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

Abstract

The present invention provides a thermosetting resin composition which is capable of achieving low dielectric constant, low thermal expansibility and high adhesiveness to a conductor. The present invention also provides a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package, which are obtained using the thermosetting resin composition. Specifically, the thermosetting resin composition contains (A) a maleimide resin which contains an indane skeleton, (B) a multifunctional maleimide resin, and (C) a maleimide resin which does not contain an indane skeleton.

Description

Thermosetting resin compositions, prepregs, resin films, laminates, printed wiring boards, and semiconductor packages

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

[0002] In various electronic devices, such as mobile communication devices typified by mobile phones, their base station equipment, network infrastructure devices such as servers and routers, and large-scale computers, the speed and capacity of signals used are increasing year by year. Accordingly, printed wiring boards mounted on these electronic devices must be able to handle higher frequencies, and substrate materials with excellent dielectric properties (dielectric constant and dielectric loss tangent) in high frequency bands (e.g., high frequency bands of 10 GHz or higher) that enable reduced transmission loss are in demand. In recent years, in addition to the above-mentioned electronic devices, new systems handling high-frequency wireless signals have been put into practical use or planned for use in the fields of ITS (Intelligent Transport Systems) and indoor short-range communications, and substrate materials with low transmission loss are in demand for printed wiring boards mounted on these devices.

[0003] As a material for use in printed wiring boards that require low transmission loss, it has been proposed to use a maleimide compound having an indane ring (see, for example, Patent Document 1).

[0004] WO 2023 / 281692, paragraph

[0027] excerpt

[0005] In order to stably mount electronic components, it is important to suppress warpage that occurs during mounting. To suppress warpage, it is necessary to reduce the thermal expansion of the substrate material. The present inventors investigated substrate materials containing maleimide compounds having an indane ring and found that they lacked low thermal expansion. Therefore, through further investigations, the present inventors attempted to improve low thermal expansion by using a maleimide resin, which has excellent low thermal expansion properties, together with a maleimide compound having an indane ring. However, they found that this reduced adhesion to the conductor, making it easier for peeling to occur between the inner layer circuit and the insulating layer.

[0006] In view of the current situation, the present disclosure aims to provide a thermosetting resin composition that can exhibit low dielectric constant, low thermal expansion, and high adhesion to conductors, as well as to provide a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package obtainable using the thermosetting resin composition.

[0007] As a result of extensive research, the present inventors have found that the thermosetting resin composition of the present disclosure can achieve the above object.

[0008] The present disclosure includes the following embodiments [1] to

[15] . [1] A thermosetting resin composition containing (A) a maleimide resin having an indane skeleton, (B) a polyfunctional maleimide resin, and (C) a maleimide resin not having an indane skeleton. [2] The thermosetting resin composition according to the above [1], wherein the component (A) is a bismaleimide resin having an indane skeleton. [3] The thermosetting resin composition according to the above [1] or [2], wherein the component (B) is an aromatic maleimide resin having three or more N-substituted maleimide groups. [4] The thermosetting resin composition according to any one of the above [1] to [3], wherein the component (B) is a maleimide resin represented by the following general formula (B-1): (In the formula, X ｂ－１ is a divalent hydrocarbon group having 1 to 20 carbon atoms (but not including an indane skeleton), and n ｂ－１ is an integer of 2 to 5.) [5] The thermosetting resin composition according to any one of the above [1] to [4], wherein the component (C) has an aliphatic hydrocarbon group. [6] The thermosetting resin composition according to any one of the above [1] to [5], wherein the component (C) has an N-substituted maleimide group directly bonded to an aromatic ring substituted with an aliphatic hydrocarbon group. [7] The thermosetting resin composition according to any one of the above [1] to [6], wherein the component (C) is a maleimide resin represented by the following general formula (C-1): (In the formula, X ｃ１ is a group represented by the following general formula (C-1-1), (C-1-2) or (C-1-3): (In the formula, R ｃ１ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ２are each independently a halogen atom. p1 is an integer of 1 to 4. p2 is an integer of 0 to 3, provided that p1 + p2 ≦ 4. (In the formula, R ｃ３ and R ｃ４ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ５ and R ｃ６ are each independently a halogen atom. At least one of q1 and q2 is an integer of 1 to 4, and the other is an integer of 0 to 4. q3 and q4 are each independently an integer of 0 to 3, provided that q1+q3≦4 and q2+q4≦4. X ｃ２ represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. (In the formula, R ｃ７ ~R ｃ１０ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ１１ ~R ｃ１４ are each independently a halogen atom. r1 to r4 are each independently an integer of 0 to 4, provided that at least one of r1 to r4 is an integer of 1 to 4. r5 to r8 are each independently an integer of 0 to 4, provided that r1+r5≦4, r2+r6≦4, r3+r7≦4, and r4+r8≦4. X ｃ３is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond.) [8] The thermosetting resin composition according to any one of [1] to [7] above, further comprising (D) a crosslinking agent. [9] The thermosetting resin composition according to any one of [1] to [8] above, further comprising (E) an inorganic filler.

[10] The thermosetting resin composition according to any one of [1] to [9] above, further comprising (F) a curing accelerator.

[11] A prepreg containing the thermosetting resin composition according to any one of [1] to

[10] above or a semi-cured product of the thermosetting resin composition.

[12] A resin film containing the thermosetting resin composition according to any one of [1] to

[10] above or a semi-cured product of the thermosetting resin composition.

[13] A laminate having a cured product of the thermosetting resin composition according to any one of [1] to

[10] above and a metal foil.

[14] A printed wiring board having a cured product of the thermosetting resin composition according to any one of [1] to

[10] above.

[15] A semiconductor package having the printed wiring board according to

[14] above and a semiconductor element.

[0009] The present disclosure makes it possible to provide a thermosetting resin composition that can exhibit low dielectric constant, low thermal expansion, and high adhesion to conductors, as well as to provide prepregs, resin films, laminates, printed wiring boards, and semiconductor packages obtained using the thermosetting resin composition.

[0010] In the numerical ranges described in this disclosure, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower or upper limit of another numerical range. In the expression "AA to BB," the numerical values ​​AA and BB at both ends are included as the lower and upper limits, respectively, of the numerical range. In this disclosure, for example, the expression "10 or more" means 10 and a numerical value greater than 10, and this also applies when the numerical values ​​differ. Furthermore, for example, the expression "10 or less" means a numerical value less than 10 and a numerical value less than 10, and this also applies when the numerical values ​​differ. Furthermore, unless otherwise specified, each component and material exemplified in this disclosure may be used alone or in combination of two or more types. In this disclosure, when multiple substances corresponding to each component are present in the resin composition, the content of each component in the resin composition refers to the total amount of the multiple substances present in the resin composition, unless otherwise specified.

