have a novolac structure. From the viewpoint of adhesion to the conductor layer, nitrogen-containing phenolic resin and nitrogen-containing naphthol resin are preferred, and triazine skeleton-containing phenolic resin and triazine skeleton-containing naphthol resin are more preferred. The phenolic resin and naphthol resin may be used alone or in combination of two or more.

[0097] Specific examples of phenol-based resins and naphthol-based resins include "MEH-7700," "MEH-7810," "MEH-7851," and "MEH-8000H" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; and "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-495V," and "SN-375" manufactured by Nippon Steel Chemical & Material Co., Ltd. and "SN-395" manufactured by DIC Corporation; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", and "KA-1165" manufactured by Gun-ei Chemical Co., Ltd.; and "GDP-6115L", "GDP-6115H", and "ELPC75" manufactured by Gun-ei Chemical Co., Ltd.

[0098] The content of the phenolic resin and naphtholic resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less, or 2.0% by mass or less.

[0099] The content of the phenolic resin and naphthol resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and even more preferably 3.0% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 6.0% by mass or less.

[0100] Examples of cyanate ester 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; polyfunctional cyanate resins derived from phenol novolac, cresol novolac, etc.; and prepolymers in which these cyanate resins are partially triazine converted. The cyanate ester resin may be used alone or in combination of two or more kinds.

[0101] Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type multifunctional cyanate ester resins), "ULL-950S" (multifunctional cyanate ester resin), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine-converted to form a trimer), all of which are manufactured by Arxada.

[0102] The content of the cyanate ester resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0103] The content of the cyanate ester resin in the resin composition layer is, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 11% by mass or less.

[0104] Specific examples of benzoxazine resins include "JBZ-OD100," "JBZ-OP100D," and "ODA-BOZ" manufactured by JFE Chemical Corporation; "Pd" and "Fa" manufactured by Shikoku Chemicals Corporation; and "HFB2006M" manufactured by Showa Polymer Co., Ltd. One type of benzoxazine resin may be used alone, or two or more types may be used in combination.

[0105] The content of the benzoxazine resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, when the nonvolatile components in the resin composition layer are taken as 100% by mass. The upper limit of the content is not particularly limited, but is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0106] The content of the benzoxazine resin in the resin composition layer is, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0107] Examples of acid anhydride resins include resins having one or more acid anhydride groups in one molecule. 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 dianhydride. Examples of suitable acid anhydrides include polymeric acid anhydrides such as styrene-maleic acid resins, styrene anhydride, ethylene glycol bis(anhydrotrimellitate), ...

[0108] Commercially available acid anhydride resins include "MH-700" manufactured by New Japan Chemical Co., Ltd.

[0109] The content of the acid anhydride resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0110] The content of the acid anhydride resin in the resin composition layer is, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0111] Examples of the amine resin include resins having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Specific examples of the amine resin include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 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-hydroxybenzoyl)methylamino). 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Examples of the amine resins include 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, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. One type of amine resin may be used alone, or two or more types may be used in combination.

[0112] Commercially available amine-based resins may be used, such as "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd., and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

[0113] The content of the amine resin in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, when the nonvolatile components in the resin composition layer are taken as 100% by mass. The upper limit of the content is not particularly limited, but is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0114] The content of the amine resin in the resin composition layer is, when the resin component in the resin composition layer is taken as 100% by mass, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The upper limit of the content is not particularly limited, but is, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0115] The radical polymerizable resin refers to a resin containing a radically polymerizable group containing an unsaturated bond. The radical polymerizable resin as component (B) does not include those corresponding to the above-mentioned component (A). The radical polymerizable resin may be used alone or in combination of two or more.

[0116] Examples of the group containing an unsaturated bond include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a fumaroyl group, a maleoyl group, a nadimide group, and a (meth)acryloyl group.

[0117] The number of groups containing an unsaturated bond contained in the radical polymerizable resin is, for example, 1 or more, and preferably 2 or more. When the radical polymerizable resin contains two or more groups containing an unsaturated bond, the two or more groups containing an unsaturated bond may be the same or different.

[0118] Examples of radically polymerizable resins include allyl resins, (meth)acrylic resins, maleimide resins, and resins having a vinylphenyl group.

[0119] The allyl resin refers to a resin having one or more, preferably two or more, allyl groups in one molecule. Examples of allyl resins include aromatic carboxylic acid allyl ester resins 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 resins such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl resins such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl resins such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl resins such as 1,3,5-triallyl ether benzene; allyl silane resins such as diallyl diphenyl silane; and resins containing multiple benzene rings and multiple allyl groups. The allyl resin may be used alone or in combination of two or more kinds.

[0120] Commercially available allyl resins include, for example, "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-naphthalenecarboxylic acid diallyl) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., and "ALP-d" (bis[3-allyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd. Examples of suitable glycidyl groups include "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemicals Corporation, and "NE-V-1100-70T" (a resin containing multiple allyl groups and multiple benzene rings) manufactured by DIC Corporation.

[0121] The (meth)acrylic resin refers to a resin having one or more, preferably two or more, (meth)acryloyl groups in one molecule. Examples of the (meth)acrylic resin include (meth)acrylic acid ester resins 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 glycol di(meth)acrylate, 3,6-dioxa-1,8 Examples of the (meth)acrylic acid ester resin include ether-containing (meth)acrylic acid ester resins such as 3,6,9-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; isocyanurate-containing (meth)acrylic acid ester resins such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate; and acrylic acid ester resins such as (meth)acrylic-modified polyphenylene ether resins. The (meth)acrylic resins may be used alone or in combination of two or more.

[0122] Examples of commercially available (meth)acrylic resins 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., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether) manufactured by SABIC.

[0123] The maleimide resin refers to a resin having one or more, preferably two or more, maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl groups) in one molecule. The maleimide resin may be an aliphatic maleimide resin containing an aliphatic amine skeleton, or an aromatic maleimide resin containing an aromatic amine skeleton. One type of maleimide resin may be used alone, or two or more types may be used in combination.

[0124] Commercially available maleimide resins include, for example, "SLK-2600" and "SLK-6895-T90" manufactured by Shin-Etsu Chemical Co., Ltd.; "BMI-1500," "BMI-1700," "BMI-3000J," "BMI-689," and "BMI-2500" (dimer diamine structure-containing maleimide resins) manufactured by Designer Molecules Inc.; "BMI-6100" (aromatic maleimide compound) manufactured by Designer Molecules Inc.; "MIR-5000-60T" and "MIR-3000-70MT" (biphenylaralkyl maleimide resins) manufactured by Nippon Kayaku Co., Ltd.; "BMI-70" and "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd.; and "BMI-2300" and "BMI-TMH" manufactured by Daiwa Chemical Industry Co., Ltd. Furthermore, as the maleimide resin, a maleimide resin (maleimide resin containing an indane ring skeleton) disclosed in the Japan Institute of Invention and Innovation's Disclosure Technical Bulletin No. 2020-500211 may be used.

[0125] Examples of resins having a vinylphenyl group include divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, bis(4-vinylphenyl)ether, vinylbenzyl-modified polyphenylene ether resin, etc. One type of resin having a vinylphenyl group may be used alone, or two or more types may be used in combination.

[0126] Commercially available resins having a vinylphenyl group include "OPE-2St," "OPE-2St 1200," and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether) manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0127] The unsaturated bond equivalent of the radical polymerizable resin is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., even more preferably 70 g / eq. to 2,000 g / eq., and still more preferably 90 g / eq. to 1,500 g / eq. The unsaturated bond equivalent represents the mass of the radical polymerizable resin per equivalent of unsaturated bonds.

[0128] The weight average molecular weight (Mw) of the radical polymerizable resin is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 3,000 or less. The lower limit of Mw is not particularly limited, but may be, for example, 150 or more. The Mw of the radical polymerizable resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0129] The content of the radical polymerizable resin in the resin composition layer is, for example, 0.01% by mass or more, 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, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 7.0% by mass or less.

