Maleimide resin composition, prepreg, resin film, laminate, multilayer printed wiring board, and semiconductor package

Abstract

To provide a maleimide resin composition that can achieve even lower dielectric loss tangent in a high frequency band of 10 GHz band or higher, and to provide a prepreg, a resin film, a laminate, a multilayer printed wiring board and a semiconductor package using the maleimide resin composition.SOLUTION: Provided is a maleimide resin composition that contains (A) one or more selected from the group consisting of maleimide compounds having one or more N-substituted maleimide group and derivatives thereof, (B) a thermoplastic elastomer, and (C) a divinyl compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a maleimide resin composition, a prepreg, a resin film, a laminate, a multilayer printed wiring board, and a semiconductor package. [Background technology]

[0002] Mobile communication devices such as mobile phones, their base station equipment, servers, routers, and other network infrastructure equipment, as well as large-capacity computers, are increasingly using faster and larger-capacity signals. This trend requires printed wiring boards (PCBs) for these devices to support higher frequencies, necessitating the development of substrate materials with excellent dielectric properties in high-frequency bands, i.e., low dielectric constants and dielectric loss tangents, which enable reduced transmission loss. In recent years, in addition to the electronic devices mentioned above, new systems using high-frequency wireless signals have been commercialized or planned for commercialization in the fields of ITS (Intelligent Transport Systems), including automobiles and transportation systems, and in indoor short-range communications. Going forward, it is expected that low-transmission-loss substrate materials will be increasingly required for the printed wiring boards used in these devices.

[0003] Conventionally, thermoplastic polymers with excellent dielectric properties in the high frequency band have been used for printed wiring boards that require low transmission loss. Examples of maleimide resin compositions containing a thermoplastic polymer include a resin composition containing one or more compounds (A) selected from the group consisting of maleimide compounds having at least two N-substituted maleimide groups and their derivatives, one or more compounds (B) selected from the group consisting of polyphenylene ethers and their derivatives, and a copolymer (C) having structural units derived from a styrene compound, structural units derived from maleic anhydride, and structural units derived from an N-substituted maleimide (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-169276 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for substrate materials to be used in fifth-generation mobile communication system (commonly known as 5G) antennas, which use radio waves in the frequency band above 6 GHz, and millimeter-wave radar, which uses radio waves in the frequency band of 30 to 300 GHz. To this end, the development of resin compositions with further improved dielectric properties in the 10 GHz band and above is necessary. Here, the inventors' studies have revealed that the resin composition described in Patent Document 1 has room for further improvement in terms of dielectric loss tangent (Df).

[0006] In view of the current situation, the present disclosure has an object to provide a maleimide resin composition that can achieve an even lower dielectric loss tangent in a high frequency band of 10 GHz or higher, and a prepreg, a resin film, a laminate, a multilayer printed wiring board, and a semiconductor package that use the maleimide resin composition. [Means for solving the problem]

[0007] As a result of investigations into achieving the above object, the inventors have found that the object can be achieved by this embodiment. This embodiment includes the following [1] to [9]. [1] (A) one or more compounds selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof; (B) a thermoplastic elastomer; (C) a divinyl compound. [2] The maleimide resin composition according to the above [1], wherein the molecular weight of the component (C) is 500 or less. [3] The maleimide resin composition according to the above [1] or [2], wherein the component (C) has an aromatic ring or a silicon atom. [4] The maleimide resin composition according to any one of the above [1] to [3], wherein the component (B) comprises at least one member selected from the group consisting of a styrene-based elastomer, an olefin-based elastomer, a urethane-based elastomer, a polyester-based elastomer, a polyamide-based elastomer, an acrylic-based elastomer, a silicone-based elastomer, and derivatives thereof. [5] A prepreg comprising the maleimide resin composition according to any one of [1] to [4] above. [6] A resin film comprising the maleimide resin composition according to any one of [1] to [4] above. [7] A laminate comprising the prepreg described in [5] above or the resin film described in [6] above. [8] A multilayer printed wiring board comprising the laminate described in [7] above. [9] A semiconductor package comprising the multilayer printed wiring board according to [8] above and a semiconductor element. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a maleimide resin composition that can achieve an even lower dielectric loss tangent in a high frequency band of 10 GHz or higher, and a prepreg, a resin film, a laminate, a multilayer printed wiring board, and a semiconductor package that use the maleimide resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower or upper limit of another numerical range. In the expression "AA to BB," the numerical values ​​AA and BB at the ends are included as the lower and upper limits, respectively, of the numerical range. In this specification, for example, the expression "10 or more" means 10 or a numerical value exceeding 10, and this also applies when the numerical values ​​are different. Furthermore, for example, the expression "10 or less" means 10 or a numerical value less than 10, and this also applies when the numerical values ​​are different. Furthermore, unless otherwise specified, each component and material exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified.

[0010] In this specification, the "number of ring carbon atoms" refers to the number of carbon atoms necessary to form a ring, and does not include the number of carbon atoms of substituents on the ring. For example, both the cyclohexane skeleton and the methylcyclohexane skeleton have 6 ring carbon atoms. In this specification, the term "resin component" is defined as all components among the solid components constituting the resin composition, excluding inorganic compounds such as inorganic fillers, flame retardants, and flame retardant assistants, which will be described later. In this specification, the term "solid content" refers to components in a resin composition other than water and volatile substances such as the solvent described below. In other words, the solid content includes substances that are liquid, syrup-like, or waxy at around 25°C, and does not necessarily mean that they are solid. Any combination of the descriptions in this specification is also included in the present disclosure and the present embodiment.

[0011] [Maleimide resin composition] The maleimide resin composition of this embodiment (hereinafter sometimes simply referred to as a resin composition) is as follows. (A) one or more maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof [hereinafter, sometimes simply referred to as maleimide compound (A) or component (A)]; (B) a thermoplastic elastomer (hereinafter, sometimes abbreviated as thermoplastic elastomer (B) or component (B)); (C) a divinyl compound (hereinafter sometimes abbreviated as divinyl compound (C) or component (C)).

[0012] The reason why the maleimide resin composition of the present embodiment can achieve a lower dielectric loss tangent in a high frequency band of 10 GHz or higher is presumed to be as follows. First, the content of the maleimide compound (A) can be reduced by the amount of the divinyl compound (C), which suppresses an increase in the dielectric loss tangent (Df) due to the influence of the polar group of the maleimide compound (A). Furthermore, because the divinyl compound (C) is bifunctional, the crosslinking density does not increase too much, which is thought to maintain a large molecular free volume after the crosslinking reaction, thereby reducing the dielectric loss tangent (Df). Hereinafter, each component that may be contained in the maleimide resin composition of the present embodiment will be described in detail in order.

[0013] <Maleimide compound (A)> The maleimide compound (A) is at least one selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof. Examples of the "derivative of a maleimide compound having one or more N-substituted maleimide groups" include an addition reaction product of the maleimide compound having one or more N-substituted maleimide groups and an amine compound such as the diamine compound (a2) described below. The component (A) may be used alone or in combination of two or more.

[0014] The maleimide compound (A) is preferably selected from the following compounds in terms of compatibility with other resins, adhesion to conductors, and dielectric properties: a maleimide compound having one or more N-substituted maleimide groups, and an aminomaleimide compound having a structural unit derived from a maleimide compound and a structural unit derived from a diamine compound; Preferably, one or more selected from the group consisting of: Examples of the maleimide compound having one or more N-substituted maleimide groups include aromatic maleimide compounds having one N-substituted maleimide group in the molecule, such as N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-benzylmaleimide, N-dodecylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide; bis(4-maleimidophenyl)methane, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, Examples of suitable bismaleimide compounds include aromatic bismaleimide compounds having two N-substituted maleimide groups in the molecule, such as 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide, and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane; aromatic polymaleimide compounds having three or more N-substituted maleimide groups in the molecule, such as polyphenylmethane maleimide and biphenylaralkyl maleimide; and aliphatic maleimide compounds such as 1,6-bismaleimide-(2,2,4-trimethyl)hexane and pyrrolidine acid binder-type long-chain alkyl bismaleimide. Examples of the structural unit derived from a maleimide compound contained in the aminomaleimide compound include structural units derived from a maleimide compound having one or more N-substituted maleimide groups. The structural unit derived from the diamine compound contained in the aminomaleimide compound is the same as the structural unit derived from the diamine compound (a2) described below.