[0011] In the present disclosure, "resin component" refers to all components of the solid content constituting the resin composition, excluding inorganic compounds such as inorganic fillers, which will be described later. In the present disclosure, "solid content" refers to components other than the organic solvent, which will be described later, and components that are liquid at 25°C are also considered to be solid content. The expression "containing XX" described in the present disclosure means that if XX is reactive, XX is contained in a reacted state, or XX is simply contained. In the present disclosure, dielectric constant means relative dielectric constant. Any combination of the items described in the present disclosure is also included in the present disclosure and the present embodiment.

[0012] [Thermosetting Resin Composition] The thermosetting resin composition of this embodiment is as follows: A thermosetting resin composition containing (A) a maleimide resin containing an indane skeleton [hereinafter, sometimes referred to as component (A)], (B) a polyfunctional maleimide resin [hereinafter, sometimes referred to as component (B)], and (C) a maleimide resin not containing an indane skeleton [hereinafter, sometimes referred to as component (C)]. The components contained in the thermosetting resin composition of this embodiment will be described in detail below.

[0013] ((A) Maleimide Resin Having an Indane Skeleton) By including the component (A) in the thermosetting resin composition of this embodiment, the cured product of the thermosetting resin composition has an excellent dielectric constant. The indane skeleton of the component (A) preferably has a divalent group represented by the following general formula (A-1):

[0014] (In the formula, R ａ１ is an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. n1 is an integer of 0 to 3. R ａ２ ~R ａ４ are each independently an alkyl group having 1 to 10 carbon atoms. * represents a bonding site.

[0015] From the viewpoint of dielectric constant (Dk), component (A) is preferably a bismaleimide resin containing an indane skeleton, and more preferably an aromatic bismaleimide resin containing an indane skeleton. The aromatic bismaleimide resin containing an indane skeleton preferably has an N-substituted maleimide group, more preferably an N-substituted maleimide group directly bonded to an aromatic ring, and even more preferably an N-substituted maleimide group in which the nitrogen atom of the N-substituted maleimide group is directly bonded to an aromatic ring.

[0016] As the component (A) having a divalent group represented by general formula (A-1), from the viewpoints of dielectric constant (Dk), adhesion to a conductor, heat resistance, and ease of production, an aromatic bismaleimide resin represented by the following general formula (A-2) is preferred.

[0017] (In the formula, R ａ１ ~R ａ４ and n1 are the same as those in the general formula (A-1). ａ５are each independently an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. Each n2 is independently an integer of 0 to 4, and n3 is a number of 0.95 to 10.0.

[0018] From the viewpoints of dielectric constant (Dk), adhesion to a conductor, solvent solubility, and ease of production, the aromatic bismaleimide resin represented by the general formula (A-2) is more preferably an aromatic bismaleimide resin represented by the following general formula (A-3) or an aromatic bismaleimide resin represented by the following general formula (A-4):

[0019] (In the formula, R ａ１ ~R ａ５ and n1 and n3 are the same as those in the general formula (A-2).

[0020] (In the formula, R ａ１ ~R ａ４ and n1 and n3 are the same as those in the general formula (A-2).

[0021] There are no particular restrictions on the method for producing component (A), and known methods can be used in reference to or adapted from known methods.

[0022] Component (A) may be an addition reaction product with an amine compound such as a monoamine compound or a diamine compound, or it may not be an addition reaction product. The addition reaction product may be an addition reaction product between a maleimide resin containing an indane skeleton and a monoamine compound, an addition reaction product between a maleimide resin containing an indane skeleton and a diamine compound, or an addition reaction product between a maleimide resin containing an indane skeleton and a monoamine compound or a diamine compound. Examples of the monoamine compound include monoamine compounds having an acidic substituent, such as o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline. Examples of the diamine compound include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylether, and 4,4'-diaminodiphenylthioe. aromatic diamine compounds in which an amino group is bonded to an aromatic hydrocarbon group, such as 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrachloro-4,4'-diaminodiphenylmethane, and 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane; siloxane diamines.

[0023] (Content of Component (A)) The content of component (A) in the thermosetting resin composition of this embodiment is not particularly limited, but from the viewpoints of dielectric constant, heat resistance, and moldability, it is preferably 10 to 90 parts by mass, more preferably 15 to 85 parts by mass, even more preferably 20 to 80 parts by mass, and particularly preferably 30 to 70 parts by mass, per 100 parts by mass of the resin components in the resin composition of this embodiment. When the content of component (A) is at least the lower limit, the dielectric constant, heat resistance, and moldability tend to improve, and when it is at most the upper limit, a decrease in low thermal expansibility tends to be suppressed.

[0024] ((B) Polyfunctional Maleimide Resin) Component (B) is a polyfunctional maleimide resin. However, component (B) does not contain an indane skeleton. By including component (B) in the thermosetting resin composition of this embodiment, the low thermal expansion property, which tends to be reduced by component (A), is improved. Here, "polyfunctional" means the presence of three or more maleimide groups. Component (B) is preferably a maleimide resin having three or more N-substituted maleimide groups, and more preferably an aromatic maleimide resin having three or more N-substituted maleimide groups. The maleimide resin having three or more N-substituted maleimide groups preferably has an N-substituted maleimide group directly bonded to an aromatic ring, and more preferably has an N-substituted maleimide group in which the nitrogen atom of the maleimide group is directly bonded to an aromatic ring, and is preferably a maleimide resin represented by the following general formula (B-1): (In the formula, X ｂ－１ is a divalent hydrocarbon group having 1 to 20 carbon atoms (but not including an indane skeleton), and n ｂ－１ is an integer from 2 to 5.

[0025] X in the general formula (B-1) ｂ－１Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by include divalent aliphatic hydrocarbon groups such as alkylene groups having 1 to 5 carbon atoms and alkylidene groups having 2 to 5 carbon atoms, and divalent hydrocarbon groups containing an aromatic hydrocarbon group represented by the following general formula (B-2). However, in this embodiment, the divalent hydrocarbon group having 1 to 20 carbon atoms does not contain an indane skeleton. Examples of the alkylene group having 1 to 5 carbon atoms include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group. Examples of the alkylene group having 1 to 5 carbon atoms are preferably alkylene groups having 1 to 3 carbon atoms, more preferably alkylene groups having 1 or 2 carbon atoms, and even more preferably a methylene group. The alkylidene group having 2 to 5 carbon atoms is preferably an alkylidene group having 2 to 4 carbon atoms, more preferably an alkylidene group having 2 or 3 carbon atoms, and even more preferably an isopropylidene group.

