Resin composition, resin film, resin film with support, printed wiring board, and semiconductor package

Abstract

Provided are a resin composition that has excellent flexibility in a solid state and can actualize a low dielectric loss tangent (Df) in a high frequency band (for example, 10 GHz or more), and a resin film, a resin film with a support, a printed wiring board, and a semiconductor package that use the resin composition. Specifically, the resin composition contains (A) an indane ring-containing maleimide resin, (B) an inorganic filler, and (X) a compound which is liquid at 25°C and has a maleimide group.

Description

Resin compositions, resin films, resin films with supports, printed circuit boards, and semiconductor packages 【0001】 This embodiment relates to a resin composition, a resin film, a resin film with a support, a printed circuit board, and a semiconductor package. 【0002】 In recent years, the miniaturization and increased performance of electronic devices have led to advancements in wiring density and integration in the fields of printed circuit boards and semiconductor packages. In these electronic devices, insulating materials such as thermosetting resins are used as encapsulants for semiconductor chips and substrate materials for printed circuit boards. However, stress can occur during component mounting due to the difference in thermal expansion coefficients between the insulating material and the semiconductor chip. This stress is thought to cause warping of the semiconductor package, potentially reducing its reliability. 【0003】 Therefore, as a method to bring the thermal expansion coefficient of the insulating material closer to that of the semiconductor chip, a method of compounding an inorganic filler into the insulating material is being used. For example, Patent Document 1 discloses a thermosetting resin composition that has a low dielectric loss tangent, low thermal expansion, and excellent wiring embedding and flatness, and describes a technique of compounding a polyimide compound having an inorganic filler, structural units derived from a maleimide resin having at least two N-substituted maleimide groups and structural units derived from a diamine compound, with a polybutadiene elastomer modified with an acid anhydride. 【0004】 Japanese Patent Publication No. 2018-012747 【0005】While the thermosetting resin composition of Patent Document 1 is excellent in terms of dielectric loss tangent, low thermal expansion, and embedding property of wiring, when it is made into a resin film having a thickness capable of sealing a semiconductor chip, cracks may occur in the resin film during handling. This problem is likely to occur particularly when using a thermosetting resin that easily obtains high heat resistance and when using an inorganic filler that contributes to low thermal expansion. In order to solve the above problem, it is considered effective to improve the flexibility of the resin composition used for forming the resin film. Note that the "flexibility of the resin composition" in this specification means the flexibility when the resin composition is solidified at room temperature (25°C) by drying the organic solvent when the resin composition contains an organic solvent or the like and is in a liquid state. The flexibility of the resin composition can be determined by forming a resin film in a B-stage state and evaluating the flexibility of the resin film. 【0006】 As a method for improving the flexibility of the resin composition in a solid state, a method of containing a small amount of an organic solvent capable of maintaining a solid state in the resin composition can be considered. However, a resin composition containing a small amount of an organic solvent may cause voids to occur in the cured product or irregularities to appear on the surface of the cured product due to the volatile organic solvent when heat-curing. In addition, since the organic solvent volatilizes during heat-curing, it is also necessary to prepare a safer working environment. Since these problems tend to become more apparent as the thickness of the resin film increases, the development of other methods for improving the flexibility of the resin composition has been desired. 【0007】 Under such circumstances, the present inventors were considering blending a liquid compound having a reactive group, such as 1,9-nonanediol diacrylate, into the resin composition as another method for improving the flexibility of the resin composition. As a result, although the flexibility of the resin composition was improved, it was found that the dielectric loss tangent (Df) in a high frequency band (for example, 10 GHz or higher) tended to increase. The dielectric loss tangent (Df) is required to be small from the viewpoint of reducing transmission loss. 【0008】In view of the current situation, this embodiment aims to provide a resin composition that exhibits excellent flexibility in a solid state and can achieve a low dielectric loss tangent (Df) in a high frequency band (for example, 10 GHz or higher), as well as a resin film, a resin film with a support, a printed circuit board, and a semiconductor package using the resin composition. 【0009】As a result of advancing studies to solve the above problems, the inventors of the present invention have found that the problems can be solved by the embodiments described in this specification. This embodiment includes the following embodiments [1] to

[13] . [1] A resin composition containing: (A) an indane ring-containing maleimide resin; (B) an inorganic filler; and (X) a compound that is liquid at 25°C and has a maleimide group. [2] The resin composition according to [1] above, which does not contain an epoxy resin or, even if it contains an epoxy resin, the content of the epoxy resin is 20% by mass or less based on the total amount of the resin components. [3] The resin composition according to [1] or [2] above, wherein the component (A) is one or more selected from the group consisting of an indane ring-containing maleimide resin having one or more N-substituted maleimide groups and derivatives of the maleimide resin. [4] The resin composition according to [3] above, wherein the indane ring-containing maleimide resin having one or more N-substituted maleimide groups contains a condensed ring of an aromatic ring and an aliphatic ring in its molecular structure and is an indane ring-containing maleimide resin having two or more N-substituted maleimide groups. [5] The resin composition according to any one of [1] to [4] above, wherein the component (X) has a structural unit derived from a dimer diamine. [6] The resin composition according to any one of [1] to [5] above, further containing (C) a radical polymerization initiator. [7] The resin composition according to any one of [1] to [6] above, further containing (D) a polymerization inhibitor. [8] The resin composition according to any one of [1] to [7] above, further containing (E) an elastomer. [9] A resin film containing the resin composition according to any one of [1] to [8] above.

[10] A resin film with a support, having a support and the resin film according to [9] above.

[11] A printed wiring board having a cured product of the resin composition according to any one of [1] to [8] above or a cured product of the resin film according to [9] above.

[12] A semiconductor package having a cured product of the resin composition according to any one of [1] to [8] above or a cured product of the resin film according to [9] above.