[0130] The content of the radical polymerizable resin in the resin composition layer is, for example, 0.1% by mass or more, preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and even more preferably 3.0% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is not particularly limited, but is, for example, 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 27% by mass or less.

[0131] The content of component (B) contained in the resin composition layer 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 40% by mass or less, more preferably 30% by mass or less, and even more preferably 27% by mass or less, assuming that the non-volatile components in the resin composition layer are 100% by mass.

[0132] The content of component (B) contained in the resin composition layer is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, and is preferably 95% by mass or less, more preferably 92% 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.

[0133] The mass ratio of the (B) component to the (A) component contained in the resin composition layer (content of the (B) component / content of the (A) component) is preferably 1 or more, more preferably 3 or more, even more preferably 4 or more, and is preferably 40 or less, more preferably 30 or less, even more preferably 27 or less.

[0134] <(C) Component having a polystyrene skeleton> The resin composition layer contains a component having a polystyrene skeleton as component (C).

[0135] The component (C) preferably contains a repeating unit represented by the following formula (c1):

[0136] [ka]

[0137] (In formula (c1), R 11 , R 12 and R 13 each independently represents a hydrogen atom or a substituent; R 14 each independently represents a substituent; m represents 0 or an integer of 1 to 5.

[0138] In formula (c1), R 11 , R 12 and R 13 R each independently represents a hydrogen atom or a substituent. 11 , R 12 and R 13 is preferably a hydrogen atom, an alkyl group, or an aryl group, more preferably a hydrogen atom or an alkyl group, and even more preferably a hydrogen atom or a methyl group.

[0139] In formula (c1), R 14 R each independently represents a substituent. 14 is preferably one or more substituents selected from an alkyl group, an aryl group, a hydroxy group, a carboxyl group, an amino group, and an acid anhydride group, is preferably an alkyl group, and is more preferably a methyl group.

[0140] In formula (c1), m represents an integer of 0 or an integer of 1 to 5, preferably 0 or an integer of 1 to 2, and more preferably 0 or 1.

[0141] Component (C) may contain any repeating unit other than the repeating unit represented by formula (c1). The optional repeating unit may contain only one type, or may contain two or more types in combination.

[0142] The optional repeating unit in component (C) may have a structure formed by polymerizing an optional monomer. Examples of the optional monomer include (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; and α,β-unsaturated carboxylic acids such as maleic acid and itaconic acid. One type of optional monomer may be used alone, or two or more types may be used in combination.

[0143] When component (C) contains any repeating unit, the order and individual arrangement of the repeating unit represented by formula (c1) and the optional repeating units are arbitrary, and include alternating copolymers, block copolymers, random copolymers, etc.

[0144] The amount of the repeating unit represented by formula (c1) in component (C) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total mass of component (C) (100% by mass). The upper limit of the amount of the repeating unit can be, for example, 100% by mass or less.

[0145] Component (C) contains at least one of (C1) a resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less (hereinafter sometimes referred to as a "low-molecular-weight polystyrene resin"), and (C2) particles having a polystyrene skeleton and an average particle size of less than 5 μm (hereinafter sometimes referred to as "small-particle-size polystyrene particles").

[0146] <(C1) Resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less (low-molecular-weight polystyrene-based resin)> In a preferred embodiment, the resin composition layer contains, as component (C1), a resin (low-molecular-weight polystyrene-based resin) that has a polystyrene skeleton and a weight-average molecular weight of 100,000 or less. As component (C1), the low-molecular-weight polystyrene-based resin may be used alone or in combination of two or more.

[0147] In this specification, a resin having a polystyrene skeleton (hereinafter sometimes referred to as a "polystyrene-based resin") refers to an amorphous resin component that has a polystyrene skeleton and is soluble in an organic solvent. The polystyrene-based resin is preferably a resin having rubber elasticity or a resin that exhibits rubber elasticity by polymerizing with other components. Examples of 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.

[0148] Examples of polystyrene resins include unmodified polystyrene resins, oxazoline-group-modified polystyrene resins, styrene block copolymers, etc. Examples of styrene block copolymers include styrene-isoprene-styrene block copolymers (SIS resins), styrene-ethylene-butylene-styrene block copolymers (SEBS resins), styrene-ethylene-propylene-styrene block copolymers (SEPS resins), styrene-butadiene-styrene block copolymers (SBS resins), and styrene-isobutylene-styrene block copolymers (SIBS resins).

[0149] The weight average molecular weight (Mw) of component (C1) is 100,000 or less. The weight average molecular weight (Mw) of component (C1) is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. The lower limit of the weight average molecular weight (Mw) of component (C1) is preferably 100 or more, more preferably 500 or more, and even more preferably 1,000 or more. The Mw of component (C1) can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0150] Commercially available products of component (C1) include, for example, "PX3-RP-37" and "RP-RX-61" (oxazoline group-containing modified polystyrene resins) manufactured by Nippon Shokubai Co., Ltd.; "HYBRAR 5125" (SIS resin) manufactured by Kuraray Co., Ltd.; "S1611" (SEBS resin) manufactured by Asahi Kasei Corporation; "H1041", "Tuftec H1043", "Tuftec P2000", and "Tuftec MP10" (hydrogenated styrene-based thermoplastic resins) manufactured by Asahi Kasei Corporation; "Epofriend AT501" and "CT310" (epoxidized styrene-butadiene thermoplastic resins) manufactured by Daicel Corporation; "Septon HG252" (hydroxyl group-containing modified polystyrene resin) manufactured by Kuraray Co., Ltd.; and "Tuftec N" manufactured by Asahi Kasei Corporation. Examples include "503M" (modified polystyrene resin having a carboxyl group); "Tuftec N501" (modified polystyrene resin having an amino group) manufactured by Asahi Kasei Corporation; "Tuftec M1913" (modified polystyrene resin having an acid anhydride group) manufactured by Asahi Kasei Corporation; "Septon S8104" (unmodified polystyrene resin) manufactured by Kuraray Co., Ltd.; "FG1924" (styrene-ethylene / butylene-styrene block copolymer) manufactured by Kraton; and "EF-40" manufactured by Cray Valley Corporation.

[0151] The content of the component (C1) in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, or 0.8% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 7.0% by mass or less, and even more preferably 5.0% by mass or less.

[0152] The content of the (C1) component in the resin composition layer is, relative to 100% by mass of the resin component in the resin composition layer, for example, 0.1% by mass or more, preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and even more preferably 3.0% by mass or more. The upper limit of the content is, for example, 30.0% by mass or less, preferably 25.0% by mass or less, more preferably 20.0% by mass or less, and even more preferably 18.0% by mass or less, or 17.0% by mass or less.

[0153] <(C2) Particles having a polystyrene skeleton and an average particle size of less than 5 μm (small-particle polystyrene particles)> In a preferred embodiment, the resin composition layer contains (C2) particles (small-sized polystyrene particles) having a polystyrene skeleton and an average particle size of less than 5 μm. The small-sized polystyrene particles as component (C2) may be used singly or in combination of two or more types.

[0154] In this specification, particles having a polystyrene skeleton (hereinafter sometimes referred to as "polystyrene particles") refer to a particulate rubber component that has a polystyrene skeleton and is insoluble or poorly soluble in organic solvents. The polystyrene particles are present in a particulate form in the resin composition layer and are usually contained in the cured product while maintaining their particulate form.

[0155] The average particle size of component (C2) is 5 μm or less. The average particle size of component (C2) is preferably 3 μm or less, and more preferably 1 μm or less. There is no particular lower limit to the average particle size of component (C2), and it can be, for example, 0.01 μm or more, 0.05 μm or more, or 0.1 μm or more.

[0156] The average particle size of component (C2) can be measured using a laser diffraction particle size distribution analyzer (e.g., Shimadzu Corporation's "SALD-2100"). This analyzer can measure the volume-average particle size as the average particle size of component (C2). Measurement can be performed by dispersing component (C2) in an organic solvent that does not dissolve component (C2). To prevent aggregation of component (C2), a low-polarity or medium-polarity solvent is usually used as the organic solvent, and toluene or tetrahydrofuran (THF) is preferably used.