[0026] (In the formula, Ar ｂ－１ is a divalent aromatic hydrocarbon group, and X ｂ－２ and X ｂ－３ are each independently a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms. * represents a bonding site.

[0027] Ar in the general formula (B-2) ｂ－１ Examples of the divalent aromatic hydrocarbon group represented by X include a phenylene group, a naphthylene group, a biphenylene group, and an anthranylene group. Of these, a biphenylene group is preferred. Examples of the biphenylene group include a 4,2'-biphenylene group, a 4,3'-biphenylene group, a 4,4'-biphenylene group, and a 3,3'-biphenylene group, and of these, a 4,4'-biphenylene group is preferred. ｂ－２ and X ｂ－３ The divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by X in the general formula (B-1) is ｂ－１ Examples of the alkylene group include the same alkylene groups having 1 to 5 carbon atoms and alkylidene groups having 2 to 5 carbon atoms as those mentioned above. Among these, a methylene group is preferred.

[0028] Among the above options, from the viewpoint of low thermal expansion, X in the general formula (B-1)ｂ－１ As the alkyl group, an aliphatic hydrocarbon group is preferable, an alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group is even more preferable.

[0029] n in the above general formula (B-1) ｂ－１ is an integer of 2 to 5, preferably an integer of 2 to 4, and more preferably 2 or 3.

[0030] (Content of Component (B)) The content of component (B) in the thermosetting resin composition of this embodiment is not particularly limited, but is preferably 5 to 60 parts by mass, more preferably 10 to 55 parts by mass, even more preferably 10 to 50 parts by mass, and particularly preferably 15 to 40 parts by mass, per 100 parts by mass of the resin components in the resin composition of this embodiment. When the content of component (B) is at least the lower limit, low thermal expansion tends to be improved, and when it is at most the upper limit, deterioration of adhesion to the conductor tends to be suppressed.

[0031] ((C) Maleimide Resin Containing No Indane Skeleton) The thermosetting resin composition of this embodiment contains, as component (C), a maleimide resin containing no indane skeleton. The inclusion of component (C) improves "adhesion to conductors," which tends to be reduced by component (B). In particular, the effect of improving adhesion to conductors with a small surface roughness Rz (e.g., Rz = 0.1 μm) is significant. Component (C) may be any maleimide resin that does not contain an indane skeleton and is different from component (B). However, component (C) is preferably an aromatic bismaleimide resin, that is, an aromatic bismaleimide resin containing no indane skeleton. Furthermore, from the viewpoint of adhesion to conductors, component (C) preferably contains an aliphatic hydrocarbon group, and more preferably contains an N-substituted maleimide group directly bonded to an aromatic ring substituted with the aliphatic hydrocarbon group. Furthermore, component (C) more preferably has two N-substituted maleimide groups, and even more preferably has two N-substituted maleimide groups directly bonded to an aromatic ring substituted with an aliphatic hydrocarbon group.

[0032] In addition, in view of adhesiveness to the conductor, it is also a preferred embodiment that the component (C) is a maleimide resin represented by the following general formula (C-1).

[0033] (In the formula, X ｃ１ is a group represented by the following general formula (C-1-1), (C-1-2) or (C-1-3):

[0034] (In the formula, R ｃ１ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ２ are each independently a halogen atom. p1 is an integer of 1 to 4. p2 is an integer of 0 to 3, provided that p1 + p2 ≦ 4.

[0035] (In the formula, R ｃ３ and R ｃ４ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ５ and R ｃ６ are each independently a halogen atom. At least one of q1 and q2 is an integer of 1 to 4, and the other is an integer of 0 to 4. q3 and q4 are each independently an integer of 0 to 3, provided that q1+q3≦4 and q2+q4≦4. X ｃ２ represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond.

[0036] (In the formula, R ｃ７ ~R ｃ１０ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ１１ ~R ｃ１４ are each independently a halogen atom. r1 to r4 are each independently an integer of 0 to 4, provided that at least one of r1 to r4 is an integer of 1 to 4. r5 to r8 are each independently an integer of 0 to 4, provided that r1+r5≦4, r2+r6≦4, r3+r7≦4, and r4+r8≦4. X ｃ３ is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond.

[0037] In the general formula (C-1-1), R ｃ１Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and an n-pentyl group. ｃ１ From the viewpoint of adhesiveness to the conductor, R is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group. ｃ２ Examples of the halogen atom represented by p1 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. p1 is an integer of 1 to 4, and from the viewpoint of availability, it is preferably an integer of 1 to 2, and more preferably 1. When p1 is an integer of 2 or more, a plurality of R ｃ１ p2 may be the same as or different from each other. p2 is an integer of 0 to 3, preferably 0 or 1, and more preferably 0. When p2 is an integer of 2 or more, a plurality of R ｃ２ They may be the same or different, provided that p1+p2≦4, and preferably p1+p2≦2.

[0038] In the general formula (C-1-2), R ｃ３ and R ｃ４ The aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R ｃ１ From the viewpoint of adhesiveness to a conductor, the aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group. ｃ５ and R ｃ６ The halogen atom represented by R ｃ２ At least one of q1 and q2 is an integer of 1 to 4, and the other is an integer of 0 to 4. q1 is preferably an integer of 1 to 2, more preferably 1. When q1 is an integer of 2 or more, a plurality of R ｃ３ q2 may be the same as or different from each other. q2 is preferably an integer of 1 to 4, more preferably an integer of 1 to 2, and even more preferably 1. When q2 is an integer of 2 or more, a plurality of R ｃ４q3 and q4 may be the same or different. q3 and q4 each independently represent an integer of 0 to 3, preferably 0 or 1, and more preferably 1. When q3 is an integer of 2 or more, a plurality of R ｃ５ When q4 is an integer of 2 or more, a plurality of R ｃ６ They may be the same or different, provided that q1+q3≦4, preferably q1+q3≦2, and q2+q4≦4, preferably q2+q4≦2.

[0039] In the general formula (c-1-2), X ｃ２ Examples of the alkylene group having 1 to 5 carbon atoms represented by X include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group. The alkylene group is preferably an alkylene group having 1 to 3 carbon atoms, and more preferably a methylene group. ｃ２ Examples of the alkylidene group having 2 to 5 carbon atoms represented by X include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group. Among these, an isopropylidene group is preferred. ｃ２ Among the above options, from the viewpoint of adhesion to a conductor, particularly from the viewpoint of the effect of improving adhesion to a conductor with a small surface roughness Rz (for example, Rz = 0.1 μm), the alkylene group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably a methylene group.

