WO2025126952A1 - Resin composition, prepreg, laminate, resin film, printed wiring board, and semiconductor package - Google Patents

Abstract

Disclosed are: a resin composition which contains (A) a siloxane-modified maleimide resin that includes a structure derived from a maleimide resin (A1) which has one or more N-substituted maleimide groups and a structure derived from a siloxane compound (A2) which has two or more primary amino groups, (B) a polyphenylene ether-based resin that has a functional group which contains an ethylenically unsaturated bond, and (C) a phosphorus-based flame retardant that has a phosphorus atom content of 12 mass% or more; and a prepreg, a laminate, a resin film, a printed wiring board, and a semiconductor package, each of which uses the resin composition.

Description

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

This embodiment relates to a resin composition, a prepreg, a laminate, a resin film, a printed wiring board, and a semiconductor package.

In electronic devices such as mobile phones, their base station equipment, servers, routers and other network infrastructure equipment, and large computers, the speed and capacity of the signals they use is increasing year by year. Accordingly, the substrate materials for the printed wiring boards used in these electronic devices are required to have dielectric properties that can reduce the transmission loss of high-frequency signals.

Patent Document 1 discloses a curable resin composition containing naphthol novolac epoxy resin and polyphenylene ether resin, which aims to provide a curable resin composition that can be used for the insulating layer of a printed wiring board and that has a low relative dielectric constant and dielectric loss tangent of the resulting cured product and excellent heat resistance.

JP 2013-185080 A

For insulating materials such as prepregs, good flame retardancy is required.
However, when a flame retardant is added to a resin composition to improve flame retardancy, the circuit embeddability is deteriorated. For example, a method for improving the circuit embeddability is to reduce the viscosity of the resin composition impregnated into the prepreg. However, when the resin composition is simply reduced in viscosity, a resin flow occurs in which the molten resin composition flows out from the end when the prepreg or the like is press molded, resulting in a problem of reduced thickness accuracy of the molded product.

In view of the current situation, the present embodiment aims to provide a resin composition that contains a flame retardant and effectively suppresses resin flow while also providing excellent circuit embedding properties, as well as a prepreg, laminate, resin film, printed wiring board, and semiconductor package that use the resin composition.

As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by the present embodiment described below.
[1] (A) a siloxane-modified maleimide resin including a structure derived from a maleimide resin (A1) having one or more N-substituted maleimide groups and a structure derived from a siloxane compound (A2) having two or more primary amino groups;
(B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond;
(C) a phosphorus-based flame retardant having a phosphorus atom content of 12 mass% or more;
A resin composition comprising:
[2] The resin composition according to the above [1], wherein the component (C) is a metal phosphate.
[3] The resin composition according to [1] or [2] above, wherein the content of the (C) component is 1 to 30 parts by mass relative to the total amount (100 parts by mass) of the resin components in the resin composition.
[4] The resin composition according to any one of the above [1] to [3], wherein the component (B) has a functional group containing an ethylenically unsaturated bond at a terminal thereof.
[5] The resin composition according to any one of the above [1] to [4], wherein the functional group containing an ethylenically unsaturated bond contained in the component (B) is a (meth)acryloyl group.
[6] The resin composition according to any one of the above [1] to [5], further comprising (D) an inorganic filler.
[7] The resin composition according to [6] above, wherein the content of the (D) component is 20 to 90 mass% relative to the total solid content (100 mass%) in the resin composition.
[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 comprising a cured product of the resin composition according to any one of [1] to [7] above and a metal foil.
[10] A resin film comprising 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 comprising the printed wiring board according to [11] above and a semiconductor element.

According to this embodiment, it is possible to provide a resin composition that contains a flame retardant and has excellent circuit embedding properties while effectively suppressing resin flow, as well as a prepreg, laminate, resin film, printed wiring board, and semiconductor package that use the resin composition.

In this specification, a numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively.
For example, a numerical range of "X to Y" (X and Y are real numbers) means a numerical range of not less than X and not more than Y. In this specification, the expression "not less than X" means X and a numerical value exceeding X. In this specification, the expression "not more than Y" means Y and a numerical value less than Y.
Each lower limit and upper limit of a numerical range described herein may be arbitrarily combined with the lower limit or upper limit of any other numerical range.
In the numerical ranges described in this specification, the lower or upper limit of the numerical range may be replaced with values shown in the examples.