[0015] In this embodiment, from the viewpoint of dielectric properties and conductor adhesion, the maleimide compound (A) is more preferably one or more compounds selected from the group consisting of the following (i) and (ii), but is not particularly limited thereto: (i) A maleimide compound (a1) containing a fused ring of an aromatic ring and an aliphatic ring in its molecular structure and having two or more N-substituted maleimide groups [hereinafter, this may be referred to as "maleimide compound (a1)" or "component (a1)"]. (ii) An aminomaleimide compound having a structural unit derived from a maleimide compound (a1) and a structural unit derived from a diamine compound (a2) [hereinafter, this may be referred to as "aminomaleimide compound (A1)" or "component (A1)"] Hereinafter, one or more compounds selected from the group consisting of (i) and (ii) above will be described in detail.

[0016] (Maleimide compound (a1)) From the viewpoints of dielectric properties, conductor adhesion, and heat resistance, the component (a1) is preferably an aromatic maleimide compound that 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 directly bonded to the aromatic ring, and more preferably an aromatic bismaleimide compound that contains a fused ring of an aromatic ring and an aliphatic ring in its molecular structure and has two N-substituted maleimide groups directly bonded to the aromatic ring.

[0017] From the viewpoints of dielectric properties, conductor adhesion, and ease of production, the fused ring contained in component (a1) preferably has a fused bicyclic structure, and more preferably is an indan ring. In this specification, the term "indan ring" refers to a fused bicyclic structure of an aromatic six-membered ring and a saturated aliphatic five-membered ring. At least one of the ring-forming carbon atoms forming the indan ring has a linking group for bonding to another group constituting component (a1). The ring-forming carbon atom having the linking group and the other ring-forming carbon atoms may or may not have a linking group, a substituent, etc. in addition to the above-mentioned linking group. In the component (a1), the indane ring is preferably contained as a divalent group represented by the following general formula (a1-1).

[0018] [ka] (In the formula, R a1is 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, and n1 is an integer of 0 to 3. a2 ~R a4 are each independently an alkyl group having 1 to 10 carbon atoms. * represents a bonding site.

[0019] R in the above general formula (a1-1) a1 Examples of the alkyl group having 1 to 10 carbon atoms represented by the formula (I) 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 decyl group, etc. These alkyl groups may be either linear or branched. R a1 Examples of the alkyl group contained in the alkyloxy group having 1 to 10 carbon atoms and the alkylthio group having 1 to 10 carbon atoms represented by the following formula include the same as the alkyl group having 1 to 10 carbon atoms described above. R a1 Examples of the aryl group having 6 to 10 carbon atoms represented by the formula include a phenyl group and a naphthyl group. R a1 Examples of the aryl group contained in the aryloxy group having 6 to 10 carbon atoms and the arylthio group having 6 to 10 carbon atoms represented by the following formula include the same as the aryl group having 6 to 10 carbon atoms described above. R a1 Examples of the cycloalkyl group having 3 to 10 carbon atoms represented by the formula include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group. When n1 in the above general formula (a1-1) is 1 to 3, R a1 From the viewpoint of solvent solubility and reactivity, 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, and alkyl groups having 1 to 4 carbon atoms are more preferred.

[0020] R a2 ~R a4Examples of the alkyl group having 1 to 10 carbon atoms represented by the formula (I) 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, and a decyl group. These alkyl groups may be either linear or branched. Among these, R a2 ~R a4 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. In the general formula (a1-1), n1 is an integer of 0 to 3. When n1 is 2 or 3, a plurality of R a1 They may be the same or different.

[0021] Among the above, the divalent group represented by the general formula (a1-1) is preferably a group in which n1 is 0 and R a2 ~R a4 is a methyl group, and more preferably includes at least one selected from the group consisting of a divalent group represented by the following formula (a1-1″) and a divalent group represented by the following formula (a1-1′″).

[0022] [ka] (In the formula, * represents a binding site.)

[0023] As the component (a1) containing a divalent group represented by the above general formula (a1-1), one represented by the following general formula (a1-2) is preferred from the viewpoints of dielectric properties, conductor adhesion, heat resistance, and ease of production.

[0024] [ka] (In the formula, R a1 ~R a4 and n1 are the same as those in the general formula (a1-1) above. a5are each independently 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 nitro group, a hydroxyl group, or a mercapto group, n2 is an integer of 0 to 4, and n3 is a number of 0.95 to 10.0.

[0025] In the general formula (a1-2), multiple R a1 between multiple n1s, between multiple Rs a5 Each n2 may be the same or different from each other. a2 R a3 R a4 Each of the two may be the same or different.

[0026] R in the above general formula (a1-2) a5 The alkyl group having 1 to 10 carbon atoms, the alkyloxy group having 1 to 10 carbon atoms, the alkylthio group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxy group having 6 to 10 carbon atoms, the arylthio group having 6 to 10 carbon atoms, and the cycloalkyl group having 3 to 10 carbon atoms represented by R a1 The explanation is the same as for the alkyl group having 1 to 10 carbon atoms, the alkyloxy group having 1 to 10 carbon atoms, the alkylthio group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxy group having 6 to 10 carbon atoms, the arylthio group having 6 to 10 carbon atoms, and the cycloalkyl group having 3 to 10 carbon atoms represented by the formula (I). Among these, R a5 From the viewpoints of solvent solubility and ease of production, the alkyl group having 1 to 4 carbon atoms, the cycloalkyl group having 3 to 6 carbon atoms, and the aryl group having 6 to 10 carbon atoms are preferred, the alkyl group having 1 to 3 carbon atoms is more preferred, and the methyl group is even more preferred.

[0027] In the above general formula (a1-2), n2 is an integer of 0 to 4, and from the viewpoints of compatibility with other resins, dielectric properties, adhesion to conductors, and ease of production, it is preferably an integer of 1 to 3, more preferably 2 or 3, and even more preferably 2. In addition, when n2 is 1 or more, the benzene ring and the N-substituted maleimide group have a twisted conformation, and the solvent solubility tends to be further improved by suppressing intermolecular stacking. From the viewpoint of suppressing intermolecular stacking, when n2 is 1 or more, R a5 The substitution position is preferably the ortho position relative to the N-substituted maleimide group. In the above general formula (a1-2), n3 is preferably a number from 0.98 to 8.0, more preferably a number from 1.0 to 7.0, and even more preferably a number from 1.1 to 6.0, from the viewpoints of dielectric properties, conductor adhesion, solvent solubility, handleability, and heat resistance.

[0028] The component (a1) represented by the above general formula (a1-2) is more preferably one represented by the following general formula (a1-3) from the viewpoints of dielectric properties, adhesion to conductors, solvent solubility, and ease of production.

[0029] [ka] (In the formula, R a1 ~R a5 , n1 and n3 are the same as those in the general formula (a1-2) above.)

[0030] The number average molecular weight of component (a1) is not particularly limited, but from the viewpoints of compatibility with other resins, conductor adhesion, and heat resistance, it is preferably 200 to 3,000, more preferably 400 to 2,000, and even more preferably 500 to 1,000. In this specification, the number average molecular weight (Mn) is measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

[0031] The component (a1) can be produced, for example, by reacting an intermediate amine compound containing a fused ring of an aromatic ring and an aliphatic ring (hereinafter sometimes simply referred to as the "intermediate amine compound") with maleic anhydride (hereinafter sometimes referred to as the "maleimidization reaction").