[0040] In the general formula (c-1-3), R ｃ７ ~R ｃ１０ The aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R ｃ１ The aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group. ｃ１１ ~R ｃ１４ The halogen atom represented by R ｃ２Examples include the same halogen atoms as those represented by the formula (1). r1 to r4 are each independently an integer of 0 to 4. However, at least one of r1 to r4 is an integer of 1 to 4, preferably 1 or 2, and more preferably 1. r5 to r8 are each independently an integer of 0 to 4, preferably 0 or 1. However, r1 + r5 ≦ 4, and preferably r1 + r5 ≦ 2. r2 + r6 ≦ 4, and preferably r2 + r6 ≦ 2. r3 + r7 ≦ 4, and preferably r3 + r7 ≦ 2. r4 + r8 ≦ 4, and preferably r4 + r8 ≦ 2.

[0041] In the general formula (c-1-3), X ｃ３ The alkylene group having 1 to 5 carbon atoms represented by X ｃ２ The alkylene group having 1 to 5 carbon atoms represented by X may be mentioned, and the preferred examples are also the same as those of the alkylene group having 1 to 5 carbon atoms represented by X. ｃ３ The alkylidene group having 2 to 5 carbon atoms represented by X ｃ２ The alkylidene group having 2 to 5 carbon atoms represented by X may be mentioned, and the preferred examples are also the same as those of the alkylidene group having 2 to 5 carbon atoms represented by X. ｃ３ Among the above options, alkylidene groups having 2 to 5 carbon atoms are preferred, and isopropylidene groups are more preferred.

[0042] In particular, from the viewpoint of improving the adhesiveness to a conductor having a small surface roughness Rz (for example, Rz=0.1 μm), ｃ１ is preferably a group represented by the general formula (C-1-2).

[0043] As component (C), a maleimide resin represented by the following structural formula is particularly preferred from the viewpoint of improving adhesion to a conductor with a small surface roughness Rz (for example, Rz=0.1 μm).

[0044] (Content of Component (C)) The content of component (C) in the thermosetting resin composition of this embodiment is not particularly limited, but is preferably 1 to 40 parts by mass, more preferably 2 to 35 parts by mass, even more preferably 3 to 30 parts by mass, and particularly preferably 5 to 25 parts by mass, relative to 100 parts by mass of the resin component in the resin composition of this embodiment, and may be 10 to 25 parts by mass, 15 to 25 parts by mass, or even 5 to 20 parts by mass. When the content of component (C) is equal to or greater than the lower limit, adhesion to the conductor and dielectric constant (Dk) tend to be excellent, and when the content is equal to or less than the upper limit, an increase in dielectric constant (Dk) tends to be suppressed.

[0045] (D) Crosslinking Agent The thermosetting resin composition of this embodiment may further contain a (D) crosslinking agent (hereinafter, sometimes referred to as component (D)). When the thermosetting resin composition contains component (D), compatibility with each component tends to be improved and the dielectric constant (Dk) tends to be further reduced. Examples of component (D) include polyphenylene ether, modified polyphenylene ether, conjugated diene polymer, modified conjugated diene polymer, etc., and among these, modified conjugated diene polymer is preferred. Examples of modified polyphenylene ether include compounds in which a functional group has been introduced into polyphenylene ether. Examples of the functional group include amino group, epoxy group, carboxyl group, styryl group, acrylic group, and methacrylic group. Among these, from the viewpoint of dielectric constant (Dk) and compatibility, acrylic group and methacrylic group are preferred, and methacrylic group is more preferred. In other words, as the modified polyphenylene ether, methacrylic-modified polyphenylene ether is preferred. The modified polyphenylene ether may have the functional group at the end of the polymer chain or inside the polymer chain, but it is preferable that the functional group be at the end of the polymer chain, and more preferably at both ends of the polymer chain.

[0046] Furthermore, examples of the conjugated diene compound that is a monomer component of the conjugated diene polymer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, etc. The conjugated diene polymer may be a polymer of one type of conjugated diene compound, or a copolymer of two or more types of conjugated diene compounds.

[0047] The conjugated diene polymer is preferably a conjugated diene polymer having a vinyl group in a side chain from the viewpoints of compatibility with other resins and dielectric constant (Dk). The number of side chain vinyl groups that the conjugated diene polymer has in one molecule is not particularly limited, but from the viewpoints of compatibility with other resins and dielectric constant (Dk), it is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. The upper limit of the number of side chain vinyl groups that the conjugated diene polymer has in one molecule is not particularly limited, but it may be, for example, 100 or less, 80 or less, or 60 or less.

[0048] Examples of conjugated diene polymers include polybutadiene having a vinyl group and polyisoprene having a vinyl group. Among these, from the viewpoints of dielectric constant (Dk) and heat resistance, polybutadiene having a vinyl group is preferred, and polybutadiene having a 1,2-vinyl group derived from 1,3-butadiene is more preferred. Furthermore, as polybutadiene having a 1,2-vinyl group derived from 1,3-butadiene, polybutadiene homopolymer having a 1,2-vinyl group derived from 1,3-butadiene is preferred. The 1,2-vinyl group derived from 1,3-butadiene contained in the conjugated diene polymer is a vinyl group contained in a structural unit represented by the following formula (d1):

[0049]

[0050] When the conjugated diene polymer is a polybutadiene having a 1,2-vinyl group, the content of structural units having a 1,2-vinyl group relative to all structural units derived from butadiene constituting the polybutadiene [hereinafter, sometimes referred to as the "vinyl group content"] is not particularly limited, but from the viewpoints of compatibility with other resins, dielectric constant (Dk), and heat resistance, it is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more. There is also no particular upper limit to the vinyl group content, and it may be 100 mol% or less, 95 mol% or less, or even 90 mol% or less. As the structural unit having a 1,2-vinyl group, a structural unit represented by the above formula (d1) is preferred. From the same viewpoint, the polybutadiene having a 1,2-vinyl group is preferably a 1,2-polybutadiene homopolymer.

[0051] The number average molecular weight (Mn) of the conjugated diene polymer is not particularly limited, but from the viewpoints of compatibility with other resins, dielectric constant (Dk) and heat resistance, it is preferably 400 to 3,000, more preferably 600 to 2,000, and even more preferably 800 to 1,500.

[0052] The modified conjugated diene polymer is a polymer obtained by modifying the conjugated diene polymer. By including the modified conjugated diene polymer, the thermosetting resin composition of the present embodiment tends to have good heat resistance and low thermal expansion, while also easily achieving an excellent dielectric constant (Dk).

[0053] As the modified conjugated diene polymer, from the viewpoints of compatibility with other resins, dielectric constant (Dk) and conductor adhesion, a modified conjugated diene polymer obtained by modifying a conjugated diene polymer having a vinyl group in a side chain with a maleimide compound having two or more N-substituted maleimide groups is preferred.

