Resin composition, prepreg, layered sheet, printed circuit board, and semiconductor package

Abstract

The present invention provides: a resin composition containing (A) a thermosetting resin, (B) an inorganic filler having a true density of no greater than 1,500 kg / m3, and (C) an inorganic filler having a true density exceeding 1,500 kg / m3; a prepreg that includes the resin composition; a layered sheet; a printed circuit board; and a semiconductor package.

Description

Resin composition, prepreg, laminate, printed wiring board, and semiconductor package

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

[0002] In electronic devices such as mobile communication devices typified by mobile phones, their base station equipment, servers, routers and other network infrastructure devices, and mainframe computers, the speed and capacity of the signals they use are increasing year by year. Accordingly, the substrate materials for the printed wiring boards used in these electronic devices are required to have dielectric properties (hereinafter sometimes referred to as "high-frequency properties") that can reduce transmission loss of high-frequency signals, i.e., low dielectric constants.

[0003] For example, Patent Document 1 discloses a resin composition as a substrate material capable of achieving low transmission loss, which contains one or more compounds (A) selected from the group consisting of maleimide compounds having at least two N-substituted maleimide groups and derivatives thereof, one or more compounds (B) selected from the group consisting of polyphenylene ethers and derivatives thereof, and a copolymer (C) having structural units derived from a styrene-based compound, structural units derived from maleic anhydride, and structural units derived from an N-substituted maleimide.

[0004] Japanese Patent Application Laid-Open No. 2020-169276

[0005] According to the technology of Patent Document 1, it is possible to exhibit excellent dielectric properties in a high frequency band of 10 GHz or higher. However, in recent years, there has been an increasing demand for a lower relative dielectric constant, and a technology to achieve this is needed.

[0006] In build-up manufacturing technology, via holes for interlayer connection are sometimes formed in metal-clad laminates, which are laminates of insulating layers and metal foils, using a laser process. However, according to the inventors' research, it has been found that when via holes are formed in metal-clad laminates using resin compositions with a low dielectric constant, the metal foil around the via holes may blister or peel. Therefore, it is necessary to achieve both a good dielectric constant (Dk) and the prevention of blistering or peeling of the metal foil during laser processing (hereinafter also referred to as "laser processability").

[0007] In view of the current situation, an object of the present embodiment is to provide a resin composition excellent in relative dielectric constant (Dk) and laser processability, and a prepreg, a laminate, a resin film, a printed wiring board, and a semiconductor package using the resin composition.

[0008] That is, this embodiment provides the following [1] to

[12] : [1] (A) a thermosetting resin and (B) a polymer having a true density of 1,500 kg / m ３ (C) a true density of 1,500 kg / m ３ and an inorganic filler of more than 100% by mass. [2] The resin composition according to the above item [1], wherein the component (B) is a particle having a siloxane bond. [3] The resin composition according to the above item [1] or [2], wherein the content of the component (B) is 1 to 30% by mass relative to the total solid content (100% by mass) of the resin composition. [4] The resin composition according to any one of the above items [1] to [3], wherein the component (C) is silica. [5] The resin composition according to any one of the above items [1] to [4], wherein the content of the component (C) is 2 to 40% by mass relative to the total solid content (100% by mass) of the resin composition. [6] The resin composition according to any one of the above items [1] to [4], wherein the content of the component (C) is 2 to 40% by mass relative to the total solid content (100% by mass) of the resin composition. [6] The difference between the true density of the component (B) and the true density of the component (C) [true density of the component (C) - true density of the component (B)] is 400 to 1,000 kg / m ３The resin composition according to any one of [1] to [5] above, wherein the component (A) is at least one selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives of the maleimide resin. [8] A prepreg containing the resin composition according to any one of [1] to [7] above or a semi-cured product of the resin composition. [9] A laminate having a cured product of the resin composition according to any one of [1] to [7] above and a metal foil.

[10] A resin film containing the resin composition according to any one of [1] to [7] above or a semi-cured product of the resin composition.

[11] A printed wiring board having a cured product of the resin composition according to any one of [1] to [7] above.

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

[11] above and a semiconductor element.

[0009] According to the present embodiment, it is possible to provide a resin composition excellent in relative dielectric constant (Dk) and laser processability, and a prepreg, a laminate, a resin film, a printed wiring board, and a semiconductor package using the resin composition.

[0010] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. For example, a numerical range "X to Y" (X and Y are real numbers) means a numerical range that is equal to or greater than X and equal to or less than Y. In this specification, the term "X or greater" means X and a numerical value that exceeds X. In addition, the term "Y or less" in this specification means Y and a numerical value that is less than Y. The lower limit and upper limit of a numerical range described in this specification can be arbitrarily combined with the lower limit or upper limit of another numerical range. In the numerical ranges described in this specification, the lower limit or upper limit of that numerical range may be replaced with a value shown in the examples.

[0011] Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, when a resin composition contains a plurality of substances corresponding to each component, the content of each component in the resin composition means the total amount of the plurality of substances present in the resin composition, unless otherwise specified.

[0012] In this specification, the term "solid content" refers to components other than the solvent, and components that are liquid at 25°C are also considered to be solid content.

[0013] The number average molecular weight (Mn) in this specification refers to a value measured in terms of polystyrene by gel permeation chromatography (GPC). Specifically, the number average molecular weight (Mn) in this specification can be measured by the method described in the examples.

[0014] In this specification, the term "semi-cured product" is synonymous with a resin composition in a B-stage state according to JIS K 6800 (2006), and the term "cured product" is synonymous with a resin composition in a C-stage state according to JIS K 6800 (2006).

[0015] The mechanism of action described in this specification is speculation and does not limit the mechanism by which the effects of this embodiment are achieved.

[0016] Any combination of the features described in this specification is also included in this embodiment.

[0017] [Resin Composition] The resin composition of the present embodiment comprises (A) a thermosetting resin and (B) a polymer having a true density of 1,500 kg / m ３ (C) a true density of 1,500 kg / m ３ and an inorganic filler of more than 100%. In this specification, each component may be abbreviated as component (A), component (B), etc., and the other components may be abbreviated in the same manner.

[0018] The reason why the resin composition of this embodiment has excellent relative dielectric constant (Dk) and laser processability is not clear, but is presumed to be as follows: The component (B) contained in the resin composition of this embodiment has a true density of 1,500 kg / m ３ or less, which provides a large amount of space at the molecular level, and it is presumed that this is one of the reasons why the dielectric constant (Dk) can be reduced. On the other hand, although the detailed cause is unknown, metal-clad laminates having an insulating layer made of a cured resin composition containing component (B) were prone to swelling or peeling of the metal foil around the via holes when via holes were formed by a laser method. The resin composition of this embodiment further contains, as component (C), a resin having a true density of 1,500 kg / m ３ It is presumed that the presence of component (C) in the vicinity of component (B), which is susceptible to damage by laser, makes the vicinity of component (B) less susceptible to damage by laser. Each component that may be contained in the resin composition of this embodiment will be described below in order.