[0157] Particles of component (C2) may have a uniform composition throughout the particle, or the particle may have a heterogeneous composition. When the components contained in particles of component (C2) are classified by composition, the particles typically include a shell portion exposed on the particle surface. This shell portion corresponds to the outermost layer of the particle of component (C2). Therefore, particles of component (C2) having a uniform composition can be understood as being formed entirely by the shell portion. Particles of component (C2) having a heterogeneous composition may have a shell portion and a core portion formed within the shell portion. In this case, particles of component (C2) may further include an optional portion within the core portion, or may include an optional portion between the shell portion and the core portion. Here, the shell portion and the core portion do not need to be clearly distinguishable, and the boundary between the shell portion and the core portion may be unclear. Furthermore, the core portion may be covered by the shell portion, or may not be completely covered. Furthermore, particles of component (C2) may have a hollow portion within the shell portion.

[0158] Component (C2) may or may not be treated with a surface treatment agent. Examples of surface treatment agents for component (C2) include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid; carboxylic acids such as acetic acid, propionic acid, butyric acid, and acrylic acid; sulfonic acids such as p-toluenesulfonic acid, ethylsulfonic acid, and dodecylbenzenesulfonic acid; phosphoric acids such as polyoxyethylene alkyl ether phosphoric acid; organic acids such as phosphonic acid and phosphinic acid; silane coupling agents such as tetraethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, and 8-(meth)acryloxyoctyltrimethoxysilane; and isocyanate compounds such as ethyl isocyanate. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

[0159] Commercially available products of component (C2) include the "SEP-03T" series, such as "SEP-03T3," "SEP-03T3A," "SEP-03T4," "SEP-03T3AB," "SEP-03T3AC," and "SEP-03T3AD," manufactured by Negami Chemical Industries, Ltd., and "SSD-001T"; "XX-6283Z," "XX-6288Z," "XX-6145Z," and "XX- Examples of such polystyrene foams include "XX-6229Z", "XX-6283Z", "XX-6214Z (hollow polystyrene)", and "XX-6430Z (hollow polystyrene)" manufactured by Aica Kogyo Co., Ltd.; "PS-050-1", "PS-050-2", and "GS-0305" manufactured by Morimoto Chemical Co., Ltd.; "SB-25" and "SB-25N" manufactured by Aica Kogyo Co., Ltd.; and "SX-130H" and "SX-350H" manufactured by Soken Chemical & Engineering Co., Ltd.

[0160] The content of the (C2) component in the resin composition layer is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, or 0.8% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer. The upper limit of the content is, for example, 15.0% by mass or less, preferably 10.0% by mass or less, more preferably 5.0% by mass or less, even more preferably 3.0% by mass or less, or 2.5% by mass or less.

[0161] The content of the (C2) component in the resin composition layer is, for example, 0.1% by mass or more, preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and even more preferably 3.0% by mass or more, based on 100% by mass of the resin component in the resin composition layer. The upper limit of the content is, for example, 20.0% by mass or less, preferably 15.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less or 7.0% by mass or less.

[0162] The total content of the (C1) component and the (C2) component contained in the resin composition layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, or 0.8% by mass or more, and is preferably 15.0% by mass or less, more preferably 10.0% by mass or less, even more preferably 8.0% by mass or less, or 7.0% by mass or less, based on 100% by mass of the non-volatile components in the resin composition layer.

[0163] The total content of the (C1) component and the (C2) component contained in the resin composition layer is preferably 1.0 mass% or more, more preferably 2.0 mass% or more, and even more preferably 3.0 mass% or more, and is preferably 30.0 mass% or less, more preferably 25.0 mass% or less, and even more preferably 23.0 mass% or less, or 22.0 mass% or less, when the resin components in the resin composition layer are taken as 100 mass%.

[0164] The mass ratio of the (C1) component and the (C2) component to the (A) component contained in the resin composition layer (total content of the (C1) component and the (C2) component / content of the (A) component) is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.4 or more, and is preferably 10.0 or less, more preferably 7.0 or less, even more preferably 5.0 or less.

[0165] <(D) Inorganic filler> The resin composition layer may further contain an inorganic filler as component (D). By including component (D), the thermal expansion coefficient and dielectric loss tangent tend to be further reduced.

[0166] Examples of materials for component (D) include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum silicate, 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. Spherical silica is preferred. Component (D) may be used alone or in combination.

[0167] Commercially available products of component (D) include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-03," and "FB-105FD" manufactured by Denka Company, Limited; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "Cellspheres" and "MGH-005" manufactured by Taiheiyo Cement Corporation; and "Sferique" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0168] The average particle size of component (D) is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, 2 μm or less, 1 μm or less, or 0.7 μm or less. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.07 μm or more, 0.1 μm or more, or 0.2 μm or more. The average particle size of component (D) can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis 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 measurement sample was measured using a laser diffraction particle size distribution analyzer, with blue and red light source wavelengths used, and the particle size distribution of the inorganic filler on a volume basis was measured using a flow cell system, and the average particle size was calculated as the median diameter from the particle size distribution obtained. An example of a laser diffraction particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0169] The specific surface area of ​​component (D) is not particularly limited, but is preferably 0.1 m 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, 3m 2 / g or more or 5m 2 The upper limit of the specific surface area is not particularly limited, but is preferably 100 m 2 / g or less, more preferably 80m 2 / g or less, more preferably 60m 2 / g or less, 50m 2 / g or less or 40m 2 The specific surface area of ​​component (D) is determined in accordance with the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Mountech Co., Ltd., "Macsorb HM-1210") and calculating the specific surface area using the BET multipoint method.

[0170] Component (D) is preferably surface-treated with an appropriate surface treatment agent. This surface treatment can enhance the moisture resistance and dispersibility of component (D). Examples of surface treatment agents include silane coupling agents such as vinyl silane coupling agents, epoxy silane coupling agents, styryl silane coupling agents, (meth)acrylic silane coupling agents, amino silane coupling agents, isocyanurate silane coupling agents, ureido silane coupling agents, mercapto silane coupling agents, isocyanate silane coupling agents, and acid anhydride silane coupling agents; non-silane coupling alkoxysilane compounds such as methyltrimethoxysilane and phenyltrimethoxysilane; and silazane compounds. The surface treatment agents may be used alone or in combination of two or more.

[0171] Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd.

[0172] 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.

[0173] 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 2On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition or the melt viscosity in the form of a sheet, it is 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. The carbon amount per unit surface area of ​​component (D) 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. The supernatant is removed, the solid content is dried, and then the carbon amount 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.

[0174] When the resin composition layer contains component (D), the content of component (D) in the resin composition is, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, 65% by mass or more, or 70% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition layer, from the viewpoint of realizing a cured product exhibiting an even lower dielectric tangent and thermal expansion coefficient. The upper limit of the content of component (D) is not particularly limited, but may be, for example, 90% by mass or less, 85% by mass or less, 80% by mass or less, 77% by mass or less, or 75% by mass or less.

[0175] <(E) Curing accelerator> The resin composition layer may further contain a curing accelerator as the component (E).

[0176] Examples of component (E) include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, peroxide-based curing accelerators, etc. One type of curing accelerator may be used alone, or two or more types may be used in combination.

[0177] 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;

[0178] Examples of the amine-based curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0179] As the amine-based curing accelerator, commercially available products may be used, such as "DMAP" manufactured by Tokyo Chemical Industry Co., Ltd. and "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd.

