Prepreg, and metal-clad laminate and wiring board using same

Abstract

One aspect of the present invention relates to a prepreg comprising: a thermosetting resin composition or a semi-cured product of the thermosetting resin composition; and a glass cloth. The thermosetting resin composition comprises a maleimide compound (A) and a high molecular weight body (B) having a weight average molecular weight of 10,000 to 900,000. The glass cloth comprises SiO2 at 45-55 mass%, Al2O3 at 20-30 mass%, MgO at 3.0 mass% or less, and P2O5 at 10-15 mass%, with respect to the total amount of the glass cloth components.

Description

Prepreg, and metal-clad laminate and wiring board using the same

[0001] The present invention relates to a prepreg, and a metal-clad laminate and a wiring board using the same.

[0002] As the amount of information processed increases in various electronic devices, advances in packaging technologies, such as higher integration of semiconductor devices, higher density wiring, and multi-layering, are being made. Furthermore, wiring boards used in various electronic devices are required to be high-frequency compatible, such as millimeter-wave radar boards for automotive applications. To increase the signal transmission speed, wiring boards used in various electronic devices are required to reduce loss during signal transmission, and this is particularly true for high-frequency compatible wiring boards. To meet this requirement, the substrate material for forming the substrate of the wiring board used in various electronic devices is required to have a low dielectric constant and dielectric loss tangent.

[0003] Such a substrate material may be, for example, a glass fiber having a SiO content in the range of 60.00 to 70.00 mass % relative to the total amount of glass fibers. ２ and Al in the range of 20.00 to 30.00 mass%. ２ O ３ and MgO in the range of 5.00 to 15.0 mass % and Fe in the range of 0.15 to 1.50 mass %. ２ O ３ and a total of 0.02 to 0.20 mass% of Li ２ O, Na ２ O and K ２ A glass fiber reinforced resin molded product (Patent Document 1) has been reported, which comprises glass fibers having a composition containing SiO and a thermoplastic resin or a thermosetting resin. ２ and Al in the range of 13.0 to 17.0 mass% ２ O ３ and B in the range of 15.0 to 21.5 mass% ２ O ３ 2.0 to 6.0% by mass of MgO; 2.0 to 6.0% by mass of CaO; and 1.0 to 4.0% by mass of TiO. ２ and less than 1.5% by mass of F. ２ and Li２ O, Na ２ O and K ２ A glass fiber reinforced resin molded article including glass fibers having a composition in which the total amount of O is less than 0.6 mass % and a thermoplastic resin or a thermosetting resin has also been reported (Patent Document 2).

[0004] Or E-glass (SiO ２ and Al ２ O ３ a layer containing a cured product of a thermosetting resin composition and S-glass (SiO ２ and Al ２ O ３ A laminated plate in which a plurality of layers containing a cured product of a thermosetting resin composition and glass fibers (the total of which is 80% or more of glass fibers) are laminated has also been reported (Patent Document 3).

[0005] The glass fibers described in Patent Documents 1 to 3 are said to have low dielectric properties and a high tensile modulus. However, with the recent trend toward even higher performance in electronic devices and significant increases in information communication speeds, substrate materials that can accommodate larger packages and more microfabrication are required for semiconductor package substrates, and even better low dielectric properties are being demanded. In particular, as wiring boards become thinner and larger, there is a problem that warping occurs in semiconductor packages that mount semiconductor chips on wiring boards, making them more susceptible to mounting defects. In order to suppress warping in semiconductor packages that mount semiconductor chips on wiring boards, the substrate material that constitutes the insulating layer of the wiring board is also required to have a low thermal expansion coefficient when cured.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a prepreg having excellent low dielectric properties and a low coefficient of thermal expansion.

[0007] International Publication No. 2022 / 075273 International Publication No. 2017 / 171101 International Publication No. 2020 / 130007

[0008] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the following constitution, and have achieved the present invention through further investigations.

[0009] That is, a prepreg according to one aspect of the present invention comprises a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, and glass cloth, wherein the thermosetting resin composition contains a maleimide compound (A) and a high molecular weight compound (B) having a weight average molecular weight of 10,000 or more and 900,000 or less, and the glass cloth contains SiO ２ 45 to 55 mass% of Al ２ O ３ 20 to 30 mass %, MgO 3.0 mass % or less, and P ２ O ５ It is characterized in that it contains 10 to 15 mass % of

[0010] Fig. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention.

[0011] Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these.

[0012] <Prepreg> The prepreg of this embodiment comprises a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, and glass cloth. The thermosetting resin composition contains a maleimide compound (A) and a high molecular weight compound (B) having a weight average molecular weight of 10,000 or more and 900,000 or less. The glass cloth contains SiO ２ 45 to 55 mass% of Al ２ O ３ 20 to 30 mass %, MgO 3.0 mass % or less, and P ２ O ５ Contains 10 to 15 mass % of

[0013] The prepreg of this embodiment having such a configuration has excellent low dielectric properties and a low coefficient of thermal expansion, so that the metal-clad laminate and wiring board obtained using the prepreg of this embodiment have excellent low dielectric properties and are also suppressed from warping. In addition, the prepreg of this embodiment also has a high Tg and adhesion (interlayer adhesion and adhesion to metal foil).

[0014] Hereinafter, each configuration of the prepreg according to this embodiment will be specifically described.

[0015] [Thermosetting Resin Composition] The thermosetting resin composition according to this embodiment (hereinafter also simply referred to as "resin composition") contains a maleimide compound (A) and a polymer (B) having a weight-average molecular weight of 10,000 or more and 900,000 or less.

[0016] (Maleimide Compound (A)) The maleimide compound (A) is a compound having a maleimide group in the molecule. In a preferred embodiment, the maleimide compound (A) has at least one of an indane structure and an arylene structure oriented and bonded at the meta position. By including such a maleimide compound (A), the resin composition of this embodiment can more reliably provide a cured product thereof with both low dielectric properties and a low thermal expansion coefficient.

[0017] Specifically, the maleimide compound (A) includes at least one selected from the group consisting of a maleimide compound (A1) having an indane structure in the molecule, a maleimide compound (A2) having an arylene structure in the molecule that is oriented and bonded at the meta position, and a maleimide compound (A3) having an indane structure and an arylene structure in the molecule that is oriented and bonded at the meta position.

[0018] Maleimide Compound (A1) Having an Indane Structure in the Molecule The maleimide compound (A1) is not particularly limited as long as it is a maleimide compound having an indane structure in the molecule. The maleimide compound (A1) has not only an indane structure but also a maleimide group in the molecule. Examples of the indane structure include an indane structure represented by the following formula (1). That is, specific examples of the maleimide compound (A1) include a maleimide compound (A1-1) having an indane structure represented by the following formula (1) in the molecule, and more specific examples include a maleimide compound (A1-1-1) represented by the following formula (3).

[0019]

[0020] In formula (1), each Rb is independent. That is, each Rb may be the same group or different groups. For example, when r is 2 or 3, two or three Rb's bonded to the same benzene ring may be the same group or different groups. Rb represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group (alkoxy 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 (thiol group). r represents an integer of 0 to 3.

[0021]

[0022] In formula (3), each Ra is independent. That is, each Ra may be the same group or different groups. For example, when q is 2 to 4, 2 to 4 Ra bonded to the same benzene ring may be the same group or different groups. Ra represents 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. Rb's are the same as Rb's in formula (1), and each independently represents 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. q represents 0 to 4. r represents 0 to 3. n represents 0.95 to 10.

[0023] r is the average value of the substitution degree of Rb, and a smaller value is preferable, specifically 0. That is, in the benzene ring to which Rb can be bonded, a hydrogen atom is preferably bonded at the position to which Rb can be bonded. Maleimide compounds (A1) having such an r are easy to synthesize. This is thought to be due to reduced steric hindrance and increased electron density in the aromatic ring. Furthermore, when r is 1 to 3, Rb is preferably at least one selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Furthermore, Ra is preferably at least one selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. The alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms improves solubility in solvents and suppresses a decrease in the reactivity of the maleimide group, resulting in a suitable cured product. This is thought to be due to a decrease in planarity in the vicinity of the maleimide group, a decrease in crystallinity, and the like.

[0024] Specific examples of the groups represented by Ra and Rb include the following groups.

[0025] The alkyl group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0026] The alkyloxy group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methyloxy group, an ethyloxy group, a propyloxy group, a hexyloxy group, and a decyloxy group.

[0027] The alkylthio group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, and a decylthio group.

[0028] The aryl group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyl group and a naphthyl group.

[0029] The aryloxy group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyloxy group and a naphthyloxy group.

[0030] The arylthio group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenylthio group and a naphthylthio group.

[0031] The cycloalkyl group having 3 to 10 carbon atoms is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and a cyclooctyl group.

[0032] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0033] q is the average value of the degree of substitution of Ra, and is preferably 2 to 3, and more preferably 2. The maleimide compound (A1) having such a q is easy to synthesize. This is thought to be because, particularly when q is 2, steric hindrance is reduced and the electron density of the aromatic ring is increased.

[0034] n is the average number of repeats, and as described above, is 0.95 to 10, preferably 0.98 to 8, more preferably 1 to 7, and even more preferably 1.1 to 6. In the maleimide compound (A1-1) having an indane structure represented by formula (1) in the molecule and the maleimide compound (A1-1-1) represented by formula (3), the content of the maleimide compound in which n, the average number of repeats (degree of polymerization), is 0, is preferably 32 mass% or less based on the total amount of the maleimide compound (A1).