[0019] <(A) Thermosetting Resin> Examples of the (A) thermosetting resin include epoxy resins, phenolic resins, maleimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. Among these, from the viewpoints of heat resistance and conductor adhesion, the (A) thermosetting resin is preferably at least one selected from the group consisting of epoxy resins, cyanate resins, and maleimide resins, more preferably maleimide resins, and even more preferably at least one selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins (hereinafter also referred to as "maleimide-based resins"). One type of (A) thermosetting resin may be used alone, or two or more types may be used in combination.

[0020] In the following description, a maleimide resin having one or more N-substituted maleimide groups may be referred to as a "maleimide resin (AX)" or an "(AX) component." Furthermore, a derivative of a maleimide resin having one or more N-substituted maleimide groups may be referred to as a "maleimide resin derivative (AY)" or an "(AY) component."

[0021] (Maleimide Resin (AX)) The maleimide resin (AX) is not particularly limited as long as it is a maleimide resin having one or more N-substituted maleimide groups. From the viewpoints of conductor adhesion and heat resistance, the maleimide resin (AX) is preferably an aromatic maleimide resin having two or more N-substituted maleimide groups, and more preferably an aromatic bismaleimide resin having two N-substituted maleimide groups.

[0022] In this specification, the term "aromatic maleimide resin" refers to a compound having an N-substituted maleimide group directly bonded to an aromatic ring. In addition, in this specification, the term "aromatic bismaleimide resin" refers to a compound having two N-substituted maleimide groups directly bonded to an aromatic ring. In addition, in this specification, the term "aromatic polymaleimide resin" refers to a compound having three or more N-substituted maleimide groups directly bonded to an aromatic ring. In addition, in this specification, the term "aliphatic maleimide resin" refers to a compound having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon.

[0023] The maleimide resin (AX) is preferably a maleimide resin represented by the following general formula (A-1).

[0024] (In the formula, X Ａ１ is a divalent organic group.

[0025] X in the above general formula (A-1) Ａ１ is a divalent organic group. Ａ１Examples of the divalent organic group represented by formula (A-2) below, a divalent organic group represented by formula (A-3) below, a divalent organic group represented by formula (A-4) below, a divalent organic group represented by formula (A-5) below, a divalent organic group represented by formula (A-6) below, and a divalent organic group represented by formula (A-7) below are exemplified.

[0026] (In the formula, R Ａ１ is an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. Ａ１ is an integer from 0 to 4. * represents a binding site.)

[0027] R in the above general formula (A-2) Ａ１ Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, and n-pentyl; alkenyl groups having 2 to 5 carbon atoms; and alkynyl groups having 2 to 5 carbon atoms. The aliphatic hydrocarbon group having 1 to 5 carbon atoms may be either linear or branched. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. In the general formula (A-2) above, n Ａ１ is an integer of 0 to 4, and from the viewpoint of availability, is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. Ａ１ is an integer of 2 or more, a plurality of R Ａ１ They may be the same or different.

[0028] (In the formula, R Ａ２ and R Ａ３ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. Ａ２ n 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, a single bond, or a divalent organic group represented by the following general formula (A-3-1): Ａ２ and n Ａ３ are each independently an integer of 0 to 4. * represents a binding site.

[0029] R in the above general formula (A-3) Ａ２ and R Ａ３ The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R Ａ１ The same can be mentioned.

[0030] X in the above general formula (A-3) Ａ２ 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 having 1 to 5 carbon atoms is preferably an alkylene group having 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and even more preferably a methylene group. Ａ２ Examples of the alkylidene group having 2 to 5 carbon atoms represented by include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group.

[0031] n in the above general formula (A-3) Ａ２ and n Ａ３ are each independently an integer of 0 to 4. Ａ２ or n Ａ３ is an integer of 2 or more, a plurality of R Ａ２ R Ａ３ They may be the same or different from each other.

[0032] X in the above general formula (A-3) Ａ２ The divalent organic group represented by formula (A-3-1) is as follows:

[0033] (In the formula, R Ａ４ and R Ａ５ are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. Ａ３ 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. Ａ４ and n Ａ５ are each independently an integer of 0 to 4. * represents a binding site.

[0034] R in the above general formula (A-3-1) Ａ４ and R Ａ５ The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R Ａ１ The same as X in the above general formula (A-3-1) can be mentioned. Ａ３ The alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms represented by the above X Ａ２ The same as those in the above general formula (A-3-1) Ａ４ and n Ａ５ are each independently an integer of 0 to 4, and from the viewpoint of availability, are each preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. Ａ４ or n Ａ５ is an integer of 2 or more, a plurality of R Ａ４ R Ａ５ They may be the same or different from each other.

[0035] (In the formula, n Ａ６ is an integer from 0 to 10. * represents a binding site.)

[0036] (In the formula, n Ａ７ is a number from 0 to 5. * represents a binding site.)

[0037] (In the formula, R Ａ６ and R Ａ７ are each independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. Ａ８ is an integer from 1 to 8. * represents a binding site.)

[0038] R in the above general formula (A-6) Ａ６ and R Ａ７ The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R Ａ１ The same as those in the general formula (A-6) above are included. Ａ８ is an integer of 2 or more, a plurality of R Ａ６ R Ａ７ They may be the same or different from each other.

[0039] (In the formula, R Ａ８ 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; n Ａ９ is an integer from 0 to 3. Ａ９ ~R Ａ１１ are each independently an alkyl group having 1 to 10 carbon atoms. Ａ１２ are 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. Ａ１０ are each independently an integer of 0 to 4, Ａ１１ is a value between 0.95 and 10.0. * indicates a binding site.)

[0040] R in the above general formula (A-7) Ａ８ Examples of the alkyl group having 1 to 10 carbon atoms represented by R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. These alkyl groups may be either linear or branched. Ａ８ Examples of the alkyl group contained in the alkyloxy group having 1 to 10 carbon atoms and the alkylthio group having 1 to 10 carbon atoms represented by the formula (I) include the same alkyl groups as those having 1 to 10 carbon atoms described above. Ａ８ Examples of the aryl group having 6 to 10 carbon atoms represented by R include a phenyl group and a naphthyl group. Ａ８ Examples of the aryl group contained in the aryloxy group having 6 to 10 carbon atoms and the arylthio group having 6 to 10 carbon atoms represented by the formula (R) include the same as the aryl group having 6 to 10 carbon atoms described above. Ａ８Examples of the cycloalkyl group having 3 to 10 carbon atoms represented by the formula (I) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group.

[0041] R Ａ９ ~R Ａ１１ The alkyl group having 1 to 10 carbon atoms represented by the formula (I) is the same as the above-mentioned R Ａ８ Among these, R Ａ９ ~R Ａ１１ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. Ａ９ is an integer from 0 to 3, and n Ａ９ When R is 2 or 3, multiple R Ａ８ They may be the same or different.

[0042] Among the above, the divalent organic group represented by the general formula (A-7) is preferred from the viewpoints of compatibility with other resins, solvent solubility, dielectric properties, adhesion to conductors, and ease of production. Ａ９ is 0, and R Ａ９ ~R Ａ１１ is preferably a divalent organic group in which R is a methyl group.