[13] The semiconductor package according to

[12] above, comprising a semiconductor chip encapsulated in the cured product of the resin composition. 【0010】According to this embodiment, it is possible to provide a resin composition that exhibits excellent flexibility in a solid state and can produce a low dielectric loss tangent (Df) in a high frequency band (for example, 10 GHz or higher), as well as a resin film, a resin film with a support, a printed circuit board, and a semiconductor package using the resin composition. 【0011】 In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. For example, the notation "X~Y" (where X and Y are real numbers) means a numerical range that is greater than or equal to X and less than or equal to Y. In this specification, "greater than or equal to X" means a number greater than or equal to X. In this specification, "less than or equal to Y" means a number less than or equal to Y. The lower and upper limits of numerical ranges described in this specification can be arbitrarily combined with the lower or upper limits of other numerical ranges. In numerical ranges described in this specification, the lower or upper limit of that numerical range may be replaced with the values ​​shown in the examples. 【0012】 Each component and material exemplified herein may be used alone or in combination of two or more, unless otherwise specified. In this specification, the content of each component in a resin composition means the total amount of multiple substances present in the resin composition, unless otherwise specified, if multiple substances corresponding to each component are present in the resin composition. In this specification, "resin composition" means a mixture of two or more components containing resin components, and includes a mixture in the B-stage state. However, the types and content of each component in a resin composition in the B-stage state mean the types and content of each component before reaching the B-stage state, that is, the types and amounts of components blended when manufacturing the resin composition. 【0013】 In this specification, "solids" refers to components in the resin composition other than organic solvents, as described later, and components that are liquid at room temperature around 25°C are also considered to be solids. Furthermore, "resin components" is defined as all components of the resin composition that constitute the solids, excluding inorganic compounds such as (B) inorganic fillers, as described later. 【0014】 In this specification, "(meth)acrylate" means "acrylate" and its corresponding "methacrylate." Similarly, "(meth)acrylic" means "acrylic" and its corresponding "methacrylic," and "(meth)acryloyl" means "acryloyl" and its corresponding "methacryloyl." 【0015】 In this specification, the "molecular weight" of a compound means the molecular weight that can be calculated from its structural formula if the compound is not a polymer and its structural formula can be identified, and the number-average molecular weight if the compound is a polymer. 【0016】 In this specification, the number-average molecular weight and weight-average molecular weight refer to values ​​measured in polystyrene equivalent by gas permeation chromatography (GPC). Specifically, the number-average molecular weight and weight-average molecular weight in this specification can be measured by the methods described in the examples. 【0017】 The mechanism of action described herein is speculative and does not limit the mechanism by which the resin composition according to this embodiment exerts its effects. 【0018】 Embodiments that combine any combination of the information described herein are also included. 【0019】 [Resin Composition] The resin composition of this embodiment is a resin composition containing: (A) an indan ring-containing maleimide resin; (B) an inorganic filler; and (X) a compound that is liquid at 25°C and has a maleimide group. 【0020】 In this embodiment, being liquid at 25°C means that the viscosity calculated by the following measurement method is 100,000 mPa·s or less. <Method for measuring viscosity> Apparatus: E-type viscometer Cone rotor: 1°34' × R24 Temperature: 25°C Sample volume: 1.0 mL Rotation speed: 20 rpm Hereinafter, in this specification, viscosity at 25°C means viscosity measured by the above method. 【0021】The resin composition of this embodiment (A) contains an indan ring-containing maleimide resin, which tends to reduce the dielectric loss tangent (Df) in high frequency bands (e.g., 10 GHz or higher) and further improve the peel strength and heat resistance of the copper foil; (B) contains an inorganic filler, which improves the low thermal expansion of the resin composition; and (X) contains a compound that is liquid at 25°C and has a maleimide group, which improves the flexibility in the solid state and reduces the dielectric loss tangent (Df) in high frequency bands (e.g., 10 GHz or higher). Here, "flexibility" refers to the flexibility of the resin composition of this embodiment when it is liquid due to containing an organic solvent, etc., and the organic solvent is dried to make the resin composition solid at room temperature (25°C). The flexibility of the resin composition of this embodiment is determined by forming a resin film in the B-stage state and evaluating the flexibility of the resin film. The components that the resin composition of this embodiment may contain will be described in order below. 【0022】 <(A) Indan ring-containing maleimide resin> (A) The indan ring-containing maleimide resin can be any compound having an indan ring and a maleimide group, and is not particularly limited in any other respect, but it is preferable that it be one or more selected from the group consisting of indan ring-containing maleimide resins having one or more N-substituted maleimide groups and derivatives of said maleimide resin. If component (A) is a maleimide resin that does not contain an indan ring, the resin composition tends to gel, making it difficult to form a resin film. In the following description, "one or more selected from the group consisting of indan ring-containing maleimide resins having one or more N-substituted maleimide groups and derivatives of said maleimide resin" may be simply referred to as "indan ring-containing maleimide resin" or "maleimide resin". Also, in the following description, an indan ring-containing maleimide resin having one or more N-substituted maleimide groups may be referred to as "maleimide resin (AX)". Furthermore, derivatives of maleimide resins containing an indan ring having one or more N-substituted maleimide groups are sometimes referred to as "maleimide resin derivatives (AY)". 【0023】(Maleimide Resin (AX)) The maleimide resin (AX) is not particularly limited as long as it is an indan ring-containing maleimide resin having one or more N-substituted maleimide groups. From the viewpoint of the peel strength and heat resistance of the copper foil, the maleimide resin (AX) is preferably an indan ring-containing aromatic maleimide resin having two or more N-substituted maleimide groups, and more preferably an indan ring-containing aromatic bismaleimide resin having two N-substituted maleimide groups. In this specification, "aromatic maleimide resin" means a compound having an N-substituted maleimide group directly bonded to an aromatic ring. In this specification, "aromatic bismaleimide resin" means a compound having two N-substituted maleimide groups directly bonded to an aromatic ring. In this specification, "aromatic polymaleimide resin" means a compound having three or more N-substituted maleimide groups directly bonded to an aromatic ring. Furthermore, in this specification, "aliphatic maleimide resin" means a compound having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon. 【0024】 As for the maleimide resin (AX), from the viewpoint of relative permittivity (Dk) and dielectric loss tangent (Df) [hereinafter, these may be collectively referred to as "dielectric properties"], the peel strength of the copper foil, and heat resistance, an indan ring-containing maleimide resin (hereinafter, sometimes referred to as "indan ring-containing maleimide resin (A1)") is preferred, which contains a fused ring of an aromatic ring and an aliphatic ring in its molecular structure and has two or more N-substituted maleimide groups. 【0025】 [Indan ring-containing maleimide resin (A1)] The indan ring in the indan ring-containing maleimide resin (A1) may have substituents. Examples of substituents include C1-C10 alkyl groups, C1-C10 alkyloxy groups, C1-C10 alkylthio groups, C6-C10 aryl groups, C6-C10 aryloxy groups, C6-C10 arylthio groups, C3-C10 cycloalkyl groups, halogen atoms, hydroxyl groups, mercapto groups, and the like. 【0026】 The indan ring-containing maleimide resin (A1) preferably contains a divalent group represented by the following general formula (A1-1). 【0027】 (In the formula, R ａ１ is an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group. n ａ１ is an integer of 0 to 3. R ａ２ to R ａ４ are each independently an alkyl group having 1 to 10 carbon atoms. * represents a bonding site.) 【0028】 In the general formula (A1-1), examples of the alkyl group having 1 to 10 carbon atoms represented by R ａ１ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and the like. These alkyl groups may be either linear or branched. Examples of the alkyl group having 1 to 10 carbon atoms included in the alkyloxy group having 1 to 10 carbon atoms and the alkylthio group having 1 to 10 carbon atoms represented by R ａ１ are the same as those of the above alkyl group having 1 to 10 carbon atoms. Examples of the aryl group having 6 to 10 carbon atoms represented by R ａ１ include a phenyl group, a naphthyl group and the like. Examples of the aryl group included in the aryloxy group having 6 to 10 carbon atoms and the arylthio group having 6 to 10 carbon atoms represented by R ａ１ are the same as those of the above aryl group having 6 to 10 carbon atoms. Examples of the cycloalkyl group having 3 to 10 carbon atoms represented by R ａ１ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group and the like. When n ａ１ in the general formula (A1-1) is an integer of 1 to 3, R ａ１ is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms from the viewpoints of solubility in an organic solvent and reactivity, and more preferably an alkyl group having 1 to 4 carbon atoms.) 【0029】 R ａ２ to R ａ４Examples of C1-C10 alkyl groups represented by include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. These alkyl groups may be linear or branched. Among these, R ａ２ ~R ａ４ The C1-C4 alkyl group is preferred, a methyl group and an ethyl group are more preferred, and a methyl group is even more preferred. n in the above general formula (A1-1) ａ１ n is an integer between 0 and 3. ａ１ If there are 2 or 3, then multiple R ａ１ They may be the same or they may be different. 【0030】 Among the above, the divalent group represented by the general formula (A1-1) is, from the viewpoint of ease of manufacture, n ａ１ R is 0, ａ２ ~R ａ４ A divalent group represented by the following formula (A1-1a), in which the group is a methyl group, is preferred, and a divalent group represented by the following formula (A1-1a') and a divalent group represented by the following formula (A1-1a'') are more preferred. 【0031】 (In the formula, * represents a bonding site.) 【0032】 The indan ring-containing maleimide resin (A1) containing a divalent group represented by the above general formula (A1-1) is preferably represented by the following general formula (A1-2) from the viewpoint of dielectric properties, copper foil peel strength, heat resistance, and ease of manufacture. 【0033】 (In the formula, R ａ１ ~R ａ４ and n ａ１ This is the same as the one in the general formula (A1-1) above. R ａ５ Each of these is independently a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. ａ２ Each of these is an integer between 0 and 4, independently of the others.ａ３ (This is a number between 0.95 and 10.0.) 【0034】 In the above general formula (A1-2), multiple R ａ１ fellows, multiple n ａ１ fellow, multiple R ａ５ fellows, multiple n ａ２ Each of these elements may be identical or different. ａ３ If the number exceeds 1, multiple R ａ２ fellow, multiple R ａ３ R with each other and with multiple Rs ａ４ Each of the members may be the same or different. 【0035】 In the above general formula (A1-2), R ａ５ Examples of C1-C10 alkyl groups represented by include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. These alkyl groups may be linear or branched. ａ５ Examples of alkyl groups included in the C1-C10 alkyloxy group and C1-C10 alkylthio group represented by the above include the same C1-C10 alkyl groups. ａ５ Examples of aryl groups having 6 to 10 carbon atoms represented by R include the phenyl group and the naphthyl group. ａ５ The aryl groups included in the aryloxy group and arylthio group having 6 to 10 carbon atoms represented by the above-mentioned aryl group having 6 to 10 carbon atoms are the same as those mentioned above. ａ５ Examples of cycloalkyl groups having 3 to 10 carbon atoms represented by R include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, and cyclodecyl group. Among these, R ａ５ From the viewpoint of solubility in organic solvents and ease of manufacture, alkyl groups having 1 to 4 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, and aryl groups having 6 to 10 carbon atoms are preferred, alkyl groups having 1 to 3 carbon atoms are more preferred, and methyl groups are even more preferred. 【0036】n in the above general formula (A1-2) ａ２ n is an integer from 0 to 4, and is preferably an integer from 1 to 3, more preferably 2 or 3, and even more preferably 2, from the viewpoint of compatibility with other resins, dielectric properties, peel strength of copper foil, and ease of manufacture. ａ２ When n is 1 or greater, the benzene ring and the N-substituted maleimide group have a twisted conformation, and solubility in organic solvents tends to improve due to the suppression of intermolecular stacking. From the perspective of suppressing intermolecular stacking, ａ２ If R is 1 or greater, ａ５ The substitution position is preferably the ortho position relative to the N-substituted maleimide group. ａ３ From the viewpoint of dielectric properties, peel strength of copper foil, solubility in organic solvents, handling properties, and heat resistance, the number is preferably 0.98 to 8.0, more preferably 1.0 to 7.0, and even more preferably 1.1 to 6.0. ａ３ This represents the average number of structural units containing an indan ring. 