[0032] Hereinafter, a method for producing the component (a1) will be described using as an example a maleimide compound containing an indan ring as a condensed ring between an aromatic ring and an aliphatic ring. An intermediate amine compound of a maleimide compound containing an indan ring can be obtained as a compound represented by the following general formula (a1-6) by reacting, for example, a compound represented by the following general formula (a1-4) [hereinafter, sometimes referred to as "compound A"] with a compound represented by the following general formula (a1-5) [hereinafter, sometimes referred to as "compound B"] in the presence of an acid catalyst [hereinafter, sometimes referred to as "cyclization reaction"].

[0033] [ka] (In the formula, R a1 and n1 are the same as those in the general formula (a1-1) above. a6 are each independently a group represented by the above formula (a1-4-1) or (a1-4-2), and two R a6 At least one of the R a6 The ortho position of is a hydrogen atom.)

[0034] [ka] (In the formula, R a5 and n2 are the same as those in the above general formula (a1-2), provided that at least one of the ortho- and para-positions of the amino group is a hydrogen atom.

[0035] [ka] (In the formula, R a1 , R a5and n1 to n3 are the same as those in the general formula (a1-2) above.)

[0036] Examples of compound A include p- or m-diisopropenylbenzene, p- or m-bis(α-hydroxyisopropyl)benzene, 1-(α-hydroxyisopropyl)-3-isopropenylbenzene, 1-(α-hydroxyisopropyl)-4-isopropenylbenzene, mixtures thereof, nuclear alkyl group-substituted products of these compounds, and nuclear halogen-substituted products of these compounds. Examples of the above-mentioned alkyl group-substituted nuclei include diisopropenyltoluene and bis(α-hydroxyisopropyl)toluene. Examples of the nuclear halogen-substituted compounds include chlorodiisopropenylbenzene and chlorobis(α-hydroxyisopropyl)benzene. These may be used alone or in combination of two or more.

[0037] Examples of compound B include aniline, dimethylaniline, diethylaniline, diisopropylaniline, ethylmethylaniline, cyclobutylaniline, cyclopentylaniline, cyclohexylaniline, chloroaniline, dichloroaniline, toluidine, xylidine, phenylaniline, nitroaniline, aminophenol, cyclohexylaniline, methoxyaniline, ethoxyaniline, phenoxyaniline, naphthoxyaniline, aminothiol, methylthioaniline, ethylthioaniline, phenylthioaniline, etc. These may be used alone or in combination of two or more.

[0038] In the cyclization reaction, for example, compound A and compound B are charged in a molar ratio (compound B / compound A) of preferably 0.1 to 2.0, more preferably 0.15 to 1.5, and even more preferably 0.2 to 1.0, and then the first-stage reaction is carried out. Next, it is preferable to add compound B at a molar ratio (additional compound B / compound A) relative to the previously added compound A of preferably 0.5 to 20, more preferably 0.6 to 10, and even more preferably 0.7 to 5, to carry out the second-stage reaction.

[0039] Examples of acid catalysts used in the cyclization reaction include inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid; organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid; solid acids such as activated clay, acid clay, silica alumina, zeolite, and strongly acidic ion exchange resins; heteropolyhydrochloric acid, etc. These may be used alone or in combination of two or more. From the viewpoints of reaction rate and reaction uniformity, the amount of the acid catalyst to be added is preferably 5 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 5 to 30 parts by mass, relative to 100 parts by mass of the total amount of Compound A and Compound B initially charged.

[0040] The reaction temperature for the cyclization reaction is preferably 100 to 300°C, more preferably 130 to 250°C, and even more preferably 150 to 230°C, from the viewpoints of reaction rate and reaction uniformity. The reaction time for the cyclization reaction is preferably 2 to 24 hours, more preferably 4 to 16 hours, and even more preferably 8 to 12 hours, from the viewpoints of productivity and allowing the reaction to proceed sufficiently. However, these reaction conditions can be appropriately adjusted depending on the types of raw materials used, and are not particularly limited. In the cyclization reaction, a solvent such as toluene, xylene, chlorobenzene, etc. may be used as needed. In addition, when water is produced as a by-product in the cyclization reaction, the dehydration reaction may be promoted by using a solvent that can be azeotropically dehydrated.

[0041] Next, the intermediate amine compound obtained above is reacted with maleic anhydride in an organic solvent to convert the amino group of the intermediate amine compound into a maleimide group, thereby obtaining component (a1). The equivalent ratio of maleic anhydride to the primary amino group equivalent of the intermediate amine compound in the maleimidation reaction (maleic anhydride / primary amino group) is not particularly limited, but from the viewpoint of reducing unreacted primary amino groups and maleic anhydride, it is preferably 1.0 to 1.5, more preferably 1.05 to 1.3, and even more preferably 1.1 to 1.2. The amount of organic solvent used in the maleimidation reaction is not particularly limited, but from the viewpoint of the reaction rate and reaction uniformity, it is preferably 50 to 5,000 parts by mass, more preferably 70 to 2,000 parts by mass, and even more preferably 100 to 500 parts by mass per 100 parts by mass of the total amount of the intermediate amine compound and maleic anhydride.

[0042] The maleimidation reaction is preferably carried out by reacting an intermediate amine compound with maleic anhydride in two steps. The reaction temperature in the first stage reaction is preferably 10 to 100°C, more preferably 20 to 70°C, and even more preferably 30 to 50°C. The reaction time in the first stage reaction is preferably 0.5 to 12 hours, more preferably 0.7 to 8 hours, and even more preferably 1 to 4 hours. The second stage reaction is preferably carried out after the completion of the first stage reaction and after adding a catalyst such as toluenesulfonic acid. The reaction temperature in the second stage reaction is preferably 90 to 130°C, more preferably 100 to 125°C, and even more preferably 105 to 120°C. The reaction time in the second stage reaction is preferably 2 to 24 hours, more preferably 4 to 10 hours, and even more preferably 6 to 10 hours. However, the above reaction conditions can be appropriately adjusted depending on the types of raw materials used, and are not particularly limited. After the reaction, unreacted raw materials and other impurities may be removed by washing with water, if necessary.

[0043] (Aminomaleimide compound (A1)) The aminomaleimide compound (A1) is an aminomaleimide compound having a structural unit derived from the maleimide compound (a1) and a structural unit derived from the diamine compound (a2). The component (A1) corresponds to a derivative of the maleimide compound (a1). The component (A1) may be used alone or in combination of two or more types.

[0044] [Structural unit derived from maleimide compound (a1)] Examples of the structural unit derived from the component (a1) include a structural unit formed by a Michael addition reaction between at least one N-substituted maleimide group of the component (a1) and an amino group of the diamine compound (a2). The structural unit derived from the component (a1) contained in the component (A1) may be of one type alone, or may be of two or more types.

[0045] The content of the structural units derived from the component (a1) in the aminomaleimide compound (A1) is not particularly limited, but is preferably 5 to 95 mass%, more preferably 30 to 93 mass%, and even more preferably 60 to 90 mass%. When the content of the structural units derived from the component (a1) in the component (A1) is within the above range, the dielectric properties and film handling properties tend to be better.

[0046] [Structural unit derived from diamine compound (a2)] Examples of the structural unit derived from the component (a2) include a structural unit formed by a Michael addition reaction between one or both of the two amino groups in the component (a2) and an N-substituted maleimide group in the maleimide compound (a1). The structural unit derived from the component (a2) contained in the component (A1) may be of one type alone, or may be of two or more types.

[0047] The amino group contained in component (a2) is preferably a primary amino group. Examples of the structural unit derived from a diamine compound having two primary amino groups include a group represented by the following general formula (a2-1) and a group represented by the following general formula (a2-2).