[0043] In the general formula (A-7), multiple R Ａ８ R Ａ１２ Multiple n Ａ９ Multiple n Ａ１０ Each of n may be the same or different. Ａ１１ If R exceeds 1, multiple R Ａ９ R Ａ１０ R Ａ１１ Each of the two may be the same or different.

[0044] R in the above general formula (A-7) Ａ１２The alkyl group having 1 to 10 carbon atoms, the alkyloxy group having 1 to 10 carbon atoms, the alkylthio group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxy group having 6 to 10 carbon atoms, the arylthio group having 6 to 10 carbon atoms, and the cycloalkyl group having 3 to 10 carbon atoms represented by R Ａ８ The same applies to the alkyl group having 1 to 10 carbon atoms, the alkyloxy group having 1 to 10 carbon atoms, the alkylthio group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxy group having 6 to 10 carbon atoms, the arylthio group having 6 to 10 carbon atoms, and the cycloalkyl group having 3 to 10 carbon atoms represented by R Ａ１２ From the viewpoints of compatibility with other resins, solvent solubility, dielectric properties, adhesion to conductors, and ease of production, n is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Ａ１０ is an integer of 0 to 4, and from the viewpoints of compatibility with other resins, solvent solubility, dielectric properties, adhesion to conductors, and ease of production, is preferably an integer of 0 to 3, more preferably 0 or 2. Ａ１１ is preferably 0.98 to 8.0, more preferably 1.0 to 7.0, and even more preferably 1.1 to 6.0, from the viewpoints of compatibility with other resins, solvent solubility, melt viscosity, handleability, and heat resistance.

[0045] Preferred examples of the divalent organic group represented by general formula (A-7) above include a divalent organic group represented by the following general formula (A-7-1), a divalent organic group represented by the following general formula (A-7-2), a divalent organic group represented by the following general formula (A-7-3), and a divalent organic group represented by the following general formula (A-7-4).

[0046] (In the formula, n Ａ１１ is the same as in the above general formula (A-7). * represents a bonding site.

[0047] Examples of the maleimide resin (AX) include aromatic bismaleimide resins, aromatic polymaleimide resins, and aliphatic maleimide resins. Among these, aromatic bismaleimide resins are preferred. Specific examples of the maleimide resin (AX) include bis(4-maleimidophenyl)methane, m-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4-methyl-1,3-phenylene bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, aromatic bismaleimide resins having an indane skeleton, and biphenylaralkyl maleimide resins. Among these, aromatic bismaleimide resins having an indane skeleton and biphenylaralkyl maleimide resins are preferred. As the aromatic bismaleimide resins having an indane skeleton, among the maleimide resins represented by the above general formula (A-1), X Ａ１ is represented by the divalent organic group represented by the above general formula (A-7) (hereinafter also referred to as "maleimide resin (A1)"). As the biphenylaralkyl type maleimide resin, among the maleimide resins represented by the above general formula (A-1), Ａ１ is a divalent organic group represented by the general formula (A-5) (hereinafter also referred to as "maleimide resin (A2)"). The content ratio of maleimide resin (A1) to maleimide resin (A2) [(A1):(A2)] is not particularly limited, but from the viewpoint of heat resistance and dielectric properties, it is preferably 30:70 to 95:5, more preferably 50:50 to 90:10, and even more preferably 70:30 to 80:20, on a mass basis. Furthermore, the total content of maleimide resin (A1) and maleimide resin (A2) in the thermosetting resin (A) is not particularly limited, but from the viewpoint of heat resistance and dielectric properties, it is preferably 60 to 100 mass%, more preferably 70 to 100 mass%, and even more preferably 80 to 100 mass%.

[0048] (Maleimide resin derivative (AY)) As the maleimide resin derivative (AY), an aminomaleimide resin having a structure derived from the above-mentioned maleimide resin (AX) and a structure derived from a diamine compound is preferred. The aminomaleimide resin has a structure derived from the maleimide resin (AX) and a structure derived from a diamine compound. The aminomaleimide resin can be obtained, for example, by Michael addition of the maleimide resin (AX) and a diamine compound. As the diamine compound, for example, the same amine compound having at least two primary amino groups in one molecule as listed in JP 2020-200406 A can be used. Among these, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, and 3,3'-diethyl-4,4'-diaminodiphenylmethane are preferred.

[0049] (Content of (A) Thermosetting Resin) The content of the (A) thermosetting resin in the resin composition of this embodiment is not particularly limited, but is preferably 30 to 90 mass %, more preferably 50 to 85 mass %, and even more preferably 60 to 80 mass %, relative to the total amount (100 mass %) of the resin components in the resin composition of this embodiment. When the content of the (A) thermosetting resin is equal to or greater than the above lower limit, the heat resistance, moldability, processability, and conductor adhesion tend to be better. Furthermore, when the content of the (A) thermosetting resin is equal to or less than the above upper limit, the dielectric properties tend to be better.

[0050] Here, in this specification, the term "resin component" refers to a resin and a compound that forms a resin through a curing reaction. In the resin composition of this embodiment, for example, component (A) corresponds to the resin component. When the resin composition of this embodiment contains, as optional components, resins or compounds that form a resin through a curing reaction in addition to the above components, these optional components are also included in the resin component. Examples of such optional resin components include component (D) and component (E), which will be described later. On the other hand, component (B), component (C), component (F), and component (G) are not included in the resin component.

[0051] The content of the resin component in the resin composition of this embodiment is not particularly limited, but is preferably 30 to 85% by mass, more preferably 50 to 80% by mass, and even more preferably 60 to 75% by mass, based on the total solid content (100% by mass) of the resin composition of this embodiment. When the content of the resin component is equal to or greater than the above-mentioned lower limit, the heat resistance, moldability, processability, and conductor adhesion tend to be improved. Furthermore, when the content of the resin component is equal to or less than the above-mentioned upper limit, the low thermal expansion property tends to be improved.

[0052] <(B) True density is 1,500 kg / m ３ The resin composition of the present embodiment contains, as component (B), an inorganic filler having a true density of 1,500 kg / m ３ The following inorganic filler is contained. Here, the true density in this embodiment is a value measured using a dry automatic density meter "AccuPycII 1340" (manufactured by Shimadzu Corporation), and more specifically, a value measured according to the method described in the examples. Furthermore, in this specification, "inorganic filler" means a filler containing an inorganic element. The component (B) may be used alone or in combination of two or more types.

[0053] The true density of component (B) is preferably 1,000 to 1,500 kg / m ３ , more preferably 1,100 to 1,450 kg / m ３ , more preferably 1,200 to 1,400 kg / m ３When the true density of component (B) is equal to or greater than the lower limit, the low thermal expansion property tends to be more favorable. When the true density of component (B) is equal to or less than the upper limit, the dielectric constant (Dk) tends to be more favorable.

[0054] Component (B) may be either solid or hollow particles, but is preferably solid particles. In this specification, "hollow particles" refers to particles that include an outer shell and voids with a diameter of 100 nm or more within the outer shell, and "solid particles" refers to particles that are not hollow. The presence of the outer shell and the diameter of the voids are observed using an electron microscope.