【0037】 The indan ring-containing maleimide resin (A1) represented by the above general formula (A1-2) is more preferably represented by the following general formula (A1-3) or the following general formula (A1-4) from the viewpoint of dielectric properties, peel strength of copper foil, solubility in organic solvents, and ease of manufacture. 【0038】 (In the formula, R ａ１ ~R ａ５ and n ａ１ and n ａ３ This is the same as the one in the general formula (A1-2) above. 【0039】 (In the formula, R ａ１ ~R ａ４ and n ａ１ and n ａ３ This is the same as the one in the general formula (A1-2) above. 【0040】Examples of the indane ring-containing maleimide resin (A1) represented by the above general formula (A1-3) include the indane ring-containing maleimide resin represented by the following general formula (A1-3-1), the indane ring-containing maleimide resin represented by the following general formula (A1-3-2), and the indane ring-containing maleimide resin represented by the following general formula (A1-3-3). 【0041】 (In the formula, n ａ３ This is the same as the one in the general formula (A1-2) above. 【0042】 Examples of indane ring-containing maleimide resins (A1) represented by the above general formula (A1-4) include indane ring-containing aromatic bismaleimide resins represented by the following general formula (A1-4-1), from the viewpoint of dielectric properties, copper foil peel strength, solubility in organic solvents, and ease of manufacture. 【0043】 (In the formula, n ａ３ This is the same as the one in the general formula (A1-2) above. 【0044】 The number-average molecular weight of the indan ring-containing maleimide resin (A1) is not particularly limited, but from the viewpoint of compatibility with other resins, peel strength of copper foil, and heat resistance, it is preferably 600 to 3,000, more preferably 800 to 2,000, and even more preferably 1,000 to 1,500. 【0045】 The method for producing the indan ring-containing maleimide resin (A1) is not particularly limited, and known methods can be used and applied. For example, the indan ring-containing maleimide resin (A1) can be produced by reacting an intermediate amine compound containing a condensed ring of an aromatic ring and an aliphatic ring with maleic anhydride. 【0046】 (Maleimide resin derivative (AY)) The maleimide resin derivative (AY) is preferably an indan ring-containing aminomaleimide resin (hereinafter sometimes abbreviated as "aminomaleimide resin (A3)") having structural units derived from the maleimide resin (AX) described above and structural units derived from a diamine compound. 【0047】[Aminomaleimide resin (A3)] Aminomaleimide resin (A3) has structural units derived from maleimide resin (AX) and structural units derived from diamine compounds (hereinafter sometimes abbreviated as "diamine compound (a)"). 【0048】 Structural units derived from maleimide resin (AX) Examples of structural units derived from maleimide resin (AX) include structural units formed by a Michael addition reaction between at least one N-substituted maleimide group of the maleimide resin (AX) and an amino group of the diamine compound. The structural units derived from maleimide resin (AX) contained in aminomaleimide resin (A3) may be one type or two or more types. 【0049】 The content of structural units derived from maleimide resin (AX) in the aminomaleimide resin (A3) is not particularly limited, but is preferably 5 to 95% by mass, more preferably 30 to 93% by mass, and even more preferably 60 to 90% by mass. When the content of structural units derived from maleimide resin (AX) in the aminomaleimide resin (A3) is within the above range, dielectric properties and film handling properties tend to be better. 【0050】 <Structural Units Derived from Diamine Compound (a)> Examples of structural units derived from diamine compound (a) include structural units formed when one or both of the two amino groups of diamine compound (a) undergo a Michael addition reaction with an N-substituted maleimide group of maleimide resin (AX). The structural units derived from diamine compound (a) contained in the aminomaleimide resin (A3) may be one type alone or two or more types. 【0051】 The content of structural units derived from diamine compound (a) in the aminomaleimide resin (A3) is not particularly limited, but is preferably 5 to 95% by mass, more preferably 7 to 70% by mass, and even more preferably 10 to 40% by mass. When the content of structural units derived from diamine compound (a) in the aminomaleimide resin (A3) is within the above range, the dielectric properties, heat resistance, flame retardancy, and glass transition temperature tend to be better. 【0052】 As the diamine compound (a), for example, one similar to the amine compound having at least two primary amino groups in one molecule as listed in Japanese Patent Application Publication No. 2020-200406 can be used. Specific examples of the diamine compound (a) include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 4,4'-diaminobiphenyl, and 3,3'-dimethyl-4,4 '-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 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, 1,3-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 1,4-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline Examples include aromatic diamine compounds such as 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 3,3'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, and 9,9-bis(4-aminophenyl)fluorene; and amine-modified siloxane compounds having a primary amino group. 【0053】 -NH of diamine compound (a) in aminomaleimide resin (A3) ２ Group derived from (-NH ２The equivalence ratio (Ta2 / Ta1) of the total equivalent (Ta2) of the groups derived from the N-substituted maleimide group of the maleimide resin (AX) to the total equivalent (Ta1) of the groups derived from the N-substituted maleimide group of the maleimide resin (AX) is not particularly limited, but from the viewpoint of dielectric properties, heat resistance, flame retardancy and glass transition temperature, it is preferably 0.05 to 10, more preferably 0.5 to 7, and even more preferably 1 to 5. Note that the -NH of the above diamine compound (a) ２ A group derived from a group is -NH ２ This shall include the N-substituted maleimide group itself. Furthermore, the group derived from the N-substituted maleimide group of the above maleimide resin (AX) shall also include the N-substituted maleimide group itself. 【0054】 The number-average molecular weight of the aminomaleimide resin (A3) is not particularly limited, but from the viewpoint of handling and moldability, it is preferably 400 to 10,000, more preferably 500 to 5,000, and even more preferably 600 to 2,000. 【0055】 The aminomaleimide resin (A3) can be manufactured, for example, by referring to the method described in "(A) Method for manufacturing modified maleimide resin" of Japanese Patent Application Publication No. 2020-200406. 【0056】 Among the (A) indan ring-containing maleimide resins described above, from the viewpoint of dielectric properties, copper foil peel strength, and heat resistance, (A) indan ring-containing maleimide resins that contain a fused ring of an aromatic ring and an aliphatic ring in their molecular structure and have two or more N-substituted maleimide groups are preferred. 【0057】 (A) The indan ring-containing maleimide resin is preferably one whose viscosity at 25°C, as measured by the above method, is greater than 100,000 mPa·s, and more preferably one that is solid at 25°C. 【0058】(Content of (A) indane ring-containing maleimide resin) In the resin composition of this embodiment, the content of (A) indane ring-containing maleimide resin is not particularly limited, but is preferably 3 to 80% by mass, more preferably 5 to 60% by mass, even more preferably 5 to 40% by mass, and particularly preferably 5 to 25% by mass, based on the total amount of solids (100% by mass) in the resin composition of this embodiment. When the content of (A) indane ring-containing maleimide resin is above the lower limit, the heat resistance, moldability, processability, low thermal expansion, and peel strength of the copper foil tend to be better. Also, when the content of (A) indane ring-containing maleimide resin is below the upper limit, the dielectric properties tend to be better. 【0059】 <(B) Inorganic Filler> The resin composition of this embodiment, by containing (B) inorganic filler, tends to provide excellent low thermal expansion, as well as excellent heat resistance and flame retardancy. (B) inorganic filler may be used alone or two or more types may be used in combination. 【0060】 (B) Examples of inorganic fillers include silica, alumina, titanium oxide, mica, beryllium, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay, talc, molybdate compounds (such as zinc molybdate), aluminum borate, silicon carbide, etc. Among these, silica, alumina, mica, and talc are preferred from the viewpoint of low thermal expansion, heat resistance, and flame retardancy, with silica and alumina being more preferred. Examples of silica include precipitated silica produced by the wet method with a high water content, and dry silica produced by the dry method that contains almost no bound water, etc. Examples of dry silica include crushed silica, fumed silica, and fused silica, depending on the manufacturing method. 【0061】(B) The average particle size of the inorganic filler is not particularly limited, but from the viewpoint of dispersibility and fine wiring properties of the inorganic filler, it is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 5 μm, and particularly preferably 0.3 to 3 μm, and may also be 0.3 to 1.5 μm or 1.5 to 3 μm. In this specification, the average particle size of the inorganic filler is the particle size at the point corresponding to 50% of the volume when the cumulative frequency distribution curve by particle size is calculated with the total volume of the particles set to 100%. The average particle size of the inorganic filler can be measured, for example, by a particle size distribution analyzer using laser diffraction scattering. The shape of the inorganic filler can be spherical, crushed, etc., and it is preferably spherical. 【0062】 The resin composition of this embodiment may contain a coupling agent for the purpose of improving the dispersibility of the inorganic filler and its adhesion to the organic component. Examples of coupling agents include silane coupling agents and titanate coupling agents. Among these, silane coupling agents are preferred. Examples of silane coupling agents include aminosilane coupling agents, vinylsilane coupling agents, acrylicsilane coupling agents, methacrylicsilane coupling agents, and epoxysilane coupling agents. 【0063】 If the resin composition of this embodiment contains a coupling agent, the surface treatment of the inorganic filler (B) may be performed by the coupling agent. Specifically, the surface treatment method for the inorganic filler (B) may be an integral blend treatment method in which the coupling agent is added after the inorganic filler (B) has been blended into the resin composition, or it may be a method of pre-treating the inorganic filler (B) with the coupling agent dry or wet. Among these, from the viewpoint of more effectively expressing the characteristics of the inorganic filler (B), the method of pre-treating the inorganic filler (B) with the coupling agent dry or wet is preferred. The inorganic filler (B) may be pre-dispersed in an organic solvent to form a slurry before being mixed with other components in order to improve its dispersibility in the resin composition. 【0064】(Content of (B) Inorganic Filler) In the resin composition of this embodiment, the content of (B) inorganic filler is not particularly limited, but is preferably 20 to 90% by mass, more preferably 40 to 85% by mass, even more preferably 45 to 80% by mass, and particularly preferably 50 to 75% by mass, based on the total solid content (100% by mass) of the resin composition. When the content of (B) inorganic filler is above the lower limit, low thermal expansion, heat resistance and flame retardancy tend to be good. Also, when the content of (B) inorganic filler is below the upper limit, moldability and copper foil peel strength tend to be good. 【0065】 <(X) Compound that is liquid at 25°C and has a maleimide group> The resin composition of this embodiment contains a compound that is liquid at 25°C and has a maleimide group (hereinafter sometimes simply referred to as "component (X)"), thereby enabling excellent flexibility in the solid state and low dielectric loss tangent (Df) in a high frequency band (e.g., 10 GHz or higher). Component (X) may be used alone or two or more may be used in combination. While many compounds having a maleimide group are solid at 25°C, component (X) is characterized by being liquid at 25°C. In other words, component (X) has a structural unit that is liquid at 25°C, and such a structural unit is not particularly limited, but examples include structural units derived from dimer amine. Here, dimer amine is a compound in which the two terminal carboxylic acid groups (-COOH) of a dimer acid are replaced by a primary aminomethyl group (-CH ２ -NH ２ ) or amino group (-NH ２Dimer acid is a diamine produced by substitution with ), and is an aliphatic diamine. The dimer acid is a fatty acid (C36 fatty acid) obtained by dimerizing natural fatty acids such as soybean oil fatty acid, sunflower oil fatty acid, and cottonseed oil fatty acid, tall oil fatty acid, and C18 unsaturated fatty acids such as oleic acid, linoleic acid, or linolenic acid obtained by refining these. The dimerization can be achieved by the Diels-Alder reaction. Commercial dimer amines may also be used. Examples of commercially available products include PRIAMINE 1073, PRIAMINE 1074, and PRIAMINE 1075 manufactured by Croda Japan. 