[0035] The maleimide compound (A1) preferably has a molecular weight distribution (Mw / Mn) measured by GPC of 1 to 4, more preferably 1.1 to 3.8, even more preferably 1.2 to 3.6, and particularly preferably 1.3 to 3.4. The molecular weight distribution is measured by gel permeation chromatography (GPC).

[0036] Maleimide Compound (A2) Having an Arylene Structure in the Molecule That is Oriented to the Meta Position The maleimide compound (A2) is not particularly limited as long as it is a maleimide compound having an arylene structure in the molecule that is Oriented to the meta position. The maleimide compound (A2) has not only an arylene structure but also a maleimide group in the molecule. Examples of the arylene structure include an arylene structure in which a structure containing a maleimide group is bonded to the meta position (an arylene structure in which a structure containing a maleimide group is substituted at the meta position). Examples of the arylene structure include m-arylene groups such as m-phenylene and m-naphthylene. Specific examples of the arylene structure possessed by the maleimide compound (A2) include an arylene group in which a structure is bonded to the meta position, such as the group represented by the following formula (4):

[0037]

[0038] Examples of the maleimide compound (A2) include a maleimide compound (A2-1) represented by the following formula (2), and more specifically, a maleimide compound (A2-1-2) represented by the below-described formula (5).

[0039]

[0040] In formula (2), Ar represents an arylene group bonded in a meta orientation. Ａ , R Ｂ , R Ｃ , and R Ｄ are independent of each other. That is, R Ａ , R Ｂ , R Ｃ , and R Ｄ may be the same group or different groups. Ａ , R Ｂ , R Ｃ , and R Ｄ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and is preferably a hydrogen atom. Ｅ and R Ｆ are independent of each other. That is, R Ｅ and R Ｆmay be the same group or different groups. Ｅ and R Ｆ represents an aliphatic hydrocarbon group. s represents 1 to 5.

[0041] The arylene group is not particularly limited as long as it is an arylene group oriented and bonded at the meta position, and examples thereof include m-arylene groups such as an m-phenylene group and an m-naphthylene group, and more specific examples thereof include groups represented by the above formula (4).

[0042] Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a neopentyl group.

[0043] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of the aliphatic hydrocarbon group include alkylene groups, more specifically, methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, dimethylmethylene groups are preferred.

[0044] In the maleimide compound (A2-1) represented by the formula (2), the repeating number s is preferably 1 to 5. This s is the average value of the repeating number (degree of polymerization).

[0045]

[0046] In formula (5), s represents 1 to 5. This s is the same as s in formula (2) and is the average value of the number of repetitions (degree of polymerization).

[0047] The maleimide compound (A2-1) represented by the formula (2) and the maleimide compound (A2-1-1) represented by the formula (5) may contain a monofunctional compound where s is 0, or a polyfunctional compound such as a heptafunctional or octafunctional compound where s is 6 or more, as long as s is the average value of the repeating number (degree of polymerization) of 1 to 5.

[0048] As the maleimide compound (A2), a commercially available product can also be used, and an example thereof is the solid content in MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd.

[0049] As the maleimide compound (A2), the maleimide compounds exemplified above may be used alone or in combination of two or more. For example, as the maleimide compound (A2), the maleimide compound (A2-1) represented by formula (2) may be used alone, or two or more types of the maleimide compounds (A2-1) represented by formula (2) may be used in combination. When two or more types of the maleimide compounds (A2-1) represented by formula (4) are used in combination, for example, a maleimide compound (A1) represented by formula (2) other than the maleimide compound (A2-1-1) represented by formula (5) may be used in combination with the maleimide compound (A2-1-1) represented by formula (5).

[0050] Maleimide Compound (A3) Having an Indane Structure and an Arylene Structure Bonded at the Meta Position in the Molecule The maleimide compound (A3) is not particularly limited as long as it has an indane structure and an arylene structure bonded at the meta position in the molecule. Note that the maleimide compound (A3) has not only the arylene structure and the indane structure but also a maleimide group in the molecule. The indane structure of the maleimide compound (A3) is the same as the indane structure in the maleimide compound (A1), and the arylene structure of the maleimide compound (A3) is the same as the arylene structure bonded at the meta position in the maleimide compound (A2). Specific examples of the maleimide compound (A3) include maleimide compounds represented by the following formulas (6) to (8).

[0051]

[0052] In formula (6), n represents 0.95 to 10.

[0053]

[0054] In formula (7), n represents 0.95 to 10.

[0055]

[0056] In formula (8), n represents 0.95 to 10.

[0057] As the maleimide compound (A3), a commercially available product can also be used, and an example thereof is the solid content of NE-X-9470S manufactured by DIC Corporation.

[0058] As the maleimide compound (A), the maleimide compounds described above may be used alone or in combination of two or more. The content of the maleimide compound (A1) in the maleimide compound (A) is preferably 40 to 100 parts by mass, more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). The content of the maleimide compound (A2) is preferably 40 to 100 parts by mass, more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). The content of the maleimide compound (A3) is preferably 40 to 100 parts by mass, more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A).

[0059] (High molecular weight material (B)) The resin composition of this embodiment contains a high molecular weight material (B) having a weight average molecular weight of 10,000 or more and 900,000 or less. This is thought to enable the cured product to have even lower dielectric properties (low dielectric tangent) and a lower thermal expansion coefficient. In this specification, the weight average molecular weight may be any molecular weight measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0060] Specifically, the polymer (B) usable in this embodiment preferably contains at least one of an acrylic resin and a styrene-based polymer, each having a weight-average molecular weight of 10,000 to 900,000. Among these, it is preferable that the polymer (B) contains a styrene-based polymer, from the viewpoint of obtaining lower dielectric properties.

[0061] Specific examples of the styrene-based copolymer of this embodiment include copolymers obtained by copolymerizing one or more styrene-containing monomers (styrene-based monomers) with one or more other monomers copolymerizable with the styrene-based monomer. The styrene-based copolymer may be a random copolymer or a block copolymer. Examples of the block copolymer include a binary copolymer of a structural unit (repeating unit) derived from the styrene-based monomer and a structural unit (repeating unit) derived from the other copolymerizable monomer, and a terpolymer of a structure (repeating unit) derived from the styrene-based monomer, a structural unit (repeating unit) derived from the other copolymerizable monomer, and a structural unit (repeating unit) derived from the styrene-based monomer. The styrene-based polymer of this embodiment may be a hydrogenated styrene-based copolymer obtained by hydrogenating the styrene-based copolymer described above.

[0062] The styrene-based monomer is not particularly limited, but examples thereof include styrene, styrene derivatives, styrene in which some of the hydrogen atoms on the benzene ring have been substituted with alkyl groups, styrene in which some of the hydrogen atoms on the vinyl group have been substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, isopropenyltoluene, etc. These styrene-based monomers may be used alone or in combination of two or more.

[0063] Furthermore, the styrene-based polymer of the present embodiment preferably contains, in the molecule, an ethylene structural unit and a butylene structural unit among units obtained by copolymerizing a styrene-based monomer with one or more other copolymerizable monomers, and more preferably contains a butylene structure among the ethylene structural unit and the butylene structure.

[0064] The ethylene structural unit is not particularly limited, and examples thereof include those having an ethylene structure among the structural units (repeating units) derived from the other copolymerizable monomers. The ethylene structural unit is a structure derived from a 1,4-bond of a conjugated diene monomer (conjugated dienes), and the atom or group bonded to the carbon of the -C-C- bond of the main chain is a hydrogen atom or a methyl group. Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Therefore, specific examples of the ethylene structural unit include structural units having an ethylene structure among structural units derived from the conjugated dienes, and more specific examples include structural units having an ethylene structure (1,4-addition structural units) among structural units (repeating units) derived from 1,3-butadiene.

[0065] The butylene structural unit is not particularly limited, and examples thereof include those having a butylene structure among the structural units (repeating units) derived from the other copolymerizable monomers. The butylene structural unit is at least one of a structure derived from a 1,2-bond of a conjugated diene monomer (conjugated dienes) and a structure derived from a 3,4-bond of a conjugated diene monomer (conjugated dienes), and at least one of the atoms or groups bonded to the carbon of the -C-C- bond of the main chain is a side chain having two or more carbon atoms. Therefore, specific examples of the butylene structural unit include structural units having a butylene structure among the structural units derived from the conjugated dienes, and more specific examples include structural units having a butylene structure (at least one of a 1,2-addition structural unit and a 3,4-addition structural unit) among the structural units (repeating units) derived from 1,3-butadiene. The butylene structural unit may be, for example, a hydrogenated structural unit.

[0066] The styrene-based polymer of the present embodiment may contain a structural unit derived from another copolymerizable monomer other than the ethylene structural unit and the butylene structural unit as the structural unit (repeating unit) derived from the other copolymerizable monomer. Examples of such another copolymerizable monomer include, but are not limited to, olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene.