[0055] Examples of the material for component (B) 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, talc, aluminum borate, silicon carbide, and silsesquioxane. Among these, the material for component (B) is preferably a silicon-containing compound containing silicon atoms, more preferably particles having a siloxane bond (hereinafter also referred to as "siloxane particles"), and even more preferably silica and silsesquioxane. A true density of 1,500 kg / m ３ The silicon-containing compound below preferably has an —Si—O— bond and an —Si—R bond (R represents an organic group). The —Si—O— bond contributes to low thermal expansion, and the —Si—R bond reduces the true density of the silicon-containing compound and contributes to a reduction in the dielectric constant (Dk).

[0056] Component (B) may be surface-treated with a surface treatment agent such as a coupling agent, or may not be surface-treated with a surface treatment agent, but is preferably surface-treated with a surface treatment agent. Examples of surface treatment agents include silane coupling agents and titanate coupling agents, and among these, silane coupling agents are preferred.Examples of the silane coupling agent include aminosilane-based coupling agents (hereinafter also referred to simply as "aminosilanes") such as N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, and N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane; isocyanate silane-based coupling agents (hereinafter also referred to simply as "isocyanate silanes") such as 3-isocyanatepropyltrimethoxysilane and 3-isocyanatepropyltriethoxysilane; and 3-(methacryloyloxy)propyltriethoxysilane. Examples of suitable coupling agents include (meth)acrylic silane coupling agents (hereinafter simply referred to as "(meth)acrylic silane") such as vinyltrimethoxysilane and 3-(methacryloyloxy)propyltriethoxysilane; vinyl silane coupling agents (hereinafter simply referred to as "vinyl silane") such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy silane coupling agents such as γ-glycidyloxypropyltrimethoxysilane and γ-glycidyloxypropyltriethoxysilane; phenyl silane coupling agents, alkyl silane coupling agents, alkynyl silane coupling agents, haloalkyl silane coupling agents, siloxane coupling agents, hydrosilane coupling agents, silazane coupling agents, alkoxysilane coupling agents, chlorosilane coupling agents, isocyanurate silane coupling agents, ureido silane coupling agents, mercapto silane coupling agents, and sulfide silane coupling agents. Among these, vinyl silane coupling agents are preferred.

[0057] Average particle diameter (D ５０) is not particularly limited, but from the viewpoint of dispersibility of component (B) and fine wiring properties, it is preferably 0.1 to 3 μm, more preferably 0.3 to 2 μm, and even more preferably 0.5 to 1 μm. ５０ The average particle diameter (D) is the particle diameter at the point corresponding to 50% volume when the cumulative frequency distribution curve of particle diameters is calculated assuming the total volume of particles to be 100%. ５０ ) can be measured, for example, by a particle size distribution measuring device using a laser diffraction scattering method.

[0058] In the resin composition of this embodiment, the content of component (B) is not particularly limited, but is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, and even more preferably 10 to 15% by mass, relative to the total solid content (100% by mass) of the resin composition. When the content of component (B) is equal to or greater than the above-mentioned lower limit, low thermal expansion and dielectric properties tend to be more favorable. On the other hand, when the content of component (B) is equal to or less than the above-mentioned upper limit, moldability and conductor adhesion tend to be more favorable.

[0059] <(C) True density is 1,500 kg / m ３ The resin composition of the present embodiment contains, as component (C), an inorganic filler having a true density of 1,500 kg / m ３ The component (C) may be used alone or in combination of two or more.

[0060] The true density of component (C) is preferably 1,600 to 4,000 kg / m ３ , more preferably 1,800 to 3,000 kg / m ３ , more preferably 2,000 to 2,300 kg / m ３ When the true density of component (C) is equal to or greater than the lower limit, the laser processability and low thermal expansion properties tend to be improved. When the true density of component (C) is equal to or less than the upper limit, the dielectric properties tend to be improved.

[0061] The difference between the true density of component (B) and the true density of component (C) [true density of component (C) - true density of component (B)] is not particularly limited, but is preferably 400 to 1,000 kg / m３ , more preferably 500 to 800 kg / m ３ , more preferably 600 to 700 kg / m ３ When the difference in true density is within the above range, there is a tendency for the dielectric properties and laser processability to be compatible to a higher degree.

[0062] The material of component (C) can be the same as that of component (B). Among these, from the viewpoints of laser processability and low thermal expansion, silicon-containing compounds are preferred, and silica is more preferred.

[0063] The component (C) may be surface-treated with a surface treatment agent such as a coupling agent, or may not be surface-treated with a surface treatment agent, but is preferably surface-treated with a surface treatment agent. Examples of the surface treatment agent include the same agents as those exemplified in the description of the component (B). Among these, from the viewpoint of laser processability, aminosilane-based coupling agents are preferred, and aminosilanes having an amino group substituted with a phenyl group (hereinafter also referred to as "aminophenylsilanes") are more preferred.

[0064] Here, metal-clad laminates undergo a desmear treatment in which the insulating layer is treated with an aqueous oxidizing agent solution to remove residual components after laser processing or to roughen the surface to improve adhesion between the insulating layer and the conductor layer. In this case, metal-clad laminates formed using a resin composition with a low dielectric constant may develop depressions with diameters exceeding several tens of nanometers on the surface of the insulating layer after the desmear treatment. Furthermore, resin compositions with a low dielectric constant may exhibit poor compatibility between the components, such as separation of some of the components before curing. By using one or more selected from the group consisting of vinylsilane coupling agents and aminosilane coupling agents as the surface treatment agent for component (B) and an aminosilane coupling agent as the surface treatment agent for component (C), the compatibility of the resin composition is improved and the occurrence of the depressions can be suppressed.

[0065] Average particle diameter (D ５０) is not particularly limited, but from the viewpoint of dispersibility of component (C) and fine wiring ability, it is preferably 0.05 to 3 μm, more preferably 0.1 to 2 μm, and even more preferably 0.3 to 1 μm.

[0066] In the resin composition of this embodiment, the content of component (C) is not particularly limited, but is preferably 2 to 40 mass%, more preferably 8 to 30 mass%, and even more preferably 15 to 20 mass%, based on the total solids content (100 mass%) of the resin composition. When the content of component (C) is equal to or greater than the above-mentioned lower limit, laser processability, low thermal expansion, heat resistance, and flame retardancy tend to be improved. On the other hand, when the content of component (C) is equal to or less than the above-mentioned upper limit, moldability and conductor adhesion tend to be improved.

[0067] In the resin composition of this embodiment, the content ratio of component (B) to component (C) [component (B):component (C)] is not particularly limited, but is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, on a mass basis. When the content ratio is within the above range, there is a tendency for both the relative dielectric constant (Dk) and laser processability to be more highly compatible.

[0068] <(D) One or more selected from the group consisting of conjugated diene polymers and modified conjugated diene polymers> The resin composition of this embodiment preferably further contains one or more selected from the group consisting of conjugated diene polymers and modified conjugated diene polymers (hereinafter also referred to as "(D) diene-based polymers"). By containing the component (D), the resin composition of this embodiment tends to be more likely to obtain better dielectric properties. The component (D) may be used alone or in combination of two or more.