[0048] [ka] (In the formula, X a1 is a divalent organic group, and * indicates the bonding position to other structures.)

[0049] X in the above general formulae (a2-1) and (a2-2) a1 is a divalent organic group, and corresponds to the divalent group obtained by removing two amino groups from component (a2).

[0050] X in the above general formula (a2-1) and the above general formula (a2-2) a1 is preferably a divalent group represented by the following general formula (a2-3).

[0051] [ka] (In the formula, R a11 and R a12 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, or a halogen atom. a2 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, a fluorenylene group, a single bond, or a divalent group represented by the following general formula (a2-3-1) or (a2-3-2). p1 and p2 each independently represent an integer of 0 to 4. * represents a bonding site.

[0052] [ka] (In the formula, R a13 and R a14 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom.a3 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an m-phenylenediisopropylidene group, a p-phenylenediisopropylidene group, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. p3 and p4 each independently represent an integer of 0 to 4. * represents a bonding site.

[0053] [ka] (In the formula, R a15 is an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. a4 and X a5 are each independently an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. p5 is an integer of 0 to 4. * represents a bonding site.

[0054] R in the above general formula (a2-3), the above general formula (a2-3-1), and the above general formula (a2-3-2) a11 , R a12 , R a13 , R a14 and R a15 Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. The aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group or an ethyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0055] X in the above general formula (a2-3) a2 , X in the above general formula (a2-3-1) a3 and X in the above general formula (a2-3-2) a4 and X a5Examples of the alkylene group having 1 to 5 carbon atoms represented by include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, a 1,5-pentamethylene group, etc. The alkylene group is preferably an alkylene group having 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and even more preferably a methylene group.

[0056] X in the above general formula (a2-3) a2 , X in the above general formula (a2-3-1) a3 and X in the above general formula (a2-3-2) a4 and X a5 Examples of the alkylidene group having 2 to 5 carbon atoms represented by include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, an isopentylidene group, etc. Among these, an alkylidene group having 2 to 4 carbon atoms is preferred, an alkylidene group having 2 or 3 carbon atoms is more preferred, and an isopropylidene group is even more preferred.

[0057] In the general formula (a2-3) above, p1 and p2 are each independently an integer of 0 to 4, and from the viewpoint of availability, both are preferably integers of 0 to 3, more preferably integers of 0 to 2, and even more preferably 0 or 2. When p1 or p2 is an integer of 2 or more, a plurality of R a11 Comrades or R a12 They may be the same or different from each other. In the general formula (a2-3-1), p3 and p4 are each independently an integer of 0 to 4, and from the viewpoint of availability, both are preferably integers of 0 to 2, more preferably 0 or 1, and even more preferably 0. When p3 or p4 is an integer of 2 or more, multiple R a13 Comrades or R a14 They may be the same or different from each other. In the general formula (a2-3-2), p5 is an integer of 0 to 4, and from the viewpoint of availability, it is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. When p5 is an integer of 2 or more, a plurality of R a15They may be the same or different from each other.

[0058] The content of the structural units derived from component (a2) in the aminomaleimide compound (A1) is not particularly limited, but is preferably 5 to 95 mass%, more preferably 7 to 70 mass%, and even more preferably 10 to 40 mass%. When the content of the structural units derived from component (a2) in component (A1) is within the above range, the dielectric properties, heat resistance, flame retardancy, and glass transition temperature tend to be better.

[0059] Examples of the component (a2) include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 4,4'-diaminobiphenyl, 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, 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, 9,9-bis(4-aminophenyl)fluorene, and the like.

[0060] Among these, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, and 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline are preferred as component (a2) from the viewpoints of excellent solubility in organic solvents, reactivity with the maleimide compound (a1), and heat resistance. Furthermore, 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane is preferred as component (a2) from the viewpoints of excellent dielectric properties and low water absorption. In addition, from the viewpoint of high adhesion to the conductor and excellent mechanical properties such as elongation and breaking strength, 2,2-bis[4-(4-aminophenoxy)phenyl]propane is preferred as component (a2). Furthermore, from the viewpoint of excellent solubility in organic solvents, reactivity during synthesis, heat resistance, high adhesion to the conductor, as well as excellent dielectric properties and low moisture absorption, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline and 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline are preferred as component (a2).

[0061] In the aminomaleimide compound (A1), the equivalent ratio (Ta2 / Ta1) of the total equivalent (Ta2) of groups (including -NH2) derived from the -NH2 groups of the diamine compound (a2) to the total equivalent (Ta1) of groups (including N-substituted maleimide groups) derived from the N-substituted maleimide groups of the maleimide compound (a1) is not particularly limited, but is preferably 0.05 to 10, more preferably 0.5 to 7, and even more preferably 1 to 5, from the viewpoints of dielectric properties, heat resistance, flame retardancy, and glass transition temperature.

[0062] The number average molecular weight of the aminomaleimide compound (A1) is not particularly limited, but from the viewpoint of handleability and moldability, it is preferably 400 to 10,000, more preferably 500 to 5,000, and even more preferably 600 to 2,000.

[0063] (Method for producing aminomaleimide compound (A1)) The component (A1) can be produced, for example, by reacting a maleimide compound (a1) with a diamine compound (a2) in an organic solvent. By reacting the maleimide compound (a1) with the diamine compound (a2), an aminomaleimide compound (A1) is obtained through a Michael addition reaction between the maleimide compound (a1) and the diamine compound (a2).

[0064] When the maleimide compound (a1) and the diamine compound (a2) are reacted, a reaction catalyst may be used as necessary. Examples of the reaction catalyst include acidic catalysts such as p-toluenesulfonic acid, amines such as triethylamine, pyridine, and tributylamine, imidazoles such as methylimidazole and phenylimidazole, and phosphorus-based catalysts such as triphenylphosphine. These may be used alone or in combination of two or more. The amount of the reaction catalyst to be added is not particularly limited, but from the viewpoint of the reaction rate and reaction uniformity, it is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the total amount of the maleimide compound (a1) and the diamine compound (a2).

[0065] The reaction temperature for the Michael addition reaction is preferably 50 to 160°C, more preferably 60 to 150°C, and even more preferably 70 to 140°C, from the viewpoints of workability such as reaction rate, suppression of gelation during the reaction, and the like. The reaction time for the Michael addition reaction is preferably 0.5 to 10 hours, more preferably 1 to 8 hours, and even more preferably 2 to 6 hours, from the viewpoints of productivity and allowing the reaction to proceed sufficiently. However, these reaction conditions can be appropriately adjusted depending on the types of raw materials used, and are not particularly limited.

[0066] In the Michael addition reaction, the solids concentration and solution viscosity of the reaction solution may be adjusted by adding or concentrating an organic solvent. The solids concentration of the reaction solution is not particularly limited, but is preferably 10 to 90% by mass, more preferably 15 to 85% by mass, and even more preferably 20 to 80% by mass. When the solids concentration of the reaction raw materials is equal to or greater than the lower limit, a good reaction rate is obtained, and productivity tends to be improved. Furthermore, when the solids concentration of the reaction raw materials is equal to or less than the upper limit, better solubility is obtained, stirring efficiency is improved, and gelation tends to be more effectively suppressed.

[0067] (Content of component (A)) The content of component (A) in the maleimide resin composition is not particularly limited, but is preferably 30 to 70 parts by mass, more preferably 35 to 60 parts by mass, and even more preferably 40 to 55 parts by mass, per 100 parts by mass of the total of components (A) to (C). When the content of component (A) is at least the lower limit, low thermal expansion, heat resistance, and adhesion to conductors tend to be good, while when it is at most the upper limit, the dielectric loss tangent tends to be kept low.