[0054] As the conjugated diene polymer having a vinyl group in a side chain, for example, those described above for the conjugated diene polymer can be used, and preferred embodiments are also the same. The conjugated diene polymer having a vinyl group in a side chain may be used alone or in combination of two or more.

[0055] As the maleimide compound having two or more N-substituted maleimide groups, for example, any of the maleimide compounds having two or more N-substituted maleimide groups described above for the maleimide compound of component (A) can be used, and preferred embodiments are also the same. Examples of maleimide compounds having two or more N-substituted maleimide groups include aliphatic hydrocarbon group-containing maleimides such as N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, bis(4-maleimidocyclohexyl)methane, and 1,4-bis(maleimidomethyl)cyclohexane; N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, and bis(

[0033] Examples of aromatic hydrocarbon group-containing maleimides include bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, 1,3-bis(4-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, and polyphenylmethane maleimide. Among these, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide is more preferred. The maleimide compound having two or more N-substituted maleimide groups may be used alone or in combination of two or more.

[0056] The modified conjugated diene polymer preferably has a substituent in its side chain formed by a reaction between a side-chain vinyl group of a conjugated diene polymer having a vinyl group in its side chain and an N-substituted maleimide group of a maleimide compound having two or more N-substituted maleimide groups [hereinafter, this may be referred to as a "maleimide compound-derived substituent"]. From the viewpoints of compatibility with other resins, dielectric constant (Dk), low thermal expansion, and heat resistance, the maleimide compound-derived substituent is preferably a group containing a structure represented by the following general formula (d2) or (d3), as a structure derived from a maleimide compound having two or more N-substituted maleimide groups:

[0057] (In the formula, X ｄ１ is a divalent group obtained by removing two N-substituted maleimide groups from a maleimide compound having two or more N-substituted maleimide groups, and * ｄ１ is a bonded site to a carbon atom derived from a vinyl group in a side chain of a conjugated diene polymer having a vinyl group in the side chain. ｄ２ is the site of attachment to another atom.)

[0058] The modified conjugated diene polymer preferably has a maleimide compound-derived substituent and a vinyl group in a side chain, and the vinyl group in the modified conjugated diene polymer is preferably a 1,2-vinyl group derived from 1,3-butadiene.

[0059] The number average molecular weight (Mn) of the modified conjugated diene polymer is not particularly limited, but from the viewpoints of compatibility with other resins, dielectric constant (Dk), low thermal expansion, and heat resistance, it is preferably 700 to 6,000, more preferably 800 to 5,000, and even more preferably 1,000 to 2,500.

[0060] The modified conjugated diene polymer can be produced by reacting a conjugated diene polymer having a vinyl group in the side chain with a maleimide compound having two or more N-substituted maleimide groups. The method for reacting a conjugated diene polymer having a vinyl group in the side chain with a maleimide compound having two or more N-substituted maleimide groups is not particularly limited. For example, a modified conjugated diene polymer can be obtained by charging a conjugated diene polymer having a vinyl group in the side chain, a maleimide compound having two or more N-substituted maleimide groups, a reaction catalyst, and an organic solvent into a reaction vessel and reacting the mixture while heating, keeping the temperature, stirring, etc., as necessary.

[0061] When the above reaction is carried out, the number of moles of the side chain vinyl groups of the conjugated diene polymer having vinyl groups in the side chains (M ｖ ) the number of moles of N-substituted maleimide groups contained in a maleimide compound having two or more N-substituted maleimide groups relative to the number of moles (M ｍ ) ratio (M ｍ / M ｖ ) is not particularly limited, but is preferably 0.001 to 0.5, more preferably 0.005 to 0.1, and even more preferably 0.008 to 0.05, from the viewpoints of compatibility of the resulting modified conjugated diene polymer with other resins and suppression of gelation of the product during the reaction.

[0062] (Content of Component (D)) When the thermosetting resin composition of this embodiment contains component (D), the content of component (D) in the thermosetting resin composition is not particularly limited, but from the viewpoints of dielectric constant (Dk) and compatibility, it is preferably 1 to 40 mass%, more preferably 3 to 30 mass%, even more preferably 5 to 25 mass%, particularly preferably 5 to 20 mass%, and most preferably 8 to 15 mass%, relative to the total amount of resin components of the thermosetting resin composition. When the content of component (D) is equal to or greater than the lower limit, the dielectric constant (Dk) and compatibility tend to be good. When the content of component (D) is equal to or less than the upper limit, the heat resistance, moldability, and processability tend to be good.

[0063] (E) Inorganic Filler) By incorporating an inorganic filler (E) [hereinafter, sometimes referred to as component (E)] into the thermosetting resin composition of this embodiment, the thermal expansion coefficient, heat resistance, and flame retardancy tend to be improved. The component (E) is not particularly limited, but examples thereof include silica, alumina, titanium oxide, mica, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay (e.g., calcined clay), molybdic acid compounds (e.g., zinc molybdate), talc, aluminum borate, and silicon carbide. One type of component (E) may be used alone, or two or more types may be used in combination. Among these, from the viewpoints of thermal expansion coefficient, heat resistance, and flame retardancy, silica, alumina, mica, and talc are preferred, silica and alumina are more preferred, and silica is even more preferred. Examples of silica include crushed silica, fumed silica, and fused silica (fused spherical silica).

[0064] The shape and particle size of component (E) are not particularly limited, but the particle size is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm. Here, particle size refers to the average particle size, and is the particle size at the point corresponding to 50% volume when a cumulative frequency distribution curve of particle sizes is calculated, with the total volume of particles being 100%. The particle size of component (E) can be measured using a particle size distribution analyzer using a laser diffraction scattering method, for example.

[0065] (Content of Component (E)) When the thermosetting resin composition of the present embodiment contains the component (E), the content of the component (E) in the thermosetting resin composition is not particularly limited, but from the viewpoints of the thermal expansion coefficient, heat resistance, and flame retardancy, it is preferably 1 to 50 vol%, more preferably 3 to 30 vol%, even more preferably 5 to 20 vol%, and particularly preferably 5 to 15 vol%, relative to the total solid content of the thermosetting resin composition.

[0066] Furthermore, when component (E) is used, a coupling agent may be used in combination, if necessary, to improve the dispersibility of component (E) and the adhesion between component (E) and the organic components in the thermosetting resin composition. The coupling agent is not particularly limited, and, for example, a silane coupling agent or a titanate coupling agent may be appropriately selected and used. One coupling agent may be used alone, or two or more coupling agents may be used in combination. The amount of coupling agent used is also not particularly limited. When a coupling agent is used, a so-called integral blending method may be used in which the coupling agent is added after blending component (E) into the thermosetting resin composition. However, a method in which an inorganic filler is previously surface-treated with a coupling agent by dry or wet processing is preferred. By employing this method, the characteristics of component (E) can be more effectively expressed.