【0066】Component (X) may be a maleimide-modified form of the amino group of the dimer amine, which can be obtained by reacting the amino group of the dimer amine with a tetracarboxylic anhydride. The tetracarboxylic anhydride may be 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic acid dianhydride, 1,4-phenylenebis(trimellitic acid monoester) dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic acid anhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, or 2,3,3',4'-benzophenonetetracarboxylic dianhydride. Water, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3',3,4'-diphenylethertetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3'',4,4''-p-terphenyltetracarboxylic dianhydride, 2,3,3'',4''-p-terphenyltetracarboxylic dianhydride, 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)-propane Dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl)ethane dianhydride, 1,2,7,8-phenanthrene-tetracarboxylic acid dianhydride, 1,2,6,7-phenanthrene-tetracarboxylic acid dianhydride, 1,2,9,10-phenanthrene-tetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 2,2 -Bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride, 2,7-Dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-(or 1,4,5,8-)tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-)tetracarboxylic dianhydride, 2,3,8,9-perylene-tetracarboxylic dianhydride, 3,4,9,10-perylene-tetracarboxylic dianhydride, 4,5,10,11-perylene-tetracarboxylic dianhydride, 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2 Examples of acid dianhydrides include 3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, p-phenylenebis(trimellitic acid monoester anhydride), ethylene glycol bis-anhydrotrimellitate, and 2,2'-bis(4-(3,4-dicarboxyphenoxy)phenyl)hexafluoropropane dianhydride. 【0067】Component (X) can be produced more specifically by reacting the dimer amine and tetracarboxylic anhydride in an organic solvent to produce polyamic acid, followed by heating and cyclization. Examples of the organic solvent include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, and cresol. Aromatic hydrocarbons such as xylene and toluene may be used in combination with the organic solvent. For example, polyamic acid, which is a precursor of component (X), can be obtained by dissolving the dimer amine and tetracarboxylic dianhydride in equimolar amounts in an organic solvent and reacting them by stirring at 0 to 100°C for 30 minutes to 24 hours. Next, the polyamic acid is cyclized by heating in the organic solvent at 80 to 400°C for 1 to 24 hours, thereby forming a maleimide group, and as a result, component (X) is obtained. 【0068】 The weight-average molecular weight (Mw) of component (X) is preferably 500 to 10,000, more preferably 1,000 to 5,000, and may also be 1,000 to 3,000 or 1,000 to 2,500. 【0069】 The viscosity of component (X) at 25°C is preferably 0.01 to 10 Pa·s, more preferably 0.1 to 7 Pa·s, and even more preferably 0.5 to 5 Pa·s. When the viscosity of component (X) at 25°C is above the lower limit, it tends to suppress the volatilization of component (X). Also, when the viscosity of component (X) at 25°C is below the upper limit, it tends to be easier to obtain better flexibility. 【0070】 For component (X), for example, BMI-689 manufactured by DESIGNER MOLUCULES INC. can be used. 【0071】(Content of component (X)) In the resin composition of this embodiment, the content of component (X) is not particularly limited, but is preferably 1 to 40 parts by mass, more preferably 3 to 35 parts by mass, and even more preferably 5 to 30 parts by mass, and may be 10 to 25 parts by mass, per 100 parts by mass of the total amount of resin components. When the content of component (X) is above the lower limit, it is easier to obtain excellent flexibility in the solid state resin composition. Also, when the content of component (X) is below the upper limit, it is easier to obtain a glass transition temperature of the cured product. 【0072】 <(C) Radical polymerization initiator> The resin composition of this embodiment may contain (C) a radical polymerization initiator. By containing (C) a radical polymerization initiator, the polymerization reaction during heating is promoted, and as a result, it tends to harden to a degree sufficient for use as an insulating layer. Furthermore, by containing (C) a radical polymerization initiator, the resin composition of this embodiment tends to improve the solder heat resistance and chemical resistance of the cured resin film. A radical polymerization initiator decomposes into a substance with unpaired electrons when exposed to energy such as light or heat. One type of (C) radical polymerization initiator may be used alone, or two or more types may be used in combination. 【0073】 (C) Examples of radical polymerization initiators include organic peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyn-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, 1,3-di(t-butylperoxyisopropyl)benzene, and α,α-bis(t-butylperoxy-m-isopropyl)benzene; inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile). (C) The radical polymerization initiator may be an organic peroxide, an inorganic peroxide, or an azo compound, but an organic peroxide is preferred. 【0074】(Content of (C) radical polymerization initiator) In the resin composition of this embodiment, the content of (C) radical polymerization initiator is not particularly limited, but is preferably 0.05 to 7 parts by mass, more preferably 0.5 to 5 parts by mass, even more preferably 0.5 to 3 parts by mass, and particularly preferably 1.0 to 2.5 parts by mass, per 100 parts by mass of the total amount of resin components. When the content of (C) radical polymerization initiator is above the lower limit, the effects of component (C) tend to be easier to obtain. Also, when the content of (C) radical polymerization initiator is below the upper limit, the storage stability tends to be better. 【0075】 <(D) Polymerization Inhibitor> The resin composition of this embodiment may contain (D) a polymerization inhibitor. By containing (D) a polymerization inhibitor, the (D) polymerization inhibitor traps the radicals generated by (C) a radical polymerization initiator, temporarily preventing the thickening of the molten resin film during heat curing, and tends to make it easier to embed the resin film to conform to the irregularities of the circuit board. (D) A single polymerization inhibitor may be used, or two or more may be used in combination. 【0076】 (D) The polymerization inhibitor is not particularly limited, but from the viewpoint of embedding into the circuit board, a hindered amine compound is preferred. Examples of hindered amine compounds include piperidine derivatives such as compounds having a 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton, compounds having a 2,2,6,6-tetramethylpiperidine skeleton, compounds having a 2,2,6,6-tetramethylpiperidine-N-alkyl skeleton, and compounds having a 2,2,6,6-tetramethylpiperidine-N-acyl skeleton. Among these, compounds having a 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton are preferred from the viewpoint of embedding into the circuit board. 【0077】Compounds having a 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton include 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 4,4'-[(1,10-dioxo-1,10-decanediyl)bis(oxy)]bis[2,2,6,6-tetramethyl]-1-piperidinyloxy, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, bis(1-oxyl-2,2,6,6-tetramethylpiperidinyl-4-yl) sebacate, and bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester of decandioate. 【0078】(D) A commercially available polymerization inhibitor may be used. There are also commercially available hindered amine compounds, such as "ADEKASTAB LA-7RD" (2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl) (manufactured by ADEKA Corporation); "IRGASTAB UV 10" (4,4'-[(1,10-dioxo-1,10-decanediyl)bis(oxy)]bis[2,2,6,6-tetramethyl]-1-piperidinyloxy) (CAS. 2516-92-9), "TINUVIN 123" (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) (both manufactured by BASF); "FA-711HM", "FA-712HM" (2,2,6,6-tetramethylpiperidinyl methacrylate, manufactured by Resonaq Corporation); "TINUVIN 111FDL”, “TINUVIN 144”, “TINUVIN 152”, “TINUVIN 292”, “TINUVIN 765”, “TINUVIN 770DF”, “TINUVIN 5100”, “SANOL LS-2626", "CHIMASSORB 119FL", "CHIMASSORB 2020 FDL", "CHIMASSORB 944 FDL", "TINUVIN 622 Examples include "LD" (manufactured by BASF); "LA-52", "LA-57", "LA-62", "LA-63P", "LA-68LD", "LA-77Y", "LA-77G", "LA-81", "LA-82" (1,2,2,6,6-pentamethyl-4-piperidyl methacrylate), "LA-87" (manufactured by ADEKA Corporation); and others. Of the above commercially available products, "LA-82" is a compound having the 2,2,6,6-tetramethylpiperidine-N-methyl skeleton, and "ADEKA STAB LA-7RD" is a compound having the 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton. 【0079】Polymerization inhibitors other than hindered amine compounds are not particularly limited, but include p-methoxyphenol, hydroquinone, hydroquinone monomethyl ether (MEHQ), cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), phenothiazine, etc. (D) Polymerization inhibitors other than hindered amine compounds can also be selected. Furthermore, hindered amine compounds and polymerization inhibitors other than hindered amine compounds can be used in combination. Note that hindered amine compounds tend to have a greater effect on improving the embedding properties of circuit boards than polymerization inhibitors other than hindered amine compounds. 【0080】(Content of (D) Polymerization Inhibitor) In the resin composition of this embodiment, the content of (D) polymerization inhibitor is preferably 1 to 90 parts by mass, more preferably 3 to 80 parts by mass, even more preferably 5 to 75 parts by mass, particularly preferably 7 to 70 parts by mass, and most preferably 13 to 70 parts by mass, per 100 parts by mass of component (C), and may also be 20 to 70 parts by mass, 30 to 70 parts by mass, 35 to 70 parts by mass, or 40 to 65 parts by mass. When the content of (D) polymerization inhibitor is above the lower limit, it becomes easier to efficiently trap the radicals generated by (C) radical polymerization initiator, temporarily hindering the thickening of the molten resin film during heat curing, and tends to allow the resin film to be embedded to conform to the irregularities of the circuit board. When the content of (D) polymerization inhibitor is below the upper limit, after the disappearance of (D) polymerization inhibitor, the effect of (C) radical polymerization initiator, that is, the polymerization reaction, is promoted, and as a result, it tends to harden to a degree sufficient for use as an insulating layer. Furthermore, the content of (D) polymerization inhibitor may be 0.001 to 1 part by mass, 0.003 to 0.8 parts by mass, 0.005 to 0.5 parts by mass, 0.01 to 0.4 parts by mass, 0.03 to 0.4 parts by mass, 0.05 to 0.3 parts by mass, or 0.08 to 0.3 parts by mass per 100 parts by mass of the total amount of resin components. 【0081】 <(E) Elastomer> The resin composition of this embodiment may further contain (E) elastomer. The resin composition of this embodiment tends to have better dielectric properties when it contains (E) elastomer. Here, "elastomer" means a polymer whose glass transition temperature, as measured by differential scanning calorimetry in accordance with JIS K6240:2011, is 25°C or lower. One type of (E) elastomer may be used alone, or two or more types may be used in combination. 【0082】(E) The molecular weight of the elastomer is preferably greater than 1,000, more preferably 1,050 to 500,000, even more preferably 1,100 to 350,000, and particularly preferably 1,150 to 200,000, and may also be 1,200 to 100,000 or 1,300 to 85,000. When the molecular weight of the elastomer is above the lower limit, the heat resistance and other properties of the resulting resin composition tend to be better maintained. Also, when the molecular weight of the elastomer is below the upper limit, the dielectric properties of the resulting resin composition and the peel strength of the copper foil tend to be better. 【0083】 (E) Preferred elastomers include conjugated diene polymers (E1), modified conjugated diene polymers (E2), and styrene-based elastomers (E3). Preferred embodiments of these components will be described below. 【0084】 (Conjugated Diene Polymer (E1)) In this specification, "conjugated diene polymer" means a polymer of a conjugated diene compound. The resin composition of this embodiment tends to easily obtain better dielectric properties by containing conjugated diene polymer (E1). One type of conjugated diene polymer (E1) may be used alone, or two or more types may be used in combination. Note that conjugated diene polymer (E1) does not contain modified conjugated diene polymer (E2). 【0085】 Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene. The conjugated diene polymer (E1) may be a polymer of one conjugated diene compound, or a copolymer of two or more conjugated diene compounds. Furthermore, the conjugated diene polymer (E1) may be a copolymer of one or more conjugated diene compounds and one or more monomers other than conjugated diene compounds. When the conjugated diene polymer (E1) is a copolymer, the polymerization method is not particularly limited and may be random polymerization, block polymerization, or graft polymerization. 【0086】As the conjugated diene polymer (E1), a conjugated diene polymer having multiple vinyl groups in its side chains is preferred from the viewpoint of compatibility with other resins and dielectric properties. The number of vinyl groups in one molecule of the conjugated diene polymer (E1) is not particularly limited, but from the viewpoint of compatibility with other resins and dielectric properties, it is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more. The upper limit of the number of vinyl groups in one molecule of the conjugated diene polymer (E1) is not particularly limited, but it may be 100 or less, 80 or less, or 60 or less. 