[0068] <Thermoplastic elastomer (B)> Although the component (B) is not particularly limited, it preferably contains at least one selected from the group consisting of styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, silicone-based elastomers, and derivatives thereof. The component (B) may be used alone or in combination of two or more.

[0069] Furthermore, component (B) can be one having a reactive functional group at the molecular end or in the molecular chain. Examples of reactive functional groups include epoxy groups, hydroxyl groups, carboxyl groups, amino groups, amide groups, isocyanate groups, acrylic groups, methacrylic groups, and vinyl groups. Having such a reactive functional group at the molecular end or in the molecular chain improves compatibility, more effectively reduces internal stress generated during curing of the thermosetting resin composition, and reduces warpage of the substrate. Among these reactive functional groups, from the viewpoint of adhesion to the metal foil, it is preferable to have an epoxy group, a hydroxyl group, a carboxyl group, an amino group, or an amide group, and from the viewpoint of heat resistance and insulation reliability, it is more preferable to have an epoxy group, a hydroxyl group, or an amino group.

[0070] Examples of styrene-based elastomers include styrene-butadiene copolymers such as styrene-butadiene-styrene block copolymers; styrene-isoprene copolymers such as styrene-isoprene-styrene block copolymers; styrene-ethylene-butylene-styrene block copolymers, and styrene-ethylene-propylene-styrene block copolymers. In addition to styrene, styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene can be used as raw material monomers for styrene-based elastomers. Among these, styrene-butadiene copolymers and styrene-isoprene copolymers are preferred, and hydrogenated styrene-based thermoplastic elastomers, such as hydrogenated styrene-butadiene copolymer resins and hydrogenated styrene-isoprene copolymer resins, in which the double bonds of these copolymers have been hydrogenated, are more preferred. As the styrene-based elastomer, commercially available products may be used, and examples of commercially available products include "Tufprene (registered trademark)", "Asaprene (registered trademark) T", "Tuftec (registered trademark) H1043", "Tuftec (registered trademark) MP10", "Tuftec (registered trademark) M1911", and "Tuftec (registered trademark) M1913" (all manufactured by Asahi Kasei Chemicals Corporation), "Epofriend (registered trademark) AT501", and "Epofriend (registered trademark) CT310" (all manufactured by Daicel Corporation), and "Septon (registered trademark) 2063" (manufactured by Kuraray Co., Ltd.).

[0071] Examples of olefin-based elastomers include copolymers of α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene; copolymers of the above α-olefins with non-conjugated dienes having 2 to 20 carbon atoms, such as dicyclopentadiene, 1,4-hexadiene, cyclooctanediene, methylenenorbornene, ethylidenenorbornene, butadiene, and isoprene; and carboxy-modified butadiene-acrylonitrile rubber obtained by copolymerizing a butadiene-acrylonitrile copolymer with methacrylic acid. Examples of the α-olefin copolymer include ethylene-propylene copolymer (EPR) and ethylene-propylene-diene copolymer (EPDM). As the olefin-based elastomer, a commercially available product may be used.

[0072] Examples of urethane-based elastomers include those having a hard segment made of a low-molecular-weight (short-chain) diol and a diisocyanate, and a soft segment made of a high-molecular-weight (long-chain) diol and a diisocyanate. Examples of low molecular weight (short chain) diols include ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A. The number average molecular weight of the low molecular weight (short chain) diol is preferably 48-500. Examples of the polymeric (long-chain) diol include polypropylene glycol, polytetramethylene oxide, poly(1,4-butylene adipate), poly(ethylene·1,4-butylene adipate), polycaprolactone, poly(1,6-hexylene carbonate), poly(1,6-hexylene·neopentylene adipate), etc. The number average molecular weight of the polymeric (long-chain) diol is preferably 500 to 10,000. As the urethane-based elastomer, commercially available products may be used.

[0073] Examples of polyester elastomers include those obtained by polycondensation of dicarboxylic acid or a derivative thereof with a diol compound or a derivative thereof. Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; aromatic dicarboxylic acids in which the hydrogen atoms of the aromatic nuclei of these aromatic dicarboxylic acids are substituted with methyl groups, ethyl groups, phenyl groups, etc.; aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid, and dodecanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. One type of dicarboxylic acid may be used alone, or two or more types may be used in combination. Examples of the diol compound include aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol; alicyclic diols such as 1,4-cyclohexanediol; and aromatic diols such as bisphenol A, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)propane, and resorcinol. One type of diol compound may be used alone, or two or more types may be used in combination. Alternatively, a multiblock copolymer may be used in which an aromatic polyester (e.g., polybutylene terephthalate) portion serves as the hard segment component and an aliphatic polyester (e.g., polytetramethylene glycol) portion serves as the soft segment component. Such multiblock copolymers are commercially available in various grades depending on the type, ratio, and molecular weight of the hard and soft segments. Specific examples include "Hytrel (registered trademark)" (manufactured by DuPont-Toray Co., Ltd.), "Pelprene (registered trademark)" (manufactured by Toyobo Co., Ltd.), and "Espel (registered trademark)" (manufactured by Showa Denko Materials K.K.).

[0074] Examples of polyamide-based elastomers include block copolymers in which polyamide is used as a hard segment component and polybutadiene, butadiene-acrylonitrile copolymer, styrene-butadiene copolymer, polyisoprene, ethylene-propylene copolymer, polyether, polyester, polybutadiene, polycarbonate, polyacrylate, polymethacrylate, polyurethane, silicone rubber, or the like is used as a soft segment component. As the polyamide elastomer, commercially available products may be used.

[0075] Examples of acrylic elastomers include polymers obtained by polymerizing raw material monomers whose main component is an acrylic acid ester. Examples of acrylic acid esters include ethyl acrylate, butyl acrylate, methoxyethyl acrylate, and ethoxyethyl acrylate. Furthermore, the crosslinking point monomer may be one obtained by using glycidyl methacrylate, allyl glycidyl ether, or the like as a raw material, and may further be one obtained by copolymerizing acrylonitrile, ethylene, or the like. Specific examples include acrylonitrile-butyl acrylate copolymer, acrylonitrile-butyl acrylate-ethyl acrylate copolymer, and acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer.

[0076] Silicone elastomers are primarily composed of organopolysiloxane, and are classified into polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and the like depending on the structure of the skeleton. As the silicone elastomer, commercially available products may be used.

[0077] Among these components (B), from the viewpoints of heat resistance and insulation reliability, styrene-based elastomers, olefin-based elastomers, polyamide-based elastomers, and silicone-based elastomers are preferred, and from the viewpoint of dielectric properties, styrene-based elastomers and olefin-based elastomers are more preferred, and hydrogenated styrene-based thermoplastic elastomers are even more preferred.

[0078] The weight average molecular weight (Mw) of component (B) is preferably 1,000 to 300,000, and more preferably 2,000 to 150,000. When the weight average molecular weight (Mw) of component (B) is at least the lower limit, the low thermal expansion properties tend to be excellent, and when it is at most the upper limit, the compatibility tends to be excellent. The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

[0079] ((B) Component Content) The content of component (B) in the maleimide resin composition is not particularly limited, but is preferably 5 to 50 parts by mass, more preferably 10 to 45 parts by mass, even more preferably 20 to 45 parts by mass, and particularly preferably 25 to 45 parts by mass, per 100 parts by mass of the total of components (A) to (C). When the content of component (B) is at least the lower limit, the effect of lowering the dielectric constant tends to be sufficient, while when the content is at most the upper limit, component (B) is compatibilized and sufficiently dispersed in the resin, which tends to prevent a significant decrease in heat resistance and provide excellent peel strength.