[0067] When the component (E) is used in this embodiment, in order to improve the dispersibility of the component (E) in the thermosetting resin composition, the component (E) may be used as a slurry in which the component (E) is dispersed in an organic solvent in advance, as needed. Examples of the organic solvent include the same organic solvents as those described below.

[0068] ((F) Curing Accelerator) Examples of the (F) curing accelerator [hereinafter, sometimes referred to as component (F)] include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, organometallic salts, acidic catalysts, and organic peroxides. In the present disclosure, imidazole-based curing accelerators are not classified as amine-based curing accelerators. One type of curing accelerator may be used alone, or two or more types may be used in combination. The curing accelerator preferably includes at least one selected from the group consisting of imidazole-based curing accelerators and organic peroxides. Examples of the imidazole-based curing accelerator include imidazole compounds such as methylimidazole, phenylimidazole, and 2-undecylimidazole; and isocyanate-masked imidazoles such as an addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole. Examples of the organic peroxide include dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, and α,α'-bis(t-butylperoxy)diisopropylbenzene.

[0069] (Content of (F) Curing Accelerator) When the thermosetting resin composition of the present embodiment contains the component (F), the content of the component (F) is not particularly limited, but in any case, it is preferably 0.01 to 3 parts by mass, more preferably 0.05 to 2.5 parts by mass, still more preferably 0.1 to 2.5 parts by mass, and particularly preferably 0.5 to 2.5 parts by mass, relative to 100 parts by mass of the resin components in the thermosetting resin composition. When the content of the (F) curing accelerator is within the above range, better heat resistance, storage stability, and moldability tend to be obtained.

[0070] (Other Components) The thermosetting resin composition of the present embodiment preferably further contains one or more other components selected from the group consisting of flame retardants, flame retardant aids, antioxidants, adhesion improvers, heat stabilizers, antistatic agents, UV absorbers, pigments, colorants, and lubricants. Components other than those described above may also be contained. When the thermosetting resin composition of the present embodiment contains these other components (flame retardants, flame retardant aids, antioxidants, adhesion improvers, heat stabilizers, antistatic agents, UV absorbers, pigments, colorants, lubricants, and other components), the content of each of these components is not particularly limited, and may be, for example, 0.01 parts by mass or more, 10 parts by mass or less, 5 parts by mass or less, 1 part by mass or less, or none at all, relative to 100 parts by mass of the resin components in the thermosetting resin composition.

[0071] (Organic Solvent) The thermosetting resin composition of this embodiment may be a so-called "varnish" containing an organic solvent from the viewpoint of ease of handling and ease of production of the prepreg or resin film described below. The organic solvent is not particularly limited, but examples thereof include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone. From the viewpoint of solubility, ketone-based solvents are preferred, and methyl ethyl ketone is more preferred. The organic solvent may be used alone or in combination of two or more.

[0072] When the thermosetting resin composition of this embodiment is used as a varnish, the solids concentration is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 60% by mass. When the solids concentration of the thermosetting resin composition is within this range, the thermosetting resin composition is easy to handle, the impregnation into a substrate and the appearance of the produced prepreg are good, and the coatability when made into a resin film is also good.

[0073] The thermosetting resin composition of this embodiment can be produced by mixing components (A) to (C) and the other optional components using a known method. In this process, each component may be dissolved or dispersed in the organic solvent while stirring. The mixing order, temperature, time, and other conditions are not particularly limited and can be set as desired.

[0074] [Prepreg] The prepreg of this embodiment is a prepreg containing the thermosetting resin composition of this embodiment or a semi-cured product of the thermosetting resin composition. The prepreg of this embodiment contains, for example, the thermosetting resin composition of this embodiment or a semi-cured product of the thermosetting resin composition and a sheet-like fiber substrate. The prepreg is formed using the thermosetting resin composition of this embodiment or a resin film described below and a sheet-like fiber substrate. For example, the prepreg can be obtained by impregnating a sheet-like fiber substrate with the thermosetting resin composition of this embodiment or a resin film described below, followed by heating and drying to semi-cure (B-staging) as needed. More specifically, the prepreg of this embodiment can be produced by, for example, heating and drying in a drying oven, typically at 80 to 200°C for 1 to 30 minutes to semi-cure (B-staging). Here, in this disclosure, B-staging refers to achieving a B-stage state as defined in JIS K6900 (1994). The amount of the thermosetting resin composition used can be appropriately determined so that the solid content concentration of the thermosetting resin composition in the dried prepreg is 30 to 90 mass %. By setting the solid content concentration within this range, better moldability tends to be obtained when the prepreg is made into a laminate.

[0075] As the sheet-like fiber substrate for the prepreg, known materials used in various laminates for electrical insulating materials are used. Examples of materials for the sheet-like fiber substrate include inorganic fibers such as E-glass, D-glass, S-glass, and Q-glass; organic fibers such as polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. These sheet-like fiber substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat. The thickness of the sheet-like fiber substrate is not particularly limited, but may be 1 to 100 μm, 3 to 70 μm, or 5 to 35 μm.

[0076] [Resin Film] The resin film of this embodiment is a resin film containing the thermosetting resin composition of this embodiment or a semi-cured product of the thermosetting resin composition. The resin film of this embodiment can be produced, for example, by applying a thermosetting resin composition containing an organic solvent, i.e., a varnish, to a support, drying it by heating, and semi-curing (B-staging) as needed. The thickness of the resin film is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 70 μm, and even more preferably 5 to 35 μm. Examples of the support include plastic film, metal foil, and release paper. The drying temperature and drying time can be determined appropriately depending on the amount of organic solvent used, the boiling point of the organic solvent, and the like. However, a resin film can be suitably formed by drying at 50 to 200°C for about 1 to 10 minutes.

[0077] [Laminate] The laminate of this embodiment is a laminate having a cured product of the thermosetting resin composition of this embodiment or a cured product of the prepreg of this embodiment and a metal foil. The laminate of this embodiment can be produced, for example, by placing a metal foil on one or both sides of a single prepreg of this embodiment, or by placing a metal foil on one or both sides of a laminate obtained by stacking two or more prepregs of this embodiment, and then hot-pressing and molding. In the laminate obtained by this production method, the prepreg of this embodiment is C-staged. In this disclosure, C-staging refers to bringing the prepreg into a C-stage state as defined in JIS K6900 (1994). Note that a laminate having a metal foil is sometimes referred to as a metal-clad laminate. The metal of the metal foil is not particularly limited, but from the viewpoint of electrical conductivity, it may be copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing one or more of these metal elements. Copper and aluminum are preferred, and copper is more preferred. The method for carrying out hot-press molding is not particularly limited, but may be carried out, for example, under conditions of a temperature of 100 to 300°C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. Alternatively, hot-press molding may be carried out using a vacuum press or the like to maintain a vacuum state for 0.5 to 5 hours.