[0180] 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, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-methyl ... 1-Cyanoethyl-2-undecylimidazole, 1-Cyanoethyl-2-ethyl-4-methylimidazole, 1-Cyanoethyl-2-phenylimidazole, 1-Cyanoethyl-2-undecylimidazole trimellitate, 1-Cyanoethyl-2-phenylimidazolium trimellitate, 2,4-Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-Diamino-6-[2'-undecylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H imidazole compounds such as 1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, 1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 6-2-(2-methyl-1H-imidazol-1-yl)ethyl-1,3,5-triazine-2,4-diamine; mixtures of these; and adducts of imidazole compounds with epoxy resins.

[0181] As the imidazole-based curing accelerator, commercially available products may be used, such as "1B2PZ", "2MZA-PW", "2PHZ-PW", "C11Z-A", "2MAOK-PW", and "2E4MZ" manufactured by Shikoku Chemical Industry Co., Ltd., and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0182] 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.

[0183] 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.

[0184] Examples of peroxide-based curing accelerators include cyclohexanone peroxide, tert-butyl peroxybenzoate, methyl ethyl ketone peroxide, dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, and tert-butyl hydroperoxide. Commercially available peroxide-based curing accelerators can be used, such as "Percumyl D" manufactured by NOF Corporation.

[0185] When the resin composition layer contains the (E) component, the content of the (E) component in the resin composition layer is, when the non-volatile components in the resin composition layer are taken as 100% by mass, for example, 0.001% by mass or more, preferably 0.010% by mass or more, more preferably 0.020% by mass or more, and even more preferably 0.030% by mass or more, and for example, 1.000% by mass or less, preferably 0.500% by mass or less, more preferably 0.300% by mass or less, and even more preferably 0.200% by mass or less, or 0.150% by mass or less.

[0186] When the resin composition layer contains the (E) component, the content of the (E) component in the resin composition layer is, when the resin component in the resin composition layer is taken as 100% by mass, for example, 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.08% by mass or more, and even more preferably 0.10% by mass or more, and for example, 5.00% by mass or less, preferably 1.00% by mass or less, more preferably 0.70% by mass or less, and even more preferably 0.50% by mass or less.

[0187] <(F) Other additives> The resin composition layer may further contain (F) other additives in addition to the above-described components (A) to (E). Examples of such additives include radical polymerization initiators such as peroxide radical polymerization initiators and azo radical polymerization initiators; thermoplastic resins such as polyvinyl acetal resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, and polyester resins; 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 leveling agents and acrylic polymer leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone antifoaming agents, acrylic antifoaming agents, fluorine-based antifoaming agents, and vinyl resin antifoaming agents; and ultraviolet absorbing agents such as benzotriazole ultraviolet absorbers. surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The content of such additives may be determined depending on the properties required for the resin composition. (F) Other additives may be used alone or in combination of two or more.

[0188] <(G) Organic Solvent> The resin composition layer may further contain (G) an organic solvent as a volatile component in addition to the nonvolatile components (A) to (E) described above. Examples of (G) organic solvents 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, and diphenyl ether; 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 organic solvents include ether ester 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. (G) Organic solvents may be used singly or in combination of two or more.

[0189] From the viewpoint of thinning, the thickness of the resin composition layer is preferably 600 μm or less, more preferably 550 μm or less, and even more preferably 500 μm or less, 400 μm or less, 350 μm or less, 300 μm or less, or 250 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be, for example, 1 μm or more, 5 μm or more, or 10 μm or more.

[0190] <Other layers> In one embodiment, the resin sheet may further include other layers as necessary. Examples of such other layers include a protective film provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed.

[0191] [Manufacturing method of 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 an organic solvent, applying the resin varnish to a support using a die coater or the like, and then drying the varnish to form a resin composition layer. As the organic solvent, the organic solvents described above can be used.

[0192] Drying may be carried out by known methods such as heating or hot air blowing. Drying conditions are not particularly limited, but drying is carried out so that the content of organic solvent 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 varnish, for example, when a resin varnish 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 1 minute to 10 minutes.

[0193] The resin sheet can be stored in a rolled state. When the resin sheet has a protective film, it can be used by peeling off the protective film.

[0194] [Characteristics and uses of resin sheets] The resin composition layer contained in the resin sheet contains a combination of the (A) component, the (B) component, and the (C) component (and, as necessary, the (D), the (E), the (F), and the (G) component), and therefore can form a cured product that has a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with the conductor layer.

[0195] The cured product of the resin composition layer contained in the resin sheet is characterized by a low dielectric dissipation factor (Df). Therefore, the cured product provides an insulating layer with a low dielectric dissipation factor. For example, when measured at 5.8 GHz and 23°C as described in the section <Test Example 1: Measurement of Dielectric Dissipation Factor (Df)> below, the dielectric dissipation factor of the cured product obtained by thermally curing the resin composition layer at 190°C for 90 minutes is preferably less than 0.0045, more preferably 0.0042 or less, and even more preferably 0.0040 or less. The lower limit of the dielectric dissipation factor may be 0.0001 or more.

[0196] The cured product of the resin composition layer contained in the resin sheet exhibits excellent smear removability. The maximum smear length of the cured product is preferably less than 5 μm. The "maximum smear length" refers to the maximum length of the smear from the circumference of the bottom of the via to the center of the circle. The evaluation of the maximum smear length can be measured according to the method described in the section <Test Example 2: Evaluation of Smear Removability> below.

[0197] The insulating layer formed from the cured resin composition layer contained in the resin sheet exhibits excellent adhesive strength (peel strength) between the insulating layer and the conductor layer. The adhesive strength is preferably 0.30 kgf / cm or more, more preferably 0.35 kgf / cm or more, and even more preferably 0.40 kgf / cm or more. The peel strength can be measured according to the method described in the section <Test Example 3: Measurement of adhesive strength (peel strength) with conductor layer> below.

[0198] As described above, the resin composition layer contained in the resin sheet can form a cured product having a low dielectric tangent, excellent smear removal properties, and excellent adhesion strength with a conductor layer. Therefore, the resin sheet of the present invention can be suitably used as a resin sheet for forming an insulating layer of a semiconductor package substrate.

[0199] Examples of semiconductor packages include FC-CSP, MIS-BGA package, ETS-BGA package, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. The resin sheet of the present invention can be suitably used in such semiconductor packages to form an insulating layer of a rewiring substrate or a circuit board for electrically connecting a semiconductor chip to a printed wiring board (motherboard). In the present invention, these rewiring substrates and circuit boards are collectively referred to as "semiconductor package substrates."

[0200] [Semiconductor package substrate] A semiconductor package substrate (and thus a semiconductor package) according to one embodiment of the present invention includes an insulating layer formed from a cured product of the resin composition layer contained in the resin sheet. The insulating layer includes a cured product of the resin composition layer contained in the resin sheet, and preferably includes only a cured product of the resin composition layer contained in the resin sheet. Examples of this semiconductor package substrate include the circuit boards and rewiring boards used in the semiconductor packages described below.

[0201] A semiconductor package according to a first example 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 package can be produced by bonding the semiconductor chip to the circuit board. The circuit board will be described later.

[0202] The bonding conditions for the circuit board and the semiconductor chip can be any conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the circuit wiring of the circuit board. For example, the conditions used in flip-chip mounting of semiconductor chips can be used. Furthermore, for example, the semiconductor chip and the circuit board can be bonded via an insulating adhesive.

[0203] An example of a bonding method is a method in which a semiconductor chip is pressure-bonded to a circuit board. Pressure-bonding conditions are a pressure-bonding temperature typically 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 typically in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

[0204] Another example of a bonding method is to bond the semiconductor chip to the circuit board by reflow. The reflow conditions may be in the range of 120°C to 300°C.

[0205] After bonding the semiconductor chip to the circuit board, the semiconductor chip may be filled with a mold underfill material, which may be made of the components contained in the resin composition layer described above.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] The support may be removed between step (I) and step (II), or may be removed after step (II).