[0080] <Divinyl Compound (C)> The two vinyl groups in component (C), i.e., the two crosslinkable functional groups, result in a moderately high crosslink density, which in turn increases the molecular free volume and reduces the dielectric loss tangent (Df). In other words, using a trivinyl compound instead of component (C) tends to increase the crosslink density too much, reducing the free volume and causing an increase in the dielectric loss tangent (Df) (see Comparative Example 2). Furthermore, because the reactive component (C) is used as a partial substitute for the thermosetting resin component (A), reducing the content of the polar group-containing component (A) is also thought to contribute to a reduction in the dielectric loss tangent (Df). Furthermore, since both functional groups of component (C) are vinyl groups, it has good reactivity with component (A), which is thought to tend to improve heat resistance. For example, if a diallyl compound is used instead of component (C), unreacted diallyl compound remains after the resin composition is cured, resulting in a decrease in heat resistance (see Comparative Example 4).

[0081] In this embodiment, component (C) is not an elastomer. From the viewpoint of reactivity with component (A), the molecular weight of component (C) is preferably not more than 500, more preferably not more than 400, even more preferably not more than 300, and particularly preferably not more than 200. Setting a lower limit for the molecular weight of component (C) is of little technical significance and is therefore not necessary, but it may be, for example, not less than 100, not less than 110, or not less than 120.

[0082] The component (C) is not particularly limited, but examples thereof include divinyl compounds having an aromatic ring or a silicon atom. The aromatic ring preferably has 6 to 20 ring carbon atoms, and may have 6 to 12 ring carbon atoms. Examples of aromatic rings include a benzene ring, a naphthalene ring, and a biphenyl ring. Of these, a benzene ring is preferred as the aromatic ring. The aromatic ring may have a substituent. The substituent is a substituent that does not have reactivity with component (A), and examples thereof include an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, and a halogen atom. When component (C) has an aromatic ring, the number of rings is not particularly limited, but is preferably 1 to 3, more preferably 1 or 2, and may be 1. Specific examples of divinyl compounds having an aromatic ring include divinylbenzene. Examples of divinylbenzene include m-divinylbenzene and p-divinylbenzene, and the divinylbenzene may be a mixture of m-divinylbenzene and p-divinylbenzene.

[0083] Furthermore, when component (C) is a divinyl compound having a silicon atom, the number of silicon atoms is preferably 1 to 6, more preferably 1 to 3, and even more preferably 2. Furthermore, component (C) is preferably an embodiment in which a vinyl group is bonded to the silicon atom. Examples of the divinyl compound having a silicon atom include divinyl compounds represented by the following structural formula: [ka] (In the above formula, R C1 ~R C4each independently represents an alkyl group having 1 to 6 carbon atoms. R C1 ~R C4 Examples of the alkyl group having 1 to 6 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. The alkyl group may be an alkyl group having 1 to 3 carbon atoms or a methyl group.

[0084] From the viewpoint of greatly improving heat resistance, component (C) is preferably a divinyl compound having an aromatic ring. More preferred embodiments of divinyl compounds having an aromatic ring are as described above. When component (C) has an aromatic ring, the molecules become rigid after the crosslinking reaction with the maleimide compound (A), which is thought to significantly improve the heat resistance of the resin composition. Maleimide resin compositions containing thermoplastic elastomers generally tend to have a small dielectric dissipation factor (Df) while making it difficult to improve their heat resistance. Therefore, it is extremely beneficial to be able to significantly improve heat resistance while maintaining a small dielectric dissipation factor (Df).

[0085] ((C) Component Content) The content of component (C) in the maleimide resin composition is not particularly limited, but is preferably 3 to 30 parts by mass, more preferably 5 to 25 parts by mass, even more preferably 10 to 25 parts by mass, and particularly preferably 13 to 22 parts by mass, per 100 parts by mass of the total of components (A) to (C). When the content of component (C) is at or above the lower limit, the effects of lowering the dielectric constant and improving heat resistance tend to be sufficient, and the viscosity of the varnish tends to be reduced, improving workability. On the other hand, when the content of component (C) is at or below the upper limit, the heat resistance derived from component (A) tends to be maintained, and an excessive decrease in the viscosity of the maleimide resin composition tends to be prevented.

[0086] <Other ingredients> The resin composition of this embodiment may further contain other components. Examples of the other components include one or more selected from the group consisting of an inorganic filler (D) (hereinafter sometimes abbreviated as component (D)) and a curing accelerator (E) (hereinafter sometimes abbreviated as component (E)). By including these components, various properties can be further improved when the laminate is formed. These other components will be described in detail below.

[0087] (Inorganic filler (D)) By including the inorganic filler (D) in the resin composition of this embodiment, the coefficient of thermal expansion, modulus of elasticity, heat resistance, and flame retardancy tend to be improved. Component (D) is not particularly limited, but examples thereof include silica, alumina, titanium oxide, mica, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clays such as calcined clay, talc, aluminum borate, and silicon carbide. These may be used alone or in combination of two or more. Among these, silica, alumina, mica, and talc are preferred, silica and alumina are more preferred, and silica is even more preferred, from the viewpoints of thermal expansion coefficient, elastic modulus, heat resistance, and flame retardancy. Examples of silica include precipitated silica produced by a wet method and having a high water content, and dry-process silica produced by a dry method and containing almost no bound water. Dry-process silica may further include crushed silica, fumed silica, and fused silica (fused spherical silica), depending on the production method. The shape and particle size of the inorganic filler (D) are not particularly limited, but for example, the particle size is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm. Here, the particle size refers to the average particle size, and is the particle size at the point corresponding to 50% volume when a cumulative frequency distribution curve of particle sizes is calculated, with the total volume of particles being 100%. The particle size of the inorganic filler (D) can be measured using a particle size distribution analyzer using a laser diffraction scattering method.

[0088] ((D) Component Content) When the resin composition of the present embodiment contains the component (D), the content of the component (D) in the resin composition is not particularly limited, but from the viewpoints of the thermal expansion coefficient, elastic modulus, heat resistance, and flame retardancy, it is preferably 5 to 70 mass%, more preferably 15 to 65 mass%, and even more preferably 20 to 60 mass%, and may be 25 to 55 mass%, 25 to 45 mass%, or 30 to 40 volume%.

[0089] When component (D) is used, a coupling agent may be used in combination, if necessary, to improve the dispersibility of component (D) and the adhesion between component (D) and the organic components in the resin composition. The coupling agent is not particularly limited, and for example, a silane coupling agent or a titanate coupling agent may be appropriately selected and used. One coupling agent may be used alone, or two or more coupling agents may be used in combination. The amount of coupling agent used is also not particularly limited, and may be, for example, 0.1 to 5 parts by mass or 0.5 to 3 parts by mass per 100 parts by mass of component (D). Within this range, there is little deterioration in various properties, and the advantages of using component (D) described above tend to be more effectively exhibited. When a coupling agent is used, the so-called integral blending method may be used, in which the coupling agent is added after blending component (D) into the resin composition, but a method in which an inorganic filler is first surface-treated with a coupling agent by a dry or wet method is preferred. By adopting this method, the characteristics of component (D) can be more effectively expressed.

[0090] When component (D) is used in this embodiment, in order to improve the dispersibility of component (D) in the resin composition, component (D) can be used as a slurry by dispersing it in an organic solvent in advance, if necessary. The organic solvent used to form the slurry of component (D) is not particularly limited, but examples of the organic solvents exemplified in the production process of component (A1) above can be used. Among these, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are preferred from the viewpoint of dispersibility. Furthermore, the solids (non-volatile content) concentration of the slurry is not particularly limited, but from the viewpoint of the sedimentation property and dispersibility of the inorganic filler (D), it may be, for example, 50 to 80 mass %, or 60 to 80 mass %.