[0078] [Printed Wiring Board] The printed wiring board of this embodiment has one or more selected from the group consisting of a cured product of the thermosetting resin composition of this embodiment, a cured product of the prepreg of this embodiment, and a laminate of this embodiment. The printed wiring board of this embodiment can be manufactured by performing circuit formation processing such as drilling, metal plating, and etching of metal foil using one or more selected from the group consisting of the prepreg of this embodiment, the resin film of this embodiment, and the laminate of this embodiment by a known method. Furthermore, a multilayer printed wiring board can also be manufactured by further performing multilayer adhesive processing as necessary. In the printed wiring board of this embodiment, the prepreg of this embodiment and the resin film of this embodiment are C-staged.

[0079] [Semiconductor Package] The semiconductor package of this embodiment is a semiconductor package including the printed wiring board of this embodiment and a semiconductor element. The semiconductor package of this embodiment can be manufactured by mounting a semiconductor element such as a semiconductor chip or memory at a predetermined position on the printed wiring board of this embodiment and sealing the semiconductor element with a sealing resin or the like.

[0080] The resin composition, prepreg, resin film, laminate, printed wiring board, and semiconductor package of the present embodiment can be suitably used in electronic devices that handle high-frequency signals of 10 GHz or more. In particular, the printed wiring board is useful as a printed wiring board for millimeter-wave radar.

[0081] Although preferred embodiments have been described above, these are merely examples for the purpose of explaining the present disclosure, and the scope of the present disclosure is not intended to be limited to these embodiments. The present disclosure also includes various aspects that differ from the above-described embodiments without departing from the gist of the present disclosure.

[0082] The present embodiment will be specifically described below with reference to examples, but the present embodiment is not limited to the following examples.

[0083] In each example, the number average molecular weight (Mn) was measured by the following method. (1. Method for measuring number average molecular weight (Mn)) The number average molecular weight was calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, trade name]. The GPC measurement conditions are shown below. Apparatus: Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation] Detector: L-3300 type RI [manufactured by Hitachi High-Technologies Corporation] Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation] Column: Guard column; TSK Guard column HHR-L + column; TSKgel G4000HHR + TSKgel G2000HHR (all product names manufactured by Tosoh Corporation) Column size: 6.0 x 40 mm (guard column), 7.8 x 300 mm (column) Eluent: tetrahydrofuran Sample concentration: 30 mg / 5 mL Injection volume: 20 μL Flow rate: 1.00 mL / min Measurement temperature: 40°C

[0084] Production Example 1 (Production of Modified Conjugated Diene Polymer D-1) Components (d1) and (d2), an organic peroxide, and toluene as an organic solvent in the amounts shown in Table 1 were placed in a 2 L glass flask equipped with a thermometer, a reflux condenser, and a stirrer, and the mixture was allowed to react with stirring at 90 to 100°C for 5 hours in a nitrogen atmosphere to obtain a liquid containing modified conjugated diene polymer D-1 (toluene diluted solution, solids concentration: 35% by mass). The vinyl group modification rate and number average molecular weight of the obtained modified conjugated diene polymer D-1 are shown in Table 1.

[0085] The details of each component listed in Table 1 are as follows: [Component (d1)] Polybutadiene 1: 1,2-polybutadiene homopolymer, number average molecular weight = 1,200, vinyl group content = 85% or more [Component (d2)] Bismaleimide compound 1: 4,4'-diphenylmethane bismaleimide [Reaction catalyst] Organic peroxide: α,α'-bis(t-butylperoxy)diisopropylbenzene

[0086] [Examples 1 to 4, Comparative Examples 1 and 2] A thermosetting resin composition (varnish) having a solid content concentration of 55% by mass was prepared by mixing and stirring at room temperature the components shown in Table 2 together with methyl ethyl ketone in the amounts shown in Table 2. The varnish obtained above was applied to a 15 μm thick glass woven fabric (NE Glass, manufactured by Asahi Kasei Corporation) and then heated and dried at 130° C. for 3 minutes to produce a prepreg having a solid content derived from the thermosetting resin composition of approximately 75% by mass. On the top and bottom of this prepreg, a 12 μm thick low-profile copper foil (3M-VLP12, manufactured by Mitsui Mining & Smelting Co., Ltd.; the "VLP" is a registered trademark) was placed so that the M side (matte side; Rz = 3.0 μm) or S side (shine side; roughened using "MEC Etch Bond CZ-8101" (manufactured by MEC Co., Ltd.) to achieve Rz = 0.1 μm) was in contact with the prepreg, and then heated and pressurized at a temperature of 230 ° C, a pressure of 3.0 MPa, and a time of 90 minutes to produce double-sided copper-clad laminate 1 (thickness: 0.30 mm) and double-sided copper-clad laminate 2 (thickness: 0.30 mm). The surface roughness (Rz) was determined as follows. First, a roughness curve was obtained by measurement using a shape analysis laser microscope "VK-X250" (manufactured by Keyence Corporation). A reference length was cut from the obtained roughness curve in the direction of the mean line, and in this cut section, the sum of the average value of the absolute values ​​of the elevations of the five highest peaks and the five lowest valleys was calculated, using the mean line as the reference. The value thus obtained and the unit of micrometers (μm) were used to define Rz. Using the double-sided copper-clad laminate 1 or double-sided copper-clad laminate 2 obtained in each example, evaluations were carried out according to the following methods. The results are shown in Table 2.

[0087] [Evaluation of Double-Sided Copper-Clad Laminates] (1. Dielectric Constant (Dk)) The outer layer copper foil of the double-sided copper-clad laminate 1 obtained in each example was removed by immersion in a copper etching solution (a 10% by mass solution of ammonium persulfate, manufactured by Mitsubishi Gas Chemical Company, Inc.), and the laminate was cut into a length of 60 mm and a width of 2 mm. The dielectric constant (Dk) was measured by a cavity resonator perturbation method. The measuring instrument used was an Agilent Technologies vector network analyzer "N5222B," the cavity resonator "CP129" (10 GHz band resonator) manufactured by Kanto Electronics Application Development Co., Ltd., and the measurement program "CPMA-V2." The measurement was performed at a frequency of 10 GHz and a measurement temperature of 25°C.