[0067] Specific examples of styrene-based polymers include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene-isoprene copolymer, styrene-isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, styrene-butadiene styrene copolymer, styrene-isobutylene styrene block copolymer, and styrene (butadiene / butylene) styrene copolymer. The styrene-based polymer may be a styrene-based polymer in which at least a portion of the styrene-based copolymer is hydrogenated. The styrene-based polymer of this embodiment may also be a styrene-based polymer in which at least a portion of the styrene-based polymer is acid-modified, specifically, a styrene-based polymer in which at least a portion of the styrene-based polymer is acid-modified with maleic anhydride. It is believed that using such an acid-modified styrene-based polymer increases the compatibility of the styrene-based polymer with the maleimide compound (A).

[0068] When an acid-modified styrene polymer is used, the acid value is 2 mg CH ３ ONa / g or more, and 2 to 10 mg CH ３ More preferably, the styrene polymer has an acid value of 2 mg CH ３It is preferable that the styrene polymer is acid-modified with maleic anhydride so that the acid value is 2 to 10 mg CH ３ It is more preferable that the styrene-based polymer is acid-modified with maleic anhydride so that the acid value is ONa / g. When the acid value of the styrene-based polymer is within the above range, the effect of the styrene-based polymer, that is, the effect of reducing the thermal expansion coefficient of the cured product of the resin composition, can be more suitably exhibited. This is thought to be due to the increased compatibility of the styrene-based polymer with the maleimide compound (A). Here, the acid value is the amount of sodium methoxide (CH ３ ONa) (mg).

[0069] The styrene-based polymer of the present embodiment preferably has a weight-average molecular weight of 10,000 to 300,000, and more preferably 10,000 to 200,000. By having the molecular weight within this range, it is believed that the glass transition temperature of the cured product of the resin composition can be maintained high, and the viscosity of the resin composition when made into a varnish and the viscosity of the resin composition during heat molding can be set within an appropriate range.

[0070] As the styrene-based polymer of the present embodiment, the above-exemplified styrene-based polymers may be used alone or in combination of two or more.

[0071] Examples of acrylic resins that can be used in this embodiment include acrylic block copolymers and acrylic random copolymers. The acrylic block copolymer is not particularly limited as long as it contains a structural unit (c1) represented by the following formula (I) and a structural unit (c2) represented by the following formula (II) and has a number average molecular weight of 10,000 to 300,000. Since the acrylic block copolymer (C) contains the structural unit (c1), the content of the structural unit (c1) is greater than 0% by mass.

[0072]

[0073]

[0074] Y in the structural unit (c2) is not particularly limited as long as it is a hydrocarbon group having 4 or more carbon atoms. Examples of the hydrocarbon group include butyl, hexyl, pentyl, heptyl, octyl, nonyl, decyl, dodecyl, lauryl, stearyl, docosyl, isostearyl, 1-methylheptyl, 2-ethylhexyl, phenoxyethyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxybutyl, 4-hydroxybutyl, 2-carboxyethyl, isobornyl, and isoamyl. Among these, butyl and 2-ethylhexyl are preferred as the hydrocarbon group. The structural unit (c2) may contain these groups alone or in combination as the hydrocarbon group. The structural unit (c2) is preferably a structural unit derived from butyl acrylate or a structural unit derived from 2-ethylhexyl acrylate. The structural unit (c1) is a structural unit derived from methyl methacrylate. Therefore, the acrylic block copolymer (C) is preferably a block copolymer of the structural unit (c1) derived from methyl methacrylate and the structural unit (c2) derived from at least one of a structural unit derived from butyl acrylate and a structural unit derived from 2-ethylhexyl acrylate. Examples of the block copolymer include a diblock copolymer of the structural unit (c1) and the structural unit (c2), and a triblock copolymer of the structural unit (c1), the structural unit (c2), and the structural unit (c1), with the triblock copolymer being preferred. Specifically, the acrylic block copolymer (C) is more preferably a block copolymer of methyl methacrylate and butyl acrylate, and even more preferably a triblock copolymer of methyl methacrylate, butyl acrylate, and methyl methacrylate. Furthermore, the structural unit (c1) serves as a hard segment in the acrylic block copolymer (C), and the glass transition temperature thereof is preferably, for example, 100 to 120°C.Furthermore, the structural unit (c2) is a soft segment in the acrylic block copolymer (C), and its glass transition temperature is preferably -60 to -40°C, more preferably -50 to -40°C.

[0075] Since the acrylic block copolymer (C) contains the structural unit (c1), the content of the structural unit (c1) is greater than 0% by mass. Therefore, the content of the structural unit (c1) is greater than 0% by mass and not more than 20% by mass, preferably 1 to 18% by mass, and more preferably 11 to 18% by mass, relative to the acrylic block copolymer (A). If the content of the structural unit (c1) in the acrylic block copolymer (A) is too low, the effect of adding the acrylic block copolymer (C) is less likely to be achieved, and it tends to be difficult to obtain a cured product with a low thermal expansion coefficient from the resin composition. Therefore, if the content of the structural unit (c1) is within the above range, it tends to be easier to obtain a cured product with a low thermal expansion coefficient from the resin composition.

[0076] The acrylic block copolymer (C) may contain the structural unit (c1) and the structural unit (c2), and may also contain a structural unit (c3) other than the structural unit (c1) and the structural unit (c2) (another structural unit). The other structural unit is not particularly limited, and examples thereof include structural units derived from methacrylic acid esters other than those derived from methyl methacrylate, structural units derived from methyl acrylate, structural units derived from ethyl acrylate, structural units derived from butyl acrylate, and structural units derived from styrene. Furthermore, examples of structural units derived from methacrylic acid esters other than those derived from methyl methacrylate include structural units derived from ethyl methacrylate, structural units derived from butyl methacrylate, and structural units derived from propyl methacrylate.

[0077] The number average molecular weight of the acrylic block copolymer (C) is 10,000 or more, preferably 30,000 or more, more preferably 40,000 or more, and preferably 300,000 or less, more preferably 200,000 or less. The acrylic block copolymer (C) may be solid or liquid at 25°C, and is preferably solid at 25°C. The number average molecular weight of the acrylic block copolymer (C) is preferably a number average molecular weight that results in a solid at 25°C. If the number average molecular weight is too low, the effect of adding the acrylic block copolymer (C) is less likely to be achieved, and it tends to be difficult to obtain a cured product with a low thermal expansion coefficient as a cured product obtained from the resin composition. If the number average molecular weight is too high, the compatibility between the maleimide compound (A) and the acrylic block copolymer (C) is so reduced that a normal cured product cannot be obtained, or the viscosity of the resin composition when made into a varnish and the viscosity of the resin composition during heat molding tend to be too high. The number average molecular weight may be measured by a general molecular weight measurement method, and specifically, may be a value measured by gel permeation chromatography (GPC).

[0078] The acrylic random copolymer preferably has a structure represented by the following formula (III), formula (IV) or formula (V).

[0079]

[0080]

[0081]

[0082] In the above formulas (III) to (V), x, y, and z represent mole fractions, and satisfy the following conditions: x+y+z≦1, 0<x≦0.2, 0.6≦y≦0.95, and 0.05≦z≦0.2.

[0083] In the above formula (IV), R １ is a hydrogen atom or a methyl group, R ２contains at least one of a glycidyl group and an epoxidized alkyl group out of a hydrogen atom, an alkyl group, a glycidyl group and an epoxidized alkyl group.

[0084] In the above formula (V), R ３ is a hydrogen atom or a methyl group, R ４ is Ph (phenyl group), -COOCH ２ Ph or -COO(CH ２ ) ２ It is Ph.

[0085] Preferably, the main chain of the acrylic resin has at least one structure represented by formula (III), at least one structure represented by formula (IV), and at least one structure represented by formula (V).

[0086] When the main chain of the acrylic random copolymer has the structures represented by formula (III), formula (IV) and formula (V), the arrangement order of the structures represented by formula (III), formula (IV) and formula (V) is not particularly limited. In this case, in the main chain of the acrylic random copolymer, the structure represented by formula (III) may be continuous or discontinuous, the structure represented by formula (IV) may be continuous or discontinuous, and the structure represented by formula (V) may be continuous or discontinuous.

[0087] Here, R in the formula (IV) ２ The meaning of containing at least one of a glycidyl group and an epoxidized alkyl group among a hydrogen atom, an alkyl group, a glycidyl group and an epoxidized alkyl group will be explained further below. ２ The acrylic random copolymer will be described separately for cases where it has only one structure represented by formula (IV) and cases where it has two or more structures represented by formula (IV).

[0088] In the former case, that is, when the acrylic random copolymer has one structure represented by formula (IV), R ２ is a glycidyl group or an epoxidized alkyl group.

[0089] In the latter case, that is, when the acrylic random copolymer has two or more structures represented by formula (IV), R in at least one of the structures represented by formula (IV) ２ is a glycidyl group or an epoxidized alkyl group, and R in the remaining structure represented by formula (IV) ２ is a hydrogen atom or an alkyl group. R in at least one structure represented by formula (IV) ２ is a glycidyl group or an epoxidized alkyl group, so that R ２ However, it may be a glycidyl group or an epoxidized alkyl group.

[0090] The structure represented by the formula (V) is a group consisting of Ph (phenyl group), —COOCH ２ Ph, -COO(CH ２ ) ２ Ph. Ph, -COOCH ２ Ph, -COO(CH ２ ) ２ Ph is thermally stable, and therefore increases the strength of the cured resin composition, and can improve the heat resistance of laminates (metal-clad laminates and wiring boards).