【0087】 Examples of conjugated diene polymers (E1) include polybutadiene having 1,2-vinyl groups, butadiene-styrene copolymer having 1,2-vinyl groups, and polyisoprene having 1,2-vinyl groups. Among these, from the viewpoint of dielectric properties and heat resistance, polybutadiene having 1,2-vinyl groups and butadiene-styrene copolymer having 1,2-vinyl groups are preferred, and polybutadiene having 1,2-vinyl groups is more preferred. Furthermore, as a polybutadiene having 1,2-vinyl groups, polybutadiene homopolymer having 1,2-vinyl groups is preferred. The 1,2-vinyl groups derived from butadiene in the conjugated diene polymer (E1) are vinyl groups contained in the butadiene-derived structural unit represented by the following formula (E1-1). 【0088】 【0089】When the conjugated diene polymer (E1) is polybutadiene having 1,2-vinyl groups, the content of structural units having 1,2-vinyl groups (hereinafter sometimes referred to as "vinyl group content") relative to the total structural units derived from butadiene constituting the polybutadiene is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties and heat resistance, it is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more. Furthermore, the upper limit of the vinyl group content is not particularly limited and may be 100 mol% or less, 95 mol% or less, or 90 mol% or less. In other words, the vinyl group content may be 50 to 100 mol%. As the structural units having 1,2-vinyl groups, structural units derived from butadiene represented by the above formula (E1-1) are preferred. From a similar viewpoint, the polybutadiene having 1,2-vinyl groups is preferably a 1,2-polybutadiene homopolymer. 【0090】 The number-average molecular weight of the conjugated diene polymer (E1) is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties and heat resistance, it is preferably 1,050 to 3,000, more preferably 1,100 to 2,000, and even more preferably 1,150 to 1,500. 【0091】 (Modified Conjugated Diene Polymer (E2)) Modified conjugated diene polymer (E2) is a polymer obtained by modifying a conjugated diene polymer. The resin composition of this embodiment, by containing modified conjugated diene polymer (E2), tends to have good heat resistance and low thermal expansion while also easily obtaining superior dielectric properties. Modified conjugated diene polymer (E2) may be used alone or two or more types may be used in combination. 【0092】 For example, as the modified conjugated diene polymer (E2), from the viewpoint of compatibility with other resins, dielectric properties and conductor adhesion, a modified conjugated diene polymer is preferred, which is obtained by modifying (e1) a conjugated diene polymer having vinyl groups in its side chains (hereinafter sometimes abbreviated as "conjugated diene polymer (e1)") with (e2) a maleimide resin having two or more N-substituted maleimide groups (hereinafter sometimes abbreviated as "maleimide resin (e2)"). 【0093】 As the conjugated diene polymer (e1), for example, a conjugated diene polymer having vinyl groups in its side chains, as described above as the conjugated diene polymer (E1), can be used, and the preferred embodiment is the same. The conjugated diene polymer (e1) may be used alone or two or more may be used in combination. 【0094】 As the maleimide resin (e2), for example, a maleimide resin having two or more N-substituted maleimide groups as described above as maleimide resin (AX) can be used, and the preferred embodiment is the same. Maleimide resin (e2) may be used alone or two or more types may be used in combination. 【0095】 The modified conjugated diene polymer (E2) preferably has substituents (hereinafter sometimes referred to as "substituents (x)") in its side chains, which are formed by the reaction of a vinyl group of the conjugated diene polymer (e1) and an N-substituted maleimide group of the maleimide resin (e2). From the viewpoint of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, substituents (x) preferably include a structure derived from the maleimide resin (e2) that is represented by the following general formula (E2-1) or (E2-2). 【0096】 (In the formula, X e１ This is a divalent group obtained by removing two N-substituted maleimide groups from maleimide resin (e2), * e１ This is a site where the conjugated diene polymer (e1) bonds to carbon atoms derived from vinyl groups in its side chains. * e２ (This is a site that bonds to other atoms.) 【0097】The modified conjugated diene polymer (E2) preferably has a substituent (x) and a vinyl group (y) in its side chain. The extent to which substituents (x) are present in the modified conjugated diene polymer (E2) can be indicated by the extent to which the vinyl group of the conjugated diene polymer (e1) has been modified by the maleimide resin (e2) (hereinafter sometimes referred to as the "vinyl group modification rate"). The vinyl group modification rate is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, it is preferably 20 to 70%, more preferably 30 to 60%, and even more preferably 35 to 50%. Here, the vinyl group modification rate is the value obtained by the method described in the examples. The vinyl group (y) is preferably a 1,2-vinyl group possessed by a structural unit derived from butadiene. 【0098】 The number-average molecular weight of the modified conjugated diene polymer (E2) is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, it is preferably 1,100 to 6,000, more preferably 1,300 to 4,000, and even more preferably 1,500 to 2,000. 【0099】 Modified conjugated diene polymer (E2) can be produced by reacting a conjugated diene polymer (e1) with a maleimide resin (e2). The method for reacting the conjugated diene polymer (e1) with the maleimide resin (e2) is not particularly limited. For example, the modified conjugated diene polymer (E2) can be obtained by charging the conjugated diene polymer (e1), maleimide resin (e2), a reaction catalyst, and an organic solvent into a reaction vessel and reacting them while heating, maintaining the temperature, stirring, etc., as necessary. The reaction temperature for the above reaction is preferably 70 to 120°C, more preferably 80 to 110°C, and even more preferably 85 to 105°C, from the viewpoint of workability and suppression of gelation of the product during the reaction. The reaction time for the above reaction is preferably 0.5 to 15 hours, more preferably 1 to 10 hours, and even more preferably 3 to 7 hours, from the viewpoint of productivity and allowing the reaction to proceed sufficiently. However, these reaction conditions can be appropriately adjusted depending on the type of raw materials used, etc., and are not particularly limited. 【0100】Examples of organic solvents used in the above reaction include alcoholic solvents such as methanol, ethanol, butanol, butyl cellosolve, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene; ester solvents such as methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, and ethyl acetate; and nitrogen atom-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. One organic solvent may be used alone, or two or more may be used in combination. Among these, toluene is preferred from the viewpoint of resin solubility. 【0101】 When the above reaction is carried out in an organic solvent, the total content of the conjugated diene polymer (e1) and maleimide resin (e2) in the reaction solution is not particularly limited, but is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass. When the total content of the conjugated diene polymer (e1) and maleimide resin (e2) is above the lower limit, a good reaction rate is obtained and productivity tends to be better. Furthermore, when the total content of the conjugated diene polymer (e1) and maleimide resin (e2) is below the upper limit, better solubility is obtained, stirring efficiency is improved, and gelation of the product during the reaction tends to be further suppressed. 【0102】 As a reaction catalyst, organic peroxides are preferred from the viewpoint of obtaining sufficient reactivity while suppressing gelation of the product during the reaction. As organic peroxides, those listed as curing accelerators (F) described later can be used. One type of reaction catalyst may be used alone, or two or more types may be used in combination. The amount of reaction catalyst used is not particularly limited, but from the viewpoint of reaction rate and reaction uniformity, it is preferably 0.001 to 1 part by mass, more preferably 0.003 to 0.1 parts by mass, and even more preferably 0.005 to 0.02 parts by mass, per 100 parts by mass of the total amount of conjugated diene polymer (e1) and maleimide resin (e2). 【0103】 When carrying out the above reaction, the number of moles (M) of side-chain vinyl groups in the conjugated diene polymer (e1) ｖ The number of moles (M) of N-substituted maleimide groups in the maleimide resin (e2) relative to ) ｍ ) ratio (M ｍ / M ｖ The coefficient of ) is not particularly limited, but from the viewpoint of compatibility of the obtained modified conjugated diene polymer (E2) with other resins and suppression of gelation of the product during the reaction, it is preferably 0.001 to 0.5, more preferably 0.005 to 0.1, and even more preferably 0.008 to 0.05. 【0104】 <Styrene-based elastomer (E3)> The styrene-based elastomer (E3) can be any elastomer having structural units derived from styrene compounds, and is not particularly limited in any other respect. The resin composition of this embodiment tends to yield better dielectric properties by containing the styrene-based elastomer (E3). One type of styrene-based elastomer (E3) may be used alone, or two or more types may be used in combination. 【0105】 As the styrene-based elastomer (E3), it is preferable to have structural units derived from a styrene-based compound represented by the following general formula (E3-1). 【0106】 (In the formula, R ｅ１ R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ｅ２ n is an alkyl group having 1 to 5 carbon atoms. ｅ１ (This is an integer between 0 and 5.) 【0107】 In the above general formula (E3-1), R ｅ１ and R ｅ２ Examples of C1-C5 alkyl groups represented by include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, and n-pentyl groups. C1-C5 alkyl groups may be linear or branched. Among these, C1-C3 alkyl groups are preferred, C1 or C2 alkyl groups are more preferred, and methyl groups are even more preferred. n in the above general formula (E3-1)ｅ１ is an integer between 0 and 5, preferably between 0 and 2, more preferably 0 or 1, and even more preferably 0. 【0108】 The styrene-based elastomer (E3) may contain structural units other than those derived from styrene compounds. Examples of structural units other than those derived from styrene compounds that the styrene-based elastomer (E3) may contain include structural units derived from butadiene, isoprene, maleic acid, and maleic anhydride. The above-mentioned structural units derived from butadiene and isoprene may be hydrogenated. When hydrogenated, the structural units derived from butadiene become structural units that are a mixture of ethylene units and butylene units, and the structural units derived from isoprene become structural units that are a mixture of ethylene units and propylene units. 【0109】 Examples of styrene-based elastomers (E3) include hydrogenated styrene-butadiene-styrene block copolymers, hydrogenated styrene-isoprene-styrene block copolymers, and styrene-maleic anhydride copolymers. Hydrogenated styrene-butadiene-styrene block copolymers include SEBS, which is obtained by fully hydrogenating the carbon-carbon double bonds in the butadiene block, and SBBS, which is obtained by partially hydrogenating the carbon-carbon double bonds at the 1,2-bonding sites in the butadiene block. In SEBS, full hydrogenation usually means 90% or more of the total carbon-carbon double bonds, but it may also be 95% or more, 99% or more, or 100%. In SBBS, the partial hydrogenation rate is preferably 60-85% of the total carbon-carbon double bonds. Hydrogenated styrene-isoprene-styrene block copolymers are obtained as SEPS by hydrogenating the polyisoprene portion. Among these, SEBS and SEPS are preferred from the viewpoint of dielectric properties, copper foil peel strength, heat resistance, glass transition temperature, and low thermal expansion, with SEBS being more preferred. 【0110】In the above-mentioned SEBS, the content of styrene-derived structural units (hereinafter sometimes abbreviated as "styrene content") is not particularly limited, but is preferably 5 to 60% by mass, more preferably 7 to 40% by mass, and even more preferably 10 to 35% by mass, and may also be 15 to 35% by mass or 20 to 35% by mass. 【0111】 The melt flow rate (MFR) of SEBS is not particularly limited, but under measurement conditions of 230°C and a load of 2.16 kgf (21.2 N), it is preferably 0.1 to 40 g / 10 min, more preferably 1 to 35 g / 10 min, and even more preferably 5 to 35 g / 10 min, and may also be 10 to 35 g / 10 min or 20 to 35 g / 10 min. 【0112】 Examples of commercially available SEBS products include the ToughTec H series and ToughTec M series from Asahi Kasei Corporation, the Septon series from Kuraray Co., Ltd., and the Kraton series from Kraton Polymer Japan Co., Ltd. 【0113】 The number-average molecular weight of the styrene-based elastomer (E3) is not particularly limited, but is preferably 10,000 to 500,000, more preferably 20,000 to 350,000, and even more preferably 40,000 to 200,000, and may also be 50,000 to 100,000 or 50,000 to 85,000. 【0114】 Other elastomers (E) besides conjugated diene polymers (E1), modified conjugated diene polymers (E2), and styrene-based elastomers (E3) include other polyolefin resins, polyphenylene ether resins, polyester resins, polyamide resins, polyacrylic resins, and the like. 【0115】(Content of (E) elastomer) When the resin composition of this embodiment contains (E) elastomer, the content of (E) elastomer is not particularly limited, but is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, even more preferably 5 to 25% by mass, and particularly preferably 5 to 20% by mass, based on the total amount of solids (100% by mass) in the resin composition of this embodiment. When the content of (E) elastomer is above the lower limit, it tends to be easier to obtain better dielectric properties. Also, when the content of (E) elastomer is below the upper limit, it tends to be easier to obtain better heat resistance. 