[0088] (2. Thermal Expansion Coefficient) After etching to remove the copper foil on both sides of the double-sided copper-clad laminate 1 obtained in each example, a 5 mm square test piece was prepared. Next, the thermal expansion coefficient of the test piece was measured using a thermomechanical analyzer (TMA) (manufactured by TA Instruments Japan, product name: Q400) in accordance with the IPC (The Institute for Interconnecting and Packaging Electronic Circuits) standard, and evaluated according to the following evaluation criteria. More specifically, measurements were performed twice in the temperature range of 50 to 280°C under conditions of a load of 0.05 N and a heating rate of 10°C / min, and the thermal expansion coefficient was taken as the average thermal expansion coefficient of the second measurement. The thermal expansion coefficient was the thermal expansion coefficient in the thickness direction of the test piece. A: The thermal expansion coefficient was 80 ppm / °C or less. B: The thermal expansion coefficient was greater than 80 ppm / °C and less than 95 ppm / °C. C: The thermal expansion coefficient was greater than 95 ppm / °C.

[0089] (3. Adhesion to Conductor) Peel strength was measured using Shimadzu Corporation's "EZ-Test / CE" according to the following method. The copper foil of the double-sided copper-clad laminate 1 or 2 obtained in each example was etched into a 3 mm wide straight line, and then dried at 105°C / hr to prepare a test specimen. Using the test specimen, the copper foil was peeled off in a 90° direction in accordance with JIS C6481 (1996), to measure the peel strength, which was used as an index of adhesion to the conductor. The pulling speed was 50 mm / min. A peel strength of 4.5 kN / m or more, and even 5.0 kN / m or more, can be said to be excellent adhesion to the conductor.

[0090]

[0091] Details of each component listed in Table 2 are as follows: [Component (A)] Maleimide resin containing an indane skeleton: an aromatic bismaleimide resin containing an indane skeleton represented by the following general formula: (In the above formula, the definitions of each group are as described above.)

[0092] [Component (B)] Polyfunctional maleimide resin: a polyfunctional maleimide resin represented by the following structural formula: (In the formula, n ｂ－１ is an integer from 2 to 5.

[0093] [Component (C)] Maleimide resin C-1 not containing an indane skeleton; a bismaleimide resin represented by the following structural formula:

[0094] Maleimide resin C-2 not containing an indane skeleton: a bismaleimide resin represented by the following structural formula: (In the formula, X ｃ１ is a group represented by the general formula (C-1-2) or (C-1-3). [Component (D)] Crosslinking agent: modified conjugated diene polymer D-1 obtained in Production Example 1

[0095] [(E) Inorganic filler] Inorganic filler: spherical fused silica, average particle size = 0.5 μm

[0096] [(F) Curing Accelerator] Imidazole-based curing accelerator E-1: Isocyanate masked imidazole "G8009L" (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) Organic peroxide E-2: α,α'-bis(t-butylperoxy)diisopropylbenzene

[0097] The results in Table 2 show that the cured products of the thermosetting resin compositions (Examples 1 to 4) containing all of the components (A) to (C) achieved low dielectric constants, low thermal expansion, and high adhesion to conductors. In particular, adhesion to conductors when the conductor surface roughness Rz was 0.1 μm was significantly improved compared to Comparative Example 2, indicating significant improvement in adhesion between the inner layer circuit and the insulating layer. On the other hand, the cured product of the thermosetting resin composition (Comparative Example 1) that did not contain components (B) and (C) failed to achieve low thermal expansion. Furthermore, the cured product of the thermosetting resin composition (Comparative Example 2) that contained components (A) and (B) but not component (C) achieved low thermal expansion, but exhibited reduced adhesion to conductors compared to Example 2, which contained the same total amount of maleimide resin.

Claims

1. A thermosetting resin composition comprising: (A) a maleimide resin having an indane skeleton; (B) a polyfunctional maleimide resin; and (C) a maleimide resin not having an indane skeleton.

2. The thermosetting resin composition according to claim 1, wherein the component (A) is a bismaleimide resin containing an indane skeleton.

3. The thermosetting resin composition according to claim 1, wherein the component (B) is an aromatic maleimide resin having three or more N-substituted maleimide groups.

4. The thermosetting resin composition according to claim 1, wherein the component (B) is a maleimide resin represented by the following general formula (B-1): (In the formula, X ｂ－１ is a divalent hydrocarbon group having 1 to 20 carbon atoms (but not including an indane skeleton), ｂ－１ is an integer from 2 to 5.

5. The thermosetting resin composition according to claim 1, wherein the component (C) has an aliphatic hydrocarbon group.

6. The thermosetting resin composition according to claim 1, wherein said component (C) has an N-substituted maleimide group directly bonded to an aromatic ring substituted with an aliphatic hydrocarbon group.

7. The thermosetting resin composition according to claim 1, wherein the component (C) is a maleimide resin represented by the following general formula (C-1): (In the formula, X ｃ１ is a group represented by the following general formula (C-1-1), (C-1-2) or (C-1-3). (In the formula, R ｃ１ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ２ are each independently a halogen atom. p1 is an integer of 1 to 4. p2 is an integer of 0 to 3, provided that p1+p2≦4. (In the formula, R ｃ３ and R ｃ４ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ５ and R ｃ６ are each independently a halogen atom. At least one of q1 and q2 is an integer of 1 to 4, and the other is an integer of 0 to 4. q3 and q4 are each independently an integer of 0 to 3, provided that q1+q3≦4 and q2+q4≦4. X ｃ２ is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. (In the formula, R ｃ７ ~R ｃ１０ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ｃ１１ ~R ｃ１４ are each independently a halogen atom. r1 to r4 are each independently an integer of 0 to 4, provided that at least one of r1 to r4 is an integer of 1 to 4. r5 to r8 are each independently an integer of 0 to 4, provided that r1+r5≦4, r2+r6≦4, r3+r7≦4, and r4+r8≦4. X ｃ３ is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond.

8. The thermosetting resin composition according to claim 1, further comprising (D) a crosslinking agent.

9. The thermosetting resin composition according to claim 1, further comprising (E) an inorganic filler.

10. The thermosetting resin composition according to claim 1, further comprising (F) a curing accelerator.

11. A prepreg comprising the thermosetting resin composition according to claim 1 or a semi-cured product of said thermosetting resin composition.

12. A resin film comprising the thermosetting resin composition according to claim 1 or a semi-cured product of said thermosetting resin composition.

13. A laminate comprising a cured product of the thermosetting resin composition according to claim 1 and a metal foil.

14. A printed wiring board having a cured product of the thermosetting resin composition according to claim 1.

15. A semiconductor package comprising the printed wiring board according to claim 14 and a semiconductor element.

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