[0213] 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 circuit board.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] A semiconductor package according to the second example includes a semiconductor chip and an insulating layer formed of a cured resin composition layer. Examples of semiconductor packages according to the second example include fan-out WLPs and fan-out PLPs. Specifically, the semiconductor package may include a semiconductor chip; a sealing layer formed to cover the periphery of the semiconductor chip; a rewiring layer serving as an insulating layer provided on the surface of the semiconductor chip opposite the sealing layer; a rewiring layer serving as a conductor layer; a solder resist layer; and bumps. In the present invention, the laminated structure consisting of the rewiring layer (insulating layer) and the rewiring layer (conductor layer) is also referred to as a rewiring substrate.

[0230] A method for manufacturing such a semiconductor package includes, for example, (i) a step of laminating a temporary fixing film on a substrate; (ii) a step of temporarily fixing the semiconductor chip on the temporary fixing film; (iii) forming an encapsulation layer on the semiconductor chip; (iv) peeling the substrate and the temporary fixing film from the semiconductor chip; (v) forming a rewiring formation layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off; and (vi) A step of forming a rewiring layer as a conductor layer on the rewiring formation layer. The method for manufacturing the semiconductor package further includes: (vii) forming a solder resist layer on the rewiring layer; (viii) Step of forming bumps (ix) A process of dicing and singulating a plurality of semiconductor packages into individual semiconductor packages. may also include:

[0231] Step (i) is a step of laminating a temporary fixing film on a substrate.

[0232] Examples of the substrate include silicon wafers; glass wafers; glass substrates; metal substrates such as copper, titanium, stainless steel, and cold-rolled steel sheets (SPCC); substrates such as FR-4 substrates in which glass fibers are impregnated with epoxy resin or the like and then thermoset; substrates made of bismaleimide triazine resins such as BT resin; and polyimide substrates.

[0233] The temporary fixing film may be made of any material that can be peeled off from the semiconductor chip and can temporarily fix the semiconductor chip. Commercially available products include "Riva Alpha" manufactured by Nitto Denko Corporation.

[0234] The substrate and the temporary fixing film can be laminated, for example, by thermocompression bonding the temporary fixing film to the substrate. Examples of a member for thermocompression bonding the temporary fixing film to the 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 instead of pressing the thermocompression bonding member directly onto the temporary fixing film, pressing may be performed via an elastic material such as heat-resistant rubber so that the temporary fixing film can sufficiently conform to the surface irregularities of the substrate.

[0235] The substrate and the temporary fixing film may be laminated 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 26.7 hPa or less.

[0236] 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.

[0237] After lamination, the laminated temporary fixing film may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the temporary fixing film side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. The smoothing treatment may be carried out using a commercially available laminator. Note that lamination and smoothing treatment may be carried out consecutively using the commercially available vacuum laminator.

[0238] Step (ii) is a step of temporarily fixing the semiconductor chips on the temporary fixing film. The temporary fixing of the semiconductor chips can be performed using, for example, a device such as a flip chip bonder or a die bonder. The layout and number of semiconductor chips to be arranged can be appropriately set depending on the shape and size of the temporary fixing film, the number of semiconductor packages to be produced, etc. For example, the semiconductor chips may be temporarily fixed by arranging them in a matrix of multiple rows and multiple columns.

[0239] Step (iii) is a step of forming an encapsulating layer on the semiconductor chip. The encapsulating layer is usually formed by a method including forming a resin composition layer for the encapsulating layer on the semiconductor chip and curing the resin composition layer to form the encapsulating layer. The resin composition layer for the encapsulating layer may be formed from a thermosetting resin composition or a photocurable resin composition. Furthermore, the resin composition layer contained in the above-mentioned resin sheet may be used as the resin composition layer for the encapsulating layer.

[0240] The encapsulating layer is usually formed by a method including a step of forming an encapsulating resin composition layer made of an encapsulating resin composition on a semiconductor chip, and a step of thermally curing the encapsulating resin composition layer to form the encapsulating layer.

[0241] The encapsulating resin composition layer may be formed by a compression molding method, in which a semiconductor chip and the encapsulating resin composition are typically placed in a mold, and pressure and, if necessary, heat are applied to the encapsulating resin composition in the mold to form an encapsulating resin composition layer that covers the semiconductor chip.

[0242] Specific operations of the compression molding method can be, for example, as follows. An upper mold and a lower mold are prepared as molds for compression molding. An encapsulating resin composition is applied to the semiconductor chip temporarily fixed on the temporary fixing film as described above. The semiconductor chip to which the encapsulating resin composition has been applied is attached to the lower mold together with the substrate and the temporary fixing film. Thereafter, the upper and lower molds are clamped together, and heat and pressure are applied to the encapsulating resin composition to perform compression molding.

[0243] Furthermore, specific operations of the compression molding method may be, for example, as follows: An upper mold and a lower mold are prepared as molds for compression molding. An encapsulating resin composition is placed on the lower mold. A semiconductor chip is attached to the upper mold together with a substrate and a temporary fixing film. Thereafter, the upper and lower molds are clamped together so that the encapsulating resin composition placed on the lower mold contacts the semiconductor chip attached to the upper mold, and heat and pressure are applied to perform compression molding.

[0244] The molding conditions vary depending on the composition of the encapsulating resin composition, and appropriate conditions can be adopted to achieve good encapsulation. For example, the mold temperature during molding is preferably a temperature at which the encapsulating resin composition exhibits excellent compression moldability, and is preferably 80°C or higher, more preferably 100°C or higher, particularly preferably 120°C or higher, and preferably 200°C or lower, more preferably 170°C or lower, and particularly preferably 150°C or lower. The pressure applied during molding is preferably 1 MPa or higher, more preferably 3 MPa or higher, particularly preferably 5 MPa or higher, and preferably 50 MPa or lower, more preferably 30 MPa or lower, and particularly preferably 20 MPa or lower. The cure time is preferably 1 minute or longer, more preferably 2 minutes or longer, particularly preferably 5 minutes or longer, and preferably 60 minutes or shorter, more preferably 30 minutes or shorter, and particularly preferably 20 minutes or shorter. Typically, the mold is removed after the encapsulating resin composition layer is formed. The mold may be removed before or after the encapsulating resin composition layer is thermally cured.

[0245] The encapsulating resin composition layer may be formed by laminating an encapsulating resin sheet and a semiconductor chip. For example, the encapsulating resin composition layer of the encapsulating resin sheet and the semiconductor chip are heat-pressed together to form the encapsulating resin composition layer on the semiconductor chip. The lamination of the encapsulating resin sheet and the semiconductor chip can usually be performed in the same manner as the lamination of the substrate and the temporary fixing film, using the semiconductor chip instead of the substrate.

[0246] After forming the encapsulating resin composition layer on the semiconductor chip, the encapsulating resin composition layer is thermally cured to obtain an encapsulating layer that covers the semiconductor chip, thereby encapsulating the semiconductor chip with the cured product of the encapsulating resin composition.

[0247] The thermal curing conditions for the encapsulating resin composition layer vary depending on the type of encapsulating resin composition, but the curing temperature is preferably 120° C. to 240° C., more preferably 150° C. to 220° C., and even more preferably 170° C. to 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.

[0248] Before thermally curing the encapsulating resin composition layer, the encapsulating resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the encapsulating resin composition layer, the encapsulating resin composition layer may be preheated at a temperature of 50°C or higher but lower than 120°C (preferably 60°C or higher but 115°C or lower, more preferably 70°C or higher but 110°C or lower) for 5 minutes or longer (preferably 5 to 150 minutes, more preferably 15 to 120 minutes, and even more preferably 15 to 100 minutes).

[0249] Step (iv) is a step of peeling the substrate and the temporary fixing film from the semiconductor chip. It is desirable to adopt an appropriate peeling method depending on the material of the temporary fixing film. Examples of peeling methods include a method in which the temporary fixing film is heated, foamed, or expanded to peel it off. Another example of a peeling method is a method in which the temporary fixing film is irradiated with ultraviolet light through the substrate to reduce the adhesive strength of the temporary fixing film, thereby peeling it off.