[0091] (Curing Agent (C)) The resin composition of this embodiment may further contain a curing agent (C). Examples of the curing agent (C) include a compound that is different from the maleimide compound (A) and that can react with the maleimide compound (A) to cure the resin composition. Examples of the curing agent (C) include a curing agent having a carbon-carbon unsaturated bond in the molecule, and more specifically, examples of the curing agent (C) include a benzoxazine compound (C1) having an alkenyl group in the molecule, a hydrocarbon-based compound (C2) having a carbon-carbon unsaturated double bond in the molecule, and a polybutadiene compound (C3) having an epoxy group in the molecule. As the curing agent (C), these may be used alone or in combination of two or more.

[0092] Benzoxazine Compound (C1) Having an Alkenyl Group in the Molecule The benzoxazine compound (C1) is not particularly limited as long as it is a benzoxazine compound having an alkenyl group in the molecule. The benzoxazine compound (C1) has not only an alkenyl group but also a benzoxazine group in the molecule. The alkenyl group is not particularly limited, but examples thereof include alkenyl groups having 2 to 6 carbon atoms. Specific examples of the alkenyl group include vinyl groups, allyl groups, propenyl groups, and butenyl groups. Of these, allyl groups and propenyl groups are preferred, and allyl groups are more preferred. In other words, the curing agent (C) preferably contains a benzoxazine compound having an allyl group in the molecule. Examples of the benzoxazine group include a benzoxazine group represented by the following formula (9) and a benzoxazine group represented by the following formula (10). Examples of the benzoxazine compound (C1) include not only a benzoxazine compound (C1-1) having a benzoxazine group represented by the following formula (9) in the molecule and a benzoxazine compound (C1-2) having a benzoxazine group represented by the following formula (10) in the molecule, but also a benzoxazine compound (C1-3) having a benzoxazine group represented by the following formula (9) and a benzoxazine group represented by the following formula (10) in the molecule.

[0093]

[0094] In formula (9), R １ represents an allyl group, and a represents 1 to 4. a represents R １ is an average value of the degree of substitution of 1 to 4, and is preferably 1.

[0095]

[0096] In formula (10), R ２ indicates an allyl group.

[0097] Specific examples of the benzoxazine compound (C1) include the benzoxazine compound (C1-1) represented by the following formula (11):

[0098]

[0099] In formula (11), R ３ and R ４ represents an allyl group; Y represents an alkylene group; b and c each independently represent 1 to 4;

[0100] The alkylene group is not particularly limited and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octane group, an icosane group, and a hexatriacontane group. Among these, a methylene group is preferred.

[0101] b is R ３ is the average value of the degree of substitution of R ４ is an average value of the degree of substitution of 1 to 4, and is preferably 1.

[0102] As the benzoxazine compound (C1), a commercially available product may be used, for example, "ALPd" manufactured by Shikoku Chemicals Corporation.

[0103] As the benzoxazine compound (C1), the benzoxazine compounds exemplified above may be used alone or in combination of two or more kinds.

[0104] Hydrocarbon Compound (C2) Having a Carbon-Carbon Unsaturated Double Bond in the Molecule The hydrocarbon compound (C2) is not particularly limited as long as it is a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule. The carbon-carbon unsaturated group is not particularly limited, but examples thereof include alkenyl groups. Examples of the alkenyl group include alkenyl groups having 2 to 6 carbon atoms, specifically vinyl groups, allyl groups, propenyl groups, and butenyl groups, with allyl groups and propenyl groups being preferred. Examples of the hydrocarbon compound (C2) include divinylbenzenes such as o-divinylbenzene, m-divinylbenzene, and p-divinylbenzene; hydrocarbon compounds (C2-1) represented by the following formula (12); and hydrocarbon compounds (C2-2) represented by the following formula (14).

[0105]

[0106] In formula (12), X represents a hydrocarbon group having 6 or more carbon atoms and containing at least one selected from an aromatic cyclic group and an aliphatic cyclic group, and m represents 1 to 10.

[0107] The aromatic cyclic group is not particularly limited, but examples thereof include a phenylene group, a xylylene group, a naphthylene group, a tolylene group, and a biphenylene group. The aliphatic cyclic group is not particularly limited, but examples thereof include a group containing an indane structure and a group containing a cycloolefin structure. Among these, X is preferably the aromatic cyclic group, and more preferably a xylylene group. The number of carbon atoms in the hydrocarbon group is not particularly limited as long as it is 6 or more, but is preferably 6 to 20. More specific examples of the hydrocarbon compound (C2-1) include a hydrocarbon compound (C2-1-1) represented by the following formula (13):

[0108]

[0109] In formula (13), m represents 1 to 10.

[0110]

[0111] In formula (14), e represents 1 to 20.

[0112] In the hydrocarbon compound (C2-2), e is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 6. Specific examples of the hydrocarbon compound (C2-2) include a compound represented by the formula (14) above where e is 1 [bis-(4-vinylphenyl)methane (BVPM)], a compound represented by the formula (14) above where e is 2 [1,2-bis(vinylphenyl)ethane (BVPE)], a compound represented by the formula (14) above where e is 6 [1,6-bis(4-vinylphenyl)hexane (BVPH)], and divinylbenzene.

[0113] Of the above-mentioned examples of the hydrocarbon compound (C2), the hydrocarbon compound (C2-1) represented by the formula (12) is preferred, and the hydrocarbon compound (C2-1-1) represented by the formula (13) is more preferred.

[0114] Polybutadiene Compound (C3) Having Epoxy Groups in the Molecule The polybutadiene compound (C3) having epoxy groups in the molecule is not particularly limited, and examples thereof include epoxidized polybutadiene, i.e., a compound in which epoxy groups have been introduced into the molecule by epoxidizing at least a portion of the carbon-carbon double bonds contained in polybutadiene, and a compound in which both terminals of polybutadiene have been glycidyl-etherified. The epoxidation is carried out, for example, by adding one oxygen atom to the carbon-carbon double bond contained in polybutadiene (polybutadiene before epoxidation) using an epoxidizing agent to form a three-membered ring epoxy group. A compound in which both terminals of polybutadiene have been glycidyl-etherified can be obtained by adding epichlorohydrin to polybutadiene having hydroxyl groups at both terminals.

[0115] The polybutadiene (before epoxidation) may have a stereostructure of carbon-carbon double bonds of any of cis-1,4, trans-1,4, cis-1,2, and trans-1,2, and the ratio thereof is not particularly limited.

[0116] The epoxidizing agent is not particularly limited as long as it can epoxidize the carbon-carbon double bonds contained in polybutadiene, and examples of the epoxidizing agent include percarboxylic acids such as peracetic acid, performic acid, perbenzoic acid, trifluoroperacetic acid, and perpropionic acid, organic hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide, and hydrogen peroxide.

[0117] The polybutadiene compound (C3) having an epoxy group in its molecule preferably has an oxirane oxygen concentration of 1 to 10% by mass, more preferably 5 to 9% by mass. If the oxirane oxygen concentration is too low, the effect of adding the polybutadiene compound (C3), namely, the effect of improving the adhesion of the cured resin composition to metal foil, tends to be insufficient. On the other hand, if the oxirane oxygen concentration is too high, the epoxy groups tend to become too numerous, resulting in a deterioration in low dielectric properties. By using the polybutadiene compound (C3) having an oxirane oxygen concentration within the above range, a resin composition can be obtained that, when cured, results in a cured product with low dielectric properties and high adhesion to metal foil.

[0118] The concentration of oxirane oxygen is an index of the content of epoxy groups contained in the polybutadiene compound (C3), and can be measured, for example, by a hydrogen bromide-glacial acetic acid solution method.

[0119] The curing agent that reacts with the maleimide compound (A) may contain a vinyl compound (C4) other than the compounds (C1) to (C3). (C4) is a compound having a vinyl group in the molecule, and examples thereof include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in the molecule, and polyfunctional vinyl compounds having two or more vinyl groups in the molecule. Examples thereof include vinylbenzene compounds having a skeleton containing a phosphorus atom in the molecule, such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO).

[0120] (Inorganic Filler (D)) The resin composition of this embodiment may contain an inorganic filler (D) as needed, as long as the effects of the present invention are not impaired. This is thought to improve the low thermal expansion properties of the cured product of the resin composition. The inorganic filler (D) is not particularly limited as long as it is an inorganic filler that can be used as an inorganic filler contained in a thermosetting resin composition. Examples of the inorganic filler (D) include metal oxide fillers, metal hydroxide fillers, molybdate fillers, nitride fillers, titanate fillers, magnesium carbonate fillers such as anhydrous magnesium carbonate fillers, calcium carbonate fillers, quartz glass fillers, talc fillers, aluminum borate fillers, and barium sulfate fillers. Examples of the metal oxide fillers include silica fillers, alumina fillers, titanium oxide fillers, magnesium oxide fillers, and mica fillers. Examples of the silica fillers include crushed silica, spherical silica such as fused spherical silica, and silica particles. Examples of the metal hydroxide filler include magnesium hydroxide filler and aluminum hydroxide filler. Examples of the molybdate filler include zinc molybdate filler, calcium molybdate filler, and magnesium molybdate filler. Examples of the nitride filler include aluminum nitride filler and boron nitride filler. Examples of the titanate filler include barium titanate filler, strontium titanate filler, calcium titanate filler, and aluminum titanate filler. Among these, metal hydroxide fillers such as silica filler, magnesium hydroxide filler, and aluminum hydroxide filler, aluminum oxide filler, boron nitride filler, strontium titanate filler, calcium titanate filler, and zinc molybdate filler are preferred, with silica filler being more preferred. The inorganic fillers may be used alone or in combination of two or more. When two or more of the inorganic fillers are used in combination, a silica filler may be used in combination with one or more inorganic fillers other than a silica filler.