【0116】 The total content of one or more selected from the group consisting of conjugated diene polymer (E1), modified conjugated diene polymer (E2), and styrene-based elastomer (E3) is not particularly limited, but from the viewpoint of dielectric properties and the peel strength of the copper foil, it is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, relative to the total amount of (E) elastomer (100% by mass). 【0117】 (E) The elastomer preferably contains one or more selected from the group consisting of conjugated diene polymers (E1) and modified conjugated diene polymers (E2), and a styrene-based elastomer (E3), from the viewpoint of dielectric properties and compatibility. When the elastomer (E) contains one or more selected from the group consisting of conjugated diene polymers (E1) and modified conjugated diene polymers (E2), and a styrene-based elastomer (E3), the ratio of the total content of conjugated diene polymers (E1) and modified conjugated diene polymers (E2) to the content of styrene-based elastomer (E3) [[(E1) + (E2)] / (E3)] is not particularly limited, but from the viewpoint of dielectric properties and compatibility, it is preferably 0.1 to 5, more preferably 0.2 to 1, and even more preferably 0.3 to 0.7. 【0118】((F) Curing accelerator) The resin composition of this embodiment may further contain (F) a curing accelerator. The (F) curing accelerator does not contain the (C) radical polymerization initiator. The resin composition of this embodiment tends to have improved curability due to the inclusion of the (F) curing accelerator, and is more likely to yield superior dielectric properties, heat resistance, and peel strength of copper foil. The (F) curing accelerator may be used alone or in combination of two or more types. 【0119】 (F) Examples of curing accelerators include acidic catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, pyridine, tributylamine, and dicyandiamide; imidazole compounds such as methylimidazole, phenylimidazole, and 1-cyanoethyl-2-phenylimidazole; isocyanate-masquimidazole compounds such as the addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; tertiary amine compounds; quaternary ammonium compounds; phosphorus compounds such as triphenylphosphine; and carboxylates of manganese, cobalt, zinc, etc. Among these, imidazole compounds, isocyanate-masquimidazole compounds, and carboxylates are preferred from the viewpoint of curing acceleration effect and storage stability, and isocyanate-masquimidazole compounds are more preferred. 【0120】 (Content of (F) curing accelerator) When the resin composition of this embodiment contains (F) curing accelerator, the content of (F) curing accelerator is not particularly limited, but is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, even more preferably 0.03 to 2 parts by mass, and particularly preferably 0.1 to 1.5 parts by mass, per 100 parts by mass of the total amount of resin components. When the content of (F) curing accelerator is above the lower limit, a sufficient curing acceleration effect tends to be easily obtained. Also, when the content of (F) curing accelerator is below the upper limit, storage stability tends to be better. 【0121】<Other Components> The resin composition of this embodiment may further contain, if necessary, one or more optional components selected from the group consisting of resin materials other than the above components, flame retardants, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, organic solvents, and other additives. Examples of resin materials other than the above components include one or more thermosetting resins selected from the group consisting of maleimide resins that do not contain indan rings, epoxy resins, phenolic resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. The thermosetting resin is preferably one or more selected from the group consisting of epoxy resins, phenolic resins, cyanate resins, isocyanate resins, amino resins, unsaturated polyester resins, and silicone resins; more preferably one or more selected from the group consisting of epoxy resins, phenolic resins, cyanate resins, and isocyanate resins; and even more preferably one or more selected from the group consisting of epoxy resins, phenolic resins, and cyanate resins. Each of the above optional components may be used alone or in combination of two or more. A preferred embodiment of the resin composition of this embodiment is a resin composition that does not contain epoxy resin, or, if it contains epoxy resin, the epoxy resin content is 20% by mass or less based on the total amount of resin components. The content of the above optional components in the resin composition of this embodiment is not particularly limited and may be used as needed, within a range that does not hinder the effects of this embodiment. Furthermore, the resin composition of this embodiment may not contain the above optional components, depending on the desired performance. 【0122】 (Resin component content) The resin component content in the resin composition of this embodiment is not particularly limited, but from the viewpoint of low thermal expansion, heat resistance, flame retardancy, and the peel strength of the copper foil, it is preferably 5 to 80% by mass, more preferably 10 to 60% by mass, and even more preferably 20 to 40% by mass, relative to the total solid content (100% by mass) of the resin composition of this embodiment. 【0123】(Total content of components (A) to (F)) The total content of components (A) to (F) in the resin composition of this embodiment is not particularly limited, but may be 50 to 100% by mass, 70 to 100% by mass, 80 to 100% by mass, 90 to 100% by mass, or 95 to 100% by mass, based on the total solid content (100% by mass) of the resin composition. 【0124】 The resin composition of this embodiment is suitable as a resin composition for constituting a resin film. The resin composition of this embodiment is preferably used to form a resin film with a thickness of 10 μm or more, more preferably to form a resin film with a thickness of 25 μm or more, more preferably to form a resin film with a thickness of 50 μm or more, even more preferably to form a resin film with a thickness of 80 μm or more, even more preferably to form a resin film with a thickness of 100 μm or more, even more preferably to form a resin film with a thickness of 130 μm or more, and particularly preferably to form a resin film with a thickness of 150 μm or more. Furthermore, from the viewpoint of ease of handling, the resin composition of this embodiment is preferably used to form a resin film with a thickness of 1,000 μm or less, more preferably to form a resin film with a thickness of 700 μm or less, and even more preferably to form a resin film with a thickness of 500 μm or less. In other words, the resin composition of this embodiment is preferably used to form a resin film with a thickness of 10 to 1,000 μm. Furthermore, the lower and upper limits of the numerical range "10 to 1,000 μm" can be replaced with the aforementioned preferred values. 【0125】[Resin Film and Resin Film with Support] The resin film of this embodiment is a resin film containing the resin composition of this embodiment. In this specification, "containing" means that the contained substances may be contained as they are, the contained substances may be reacted with each other, or both of these forms may be included. The resin film of this embodiment can be manufactured, for example, by applying the resin composition of this embodiment containing an organic solvent, i.e., a resin varnish, to a support and then heating and drying it. In this way, a resin film with a support is obtained, comprising a support and the resin film of this embodiment. 【0126】 Examples of the support include plastic films, metal foils, and release paper. Examples of plastic films include polyolefin films such as polyethylene, polypropylene, and polyvinyl chloride; polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate films and polyimide films. Among these, polyethylene terephthalate film is preferred from the viewpoint of economy and ease of handling. Examples of metal foil include copper foil and aluminum foil. When copper foil is used as the support, the copper foil can be used as the conductive layer to form a circuit. In this case, rolled copper foil, electrolytic copper foil, etc. can be used as the copper foil. When using thin copper foil, a carrier-attached copper foil may be used from the viewpoint of improving workability. The support may be surface-treated with matte treatment, corona treatment, etc. The support may also be release-treated with a silicone resin-based release agent, an alkyd resin-based release agent, a fluororesin-based release agent, etc. The thickness of the support is not particularly limited, but from the viewpoint of handling and economy, it is preferably 10 to 150 μm, more preferably 20 to 100 μm, and even more preferably 25 to 50 μm. 【0127】For applying the resin varnish, coating devices known to those skilled in the art, such as comma coaters, bar coaters, kiss coaters, roll coaters, gravure coaters, and die coaters, can be used. These coating devices should be appropriately selected depending on the film thickness to be formed. The drying conditions after applying the resin varnish can be appropriately determined according to the content and boiling point of the organic solvent, and are not particularly limited. For example, in the case of a resin varnish containing 40 to 60% by mass of an aromatic hydrocarbon solvent, the drying temperature is not particularly limited, but from the viewpoint of productivity and appropriately B-stage the resin composition of this embodiment, it is preferably 50 to 200°C, more preferably 80 to 150°C, and even more preferably 95 to 130°C. In the case of the above resin varnish, the drying time is not particularly limited, but from the viewpoint of productivity and appropriately B-stage the resin composition of this embodiment, it is preferably 1 to 30 minutes, more preferably 2 to 15 minutes, and even more preferably 3 to 10 minutes. 【0128】 The thickness of the resin film in this embodiment can be appropriately determined depending on the application of the resin film, but from the viewpoint of obtaining sufficient insulation reliability and enabling the embedding of semiconductor chips, etc., it is preferably 10 μm or more, more preferably 50 μm or more, even more preferably 80 μm or more, even more preferably 100 μm or more, even more preferably 130 μm or more, and particularly preferably 150 μm or more. Furthermore, from the viewpoint of ease of handling, the thickness of the resin film in this embodiment is preferably 1,000 μm or less, more preferably 700 μm or less, and even more preferably 500 μm or less. In other words, the thickness of the resin film in this embodiment is preferably 10 to 1,000 μm, and the lower and upper limits of this numerical range can be replaced with the above preferred values. 【0129】 The resin film of this embodiment may have a protective film. The protective film is provided on the side of the resin film of this embodiment opposite to the side on which the support is provided, and is used for the purpose of preventing foreign matter from adhering to the resin film and from being scratched. 【0130】(Relative permittivity (Dk) and dielectric loss tangent (Df)) The relative permittivity (Dk) at 10 GHz of the cured resin composition and cured resin film of this embodiment may be 3.3 or less, 3.2 or less, 3.1 or less, or 3.0 or less. The smaller the relative permittivity (Dk), the better, and its lower limit is not particularly limited, but considering the balance with other physical properties, it may be 2.6 or more, or 2.8 or more. In other words, the relative permittivity (Dk) may be between 2.6 and 3.3. The dielectric loss tangent (Df) at 10 GHz of the cured resin composition and cured resin film of this embodiment may be 0.0012 or less, 0.0010 or less, 0.0009 or less, or 0.0008 or less. The dielectric loss tangent (Df) is preferably as small as possible, and its lower limit is not particularly limited, but considering the balance with other physical properties, it may be 0.0005 or higher, or 0.0006 or higher. In other words, the dielectric loss tangent (Df) may be between 0.0005 and 0.0012. The relative permittivity (Dk) and dielectric loss tangent (Df) are values ​​obtained in accordance with the cavity resonator perturbation method, and more specifically, are values ​​measured by the method described in the examples. 【0131】 The resin film of this embodiment is suitable, for example, as a resin film for forming an insulating layer on printed circuit boards such as multilayer printed circuit boards, and as a resin film for semiconductor encapsulation in semiconductor packages. 【0132】 [Printed Wiring Board] The printed wiring board of this embodiment is a printed wiring board having a cured product of the resin composition of this embodiment or a cured product of the resin film of this embodiment. In other words, the printed wiring board of this embodiment can also be said to contain the resin composition of this embodiment or the resin film of this embodiment. 【0133】The printed circuit board of this embodiment is preferably a multilayer printed circuit board having a cured product of the resin composition of this embodiment or a cured product of the resin film of this embodiment. That is, the multilayer printed circuit board of this embodiment includes at least a multilayer structure containing a cured product of the resin composition of this embodiment or a cured product of the resin film of this embodiment, and a conductor circuit layer. A method for manufacturing the multilayer printed circuit board of this embodiment using the resin film of this embodiment will be described below. 【0134】 When manufacturing a multilayer printed circuit board using the resin film of this embodiment, first, the resin film of this embodiment is laminated onto one or both sides of the circuit board. Specifically, the resin film of this embodiment can be laminated onto the circuit board by placing the resin film of this embodiment on the circuit board and then laminating it onto the circuit board while applying pressure and heating with a vacuum laminator. Examples of circuit boards used in multilayer printed circuit boards include those with patterned conductive layers (circuits) formed on one or both sides of glass epoxy, metal substrates, polyester substrates, polyimide substrates, BT (bismaleimidotriazine) resin substrates, thermosetting polyphenylene ether substrates, etc. From the viewpoint of adhesion, the surface of the conductive layer of the circuit board may be roughened in advance by blackening treatment or the like. 