[0069] (Conjugated diene polymer) In this specification, the term "conjugated diene polymer" refers to a polymer of a conjugated diene compound. By including a conjugated diene polymer, the resin composition of the present embodiment tends to easily obtain better dielectric properties.

[0070] Examples of conjugated diene compounds that are monomer components of conjugated diene polymers include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene. The conjugated diene polymer may be a polymer of one type of conjugated diene compound, or a copolymer of two or more types of conjugated diene compounds. The conjugated diene polymer may also be a copolymer of one or more types of conjugated diene compounds and one or more types of monomers other than conjugated diene compounds. When the conjugated diene polymer is a copolymer, the polymerization mode is not particularly limited, and may be any of random polymerization, block polymerization, and graft polymerization.

[0071] As the conjugated diene polymer, a conjugated diene polymer having a vinyl group in a side chain is preferred from the viewpoints of compatibility with other resins and dielectric properties. 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 properties, 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 may be, for example, 100 or less, 80 or less, or 60 or less.

[0072] Examples of conjugated diene polymers include polybutadiene having a 1,2-vinyl group, and butadiene-styrene copolymer having a 1,2-vinyl group. Among these, from the viewpoint of dielectric properties and heat resistance, polybutadiene having a 1,2-vinyl group and butadiene-styrene copolymer having a 1,2-vinyl group are preferred, and polybutadiene having a 1,2-vinyl group is more preferred. Furthermore, as polybutadiene having a 1,2-vinyl group, polybutadiene homopolymer having a 1,2-vinyl group is preferred. The butadiene-derived 1,2-vinyl group contained in the conjugated diene polymer is a vinyl group contained in a butadiene-derived structural unit represented by the following formula (D-1):

[0073]

[0074] 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 properties, and heat resistance, it is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more. 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 butadiene-derived structural unit represented by the above formula (D-1) is preferred. From the same viewpoint, the polybutadiene having a 1,2-vinyl group is preferably a 1,2-polybutadiene homopolymer.

[0075] 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 properties, and heat resistance, it is preferably 400 to 3,000, more preferably 600 to 2,000, and even more preferably 800 to 1,500.

[0076] (Modified Conjugated Diene Polymer) The modified conjugated diene polymer is a polymer obtained by modifying a conjugated diene polymer. By containing the modified conjugated diene polymer, the resin composition of the present embodiment tends to have good heat resistance and low thermal expansion, while also being more likely to obtain excellent dielectric properties. The modified conjugated diene polymer may be used alone or in combination of two or more.

[0077] As the modified conjugated diene polymer, from the viewpoints of compatibility with other resins, dielectric properties, 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 resin having two or more N-substituted maleimide groups (hereinafter also referred to as a "modifying maleimide resin") is preferred.

[0078] As the conjugated diene polymer having a vinyl group in a side chain, for example, the conjugated diene polymer having a vinyl group in a side chain described above can be used, and the 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.

[0079] As the maleimide resin for modification, for example, a maleimide resin having two or more N-substituted maleimide groups as explained as component (A) can be used.

[0080] The modified conjugated diene polymer preferably has, in its side chain, a substituent formed by 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 modifying maleimide resin [hereinafter, this may be referred to as a "maleimide resin-derived substituent"], and more preferably has, in its side chain, a maleimide resin-derived substituent and a vinyl group.

[0081] From the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, the maleimide resin-derived substituent is preferably a group containing a structure represented by the following general formula (D-2) or (D-3) as a structure derived from the maleimide resin for modification:

[0082] (In the formula, X Ｄ１ is a divalent group obtained by removing two N-substituted maleimide groups from a maleimide resin 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.)

[0083] The extent to which maleimide resin-derived substituents are present in a modified conjugated diene polymer can be determined by the extent to which the vinyl groups of a conjugated diene polymer having vinyl groups in its side chains have been modified by the modifying maleimide resin [hereinafter, this may be referred to as the "vinyl group modification rate"]. The vinyl group modification rate is not particularly limited, but from the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, it is preferably 20 to 70%, more preferably 30 to 60%, and even more preferably 35 to 50%. Here, the vinyl group modification rate is a value determined by the method described in the Examples. The vinyl groups in the modified conjugated diene polymer are preferably 1,2-vinyl groups contained in structural units derived from butadiene.

[0084] 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 properties, 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.

[0085] The reaction conditions for the conjugated diene polymer and the modifying maleimide resin are not particularly limited. For example, the raw materials and the organic solvent are charged into a reaction vessel, and the reaction is carried out while heating, stirring, etc., as necessary, to obtain a modified conjugated diene polymer.

[0086] 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 in the modifying maleimide resin (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.

[0087] When the resin composition of this embodiment contains component (D), the content of component (D) is not particularly limited, but is preferably 1 to 40 mass%, more preferably 10 to 35 mass%, and even more preferably 15 to 30 mass%, relative to the total amount (100 mass%) of the resin components in the resin composition of this embodiment. When the content of component (D) is equal to or greater than the above-mentioned lower limit, the dielectric properties tend to be better. On the other hand, when the content of component (D) is equal to or less than the above-mentioned upper limit, the heat resistance and flame retardancy tend to be better.

[0088] <(E) Styrene-based thermoplastic resin> The resin composition of this embodiment preferably further contains (E) a styrene-based thermoplastic resin. By containing (E) a styrene-based thermoplastic resin, the resin composition of this embodiment tends to have better dielectric properties. One type of (E) styrene-based thermoplastic resin may be used alone, or two or more types may be used in combination.

[0089] (E) The styrene-based thermoplastic resin has structural units derived from styrene-based compounds (hereinafter, sometimes referred to as "styrene-based units"). Examples of styrene-based compounds include styrene; and alkyl-substituted styrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. The alkyl group of the alkyl-substituted styrene preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0090] The (E) styrene-based thermoplastic resin may contain structural units other than styrene-based units. Examples of structural units other than styrene-based units include butadiene-derived structural units, isoprene-derived structural units, maleic acid-derived structural units, and maleic anhydride-derived structural units. The butadiene-derived structural units and isoprene-derived structural units may be hydrogenated. When hydrogenated, the butadiene-derived structural units become structural units in which ethylene units and butylene units are mixed, and the isoprene-derived structural units become structural units in which ethylene units and propylene units are mixed.

[0091] Examples of (E) styrene-based thermoplastic resins include hydrogenated products of styrene-butadiene-styrene block copolymers, hydrogenated products of styrene-isoprene-styrene block copolymers, and styrene-maleic anhydride copolymers. Examples of hydrogenated products of styrene-butadiene-styrene block copolymers include SEBS, which is obtained by completely hydrogenating the carbon-carbon double bonds in the butadiene block, and SBBS, which is obtained by partially hydrogenating the carbon-carbon double bonds at 1,2-bond sites in the butadiene block. Hydrogenated products of styrene-isoprene-styrene block copolymers are obtained as SEPS by hydrogenating the polyisoprene portion. Among these, SEBS and SEPS are preferred, with SEBS being more preferred, from the viewpoints of dielectric properties, conductor adhesion, heat resistance, glass transition temperature, and low thermal expansion.