[0250] In the method of peeling off the temporary fixing film by heating, foaming or expanding it, the heating conditions are usually 100°C to 250°C for 1 second to 90 seconds or 5 minutes to 15 minutes. In the method of peeling off the temporary fixing film by irradiating it with ultraviolet light to reduce the adhesive strength of the temporary fixing film, the irradiation dose of ultraviolet light is usually 10 mJ / cm. 2 ~1000mJ / cm 2 is.

[0251] Step (v) is a step of forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off. The rewiring formation layer is usually formed on the semiconductor chip and the sealing layer.

[0252] The insulating layer included in the rewiring formation layer is formed using the resin sheet of the present invention. Specifically, a resin composition layer is formed on the sealing layer by laminating the resin sheet of the present invention on the sealing layer. The lamination of the sealing layer and the resin sheet can be performed by thermocompression bonding the resin sheet to the sealing layer from the support side. Examples of a member (thermocompression bonding member) that thermocompresses the resin sheet to the sealing layer include a heated metal plate (e.g., a SUS panel) or a metal roll (e.g., a SUS roll). Note that instead of directly pressing the resin sheet with the thermocompression bonding member, the resin sheet may be pressed via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the sealing layer.

[0253] The sealing layer and the resin sheet may be laminated by a vacuum lamination method, in which the temperature for heat and pressure bonding is preferably 60°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher, and is preferably 160°C or lower, more preferably 140°C or lower, and even more preferably 100°C or lower.

[0254] The thermocompression pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, 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 26.7 hPa or less.

[0255] The lamination can be carried out using a commercially available vacuum laminator, which may be the same as the commercially available vacuum laminator that can be used to laminate the substrate and the temporary fixing film.

[0256] After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the resin sheet 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.

[0257] After lamination, 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 vary depending on the components contained in the resin composition layer. In one example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0258] Step (v) preferably includes preheating the resin composition layer at a temperature lower than the curing temperature before thermally curing the resin composition layer. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C for typically 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0259] After forming the insulating layer, via holes for interlayer connection between the semiconductor chip and the rewiring layer may be formed in the insulating layer. Examples of methods for forming the via holes include laser irradiation, etching, and mechanical drilling. Laser irradiation is preferred. Laser irradiation can be performed using an appropriate laser processing machine that uses a light source such as a carbon dioxide laser, a UV-YAG laser, or an excimer laser.

[0260] The shape of the via hole is not particularly limited, but is generally circular (approximately circular). The top diameter of the via hole is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less, and is preferably 3 μm or more, preferably 10 μm or more, and more preferably 15 μm or more. Here, the top diameter of the via hole refers to the diameter of the opening of the via hole at the surface of the insulating layer in the redistribution layer.

[0261] After forming the via hole in the insulating layer, a desmearing process may be performed. Smears as resin residues may be present inside the via hole. Since these smears may cause poor electrical connection, a desmearing process may be performed to remove the smears.

[0262] The desmearing treatment may be performed by a dry desmearing treatment, a wet desmearing treatment, or a combination thereof.

[0263] An example of a dry desmear treatment is a desmear treatment using plasma. In the desmear treatment using plasma, a gas is introduced into a plasma generator to generate plasma, and the plasma is used to treat the insulating layer, thereby removing smears generated in the via hole. The method for generating plasma is not particularly limited, and examples include microwave plasma, which generates plasma using microwaves, high-frequency plasma, atmospheric pressure plasma, which is generated under atmospheric pressure, and vacuum plasma, which is generated under vacuum, with vacuum plasma, which is generated under vacuum, being preferred. Furthermore, the plasma used in the desmear treatment is preferably RF plasma, which is excited by high frequency.

[0264] The gas to be converted into plasma is not particularly limited as long as it can remove smears from inside the holes, and it is preferable to use, for example, a gas containing fluorine atoms, or a gas containing either N or O. Examples of gases containing fluorine atoms include F, CF, CF, and SF. In this case, in addition to the gas containing fluorine atoms, N, or O, other gases such as Ar may be contained. Among these, from the viewpoint of improving smear removal, the gas species preferably contains a gas containing fluorine atoms, either N or O, more preferably a gas containing fluorine atoms and O, even more preferably a mixed gas containing O and at least one of N and CF, and even more preferably a mixed gas containing O and CF.

[0265] The time for the desmear treatment using plasma is not particularly limited, but is preferably 30 seconds or more, more preferably 60 seconds or more, 90 seconds or more, or 120 seconds or more. The upper limit of the time for the desmear treatment is preferably 10 minutes or less, more preferably 5 minutes or less.

[0266] The desmear treatment using plasma can be carried out using a commercially available plasma desmear treatment device. Among commercially available plasma desmear treatment devices, examples suitable for circuit board manufacturing applications include a plasma dry etching device manufactured by Oxford Instruments, a microwave plasma device manufactured by Nissin, and an atmospheric pressure plasma etching device manufactured by Sekisui Chemical Co., Ltd.

[0267] The dry desmearing treatment may also be a dry sandblasting treatment in which an abrasive is sprayed from a nozzle to polish the treatment object. The dry sandblasting treatment can be performed using a commercially available dry sandblasting treatment device. When a water-soluble abrasive is used as the abrasive, washing with water after the dry sandblasting treatment prevents the abrasive from remaining inside the via hole, and smears can be effectively removed.

[0268] Examples of wet desmear treatments include desmear treatments using an oxidizing agent solution, etc. When desmear treatments using an oxidizing agent solution are performed, it is preferable to perform a swelling treatment using a swelling liquid, an oxidation treatment using an oxidizing agent solution, and a neutralization treatment using a neutralizing liquid in this order.

[0269] Examples of swelling liquids include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solutions and potassium hydroxide solutions are more preferred as alkaline solutions. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. Swelling treatment with a swelling liquid may be performed by immersing the film in the swelling liquid at 30°C to 90°C for 1 to 20 minutes.

[0270] The oxidizing agent solution is preferably an alkaline permanganate aqueous solution, such as a solution prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment using the oxidizing agent solution is preferably carried out by immersing the solder resist layer in the 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% 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.

[0271] The neutralizing solution is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralizing solution may be carried out by immersing the surface that has been roughened with an oxidizing agent in the neutralizing solution at 30°C to 80°C for 5 to 30 minutes.

[0272] When the dry desmear treatment and the wet desmear treatment are performed in combination, the dry desmear treatment may be performed first, or the wet desmear treatment may be performed first.

[0273] The support in the resin sheet may be peeled off before or after the heat curing.

[0274] An insulating adhesive such as polyimide may be interposed between the insulating layer and the semiconductor chip.

[0275] Step (vi) is a step of forming a redistribution layer as a conductor layer on the redistribution formation layer. The conductor material used for the redistribution layer is not particularly limited. In a preferred embodiment, the redistribution 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 redistribution 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 redistribution 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.

[0276] The rewiring layer may have a single layer structure, or may have 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.

[0277] The thickness of the rewiring 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.

[0278] The conductor layer is preferably formed by plating. For example, a rewiring layer having a desired wiring pattern can be formed by plating the surface of the rewiring formation layer by a method such as a semi-additive method or a full-additive method. From the viewpoint of ease of manufacturing, the semi-additive method is preferable. An example of forming a rewiring layer by a semi-additive method will be described below.

[0279] A plating seed layer is formed on the surface of the rewiring formation layer. 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.

[0280] The plating seed layer may be formed by dry plating or wet plating. Examples of dry plating include physical vapor deposition (PVD) methods such as sputtering, ion plating, and vacuum deposition, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. Examples of wet plating include electroless plating.

[0281] The rewiring layer may be patterned. In this case, the line (circuit width) / space (width between circuits) ratio of the conductor layer is not particularly limited, but is preferably 20 / 20 μm or less (i.e., a pitch of 40 μm or less), more preferably 10 / 10 μm or less, even more preferably 5 / 5 μm or less, even more preferably 1 / 1 μm or less, and particularly preferably 0.5 / 0.5 μm or more. The pitch does not need to be uniform throughout the conductor layer. The minimum pitch of the conductor layer may be, for example, 40 μm or less, 36 μm or less, or 30 μm or less.