【0135】 Next, after peeling off the support of the resin film as necessary, the resin film is heat-cured to form an insulating layer. The heating temperature during heat curing is not particularly limited, but is preferably 100 to 300°C, more preferably 120 to 280°C, and even more preferably 150 to 250°C. The heating time during heat curing is not particularly limited, but is preferably 2 to 300 minutes, more preferably 5 to 200 minutes, and even more preferably 10 to 150 minutes. 【0136】After forming the insulating layer using the method described above, drilling may be performed as needed. Drilling is a process of creating via holes, through holes, etc., in the circuit board and the formed insulating layer using methods such as drills, lasers, plasma, or combinations thereof. Lasers used for drilling include carbon dioxide lasers, YAG lasers, UV lasers, and excimer lasers. 【0137】 Next, the surface of the insulating layer may be roughened with an oxidizing agent. Furthermore, if via holes, through holes, etc., are formed in the insulating layer and the circuit board, the so-called "smear" generated during their formation may be removed with an oxidizing agent. The roughening treatment and smear removal can be performed simultaneously. The roughening treatment can create anchors of irregularities on the surface of the insulating layer. 【0138】 Next, a conductive layer is formed on the surface of the roughened insulating layer. The conductive layer can be formed, for example, by plating. Examples of plating methods include electroless plating and electrolytic plating. Examples of metals for plating include copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, and alloys containing at least one of these metal elements. Among these, copper and nickel are preferred, with copper being more preferred. Alternatively, a method can be adopted in which a plating resist with a pattern in the reverse of the wiring pattern is formed first, and then the wiring pattern is formed by electroless plating alone. Furthermore, annealing treatment may be performed after the conductive layer is formed. By performing annealing treatment, the adhesive strength between the interlayer insulating layer and the conductive layer tends to be further improved and stabilized. 【0139】 Known methods such as the subtractive method, the fully additive method, the semi-additive method (SAP: Semi-Additive Process), and the modified semi-additive method (m-SAP: modified Semi-Additive Process) can be used to pattern the conductive layer and form a circuit. 【0140】[Semiconductor Package] The semiconductor package of this embodiment is a semiconductor package having a cured product of the resin composition of this embodiment or a cured product of the resin film of this embodiment. In other words, the semiconductor package of this embodiment can also be said to be a semiconductor package containing the resin composition of this embodiment or the resin film of this embodiment. The semiconductor package of this embodiment may, for example, be one in which a semiconductor chip is mounted on a printed circuit board of this embodiment, or it may be one in which a semiconductor chip is sealed in a cured product of the resin film of this embodiment. 【0141】 A semiconductor package comprising a semiconductor chip mounted on a printed circuit board according to this embodiment can be manufactured, for example, by mounting a semiconductor chip, memory, etc., on the printed circuit board according to this embodiment using a known method. The printed circuit board used in the manufacture of the semiconductor package is preferably a multilayer printed circuit board. 【0142】 A semiconductor package comprising a semiconductor chip sealed in a cured resin film of this embodiment can be manufactured, for example, by the following method. First, the resin film of this embodiment is placed on the semiconductor chip. Next, the resin film is heated and melted to embed the semiconductor chip with the resin composition constituting the resin film. Subsequently, the resin composition in which the semiconductor chip is embedded is cured by heating to manufacture a semiconductor package in which the semiconductor chip is sealed by the cured resin composition. 【0143】 The embodiment will be described in detail below with reference to examples. However, this embodiment is not limited to the following examples. 【0144】The number-average molecular weight and weight-average molecular weight were measured using the following procedure. (Method for measuring number-average molecular weight and weight-average molecular weight) The number-average molecular weight and weight-average molecular weight were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) (manufactured by Tosoh Corporation, trade name). The GPC measurement conditions are shown below. [GPC Measurement Conditions] Instrument: High-speed GPC instrument HLC-8320GPC Detector: UV absorbance detector UV-8320 [Manufactured by Tosoh Corporation] Column: Guard column; TSK Guardcolumn SuperHZ-L + Column; TSKgel SuperHZM-N + TSKgel SuperHZM-M + TSKgel SuperH-RC (All manufactured by Tosoh Corporation, product names) Column size: 4.6 × 20 mm (guard column), 4.6 × 150 mm (column), 6.0 × 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 5 mL Injection volume: 25 μL Flow rate: 1.00 mL / min Measurement temperature: 40°C 【0145】 Production Example 1 [Production of Modified Conjugated Diene Polymer] In a 2 L glass flask container capable of heating and cooling, equipped with a thermometer, reflux condenser, and stirring device, 33.8 parts by mass of 1,2-polybutadiene homopolymer (number average molecular weight = 1,200, vinyl group content = 85 mol% or more), 1.43 parts by mass of aromatic bismaleimide resin containing an indan ring (compound represented by the above general formula (A1-4-1), number average molecular weight = 1,300), 0.0035 parts by mass of t-butyl peroxyisopropyl carbonate, and toluene as an organic solvent were added. The mixture was then reacted under a nitrogen atmosphere at 90-100°C for 5 hours with stirring to obtain a solution of modified conjugated diene polymer (solid content concentration: 35% by mass). The number average molecular weight of the obtained modified conjugated diene polymer was 1,700. 【0146】Furthermore, GPC measurements were taken using the method described above for a solution containing 1,2-polybutadiene homopolymer and aromatic bismaleimide resin containing an indan ring before the reaction and for the solution after the reaction, and the peak area derived from the aromatic bismaleimide resin containing an indan ring before and after the reaction was determined. Next, the vinyl group modification rate of the aromatic bismaleimide resin containing an indan ring was calculated using the following formula. The vinyl group modification rate corresponds to the rate of decrease in the peak area derived from the aromatic bismaleimide resin containing an indan ring due to the reaction. Vinyl group modification rate (%) = [(Peak area derived from aromatic bismaleimide resin containing an indan ring before the reaction) - (Peak area derived from aromatic bismaleimide resin containing an indan ring after the reaction)] × 100 / (Peak area derived from aromatic bismaleimide resin containing an indan ring before the reaction) The vinyl group modification rate obtained from the above formula was 40%. 【0147】 [Preparation of Resin Composition] Example 1, Comparative Examples 1-2 Each component listed in Table 1 was blended with toluene according to the blending amounts listed in Table 1. Then, the mixture was stirred and mixed while heating at 25°C or 50-80°C to prepare a resin composition with a solid content of approximately 50% by mass. In Table 1, the unit of blending amount for each component is parts by mass, and in the case of a solution or dispersion, it means parts by mass on a solid content basis. 【0148】 [Manufacturing of Resin Film] The resin composition obtained in each example was applied to one side of a 50 μm thick PET film (manufactured by Toyobo Co., Ltd., product name "Purex A53") to a thickness such that the resin layer thickness after drying would be 150 μm. Then, by heating and drying at 105°C for 5 minutes, the resin composition was brought to the B stage, and a single-sided PET film-coated resin film (1) (resin film thickness: 150 μm) was produced. Next, the obtained single-sided PET film-coated resin film (1) was cut to 200 mm x 200 mm and the resin films were overlapped so that they faced each other. Subsequently, a double-sided PET film-coated resin film (2) (resin film thickness: 300 μm) was obtained by laminating using a vacuum laminator at a temperature of 100°C and a pressurizing time of 5 seconds. 【0149】[Manufacturing of double-sided copper foil-coated resin sheet] The double-sided PET film-coated resin film (2) obtained above was cut to a size of 90 mm in length x 50 mm in width. After peeling off the PET films from both sides, it was placed in a Teflon sheet that had been die-cut to a size of 0.3 mm in thickness x 90 mm in length x 50 mm in width. Low-profile copper foil with a thickness of 18 μm (manufactured by Mitsui Mining & Smelting Co., Ltd., product name "3EC-VLP-18") was placed on the top and bottom of the resin film contained in the die-cut Teflon sheet. The low-profile copper foil was placed with the M side facing the resin film. Next, this laminate before heat-pressure molding was heat-pressure molded at a temperature of 180°C, a pressure of 2.0 MPa, and a time of 60 minutes to mold and cure the resin film into a resin sheet, thereby producing a double-sided copper foil-coated resin sheet. The thickness of the resin sheet portion of the obtained double-sided copper foil-coated resin sheet was 0.3 mm. 【0150】 [Measurement and Evaluation Methods] Using the resin films or double-sided copper foil-coated resin plates obtained in the above examples and comparative examples, each measurement or evaluation was performed according to the following methods. The results are shown in Table 1. 【0151】 (1. Method for evaluating flexibility) The resin film (1) with a PET film on one side obtained in each example was wrapped around a resin cylinder with a diameter of 85 mm at 25°C, with the resin film side facing outwards. The appearance of the wrapped resin film was visually observed, and the flexibility of the resin film (resin composition) was evaluated according to the following criteria. <Criteria for evaluating flexibility> A: No cracks in the resin film or delamination from the PET film were observed. C: Cracks in the resin film or delamination from the PET film were observed. 【0152】 (2. Measurement Method for Relative Permittivity (Dk) and Dielectric Loss Tangent (Df)) The copper foil was removed from the double-sided copper foil-covered resin plates obtained in each example by immersion in a 10% by mass solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is a copper etching solution. The resulting resin plates were cut into 2 mm x 50 mm pieces and dried at 105°C for 1 hour to prepare the test specimens. Next, the relative permittivity (Dk) and dielectric loss tangent (Df) of the test specimens were measured in accordance with the cavity resonator perturbation method at an ambient temperature of 25°C and in the 10 GHz band. 【0153】 【0154】 The details of each component shown in Table 1 are as follows: [Component (A)] Maleimide resin: Aromatic bismaleimide resin containing an indan ring represented by the general formula (A1-4-1): Number average molecular weight = 1,300, solid at 25°C 【0155】 [Component (B)] Silica: Spherical silica treated with an aminosilane coupling agent, average particle size 2.3 μm 【0156】 [Component (X)] BMI-689 manufactured by DESIGNER MOLUCULES INC., liquid at 25°C (viscosity at 25°C = 2 Pa·s) 【0157】 [Comparative component for (X)] ・1,9-nonanediol dimethacrylate: liquid at 25°C (viscosity at 25°C = 8 mPa·s), molecular weight: 296.4 【0158】 [Component (C)] • Organic peroxide: α,α-bis(t-butylperoxy-m-isopropyl)benzene 【0159】 [Component (E)] ・Modified conjugated diene polymer (E2): Modified conjugated diene polymer obtained in Production Example 1, number average molecular weight = 1,700 ・Styrene elastomer (E3): Hydrogenated styrene thermoplastic elastomer (styrene-ethylene-butylene-styrene copolymer), trade name "MD1653", styrene content = 31% by mass, MFR = 28 g / 10 min under measurement conditions of 230°C and load of 2.16 kgf (21.2 N), number average molecular weight = 70,000 【0160】 [(F) Ingredients] Imidazole-based curing accelerator: Isocyanate-masquimidazole, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "G-8009L" 【0161】Table 1 shows that the resin composition (resin film) obtained in Example 1 exhibited excellent flexibility and a low dielectric loss tangent (Df). On the other hand, Comparative Example 1, which used a resin composition containing 1,9-nonanediol dimethacrylate instead of component (X) to impart flexibility, exhibited excellent flexibility, but had a high dielectric loss tangent (Df), indicating room for improvement. Furthermore, Comparative Example 2, which did not contain component (X) and did not use any substitute component for component (X), exhibited poor flexibility and was prone to cracking in the resin film. 【0162】 [Production of Resin Composition] Comparative Example 3 A resin composition with a solid content of approximately 50% by mass was prepared by performing the same procedure as in Example 1, except that the aromatic polymaleimide resin "MIR-3000" (manufactured by Nippon Kayaku Co., Ltd.), which does not contain an indan ring, was used as component (A) instead of the aromatic bismaleimide resin containing an indan ring represented by general formula (A1-4-1). However, the obtained resin composition was gel-like, and it was not possible to attempt to form a resin film.