[0091] (Curing accelerator (E)) By adding the curing accelerator (E) to the resin composition of the present embodiment, the curability of the resin composition is improved, and the dielectric properties, heat resistance, adhesion to a conductor, elastic modulus, and glass transition temperature tend to be improved. Examples of component (E) include acidic catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, pyridine, and tributylamine; imidazole compounds such as methylimidazole, phenylimidazole, and isocyanate-masque imidazole (for example, the addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole); tertiary amine compounds; quaternary ammonium compounds; phosphorus compounds such as triphenylphosphine; organic peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, and α,α'-bis(t-butylperoxy)diisopropylbenzene; and carboxylates of manganese, cobalt, zinc, and the like. These may be used alone or in combination of two or more. Among these, from the viewpoints of heat resistance, glass transition temperature, and storage stability, imidazole compounds, organic peroxides, and carboxylates may be used, and from the viewpoints of heat resistance, glass transition temperature, elastic modulus, and thermal expansion coefficient, imidazole compounds may be used in combination with organic peroxides or carboxylates. Furthermore, among imidazole compounds, isocyanate-masked imidazole may be selected, and among organic peroxides, α,α'-bis(t-butylperoxy)diisopropylbenzene may be selected.

[0092] (Content of component (E)) When the resin composition of this embodiment contains component (E), the content of component (E) is not particularly limited, but is, for example, preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, even more preferably 0.1 to 6 parts by mass, and particularly preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total of the resin components in the resin composition. When the content of component (E) is within the above range, better heat resistance and storage stability tend to be obtained.

[0093] The resin composition of this embodiment may further contain, as needed, resin materials such as thermoplastic resins, flame retardants, flame retardant assistants, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, etc. These may be used alone or in combination of two or more. The amounts of these used are not particularly limited, and may be used within a range that does not impair the effects of this embodiment.

[0094] (organic solvent) The resin composition of the present embodiment may contain an organic solvent from the viewpoint of facilitating handling by dilution and facilitating production of a prepreg, which will be described later. A resin composition containing an organic solvent is generally referred to as a resin varnish or a varnish. The organic solvent is not particularly limited, but examples thereof include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone. Among these, from the viewpoint of solubility, alcohol solvents, ketone solvents, and nitrogen atom-containing solvents are preferred, ketone solvents are more preferred, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are even more preferred, and methyl ethyl ketone is particularly preferred. The organic solvent may be used alone or in combination of two or more kinds.

[0095] When the resin composition of this embodiment contains an organic solvent, the solids concentration of the varnish is, for example, 30 to 90% by mass, or alternatively 35 to 80% by mass, or 40 to 60% by mass. Using a resin composition having a solids concentration within the above range tends to facilitate handling, improve the impregnation of the substrate and the appearance of the produced prepreg, facilitate adjustment of the solids concentration of the resin in the prepreg, as described below, and make it easier to produce a prepreg having a desired thickness.

[0096] The resin composition of this embodiment can be produced by mixing components (A) to (C) and other components used as needed using a known method. During this process, each component may be dissolved or dispersed while stirring. The mixing order, temperature, time, and other conditions are not particularly limited and may be set as desired depending on the types of raw materials, etc.

[0097] The dielectric loss tangent (Df) at 10 GHz of a cured product of the resin composition of this embodiment (i.e., a laminate not containing a fiber substrate such as glass cloth, and a cured product of a resin film) is preferably 0.0013 or less, more preferably 0.0012 or less. Since the smaller the dielectric loss tangent (Df), the better, the lower limit thereof is not particularly limited, but may be, for example, 0.0010 or more in consideration of the balance with other physical properties. The dielectric loss tangent (Df) is a value based on the cavity resonator perturbation method, and more specifically, is a value measured by the method described in the examples.

[0098] [Prepreg] The prepreg of this embodiment is a prepreg containing the maleimide resin composition of this embodiment. The prepreg of this embodiment contains, for example, the resin composition of this embodiment and a sheet-like fiber-reinforced substrate. The prepreg is formed using the resin composition of this embodiment and a sheet-like fiber-reinforced substrate, and can be obtained, for example, by impregnating or coating the resin composition of this embodiment onto a sheet-like fiber-reinforced substrate and drying it. More specifically, the prepreg of this embodiment can be produced by, for example, heating and drying at a temperature of 80 to 200°C for 1 to 30 minutes to bring the prepreg to a B-stage. Here, in this specification, "B-staging" refers to bringing the prepreg to a B-stage state as defined in JIS K6900 (1994), and is also referred to as "semi-curing." The amount of the resin composition used can be determined so that the solid content concentration derived from the resin composition in the prepreg after drying is 30 to 90 mass %. By setting the solid content concentration within this range, better moldability tends to be obtained when the prepreg is made into a laminate.

[0099] As the sheet-like fiber reinforcing substrate for the prepreg, known materials used in various laminates for electrical insulating materials are used. Materials for the sheet-like reinforcing substrate include inorganic fibers such as E-glass, D-glass, S-glass, and Q-glass; organic fibers such as polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. These sheet-like reinforcing substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat. The thickness of the sheet-like fiber-reinforced substrate is not particularly limited, but for example, one having a thickness of 0.02 to 0.5 mm can be used. Furthermore, from the viewpoints of impregnation with the resin composition, heat resistance, moisture absorption resistance, and processability when formed into a laminate, the sheet-like fiber-reinforced substrate may be surface-treated with a coupling agent or the like, or may be mechanically subjected to fiber-opening treatment.

[0100] The following hot melt method or solvent method can be used as a method for impregnating or coating the resin composition on the sheet-like reinforcing substrate. The hot melt method does not contain an organic solvent in the resin composition, and is either (1) a method in which the resin composition is first coated onto a coated paper that has good peelability from the resin composition and then laminated onto a sheet-like reinforcing substrate, or (2) a method in which the resin composition is directly coated onto a sheet-like reinforcing substrate using a die coater. On the other hand, the solvent method is a method in which an organic solvent is added to a resin composition, a sheet-like reinforcing substrate is immersed in the obtained resin composition to impregnate the sheet-like reinforcing substrate with the resin composition, and then the sheet-like reinforcing substrate is dried.

[0101] [Resin film] The resin film of the present embodiment is a resin film containing the resin composition of the present embodiment. The resin film may be provided with a support, which will be described later. The resin film of the present embodiment can be produced, for example, by applying a resin composition containing an organic solvent, that is, a resin varnish, to a support and drying it by heating. Examples of the support include polyolefin films such as polyethylene, polypropylene, and polyvinyl chloride; polyester films such as polyethylene terephthalate (hereinafter also referred to as "PET") and polyethylene naphthalate; and various plastic films such as polycarbonate and polyimide films. Metal foils such as copper foil and aluminum foil, and release paper may also be used as the support. The support may be subjected to a surface treatment such as a matte finish or a corona treatment. The support may also be subjected to a release treatment using a silicone resin-based release agent, an alkyd resin-based release agent, a fluororesin-based release agent, or the like. The thickness of the support is not particularly limited, but is preferably 10 to 150 μm, more preferably 25 to 50 μm.

[0102] The method for applying the resin varnish to the support is not particularly limited, and any coating device known to those skilled in the art can be used, such as a comma coater, bar coater, kiss coater, roll coater, gravure coater, die coater, etc. These coating devices may be appropriately selected depending on the film thickness. The drying temperature and drying time may be determined appropriately depending on the amount of organic solvent used, the boiling point of the organic solvent used, etc. For example, in the case of a resin varnish containing about 40 to 60 mass% of organic solvent, a resin film can be suitably formed by drying at 50 to 150°C for about 3 to 10 minutes.