[0092] In the (E) styrene-based thermoplastic resin, the content of styrene-based units (hereinafter, may be referred to as "styrene content") is preferably 5 to 60 mass%, more preferably 7 to 40 mass%, and even more preferably 10 to 20 mass%, from the viewpoints of dielectric properties, conductor adhesion, heat resistance, and low thermal expansion.

[0093] The number average molecular weight (Mn) of the (E) styrene-based thermoplastic resin is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and even more preferably 100,000 to 200,000.

[0094] When the resin composition of this embodiment contains (E) a styrene-based thermoplastic resin, the content of the (E) styrene-based thermoplastic resin is preferably 1 to 30 mass%, more preferably 2 to 20 mass%, and even more preferably 3 to 10 mass%, relative to the total amount (100 mass%) of the resin components in the resin composition of this embodiment. When the content of the (E) styrene-based thermoplastic resin is equal to or greater than the above-mentioned lower limit, the dielectric properties tend to be better. Furthermore, when the content of the (E) styrene-based thermoplastic resin is equal to or less than the above-mentioned upper limit, the heat resistance and flame retardancy tend to be better.

[0095] <(F) Flame Retardant> The resin composition of this embodiment preferably further contains a flame retardant (F). By containing the flame retardant (F), the resin composition of this embodiment tends to have further improved flame retardancy. The flame retardant (F) may be used alone or in combination of two or more. Furthermore, a flame retardant auxiliary may be contained as necessary.

[0096] Examples of (F) flame retardants include phosphorus-based flame retardants, metal hydrates, and halogen-based flame retardants. The phosphorus-based flame retardant may be an inorganic phosphorus-based flame retardant or an organic phosphorus-based flame retardant. Examples of inorganic phosphorus-based flame retardants include red phosphorus; ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate; inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide; phosphoric acid; and phosphine oxide. Examples of organic phosphorus-based flame retardants include aromatic phosphate ester compounds, monosubstituted phosphonic acid diester compounds, disubstituted phosphinic acid ester compounds, metal salts of disubstituted phosphinic acids, organic nitrogen-containing phosphorus compounds, and cyclic organic phosphorus compounds. Among these, aromatic phosphate ester compounds are preferred.

[0097] Examples of aromatic phosphate ester compounds include triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl di-2,6-xylenyl phosphate, resorcinol bis(diphenyl phosphate), 1,3-phenylene bis(di-2,6-xylenyl phosphate), bisphenol A-bis(diphenyl phosphate), 1,3-phenylene bis(diphenyl phosphate), 4,4'-biphenol-bis(di-2,6-xylenyl phosphate), etc. Among these, 4,4'-biphenol-bis(di-2,6-xylenyl phosphate) is preferred.

[0098] Examples of metal hydrates include aluminum hydroxide hydrate, magnesium hydroxide hydrate, etc. Examples of halogen-based flame retardants include chlorine-based flame retardants, bromine-based flame retardants, etc.

[0099] When the resin composition of this embodiment contains a flame retardant (F), the content of the flame retardant (F) is not particularly limited, but is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 5 to 12 parts by mass, per 100 parts by mass of the total resin components in the resin composition of this embodiment. When the content of the flame retardant (F) is equal to or greater than the above-mentioned lower limit, the flame retardancy tends to be better. On the other hand, when the content of the flame retardant (F) is equal to or less than the above-mentioned upper limit, the dielectric properties, moldability, and conductor adhesion tend to be better.

[0100] <(G) Curing Accelerator> The resin composition of this embodiment preferably further contains a (G) curing accelerator. By containing the (G) curing accelerator, the resin composition of this embodiment tends to have improved curability and more excellent dielectric properties, heat resistance, and conductor adhesion. One (G) curing accelerator may be used alone, or two or more (G) curing accelerators may be used in combination.

[0101] Examples of the (G) curing accelerator include acidic catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, tributylamine, pyridine, and dicyandiamide; imidazole compounds such as methylimidazole, phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-phenylimidazolium trimellitate; isocyanate-masked imidazole compounds such as the addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; quaternary ammonium compounds; phosphorus compounds such as triphenylphosphine; organic peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, and α,α'-bis(t-butylperoxy)diisopropylbenzene; and carboxylates of manganese, cobalt, zinc, and the like. Among these, imidazole compounds and organic peroxides are preferred.

[0102] (Content of (G) Curing Accelerator) When the resin composition of the present embodiment contains a (G) curing accelerator, the content of the (G) curing accelerator is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass relative to the total amount (100 parts by mass) of the resin components in the resin composition of the present embodiment. When the content of the (G) curing accelerator is equal to or greater than the above lower limit, a sufficient curing acceleration effect tends to be easily obtained. Furthermore, when the content of the (G) curing accelerator is equal to or less than the above upper limit, storage stability tends to be more easily improved.

[0103] <Other Components> The resin composition of the present embodiment may further contain, as necessary, one or more additives selected from the group consisting of resin materials other than the above components, antioxidants, heat stabilizers, antistatic agents, UV absorbers, pigments, colorants, lubricants, organic solvents, and other additives. Each of these may be used alone, or two or more may be used in combination. The amount of these additives used is not particularly limited, and they may be used as needed within a range that does not inhibit the effects of the present embodiment.

[0104] (Organic Solvent) The resin composition of the present embodiment may contain an organic solvent from the viewpoint of facilitating handling and facilitating production of a prepreg, which will be described later. The organic solvent may be used alone or in combination of two or more.

[0105] Examples of organic solvents 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 hydrocarbon-based solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone. Among these, from the viewpoint of solubility, alcohol-based solvents, ketone-based solvents, nitrogen-containing solvents, and aromatic hydrocarbon-based solvents are preferred, aromatic hydrocarbon-based solvents are more preferred, and toluene is even more preferred.

[0106] <Method for producing resin composition> The resin composition of this embodiment can be produced by mixing the above-mentioned components. When mixing the components, the components may be dissolved or dispersed while stirring. Furthermore, the conditions for mixing the raw materials, such as the order in which the raw materials are mixed, the mixing temperature, and the mixing time, are not particularly limited and may be set as desired depending on the types of raw materials, etc.

[0107] [Prepreg] The prepreg of the present embodiment is a prepreg containing the resin composition of the present embodiment or a semi-cured product of the resin composition. The prepreg of the present embodiment contains, for example, the resin composition of the present embodiment or a semi-cured product of the resin composition and a sheet-like fiber base material.

[0108] The sheet-like fiber substrate contained in the prepreg of this embodiment can be, for example, a known sheet-like fiber substrate used in various laminates for electrical insulating materials. Examples of the material 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.

[0109] The prepreg of this embodiment can be produced, for example, by impregnating or applying the resin composition of this embodiment to a sheet-like fiber substrate, and then heating and drying to B-stage it. The temperature and time of heating and drying are not particularly limited, but from the viewpoints of productivity and appropriately B-staging the resin composition of this embodiment, it can be, for example, 50 to 200°C and 1 to 30 minutes.