Claims

1. A resin composition comprising: (A) an indan ring-containing maleimide resin; (B) an inorganic filler; and (X) a compound that is liquid at 25°C and has a maleimide group.

2. The resin composition according to claim 1, which does not contain epoxy resin, or if it does contain epoxy resin, the epoxy resin content is 20% by mass or less based on the total amount of resin components.

3. The resin composition according to claim 1, wherein component (A) is one or more selected from the group consisting of indan ring-containing maleimide resins having one or more N-substituted maleimide groups and derivatives of said maleimide resin.

4. The resin composition according to claim 3, wherein the indan ring-containing maleimide resin having one or more N-substituted maleimide groups is an indan ring-containing maleimide resin having two or more N-substituted maleimide groups, and containing a fused ring of an aromatic ring and an aliphatic ring in its molecular structure.

5. The resin composition according to claim 1, wherein the component (X) has a structural unit derived from a dimer amine.

6. The resin composition according to claim 1, further comprising (C) a radical polymerization initiator.

7. The resin composition according to claim 1, further comprising (D) a polymerization inhibitor.

8. The resin composition according to claim 1, further comprising (E) an elastomer.

9. A resin film comprising the resin composition described in claim 1.

10. A resin film with a support, comprising a support and the resin film described in claim 9.

11. A printed circuit board having a cured product of the resin composition described in claim 1 or a cured product of the resin film described in claim 9.

12. A semiconductor package having a cured product of the resin composition according to claim 1 or a cured product of the resin film according to claim 9.

13. The semiconductor package according to claim 12, comprising a semiconductor chip sealed in a cured product of the resin composition.

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