[0121] The inorganic filler (D) may be a surface-treated or untreated inorganic filler. Examples of the surface treatment include treatment with a silane coupling agent.

[0122] (Content) The content of the maleimide compound (A) is preferably 40 to 80% by mass, and more preferably 50 to 70% by mass, based on the total amount of the maleimide compound (A) and the polymer (B).

[0123] Hereinafter, in this specification, the term "total amount of resin components" means the total amount of resin components contained in a thermosetting resin composition. For example, when the thermosetting resin composition contains a maleimide compound (A) and a polymer (B), it means the total amount of these components. When the thermosetting resin composition further contains a curing agent (C) in addition to the maleimide compound (A) and the polymer (B), it means the total amount of these components (A + B + C).

[0124] The content of the polymer (B) is preferably 5 to 20 mass %, more preferably 10 to 20 mass %, based on the total amount of the thermosetting resin composition.

[0125] When the thermosetting resin composition of the present embodiment contains a curing agent (C), the content of the curing agent (C) is preferably 1 to 15 mass % and more preferably 3 to 12 mass % relative to the total amount of the thermosetting resin composition.

[0126] By incorporating the maleimide compound (A), the polymer (B), and the curing agent (C) so that their contents fall within the above ranges, it is possible to more reliably obtain a thermosetting resin composition that has low dielectric properties and becomes a cured product with a lower thermal expansion coefficient.

[0127] The content of the thermosetting resin composition in the prepreg of this embodiment is preferably 35 to 80 mass %, more preferably 40 to 75 mass %, based on the total amount of components in the prepreg.

[0128] As described above, the thermosetting resin composition may contain an inorganic filler (D). When the inorganic filler (D) is contained, the content of the inorganic filler (D) is preferably 100 to 300 parts by mass, and more preferably 100 to 250 parts by mass, per 100 parts by mass of the organic components (other than the inorganic filler (D) in the thermosetting resin composition).

[0129] (Other Components in Thermosetting Resin Composition) The thermosetting resin composition may contain components other than the above-described components (other components) within the scope of not impairing the effects of the present invention. Examples of other components include organic components other than the above components (A) to (C), flame retardants, reaction initiators, curing accelerators, catalysts, polymerization retarders, polymerization inhibitors, dispersants, leveling agents, coupling agents, defoamers, antioxidants, heat stabilizers, antistatic agents, UV absorbers, dyes, pigments, and additives such as lubricants.

[0130] As described above, the thermosetting resin composition according to this embodiment may contain an organic component other than the components (A) to (C). The organic component may be, for example, a compound that reacts with at least one of the components (A) to (C), or a compound that does not react with the components (A) to (C). Specific examples of the organic component include epoxy compounds, cyanate ester compounds, and active ester compounds.

[0131] As described above, the thermosetting resin composition of this embodiment may contain a reaction initiator. The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the thermosetting resin composition, and examples thereof include peroxides and organic azo compounds. Examples of peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene (PBP), 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. Furthermore, if necessary, a metal carboxylate or the like can be used in combination. This can further accelerate the curing reaction. The reaction initiators may be used alone or in combination of two or more.

[0132] As described above, the thermosetting resin composition according to this embodiment may contain a curing accelerator. The curing accelerator is not particularly limited as long as it can accelerate the curing reaction of the thermosetting resin composition. Specific examples of the curing accelerator include imidazoles and their derivatives, organophosphorus compounds, amines such as secondary amines and tertiary amines, quaternary ammonium salts, organoboron compounds, and metal soaps. Examples of the imidazoles include 2-ethyl-4-methylimidazole (2E4MZ), 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenylimidazole, and 1-benzyl-2-methylimidazole. Examples of the organophosphorus compounds include triphenylphosphine, diphenylphosphine, phenylphosphine, tributylphosphine, and trimethylphosphine. Examples of the amines include dimethylbenzylamine, triethylenediamine, triethanolamine, and 1,8-diaza-bicyclo(5,4,0)undecene-7 (DBU). Examples of the quaternary ammonium salts include tetrabutylammonium bromide. Examples of the organoboron compounds include tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate, and tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium ethyltriphenylborate. The metal soap refers to a fatty acid metal salt, and may be either a linear fatty acid metal salt or a cyclic fatty acid metal salt. Specific examples of the metal soap include linear fatty acid metal salts and cyclic fatty acid metal salts having 6 to 10 carbon atoms. More specifically, examples of the curing accelerator include aliphatic metal salts composed of linear fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octylic acid, or cyclic fatty acids such as naphthenic acid, and metals such as lithium, magnesium, calcium, barium, copper, and zinc. For example, zinc octylate is included. The curing accelerator may be used alone or in combination of two or more.

[0133] [Glass Cloth] The glass cloth included in the prepreg of this embodiment contains SiO ２ 45 to 55 mass% of Al ２ O ３ 20 to 30 mass %, MgO 3.0 mass % or less, and P ２ O ５ The glass cloth contains 10 to 15 mass % of the above.

[0134] By using such glass cloth, the prepreg of this embodiment can have extremely excellent low dielectric properties and a low coefficient of thermal expansion.

[0135] In the glass cloth of this embodiment, SiO ２ If the content of SiO is less than 45% by mass, it becomes difficult to obtain sufficiently low dielectric properties, and if it exceeds 55% by mass, the viscosity increases during spinning, making it difficult to form fibers. ２ The content is 47 to 53 mass %.

[0136] In the glass cloth of this embodiment, Al ２ O ３ If the content of Al is less than 20% by mass, the water resistance deteriorates, and if it exceeds 30% by mass, the spinnability deteriorates and the dielectric constant increases. ２ O ３ The content is 22 to 28 mass %.

[0137] In the glass cloth of this embodiment, if the MgO content exceeds 3 mass%, the water resistance deteriorates and it is difficult to obtain sufficiently low dielectric properties. The lower limit of the MgO content is not particularly limited, but from the viewpoint of uniformity of the glass fibers, it is preferably 0.5% or more. The MgO content relative to the total amount of the glass cloth is more preferably 0.5 to 2.8 mass%.

[0138] In the glass cloth of this embodiment, P ２ O ５ When the amount of Al is less than 10 mass %, ２ O ３ If the content of P exceeds 15% by mass, the water resistance and weather resistance may be deteriorated.２ O ５ The content is 10 to 14 mass %.

[0139] Furthermore, in a preferred embodiment, the Al ２ O ３ and the SiO relative to the total content with the MgO ２ The ratio of the content of (SiO ２ / (Al ２ O ３ It is preferable that the content of each component is less than 2.00. The content is determined from the parts by mass of each component.

[0140] In order to suppress warpage of the semiconductor package, the substrate material constituting the insulating layer of the wiring board is required to have a low coefficient of thermal expansion in its cured state as well as a high modulus of elasticity. ２ , Al ２ O ３ By using the glass cloth containing SiO and MgO in the above ratio range, the prepreg of the present embodiment can have excellent low dielectric properties, a low coefficient of thermal expansion, and a high storage modulus.

[0141] In the glass cloth according to the preferred embodiment, SiO ２ / (Al ２ O ３ +MgO) is sufficient as long as it is less than 2, and the lower limit is not particularly limited, but in order to ensure low dielectric properties, a certain amount of SiO ２ From the viewpoint of ensuring the above, the upper limit is preferably 1.5 or more, and more preferably 1.9 or less.

[0142] The glass cloth of the present embodiment contains the above-mentioned component (SiO ２ , Al ２ O ３ , MgO, and P ２ O ５ ) may contain components other than CaO, Na ２ O, Li ２ O.K. ２ O, Fe ２ O ３ , ZnO, ZrO ２ , B ２ O３ , and TiO ２ etc. may be included.

[0143] The glass cloth of the present embodiment may contain about 0.01 to 0.05 mass % of CaO. When the glass cloth contains CaO in this range, it is possible to improve the water resistance and improve the manufacturability of the glass cloth by reducing the melt viscosity of the molten glass.

[0144] The glass cloth of this embodiment is Na ２ The glass cloth may contain 0.01 to 5 mass % of O. ２ By including O, the dielectric loss tangent (Df) can be further lowered, and the melt viscosity of the molten glass can be reduced, thereby improving the productivity of the glass cloth.

[0145] Furthermore, the glass cloth of this embodiment contains Li ２ O and / or K ２ The total content of these elements relative to the total amount of the glass cloth is preferably in the range of 0.03 to 0.15 mass%, more preferably in the range of 0.04 to 0.10 mass%. ２ O and / or K ２ It is believed that the inclusion of O can reduce the melt viscosity of the molten glass while maintaining a low dielectric constant, thereby improving the manufacturability of the glass cloth.

[0146] The glass cloth of this embodiment is made of Fe ２ O ３ The glass cloth may contain about 0.01 to 2 mass % of Fe. ２ O ３ By including the above, it is possible to suppress coloration of the glass cloth, while improving the degassing properties of the molten glass, thereby improving the productivity of the glass cloth.

[0147] The glass cloth of the present embodiment may contain ZnO in an amount of about 0.01 to 10 mass %. When the glass cloth contains ZnO in this range, thermal expansion can be suppressed.