[0282] Furthermore, the steps (v) and (vi) may be repeated to alternately build up rewiring layers (conductor layers) and rewiring formation layers (insulating layers).

[0283] The manufacturing of the semiconductor package may further include the steps of (vii) forming a solder resist layer on the conductor layer (rewiring layer), (viii) forming bumps, and (ix) dicing the plurality of semiconductor packages into individual semiconductor packages. These steps may be performed according to various methods known to those skilled in the art for use in manufacturing semiconductor packages.

[0284] [Semiconductor Devices] Examples of semiconductor devices on which the above-mentioned semiconductor package is mounted 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]

[0285] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm), unless otherwise specified.

[0286] <Synthesis Example 1: Synthesis of carbodiimide resin represented by formula (S1)>

[0287] [ka]

[0288] 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.

[0289] 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. -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 (S1); b' means the average degree of polymerization of the carbodiimide group).

[0290] <Synthesis Example 2: Synthesis of carbodiimide resin represented by formula (S2)>

[0291] [ka]

[0292] 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.

[0293] <Synthesis Example 3: Synthesis of carbodiimide resin represented by formula (S3)>

[0294] [ka]

[0295] 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.

[0296] <Synthesis Example 4: Synthesis of carbodiimide resin represented by formula (S4)>

[0297] [ka]

[0298] 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.

[0299] <Synthesis Example 5: Synthesis of carbodiimide resin represented by formula (S5)>

[0300] [ka]

[0301] 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).

[0302] <Examples 1 to 16 and Comparative Examples 1 to 6: Preparation of Resin Compositions (Resin Varnishes)> Each component was weighed out in the amount of parts by mass shown in Table 1 below, and then mixed with 15 parts of methyl ethyl ketone (MEK) and 15 parts of cyclohexanone, and uniformly dispersed using a high-speed rotating mixer to obtain a resin composition (resin varnish). Details of each component shown in Table 1 below are as follows.

[0303] (A) Carbodiimide resin containing unsaturated bonds "Synthesis Example 1": Carbodiimide resin represented by formula (S1) synthesized in Synthesis Example 1 "Synthesis Example 2": Carbodiimide resin represented by formula (S2) synthesized in Synthesis Example 2 "Synthesis Example 3": Carbodiimide resin represented by formula (S3) synthesized in Synthesis Example 3 "Synthesis Example 4": Carbodiimide resin represented by formula (S4) synthesized in Synthesis Example 4 "Synthesis Example 5": Carbodiimide resin represented by formula (S5) synthesized in Synthesis Example 5

[0304] (A') Other carbodiimide resins "V-03": Carbodiimide resin (Nisshinbo Chemical Co., Ltd., toluene solution with 50% non-volatile components)

[0305] (B) Thermosetting resin "OPE-2St 1200": Vinylbenzyl-modified polyphenylene ether resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., toluene solution with 65% non-volatile content) SLK-6895-T90: Bismaleimide resin (manufactured by Shin-Etsu Chemical Co., Ltd., maleimide equivalent weight approximately 345 g / eq., toluene solution with 90% non-volatile components) "MIR-3000-70MT": Aromatic maleimide resin (manufactured by Nippon Kayaku Co., Ltd., MEK / toluene mixed solution with 70% non-volatile content) "ZX-1059": Bisphenol epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., a 1:1 mixture of bisphenol A and bisphenol F, epoxy equivalent weight 169g / eq.) NC3000H: Biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd., epoxy equivalent: approx. 269 g / eq.) HP4032SS: Naphthalene-type epoxy resin (DIC Corporation, epoxy equivalent weight: approx. 144g / eq.) "YX4000HK": Bixylenol epoxy resin (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 185g / eq.) "HPC-8000-65T": Active ester compound (DIC Corporation, active group equivalent weight approximately 223 g / eq., toluene solution with 65% non-volatile content) LA-3018-50P: Triazine skeleton-containing phenolic resin (DIC Corporation, hydroxyl equivalent weight approximately 151 g / eq., 1-methoxy-2-propanol solution with 50% non-volatile content) BA230S75: Bisphenol A dicyanate prepolymer (manufactured by Arxada, cyanate equivalent weight approximately 235g / eq., MEK solution with 75% non-volatile content) "PT30": Phenol novolac type multifunctional cyanate ester resin (manufactured by Arxada, cyanate equivalent weight approximately 124g / eq.) "A-DOG": Dioxane acrylic monomer (manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0306] (C1) Low molecular weight polystyrene resin (polystyrene resin with a weight average molecular weight (Mw) of 100,000 or less) "PX-3-RP-61": Oxazoline group-containing polystyrene resin (Nippon Shokubai Co., Ltd., weight-average molecular weight (Mw) 25,000) L-SBR-870: Vinyl-containing liquid styrene / butadiene resin (Kuraray Co., Ltd., weight-average molecular weight (Mw) 6,000) "FTR0100": α-methylstyrene homopolymer resin (Mitsui Chemicals, weight-average molecular weight (Mw) 2,000) "FTR2085": α-methylstyrene / styrene homopolymer resin (Mitsui Chemicals, weight-average molecular weight (Mw) 1,500)

[0307] (C2) Small particle size polystyrene resin (polystyrene particles with an average particle size of less than 5 μm) · "SEP-03T": Polystyrene particles (manufactured by Negami Kogyo Co., Ltd., average particle size 0.3 μm)

[0308] (C1') High molecular weight polystyrene resin (weight average molecular weight (Mw) of 100,000 or more) "HRM26": Polystyrene resin (manufactured by Toyo Styrene Co., Ltd., weight average molecular weight (Mw) 320,000)

[0309] (C2') Polystyrene particles with an average particle size of 5 μm or more "G-800T": Polystyrene particles (manufactured by Negami Chemical Industries, average particle size 6.0 μm)

[0310] (D) Inorganic filler "SO-C2": Spherical silica (average particle size 0.5 μm, manufactured by Admatechs Co., Ltd.) surface-treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.)

[0311] (E) Curing accelerator "DMAP": 4-dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.) "Co(acac)3": Cobalt(III) acetylacetonate (Tokyo Chemical Industry Co., Ltd.)

[0312] (F) Other additives "YX7200BH35": Phenoxy resin (Mitsubishi Chemical Corporation, cyclohexanone solution with 35% non-volatile components)

[0313] [Table 1]

[0314] <Preparation of Resin Sheet A> A polyethylene terephthalate film ("Lumirror R80" manufactured by Toray Industries, Inc., thickness 38 μm, softening point 130°C) was prepared, which had been subjected to a release treatment with an alkyd resin-based release agent ("AL-5" manufactured by Lintec Corporation). The resin compositions obtained in the Examples and Comparative Examples were each uniformly applied to the support using a die coater so that the thickness of the resin composition layer after drying was 40 μm. The resin composition layer was then dried at 70 to 90°C for 3 minutes to form a resin composition layer on the support. Next, the rough surface of a polypropylene film ("Alphan MA-411" manufactured by Oji F-Tex Co., Ltd., thickness 15 μm) was attached as a protective film to the side of the resin composition layer not bonded to the support. This produced a resin sheet A having a support / resin composition layer / protective film in this order.

[0315] <Test Example 1: Measurement of dielectric loss tangent (Df)> The protective film was peeled off from Resin Sheet A, and the resin composition layer was thermally cured by heating at 190°C for 90 minutes, after which the support was peeled off. The obtained cured product was cut into a piece 2 mm wide and 80 mm long to prepare a test piece for evaluation.