[0110] The content of the resin composition in the prepreg of the present embodiment is not particularly limited, but from the viewpoint of easily obtaining better moldability when made into a laminate, it is preferably 20 to 90 mass%, more preferably 25 to 80 mass%, and even more preferably 30 to 75 mass%.

[0111] [Resin Film] The resin film of this embodiment is a resin film containing the resin composition of this embodiment or a semi-cured product of the resin composition. The resin film of this embodiment can be produced, for example, by applying the resin composition of this embodiment containing an organic solvent to a support and then heating and drying it. Examples of the support include plastic film, metal foil, and release paper. The temperature and time of the heating and drying are not particularly limited, but can be set to 50 to 200°C and 1 to 30 minutes from the viewpoints of productivity and appropriately B-staging the resin composition of this embodiment.

[0112] The resin film of this embodiment is preferably used to form an insulating layer when producing a printed wiring board.

[0113] [Laminate] The laminate of the present embodiment is a laminate having a cured product of the resin composition of the present embodiment and a metal foil. Note that a laminate having a metal foil is sometimes called a metal-clad laminate.

[0114] The metal of the metal foil is not particularly limited, and examples thereof include copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, and alloys containing one or more of these metal elements.

[0115] The laminate of this embodiment can be produced, for example, by placing metal foil on one or both sides of the prepreg of this embodiment and then hot-press molding. Typically, the B-staged prepreg is cured by this hot-press molding to obtain the laminate of this embodiment. When hot-press molding, only one prepreg may be used, or two or more prepregs may be laminated together. For hot-press molding, for example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used. The conditions for hot-press molding are not particularly limited, but can be, for example, a temperature of 100 to 300°C, a time of 10 to 300 minutes, and a pressure of 1.5 to 5 MPa.

[0116] [Printed Wiring Board] The printed wiring board of this embodiment is a printed wiring board having a cured product of the resin composition of this embodiment. The printed wiring board of this embodiment can be produced, for example, by forming a conductor circuit on one or more materials selected from the group consisting of a cured product of the prepreg of this embodiment, a cured product of the resin film of this embodiment, and a laminate by a known method. Furthermore, a multilayer printed wiring board can also be produced by further performing a multilayer adhesive process as necessary. The conductor circuit can be formed, for example, by appropriately performing drilling, metal plating, etching of metal foil, etc.

[0117] [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, for example, by mounting a semiconductor chip, a memory, etc. on the printed wiring board of this embodiment by a known method.

[0118] The present embodiment will be specifically described below with reference to examples, although the present embodiment is not limited to the following examples.

[0119] [Method for measuring number average molecular weight (Mn)] The number average molecular weight (Mn) 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 manufactured by Tosoh Corporation, trade names) 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

[0120] [Method for measuring true density of inorganic filler] A dry automatic density meter "AccuPyc II 1340" (manufactured by Shimadzu Corporation) was used to measure the true density of 1 cm. ３ The measurement sample was filled into the cell up to 80% of its capacity. The weight of the cell filled with the measurement sample was measured, and the weight of the cell alone was subtracted to determine the weight of the measurement sample filled into the cell. Next, the cell filled with the measurement sample was set into the dry automatic density meter, and the weight of the measurement sample was input. With the cell set, the cell was left at room temperature (25°C) under a nitrogen atmosphere for 1 hour, and then 10 measurements were made, and the average value was calculated, which was used as the true density.

[0121] [Production of Modified Conjugated Diene Polymer] Production Example 1 Into a 2 L glass flask equipped with a thermometer, a reflux condenser, and a stirrer and capable of heating and cooling, 33.8 parts by mass of polybutadiene (1,2-polybutadiene homopolymer, number average molecular weight (Mn) 1,200, vinyl group content = 85 mol% or more), 1.43 parts by mass of bismaleimide resin (aromatic bismaleimide resin having a group containing an indane ring: number average molecular weight (Mn) 1,300, the same as Maleimide Resin 1 described below), 0.0035 parts by mass of α,α'-bis(t-butylperoxy)diisopropylbenzene, and toluene as an organic solvent were added. The mixture was then reacted under a nitrogen atmosphere at 90 to 100°C for 5 hours with stirring to obtain a solution of a modified conjugated diene polymer (solids concentration: 35% by mass). The number average molecular weight (Mn) of the resulting modified conjugated diene polymer was 2,000.

[0122] Furthermore, GPC was measured by the above-described method for the solution containing polybutadiene and bismaleimide resin before the start of the reaction and for the solution after the reaction, and the peak areas derived from the bismaleimide resin were determined before and after the reaction. Next, the vinyl group modification rate of the bismaleimide resin was calculated using the following formula. The vinyl group modification rate corresponds to the rate of decrease in the peak area derived from the bismaleimide resin due to the reaction: Vinyl group modification rate (%) = [(peak area derived from the bismaleimide resin before the start of the reaction) - (peak area derived from the bismaleimide resin after the reaction)] x 100 / (peak area derived from the bismaleimide resin before the start of the reaction). The vinyl group modification rate determined from the above formula was 40%.

[0123] [Production of Resin Compositions] Examples 1 to 5, Comparative Examples 1 and 2 Each component shown in Table 1 was blended with toluene and methyl ethyl ketone in the amounts shown in Table 1, and the blended mixture was stirred and mixed at 25° C. to prepare a resin composition having a solids concentration of approximately 60% by mass. In Table 1, the unit of the blending amount of each component is parts by mass, and in the case of a solution, it means parts by mass converted into solids content.

[0124] (Production of Resin Film) The resin composition obtained above was applied to a 38 μm thick PET film (manufactured by Teijin Limited, product name "G2-38"), and then heated and dried at 170° C. for 5 minutes to produce a B-stage resin film.

[0125] (Production of Double-Sided Copper Foiled Resin Plate) The resin film obtained above was peeled from the PET film and then pulverized to obtain a B-stage resin powder. A 0.5 mm thick Teflon (registered trademark) sheet, die-cut to a size of 50 mm x 35 mm, was placed on top of the copper foil, and the resin powder was poured into the die-cut area. Copper foil was then placed on top of the Teflon (registered trademark) sheet to obtain a laminate. The copper foil used was a low-profile copper foil with a thickness of 18 μm (manufactured by Mitsui Mining & Smelting Co., Ltd., product name "3EC-M3-VLP-18"), positioned with the roughened surface facing the resin powder. The laminate was then heated and pressurized at a temperature of 230°C, a pressure of 2.0 MPa, and a time of 120 minutes, and the resin powder was molded into a resin plate while being cured, thereby producing a double-sided copper foiled resin plate. The thickness of the resin plate portion of the obtained double-sided copper foiled resin plate was 0.5 mm.

[0126] [Evaluation Method] Each evaluation was carried out according to the following methods. The results are shown in Table 1.

[0127] (Method for evaluating compatibility) The resin compositions obtained in each example, each having a solid content concentration of approximately 60% by mass, were observed under an optical microscope at 50x magnification to evaluate compatibility according to the following criteria: A: No separation observed. B: Slight separation observed. C: Total separation observed.