[0148] The glass cloth of this embodiment is ZrO２ The glass cloth may contain ZrO in an amount of 0.01 to 0.10 mass %. ２ By including the amount in this range, the alkali resistance of the glass cloth can be improved.

[0149] On the other hand, the glass of this embodiment is B ２ O ３ , F ２ and TiO ２ Preferably, the glass cloth is substantially free of these (i.e., the content is less than 0.01% by mass), and more preferably completely free of these (i.e., the content is 0% by mass). By substantially not including these, the acid resistance of the glass cloth can be improved while maintaining a high elastic modulus of the glass cloth.

[0150] The content of each of the above components in the glass cloth of this embodiment can be measured using an X-ray fluorescence analyzer. Specifically, the content can be measured by irradiating Rh X-rays in a vacuum atmosphere with an analysis diameter of 20 mm. Alternatively, the content can be measured by ICP emission spectroscopy.

[0151] The glass cloth of the present embodiment may be a surface-treated glass cloth, and as the surface treatment agent, for example, a silane coupling agent having a functional group such as a vinyl group, a styryl group, a methacryl group, an acrylic group, or a phenylamino group can be preferably used.

[0152] The glass cloth of this embodiment is preferably a glass cloth that has been further subjected to flattening processing. Specific examples of flattening processing include a method in which the glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns into a flat shape. The thickness of the glass cloth of this embodiment is not particularly limited, and glass cloths of, for example, about 0.02 to 0.2 mm can be used without any particular limitation.

[0153] The proportion of the glass cloth relative to the total amount of the prepreg of this embodiment is preferably about 20 to 65 mass %. By including the glass cloth at such a content, the prepreg of this embodiment can more reliably obtain the effects described above. A more preferable proportion of the glass cloth is 25 to 60 mass %.

[0154] [Method for Producing Prepreg] Next, a method for obtaining the prepreg of this embodiment will be described. In the following description, the following reference numerals represent: 1 prepreg, 2 thermosetting resin composition or semi-cured product of the thermosetting resin composition, 3 glass cloth, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, and 21 wiring board. First, FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0155] 1, the prepreg 1 according to this embodiment comprises the thermosetting resin composition or a semi-cured product of the thermosetting resin composition 2, and glass cloth 3. This prepreg 1 comprises the thermosetting resin composition or the semi-cured product of the thermosetting resin composition 2, and the glass cloth 3 present in the thermosetting resin composition or the semi-cured product of the thermosetting resin composition 2.

[0156] In this embodiment, the semi-cured product refers to a thermosetting resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a thermosetting resin composition that has been semi-cured (B-staged). For example, when a thermosetting resin composition is heated, the viscosity initially gradually decreases, then curing begins, and then curing begins and the viscosity gradually increases. In such a case, the semi-cured state can be exemplified by the state between when the viscosity begins to increase and when the composition is completely cured.

[0157] Furthermore, the prepreg obtained using the thermosetting resin composition according to this embodiment may comprise a semi-cured product of the thermosetting resin composition as described above, or may comprise the uncured thermosetting resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the thermosetting resin composition (the thermosetting resin composition in B stage) and a fibrous substrate, or a prepreg comprising the thermosetting resin composition before curing (the thermosetting resin composition in A stage) and a fibrous substrate. The thermosetting resin composition or the semi-cured product of the thermosetting resin composition may be obtained by drying or heat-drying the thermosetting resin composition.

[0158] When producing a prepreg, the thermosetting resin composition 2 is often prepared in the form of a varnish and used to impregnate the glass cloth 3, which is the substrate for forming the prepreg. That is, the thermosetting resin composition 2 is usually often a resin varnish prepared in the form of a varnish. Such a varnish-like thermosetting resin composition (resin varnish) can be obtained, for example, by the following method. The thermosetting resin composition can be obtained by mixing the maleimide compound (A) and the polymer (B) with, if necessary, other resin components (such as the curing agent (C)), and then, if necessary, adding and mixing the inorganic filler (D).

[0159] First, the components of the thermosetting resin composition that are soluble in an organic solvent, i.e., the maleimide compound (A) and the polymer (B), and, if necessary, other resin components (such as the curing agent (C)), are added to the organic solvent and dissolved. Heating may be performed as necessary. Subsequently, if necessary, components that are insoluble in the organic solvent (such as the inorganic filler (D)) are added and dispersed using a disperser or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like thermosetting resin composition. The organic solvent used here is not particularly limited as long as it dissolves the radical polymerizable compound and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0160] The method for producing the prepreg 1 is not particularly limited, but includes, for example, a method in which a thermosetting resin composition 2 prepared in a varnish form is impregnated into a glass cloth 3, followed by drying. The thermosetting resin composition 2 is impregnated into the glass cloth 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple thermosetting resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired one.

[0161] The glass cloth 3 impregnated with the thermosetting resin composition (resin varnish) 2 is heated under desired conditions, for example, at 80°C to 180°C for 1 minute to 10 minutes. The heating provides a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0162] The prepreg of this embodiment has both low dielectric properties and a low coefficient of thermal expansion. Therefore, a wiring board having an insulating layer formed using the prepreg of this embodiment has excellent low dielectric properties and is less prone to warping. The prepreg of this embodiment also has a high Tg and excellent adhesion (interlayer adhesion and adhesion to metal foil). Therefore, the prepreg of this embodiment can be suitably used when forming insulating layers provided in metal-clad laminates and wiring boards.

[0163] <Metal-clad laminate> FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to this embodiment.

[0164] As shown in FIG. 2, the metal-clad laminate 11 is composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. That is, the metal-clad laminate 11 has an insulating layer 12 containing a cured product of a thermosetting resin composition and a metal foil 13 provided on the insulating layer 12. The insulating layer 12 may be composed of a cured product of the thermosetting resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-attached copper foil equipped with a release layer and a carrier to improve handling.

[0165] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using a prepreg 1 can be used. Examples of such a method include stacking one or more prepregs 1, placing a metal foil 13 such as copper foil on both sides or one side of the prepreg 1, and then heat-pressing and molding the metal foil 13 and the prepreg 1 to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 can be obtained by laminating the metal foil 13 on the prepreg 1 and then heat-pressing and molding the laminate. The heat-pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 to be produced, the type of composition of the prepreg 1, and the like. For example, the temperature can be 170 to 230°C, the pressure can be 3 to 5 MPa, and the time can be 60 to 150 minutes.

[0166] <Wiring Board> FIG. 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to this embodiment.

[0167] 3, wiring board 21 according to this embodiment is composed of insulating layer 12, which is formed by curing prepreg 1 shown in FIG. 1, and wiring 14, which is laminated together with insulating layer 12 and formed by partially removing metal foil 13. Insulating layer 12 is composed of the cured product of the prepreg.

[0168] The method for manufacturing the wiring board 21 is not particularly limited as long as it can manufacture the wiring board 21. Specific examples include a method of manufacturing the wiring board 21 using the prepreg 1. Examples of this method include a method of manufacturing the wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above. That is, the wiring board 21 is obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, examples of the method for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP).

[0169] The metal-clad laminate and wiring board having an insulating layer containing the cured product of the prepreg of this embodiment have the same advantages as the prepreg described above, and are therefore useful in industrial applications.

[0170] This specification discloses various aspects of the technology as described above, but the main technologies among them are summarized below.

[0171] A prepreg according to a first aspect of the present invention comprises a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, and glass cloth, wherein the thermosetting resin composition contains a maleimide compound (A) and a high molecular weight substance (B) having a weight average molecular weight of 10,000 or more and 900,000 or less, and the glass cloth contains SiO ２ 45 to 55 mass% of Al ２ O ３ 20 to 30 mass %, MgO 3.0 mass % or less, and P ２ O ５ It is characterized in that it contains 10 to 15 mass % of

[0172] A prepreg according to a second aspect of the present invention is the prepreg according to the first aspect, wherein the glass cloth is SiO ２ , Al ２ O ３ and MgO, and the Al in the glass cloth ２ O ３ and the SiO relative to the total content with the MgO ２ The ratio of the content of (SiO ２ / (Al ２ O ３ + MgO)) is less than 2.00.

[0173] A prepreg according to a third aspect of the present invention is the prepreg according to the first or second aspect, wherein the maleimide compound (A) has at least one of an indane structure and an arylene structure oriented and bonded at the meta position.

[0174] A prepreg according to a fourth aspect of the present invention is the prepreg according to the third aspect, wherein the maleimide compound (A) comprises a maleimide compound (A1) having a structure represented by formula (1) in the molecule as the indane structure.

[0175] A prepreg according to a fifth aspect of the present invention is the prepreg according to the third or fourth aspect, wherein the maleimide compound (A) includes a maleimide compound (A2) represented by the formula (2).

[0176] A prepreg according to a sixth aspect of the present invention is the prepreg according to any one of the first to fifth aspects, wherein the polymer (B) contains at least one of an acrylic resin and a styrene-based copolymer.

[0177] A prepreg according to a seventh aspect of the present invention is the prepreg according to any one of the first to sixth aspects, wherein the thermosetting resin composition further contains a curing agent (C).

[0178] A prepreg according to an eighth aspect of the present invention is the prepreg of the seventh aspect, wherein the curing agent (C) comprises at least one selected from the group consisting of a benzoxazine compound (C1) having an alkenyl group in the molecule, a hydrocarbon compound (C2) having a carbon-carbon unsaturated double bond in the molecule, and a polybutadiene compound (C3) having an epoxy group in the molecule.