[0316] The dielectric loss tangent (Df) of each test piece was measured by the cavity resonance perturbation method using an Agilent Technologies HP8362B at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. Measurements were performed on three test pieces, and the average value was calculated. The dielectric loss tangent was evaluated based on the calculated value according to the following criteria. [Evaluation criteria for dielectric loss tangent (Df)] ○: The dielectric loss tangent (Df) value is 0.0040 or less △: Dielectric loss tangent (Df) value is over 0.0040 and less than 0.0045 ×: The dielectric loss tangent (Df) value is 0.0045 or more.

[0317] <Test Example 2: Evaluation of smear removal ability> (1) 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 0.4 mm, Panasonic "R1515A") with an inner layer circuit formed on it were etched 1 μm deep with a microetching agent (MEC "CZ8101") to roughen the copper surface.

[0318] (2) Lamination of resin sheet A Using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator "CVP700"), resin sheet A was laminated onto both sides of the inner layer substrate so that the resin composition layer was in contact with the inner layer substrate. This lamination was carried out by reducing the pressure for 30 seconds to 13 hPa or less, followed by pressure bonding at 100°C and a pressure of 0.7 MPa for 30 seconds. Next, the laminate was heat-pressed at 100°C and a pressure of 0.5 MPa for 60 seconds to smooth the surface.

[0319] (3) Thermal curing of the resin composition layer The inner layer substrate laminated with resin sheet A was placed in an oven at 130°C and heated for 30 minutes, then transferred to an oven at 170°C and heated for 30 minutes to thermally cure the resin composition layer and form an insulating layer. The support was then peeled off to obtain a cured substrate B1 having an insulating layer / inner layer substrate / insulating layer in this order.

[0320] (4) Formation of via holes The insulating layer of cured substrate B1 was drilled using a CO2 laser processing machine ("LK-2K212 / 2C" manufactured by Via Mechanics) under the conditions of a frequency of 2000 Hz, a pulse width of 3 μs, an output of 0.95 W, and the number of shots was 3. This operation formed via holes with a top diameter of 50 μm on the surface of the insulating layer and a diameter of 50 μm on the bottom surface of the insulating layer, yielding circuit substrate B2.

[0321] (5) Wet desmear treatment The insulating layer surface of circuit board B2 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. Next, the insulating layer surface of the circuit board was immersed in an oxidizing solution (Atotech Japan's "Concentrate Compact P," an aqueous solution of potassium permanganate at approximately 6% and sodium hydroxide at approximately 4%) at 80°C for 15 minutes. Finally, the insulating layer surface of the circuit board was immersed in a neutralizing solution (Atotech Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes.

[0322] (6) Evaluation of smear removal In the roughening-treated circuit board B2, the periphery of the bottom of the via hole was observed with a scanning electron microscope (SEM), and the maximum smear length from the wall surface of the bottom of the via hole was measured from the obtained image and evaluated according to the following criteria. [Evaluation criteria for smear removal] ○: Maximum smear length is less than 5 μm ×: Maximum smear length is 5 μm or more

[0323] <Test Example 3: Measurement of adhesion strength (peel strength) with conductor layer> (1) 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 0.4 mm, Panasonic "R1515A") with an inner layer circuit formed on it were etched 1 μm deep with a microetching agent (MEC "CZ8101") to roughen the copper surface.

[0324] (2) Lamination of resin sheet A Using a batch-type vacuum pressure laminator ("MVLP-500" manufactured by Meiki Seisakusho Co., Ltd.), resin sheet A was laminated onto both sides of the inner layer substrate so that the resin composition layer was in contact with the inner layer substrate. This lamination was performed by reducing the pressure for 30 seconds to adjust the air pressure to 13 hPa or less, and then pressing at 100°C and a pressure of 0.74 MPa for 30 seconds.

[0325] (3) Thermal curing of the resin composition layer The inner layer substrate laminated with resin sheet A was placed in an oven at 100°C and heated for 30 minutes, then transferred to an oven at 170°C and heated for 30 minutes to thermally cure the resin composition layer and form an insulating layer. The support was then peeled off to obtain a cured substrate C1 having an insulating layer / inner layer substrate / insulating layer in this order.

[0326] (4) Dry desmear treatment The cured substrate C1 was treated for 5 minutes using a vacuum plasma etching device (Tepla's "100-E PLASMA SYSTEM") under conditions of O2 / CF4 (mixed gas ratio) = 25 / 75 and a vacuum degree of 100 Pa.

[0327] (5) Formation of the conductor layer After the dry desmearing treatment, a titanium layer (30 nm thick) and then a copper layer (300 nm thick) were formed on the cured substrate C1 using a sputtering device (Canon Anelva "E-400S"). The resulting substrate was heated at 150°C for 30 minutes for annealing treatment, and then copper sulfate electroplating was performed to form a conductor layer with a thickness of 25 μm. After the conductor layer was formed, the substrate was heated at 190°C for 90 minutes for annealing treatment, and evaluation substrate C2 was obtained.

[0328] (6) Measurement of adhesive strength (peel strength) with the conductor layer A slit was made in the conductor layer of evaluation board C2, surrounding a rectangular area 10 mm wide and 100 mm long. One end of this rectangular area was peeled off and gripped with a gripper (TSE Corporation, Autocom type testing machine "AC-50C-SL"). A 35 mm long area of ​​the rectangular area was peeled off vertically, and the load (kgf / cm) at the time of peeling was measured as the peel strength. The peeling was performed at room temperature at a speed of 50 mm / min. The adhesive strength with the conductor layer was evaluated based on the measured value according to the following criteria. Note that in Comparative Examples 4 and 5, the conductor layer was blistered, creating a gap between the insulating layer and the conductor layer, making it impossible to accurately measure the peel strength. Such blistering of the conductor layer indicates significantly poor adhesive strength between the insulating layer and the conductor layer. [Evaluation criteria for adhesion strength with conductor layer] ○: Peel strength value is 0.40 kgf / cm or more △: Peel strength value is 0.30 kgf / cm or more and less than 0.40 kgf / cm ×: Peel strength value is less than 0.30 kgf / cm or cannot be measured

[0329] <Result> The results of the examples and comparative examples are shown in Table 2 below.

[0330] [Table 2]

Claims

1. A resin sheet comprising a support and a resin composition layer provided on the support, the resin composition layer contains (A) a carbodiimide resin containing an unsaturated bond, (B) a thermosetting resin, and (C) a component having a polystyrene skeleton, A resin sheet for forming an insulating layer of a semiconductor package substrate, wherein the component (C) includes at least one of (C1) a resin having a polystyrene skeleton and a weight-average molecular weight of 100,000 or less, and (C2) particles having a polystyrene skeleton and an average particle size of less than 5 μm.

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

3. 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 mass % or more and 5.0 mass % or less, when the non-volatile components in the resin composition layer are 100 mass %.

4. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the total content of the component (C1) and the component (C2) is 0.1% by mass or more and 10.0% by mass or less, when the total amount of non-volatile components in the resin composition layer is 100% by mass.

5. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the mass ratio of the components (C1) and (C2) to the component (A) contained in the resin composition layer (total content of the components (C1) and (C2) / content of the component (A)) is 0.1 or more and 10.0 or less.

6. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein the component (A) comprises a carbodiimide resin represented by the following formula (1): 【Chemical 1】 (In formula (1), R each independently represents a hydrogen atom or a methyl group; X １ 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; Y's each independently represent a divalent saturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent, or a divalent unsaturated hydrocarbon group having 2 to 30 carbon atoms which may have a substituent; Z's each independently represent 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; b's each independently represent an integer of 1 or more; c's each independently represent an integer of 1 or more; d represents 0 or an integer of 1 or more.

7. 2. The resin sheet for forming an insulating layer of a semiconductor package substrate according to claim 1, wherein component (B) comprises one or more thermosetting resins selected from the group consisting of epoxy resins, active ester resins, phenolic resins, naphthol resins, cyanate ester resins, and radical polymerizable resins.

8. A semiconductor package substrate comprising a cured resin composition layer of the resin sheet according to any one of claims 1 to 7.

9. A semiconductor device comprising the semiconductor package substrate according to claim 8 .

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