[0103] [Laminate] The laminate of this embodiment is a laminate containing the prepreg or resin film of this embodiment. The laminate of this embodiment can be produced, for example, by placing metal foil on one or both sides of a single prepreg of this embodiment, or by placing metal foil on one or both sides of a prepreg obtained by stacking two or more prepregs of this embodiment, and then hot-pressing the resulting prepreg. A laminate having metal foil is sometimes called a metal-clad laminate. Another method for producing a metal-clad laminate includes placing the resin film of the present embodiment on both sides or one side of the prepreg of the present embodiment or another prepreg, and then heating and pressing the prepreg. In this case, the prepreg may be one prepreg, or two or more prepregs may be stacked together. When two or more prepregs are stacked together, different prepregs may be combined and stacked. The metal of the metal foil is not particularly limited as long as it is used for electrical insulating material applications, but from the viewpoint of electrical conductivity, it may be copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing one or more of these metal elements, with copper and aluminum being preferred, and copper being more preferred. The conditions for hot pressing are not particularly limited, but may be, for example, a temperature of 100 to 300°C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. Alternatively, hot pressing may be performed using a vacuum press or the like to maintain a vacuum state for 0.5 to 5 hours.

[0104] [Multilayer printed wiring board] The multilayer printed wiring board of this embodiment contains the laminate of this embodiment. The multilayer printed wiring board of this embodiment can be manufactured by using the laminate of this embodiment having metal foil on one or both sides, i.e., a metal-clad laminate, and performing circuit formation processing and multilayer bonding processing using known methods such as drilling, metal plating, and etching of the metal foil.

[0105] [Semiconductor Package] The semiconductor package of this embodiment is a semiconductor package including a multilayer printed wiring board and a semiconductor element. The semiconductor package of this embodiment can be manufactured by mounting a semiconductor element such as a semiconductor chip or memory at a predetermined position on the printed wiring board of this embodiment and sealing the semiconductor element with a sealing resin or the like.

[0106] The resin composition, prepreg, resin film, laminate, multilayer printed wiring board, and semiconductor package of the present embodiment can be suitably used in electronic devices that handle high-frequency signals of 10 GHz or higher. In particular, the multilayer printed wiring board is useful as a multilayer printed wiring board for millimeter-wave radar.

[0107] Although preferred embodiments have been described above, these are merely examples for explaining the present disclosure, and the scope of the present disclosure is not intended to be limited to these embodiments. The present disclosure also includes implementations in various aspects different from the above-described embodiments, provided that they do not deviate from the gist of the disclosure. [Example]

[0108] The present embodiment will be specifically described below with reference to examples, although the present embodiment is not limited to the following examples.

[0109] Examples 1 to 2, Comparative Examples 1 to 5 (Preparation of Maleimide Resin Composition) Each component listed in Table 1 was mixed with a predetermined amount of curing accelerator in the amounts listed in Table 1 while stirring and heating at room temperature or 50 to 80°C to prepare a resin composition with a solids concentration of approximately 50% by mass. (Production of resin board with copper foil on both sides) The resin composition obtained in each example was applied to a 38 μm-thick PET film (Teijin Limited, product name: G2-38) and then heated and dried at 170°C for 5 minutes to produce a B-stage resin film. This resin film was peeled from the PET film and then crushed to produce a resin powder. Next, the resin powder was placed on a Teflon® sheet die-cut to a size of 1 mm thick x 50 mm long x 35 mm wide. 18 μm-thick low-profile copper foil (Furukawa Electric Co., Ltd., product name: BF-ANP18) was placed on top and bottom of the Teflon® sheet so that the M side (matte side) was in contact with the resin powder. The resin composition was cured by heat-press molding at a temperature of 230°C, a pressure of 2.0 MPa, and a time of 120 minutes to produce a resin plate with double-sided copper foil (resin plate thickness: 1 mm).

[0110] [Evaluation and measurement methods] The resin sheets with copper foil on both sides obtained in the above Examples and Comparative Examples were subjected to measurements and evaluations according to the following methods. The results are shown in Table 2.

[0111] (1. Measurement of dielectric loss tangent) The resin board with copper foil on both sides obtained in each example was immersed in a 10 mass % solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), a copper etching solution, to remove the copper foil, and a 2 mm × 50 mm evaluation board was produced from this. The dielectric loss tangent (Df) of the evaluation substrate was measured at 25° C. in the 10 GHz band in accordance with the cavity resonator perturbation method.

[0112] (2. Measurement of Glass Transition Temperature) The glass transition temperature (Tg) was measured using a 5 mm square test piece made by etching the copper foil on both sides of a double-sided copper foil-covered resin sheet, using a thermomechanical analyzer (TMA) [Model Q400, manufactured by TA Instruments Japan Co., Ltd.] in accordance with the IPC (The Institute for Interconnecting and Packaging Electronic Circuits) standard.

[0113] [Table 1]

[0114] The materials in Table 1 are as follows: [Component (A)] Bismaleimide compound: an aromatic bismaleimide compound containing an indane ring, having the following structure: [ka] (In the above formula, n3 is a number from 0.95 to 10.0.)

[0115] [(B) Component] Thermoplastic elastomer: Styrene-ethylene-butylene-styrene copolymer (SEBS), styrene content 42% by mass, Mw=75,000 [(C) component] For details on each compound, please see below. [ka]

[0116] [(C') component (for comparison)] For details on each compound, please see below. [ka]

[0117] [(D) component] Spherical silica: average particle size 0.5 μm [(E) component] Curing accelerator 1: α,α-bis(t-butylperoxy-m-isopropyl)benzene Curing accelerator 2: Isocyanate masked imidazole "G8009L" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0118] As is clear from the results shown in Table 1, the resin compositions obtained in Examples 1 and 2 of this embodiment were able to achieve even lower dielectric loss tangents in high frequency bands of 10 GHz or higher. In Example 1, not only was a low dielectric loss tangent achieved, but heat resistance was also significantly improved. On the other hand, Comparative Examples 1 to 5 had higher dielectric loss tangents in the 10 GHz band than the Examples. It is particularly noteworthy that Comparative Example 2, in which a trivinyl compound was used instead of a divinyl compound, also had a higher dielectric loss tangent in the 10 GHz band than the Examples. It is also noteworthy that Comparative Example 4, in which a diallyl compound, L-DAIC, was used instead of a divinyl compound, had insufficient heat resistance.

Claims

1. (A) one or more compounds selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof; (B) a thermoplastic elastomer; (C) a divinyl compound, and a maleimide resin composition comprising the following: the component (A) is one or more compounds selected from the group consisting of: (i) maleimide compounds (a1) containing a fused ring of an aromatic ring and an aliphatic ring in their molecular structure and having two or more N-substituted maleimide groups; and (ii) aminomaleimide compounds containing a structural unit derived from the maleimide compound (a1) and a structural unit derived from a diamine compound (a2); The component (B) is a styrene-based elastomer, The component (C) is divinylbenzene or a compound represented by the following structural formula: 【Chemistry 1】 (In the above formula, R C1 to R C4 each independently represent an alkyl group having 1 to 6 carbon atoms.) and having a molecular weight of 100 to 500, a maleimide resin composition, wherein the content of the component (A) is 30 to 70 parts by mass per 100 parts by mass of the total of the components (A), (B), and (C); the content of the component (B) is 5 to 50 parts by mass per 100 parts by mass of the total of the components (A), (B), and (C); and the content of the component (C) is 3 to 30 parts by mass per 100 parts by mass of the total of the components (A), (B), and (C).

2. 2. The maleimide resin composition according to claim 1, wherein the molecular weight of the component (C) is 100 to 300.

3. 3. The maleimide resin composition according to claim 1, wherein the component (C) is divinylbenzene.

4. 4. The maleimide resin composition according to claim 1, wherein the component (B) is a hydrogenated styrene-based thermoplastic elastomer.

5. A prepreg comprising the maleimide resin composition according to any one of claims 1 to 4.

6. A resin film comprising the maleimide resin composition according to any one of claims 1 to 4.

7. A laminate comprising the prepreg according to claim 5 or the resin film according to claim 6.

8. A multilayer printed wiring board comprising the laminate according to claim 7.

9. A semiconductor package comprising the multilayer printed wiring board according to claim 8 and a semiconductor element.

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