[0128] (Method for measuring the number of recesses) The resin board with copper foil on both sides obtained in each example was immersed in a copper etching solution to remove the copper foil, and the resin board was subjected to desmear treatment in the following order of steps (1) to (4) to prepare a resin board: (1) Immersed in a swelling solution (manufactured by Atotech Japan, product name "Swelling Dip Securigant P", glycol ethers, aqueous solution of sodium hydroxide) at 60°C for 5 minutes, followed by rinsing with water; (2) Roughening solution (manufactured by Atotech Japan, product name "Concentrate Compact P", KMnO ４(2) Immersed in a neutralizing solution (aqueous solution of sulfuric acid, "Reduction Showreusin Securigant P" manufactured by Atotech Japan Co., Ltd.) at 40°C for 5 minutes, then washed with water. (3) Immersed in a neutralizing solution (aqueous solution of sulfuric acid, "Reduction Showreusin Securigant P" manufactured by Atotech Japan Co., Ltd.) at 40°C for 5 minutes, then washed with water. (4) Drying at 80°C for 10 minutes.

[0129] The surface of the resin plate after the desmear treatment obtained above was observed in five fields of view using a scanning electron microscope (SEM) (manufactured by Hitachi High-Technologies Corporation, product name "SV-4700") under conditions of secondary electron mode, accelerating voltage of 10 kV, and magnification of 10,000 times. In the surface SEM image of each field of view, the number of depressions on the surface of the resin plate having a size exceeding 10 nm was counted, and the average value of these was calculated. Note that the size of the depression here means the length of the longest straight line that can be drawn within the depression area in a planar view of the resin plate.

[0130] (Method for measuring dielectric constant (Dk)) The resin plate with copper foil on both sides produced in each example was immersed in a 10 mass % solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is a copper etching solution, to remove the copper foil. The obtained resin plate was cut into a 2 mm x 50 mm piece and dried at 105°C for 1 hour to prepare a test piece. Next, the dielectric constant (Dk) of the test piece was measured at an ambient temperature of 25°C and in the 10 GHz band according to the cavity resonator perturbation method.

[0131] (Method for evaluating laser processability) The resin board with copper foil on both sides obtained in each example was subjected to CO ２ Using a laser processing machine (VIAMECHLC-2N252 / 2C (H18), manufactured by Via Mechanics Co., Ltd.), via holes were formed under the following conditions: mask diameter 1.6 mm, focus offset value 0.000, pulse width 10 μs, power 6.60 W, aperture 43, and number of shots 1. The copper foil around the via holes of the evaluation board obtained above was observed with a scanning electron microscope (SEM), and the laser processability was evaluated according to the following criteria. A: No peeling or swelling was observed in the copper foil around the via holes. B: Slight peeling or swelling was observed in the copper foil around the via holes. C: Numerous peelings and swellings were observed in the copper foil around the via holes.

[0132]

[0133] The details of each component listed in Table 1 are as follows: [(A) Thermosetting Resin] Maleimide resin 1: Among the maleimide resins represented by the general formula (A-1) above, X Ａ１ is a divalent organic group represented by the general formula (A-7) above, and having a group containing an indane ring: number average molecular weight (Mn) 1,300. Maleimide resin 2: biphenylaralkyl maleimide resin (manufactured by Nippon Kayaku Co., Ltd., trade name "MIR-3000")

[0134] [(B) True density is 1,500 kg / m ３ The following inorganic fillers] Inorganic filler B-1: true density of 1,350 kg / m ３ , average particle diameter (D ５０ ) 0.7 μm siloxane particles surface-treated with vinylsilane. Inorganic filler B-2: True density of 1,350 kg / m ３ , average particle diameter (D ５０ ) 0.7 μm siloxane particles surface-treated with isocyanate silane. Inorganic filler B-3: True density of 1,350 kg / m ３ , average particle diameter (D ５０ ) 0.7 μm siloxane particles surface-treated with acrylic silane. Inorganic filler B-4: True density of 1,350 kg / m ３ , average particle diameter (D ５０ ) 0.7 μm siloxane particles surface-treated with aminophenylsilane.

[0135] [(C) True density is 1,500 kg / m ３ Inorganic filler C-1: True density of 2,200 kg / m ３ , average particle diameter (D ５０ ) spherical fused silica with a diameter of 0.5 μm and surface-treated with aminophenylsilane. Inorganic filler C-2: true density of 2,200 kg / m ３ , average particle diameter (D ５０ ) spherical fused silica with a diameter of 0.5 μm, surface-treated with vinylsilane.

[0136] [(D) Diene Polymer] Modified conjugated diene polymer: modified conjugated diene polymer obtained in Production Example 1

[0137] [(E) Styrene-based thermoplastic resin] SEBS: Kraton Polymer Japan Co., Ltd., trade name "Kraton (registered trademark) MD1653MO", melt flow rate 5.0 g / 10 min, styrene content 30 mass%, hydrogenation rate 100%

[0138] [(F) Flame retardant] Phosphate ester compound: 4,4'-biphenol-bis(di-2,6-xylenyl phosphate)

[0139] [(G) Curing Accelerator] Organic peroxide: α,α'-bis(t-butylperoxy)diisopropylbenzene Imidazole curing accelerator: isocyanate-masked imidazole (addition product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole) (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "G-8009L")

[0140] From the results shown in Table 1, the resin compositions of Examples 1 to 5 of this embodiment were excellent in both dielectric constant (Dk) and laser processability. On the other hand, the resin composition of Comparative Example 1, which did not contain component (C), was inferior in laser processability, and the resin composition of Comparative Example 2, which did not contain component (B), was inferior in dielectric constant (Dk).

Claims

1. (A) Thermosetting resin and (B) a material with a true density of 1,500 kg / m ３ The following inorganic filler and (C) a true density of 1,500 kg / m ３ A resin composition comprising:

2. The resin composition according to claim 1, wherein the component (B) is a particle having a siloxane bond.

3. A resin composition according to claim 1 or 2, wherein the content of the (B) component is 1 to 30 mass % relative to the total amount (100 mass %) of solids in the resin composition.

4. The resin composition according to claim 1 or 2, wherein the component (C) is silica.

5. A resin composition according to claim 1 or 2, wherein the content of the component (C) is 2 to 40 mass % relative to the total amount (100 mass %) of solids in the resin composition.

6. The difference between the true density of the component (B) and the true density of the component (C) [true density of the component (C) - true density of the component (B)] is 400 to 1,000 kg / m ３ The resin composition according to claim 1 or 2, 7. The resin composition according to claim 1 or 2, wherein the component (A) is at least one member selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives of said maleimide resins.

8. A prepreg containing the resin composition according to claim 1 or 2 or a semi-cured product of said resin composition.

9. A laminate comprising a cured product of the resin composition according to claim 1 or 2 and a metal foil.

10. A resin film comprising the resin composition according to claim 1 or 2 or a semi-cured product of said resin composition.

11. A printed wiring board having a cured product of the resin composition according to claim 1 or 2.

12. A semiconductor package comprising the printed wiring board according to claim 11 and a semiconductor element.

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