[0179] A prepreg according to a ninth aspect of the present invention is the prepreg according to any one of the first to eighth aspects, wherein the thermosetting resin composition further contains an inorganic filler (D).

[0180] A prepreg according to a tenth aspect of the present invention is the prepreg according to any one of the first to ninth aspects, wherein the content of the maleimide compound (A) in the thermosetting resin composition is 40 to 80 mass % relative to the total amount of the maleimide compound (A) and the polymer (B).

[0181] A prepreg according to an eleventh aspect of the present invention is the prepreg according to any one of the first to tenth aspects, wherein the content of the polymer (B) in the thermosetting resin composition is 5 to 20 mass% with respect to the total amount of the thermosetting resin composition.

[0182] A prepreg according to a twelfth aspect of the present invention is the prepreg of any one of the seventh to eleventh aspects, wherein the content of the curing agent (C) in the thermosetting resin composition is 1 to 15 mass% with respect to the total amount of the thermosetting resin composition.

[0183] A prepreg according to a thirteenth aspect of the present invention is the prepreg of any one of the first to twelfth aspects, wherein the content of the thermosetting resin composition in the prepreg is 35 to 80 mass% with respect to the total amount of components in the prepreg.

[0184] A metal-clad laminate according to a fourteenth aspect of the present invention has an insulating layer containing a cured product of the prepreg according to any one of the first to thirteenth aspects, and a metal foil.

[0185] A wiring board according to a fifteenth aspect of the present invention has an insulating layer containing a cured product of the prepreg according to any one of the first to thirteenth aspects, and wiring.

[0186] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0187] First, in this example, each component used in preparing the prepreg will be described.

[0188] <Thermosetting Resin Composition> (Maleimide Compound (A)) Maleimide compound 1: a maleimide compound having an indane structure and an arylene structure oriented and bonded at the meta position in the molecule (the solid content in "NE-X-9470S" manufactured by DIC Corporation, a maleimide compound represented by the formula (6) above) Maleimide compound 2: a maleimide compound having an arylene structure substituted at the meta position in the molecule (the solid content in "MIR-5000-60T" (a toluene solution of a maleimide compound) manufactured by Nippon Kayaku Co., Ltd., a maleimide compound represented by the formula (5) above)

[0189] (High molecular weight substance (B)) Styrene-based polymer: styrene-based polymer ("Tuftec (registered trademark) H1041" manufactured by Asahi Kasei Corporation, molar ratio of ethylene structural units to the butylene structure (ethylene structural units:butylene structure) = 65:35, structural units derived from monomers containing styrene 28% by mass, weight average molecular weight Mw 75,000, solid at 25°C) Acrylic elastomer: epoxy-modified acrylic resin ("PASR-001" manufactured by Nagase ChemteX Corporation, weight average molecular weight Mw 500,000)

[0190] (Curing Agent (C)) Curing Agent 1: Divinylbenzene ("DVB" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Curing Agent 2: Benzoxazine compound having an allyl group in the molecule (represented by the above formula (11), R ３ and R ４ is an allyl group, Y is a methylene group, and b and c are 1, a benzoxazine compound "ALPd" manufactured by Shikoku Chemicals Corporation

[0191] (Reaction initiator) Organic peroxide: PBP (1,3-bis(butylperoxyisopropyl)benzene; "Perbutyl P" manufactured by NOF Corporation)

[0192] (Inorganic filler (D)) Silica filler: phenylaminosilane surface-treated spherical silica ("SC2500-SXJ" manufactured by Admatechs Co., Ltd.)

[0193] <Glass Cloth> (Glass Cloths 1 to 3) Three types of glass cloths 1 to 3 (thickness: 0.1 mm) having the compositions shown below were prepared. Glass cloth 1 corresponds to conventional T-glass, and glass cloth 2 corresponds to conventional S-glass. Glass cloth 1: T-glass manufactured by Nitto Boseki Co., Ltd., Cross Style 2118 (SiO 2 ) ２ :66% by mass, Al ２ O ３ : 25 mass%, MgO: 7.3 mass%, and P ２ O ５ :0% by mass), (SiO ２ / (Al ２ O ３+ MgO) ratio: 2.04) Glass cloth 2: S3 glass, Cross Style 2118 (SiO relative to the total amount of glass cloth components) manufactured by Nanya Plastics Industrial Co., Ltd. ２ :66% by mass, Al ２ O ３ : 25 mass%, MgO: 6.1 mass%, and P ２ O ５ :0.003% by mass), (SiO ２ / (Al ２ O ３ + MgO) ratio: 2.12) Glass cloth 3: V-glass, Cross Style 2118 manufactured by Nitto Boseki Co., Ltd. (SiO ２ :50% by mass, Al ２ O ３ : 25% by mass, MgO: 2.3% by mass, and P ２ O ５ : 12% by mass), (SiO ２ / (Al ２ O ３ +MgO) ratio: 1.83)

[0194] [Examples 1 to 3 and Comparative Examples 1 to 4] (Preparation of Evaluation Samples) First, a resin varnish was prepared. The components other than the inorganic filler were added to a mixed solvent of toluene and methyl ethyl ketone (MEK) (mass ratio of approximately 2:1) so that the solids concentration was 40 to 50 mass% in the composition (parts by mass) shown in Table 1, and mixed. The resulting mixture was stirred for 60 minutes. Thereafter, the inorganic filler was added to the resulting mixture in the composition (parts by mass) shown in Table 1, and the mixture was dispersed using a bead mill. This resulted in a varnish-like thermosetting resin composition (varnish).

[0195] Next, each of the varnishes obtained above was impregnated into a glass cloth shown in Table 1, and then heated and dried at 130°C for 3 minutes to produce a prepreg. The content of the components that constitute the resin by the curing reaction relative to the prepreg (resin content) was adjusted to about 43 mass%. Furthermore, the thickness after curing was adjusted to 103 μm.

[0196] Next, the obtained prepreg was used to obtain an evaluation sample (metal-clad laminate). First, 10 sheets of the obtained prepreg were stacked, and 12 μm thick copper foil (3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides. This was used as a pressure body, and heated to a temperature of 220 ° C. at a temperature increase rate of 3 ° C. / min, and heated and pressed at 220 ° C. for 120 minutes under a pressure of 43 MPa to obtain an evaluation substrate (metal-clad laminate) with copper foil bonded to both sides and a resin layer thickness of approximately 1030 μm.

[0197] Using the evaluation substrate prepared as described above, evaluation test 1 was carried out by the following method.

[0198] <Evaluation Test 1> In the evaluation tests of the dielectric properties (dielectric constant Dk and dielectric loss tangent Df) and the thermal expansion coefficient, an unclad board (cured prepreg, thickness approximately 1030 μm) obtained by removing the copper foil from a copper-clad laminate of 10 prepregs by etching was used as an evaluation sample.

[0199] [Dielectric Properties (Dielectric Constant, Dissipation Factor)] The dielectric constant (Dk) and dielectric dissipation factor (Df) of the evaluation sample at 10 GHz were measured using a cavity resonator perturbation method. Specifically, the dielectric dissipation factor of the evaluation substrate at 10 GHz was measured using a network analyzer (Keysight Technologies, Inc., N5230A). The pass criteria for this test were Dk≦3.75 and Df≦0.006.

[0200] [Thermal Expansion Coefficient (50 to 260°C)] The evaluation sample was used as a test piece (size: 13 mm x 5 mm), and the thermal expansion coefficient in the plane direction (Y direction) of the evaluation substrate at a temperature below the glass transition temperature of the cured product of the thermosetting resin composition was measured by the TMA method (thermo-mechanical analysis). Specifically, the measurement was performed using a TMA device ("TMA6000" manufactured by SII NanoTechnology Inc.) in compression mode. To eliminate the influence of thermal distortion of the test piece, the test piece was heated from 30°C to 320°C at a heating rate of 10°C / min with a load of 10 g applied in the Y direction, and then cooled to room temperature. Thereafter, the test piece was heated from 30°C to 320°C at a heating rate of 10°C / min with a load of 10 g applied in the Y direction. A temperature displacement chart was obtained during this temperature increase. The average thermal expansion coefficient from 50 to 260°C was calculated from the temperature displacement chart obtained. The lower the average coefficient of thermal expansion, the better the result. In this test, an average coefficient of thermal expansion of 5 ppm / ° C. or less was judged to be "passed."

[0201] The results of the above evaluations are shown in Table 1.

[0202]

[0203] (Discussion) As can be seen from Table 1, it was confirmed that the prepregs of Examples 1 to 3, which used the thermosetting resin composition of the present invention, all had low dielectric properties (dielectric constant, dielectric loss tangent) and low thermal expansion coefficients. On the other hand, the prepregs of Comparative Examples 1 to 4, which did not use the glass cloth of the present invention, were inferior to the Examples in both low dielectric properties and low thermal expansion coefficients.

[0204] <Evaluation Test 2> Next, the prepregs of each example were used to evaluate the glass transition temperature (Tg) and various peel strengths.

[0205] (Glass Transition Temperature (Tg)) Using an unclad plate obtained by removing the copper foil from the evaluation sample (metal-clad laminate) by etching, Tg was measured using a viscoelasticity spectrometer "DMS100" manufactured by Seiko Instruments Inc. Dynamic mechanical analysis (DMA) was performed using a double-support bending module at a frequency of 10 Hz, and the temperature at which tan δ was maximized when the temperature was increased from room temperature to 320°C at a heating rate of 5°C / min was defined as Tg. In this test, a sample with a Tg of 240°C or higher was evaluated as passing.

[0206] (Copper foil peel strength) The copper foil was peeled off from the evaluation sample (metal-clad laminate), and the peel strength at this time was measured in accordance with JIS C 6481 (1996). Specifically, the evaluation sample was made to have a width of 10 mm and a length of 100 mm, and the copper foil was peeled off at a rate of 50 mm / min using a tensile tester, and the peel strength at this time (N / mm ２ This peel strength is the copper foil peel strength, and it is understood that the higher this is, the higher the adhesion to the metal foil (copper foil). In this test, the copper foil peel strength measured was 0.35 N / mm ２ If it was above that, it was considered a pass.

[0207] (Interlayer Peel Strength) The insulating layer (prepreg) on ​​the top surface of the evaluation sample (metal-clad laminate) was peeled off at a speed of 50 mm / min using a tensile tester (i.e., the insulating layer on the top surface was peeled off from the insulating layer underneath), and the peel strength (N / mm ２ The peel strength is the interlayer peel strength. The higher the peel strength, the higher the interlayer adhesion. When the measured interlayer peel strength was 0.70 N / mm ２ If it was above that, it was considered a pass.

[0208] The results are shown in Table 2.

[0209]

[0210] (Discussion) As is clear from the results in Table 2, it was confirmed that Examples 1 to 3, which used the prepreg of the present invention, had high Tg and also excellent adhesion.

[0211] <Evaluation Test 3> In Evaluation Test 3, the following glass cloths were additionally used: Glass cloth 4: E-glass, Cross Style 2116 manufactured by Nitto Boseki Co., Ltd. (SiO 2 is a SiO 2 -based on the total amount of glass cloth components) ２ :55% by mass, Al ２ O ３ : 15 mass%, MgO: 1.7 mass%, and P ２ O ５ :0.04% by mass), (SiO ２ / (Al ２ O ３ +MgO) ratio: 3.29) Glass cloth 5: NE Glass, Cross Style 2116 manufactured by Nitto Boseki Co., Ltd. (SiO ２ :58% by mass, Al ２ O ３ : 16 mass%, MgO: 1.4 mass%, and P ２ O ５ :0.01% by mass), (SiO ２ / (Al ２ O ３ +MgO) ratio: 3.33)

[0212] (Preparation of Evaluation Sample for Comparative Example 5-6) First, a resin varnish was prepared. Components other than the inorganic filler were added to a mixed solvent of toluene and methyl ethyl ketone (MEK) (mass ratio of approximately 2:1) so that the solids concentration was 40 to 50 mass % in the composition (parts by mass) shown in Table 3, and mixed. The resulting mixture was stirred for 60 minutes. Thereafter, the inorganic filler was added to the resulting mixture in the composition (parts by mass) shown in Table 3, and dispersed using a bead mill. By doing so, a varnish-like thermosetting resin composition (varnish) was obtained.

[0213] Next, each of the varnishes obtained above was impregnated into a glass cloth shown in Table 3, and then heated and dried at 130°C for 3 minutes to produce a prepreg. The content of the components that constitute the resin by the curing reaction relative to the prepreg (resin content) was adjusted to about 43 mass%. Furthermore, the thickness after curing was adjusted to 103 μm.

[0214] Next, the obtained prepreg was used to obtain an evaluation sample (metal-clad laminate). First, 10 sheets of the obtained prepreg were stacked, and 12 μm thick copper foil (3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides. This was used as a pressure body, and heated to a temperature of 220 ° C. at a temperature increase rate of 3 ° C. / min, and heated and pressed at 220 ° C. for 120 minutes under a pressure of 4 MPa to obtain an evaluation substrate (metal-clad laminate) with copper foil bonded to both sides and a resin layer thickness of approximately 1030 μm.

[0215] Using the evaluation substrate prepared as described above and the evaluation substrates of Example 1-2 and Comparative Example 1-2, evaluations were carried out by the following methods.

[0216] The evaluation tests of the dielectric properties (relative permittivity Dk and dielectric loss tangent Df) and the thermal expansion coefficient were carried out in the same manner as in Evaluation Test 1 (note that the results of the evaluation boards of Examples 1-2 and Comparative Examples 1-2 are the same as those in Table 1, but are also listed in Table 3 below for comparison).

[0217] (Storage Modulus (E') at 30°C) Using an unclad plate obtained by removing the copper foil from the evaluation sample (metal-clad laminate) by etching, the storage modulus (GPa) at 30°C was measured using a viscoelasticity spectrometer "DMS100" manufactured by Seiko Instruments Inc. In this test, a storage modulus of 15 GPa or more at 30°C was evaluated as passing. It is believed that a high storage modulus at 30°C can suppress warpage of the semiconductor package.

[0218] The results of the above evaluations are shown in Table 3.

[0219]

[0220] (Discussion) As can be seen from Table 3, it was confirmed that the prepregs of Examples 1 and 2 all had high dielectric properties (dielectric constant, dielectric loss tangent) and low coefficient of thermal expansion, as well as high storage modulus at 30°C. On the other hand, the prepregs of Comparative Examples 1 and 2 and 5 and 6, which did not use the glass cloth of the present invention, were inferior to the Examples in both low dielectric properties and low coefficient of thermal expansion. Furthermore, the SiO of the glass cloth ２ / (Al ２ O３ The prepreg of Comparative Example 6, which had a high MgO ratio, also failed to achieve a sufficient storage modulus at 30°C.

[0221] This application is based on Japanese Patent Application Nos. 2024-55483 and 2024-56461, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0222] In order to express the present invention, the present invention has been properly and sufficiently described above through embodiments with reference to specific examples, drawings, etc., but it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, unless changes or improvements made by those skilled in the art deviate from the scope of the claims set forth in the claims, such changes or improvements are construed as being encompassed within the scope of the claims.

[0223] The present invention has wide industrial applicability in technical fields related to electronic materials, electronic devices, optical devices, and the like.

Claims

1. A thermosetting resin composition or a semi-cured product of the thermosetting resin composition, and glass cloth, wherein the thermosetting resin composition contains a maleimide compound (A) and a high molecular weight compound (B) having a weight average molecular weight of 10,000 or more and 900,000 or less, and the glass cloth contains SiO ２ 45 to 55 mass% of Al ２ O ３ 20 to 30 mass %, MgO 3.0 mass % or less, and P ２ O ５ A prepreg comprising 10 to 15 mass% of the above.

2. The glass cloth is made of SiO ２ , Al ２ O ３ and MgO, and the Al in the glass cloth ２ O ３ and the SiO relative to the total content with the MgO ２ The ratio of the content of (SiO ２ / (Al ２ O ３ 2. The prepreg of claim 1 wherein MgO) is less than 2.

00.

3. The prepreg according to claim 1, wherein the maleimide compound (A) has at least one of an indane structure and an arylene structure bonded in a meta-oriented manner.

4. The prepreg according to claim 3, wherein the maleimide compound (A) comprises a maleimide compound (A1) having, in the molecule, a structure represented by the following formula (1) as the indane structure: [In formula (1), each Rb independently represents 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 r represents 0 to 3.] 5. The prepreg according to claim 3, wherein the maleimide compound (A) comprises a maleimide compound (A2) represented by the following formula (2): [In formula (2), Ar represents an arylene group bonded to the meta position, and R Ａ , R Ｂ , R Ｃ and R Ｄ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group; R Ｅ and R Ｆ each independently represents an aliphatic hydrocarbon group, and s represents 1 to 5.

6. The prepreg according to claim 1, wherein the polymer (B) contains at least one of an acrylic resin and a styrene copolymer.

7. The prepreg according to claim 1, wherein the thermosetting resin composition further comprises a curing agent (C).

8. The prepreg according to claim 7, wherein the curing agent (C) comprises at least one selected from the group consisting of a benzoxazine compound (C1) having an alkenyl group in the molecule, a hydrocarbon compound (C2) having a carbon-carbon unsaturated double bond in the molecule, and a polybutadiene compound (C3) having an epoxy group in the molecule.

9. The prepreg according to claim 1, wherein the thermosetting resin composition further contains an inorganic filler (D).

10. The prepreg according to claim 1, wherein the content of the maleimide compound (A) in the thermosetting resin composition is 40 to 80 mass % based on the total amount of the maleimide compound (A) and the polymer (B).

11. The prepreg according to claim 1, wherein the content of the polymer (B) in the thermosetting resin composition is 5 to 20 mass % based on the total amount of the thermosetting resin composition.

12. The prepreg according to claim 7, wherein the content of the curing agent (C) in the thermosetting resin composition is 1 to 15 mass % based on the total amount of the thermosetting resin composition.

13. The prepreg according to claim 1, wherein the content of the thermosetting resin composition in the prepreg is 35 to 80 mass % based on the total amount of components in the prepreg.

14. A metal-clad laminate comprising an insulating layer containing a cured product of the prepreg according to any one of claims 1 to 13 and a metal foil.

15. A wiring board comprising an insulating layer containing a cured product of the prepreg according to any one of claims 1 to 13 and wiring.

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