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, the content of each component in a resin composition means, when a plurality of substances corresponding to each component are present in the resin composition, the total amount of the plurality of substances present in the resin composition, unless otherwise specified.

The expression "containing XX" used in this specification includes both the meaning of containing XX in a reacted state if XX is capable of reacting, and the meaning of simply containing XX.

In this specification, "solids" refers to components other than the solvent, and components that are liquid at 25°C are also considered to be solids.

In this specification, "(meth)acryloyl" means "acryloyl" and its corresponding "methacryloyl".

The weight average molecular weight (Mw) in this specification means a value measured in terms of polystyrene by gel permeation chromatography (GPC), and specifically, can be measured by the method described in the Examples.

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.

　This embodiment also includes any combination of the items described in this specification.

[Resin composition]
The resin composition of the present embodiment is
(A) a siloxane-modified maleimide resin including a structure derived from a maleimide resin (A1) having one or more N-substituted maleimide groups and a structure derived from a siloxane compound (A2) having two or more primary amino groups;
(B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond;
(C) a phosphorus-based flame retardant having a phosphorus atom content of 12 mass% or more;
Contains:

In the following description, the siloxane-modified maleimide resin (A) containing a structure derived from a maleimide resin (A1) having one or more N-substituted maleimide groups and a structure derived from a siloxane compound (A2) having two or more primary amino groups may be simply referred to as "siloxane-modified maleimide resin (A)."
Furthermore, (B) a polyphenylene ether-based resin having a functional group containing an ethylenically unsaturated bond may be referred to as "(B) a polyphenylene ether-based resin."
In addition, a phosphorus-based flame retardant having a phosphorus atom content of 12 mass% or more (C) may be referred to as a "phosphorus-based flame retardant (C)".
Furthermore, each component may be referred to as component (A), component (B), etc.
Hereinafter, each component that may be contained in the resin composition of the present embodiment will be described in order.

<(A) Siloxane-modified maleimide resin>
The siloxane-modified maleimide resin (A) contains a structure derived from a maleimide resin (A1) (hereinafter also simply referred to as "maleimide resin (A1)") having one or more N-substituted maleimide groups, and a structure derived from a siloxane compound (A2) (hereinafter also simply referred to as "siloxane compound (A2)") having two or more primary amino groups.
The siloxane-modified maleimide resin (A) may be used alone or in combination of two or more kinds.

The structure derived from the maleimide resin (A1) and the structure derived from the siloxane compound (A2) contained in the siloxane-modified maleimide resin (A) may each be one type alone or two or more types.

(Structure derived from maleimide resin (A1))
An example of the structure derived from the maleimide resin (A1) is a structure obtained by a Michael addition reaction between at least one N-substituted maleimide group among the N-substituted maleimide groups contained in the maleimide resin (A1) and a primary amino group contained in the siloxane compound (A2).

The content of the structure derived from the maleimide resin (A1) in the siloxane-modified maleimide resin (A) is not particularly limited, but from the viewpoint of dielectric properties and film handling properties, it is preferably 5 to 95 mass%, more preferably 30 to 93 mass%, and even more preferably 60 to 90 mass%.

The maleimide resin (A1) 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 (A1) is preferably a maleimide resin having two or more N-substituted maleimide groups, more preferably an aromatic maleimide resin having two or more N-substituted maleimide groups, and even more preferably an aromatic bismaleimide resin having two N-substituted maleimide groups.
In this specification, the term "aromatic maleimide resin" refers to a compound having an N-substituted maleimide group directly bonded to an aromatic ring, and 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" means 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" means a compound having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon.

As the maleimide resin (A1), a maleimide resin represented by the following general formula (A1-1) [hereinafter, sometimes referred to as "maleimide resin (A1)"] is preferred.

（式中、Ｘ^Ａ１１は２価の有機基である。）

(In the formula, X ^A11 is a divalent organic group.)

X ^A11 in the above general formula (A1-1) is a divalent organic group.
Examples of the divalent organic group represented by X ^A11 in the above general formula (A1-1) include a divalent group represented by the following general formula (A1-2), a divalent group represented by the following general formula (A1-3), a divalent group represented by the following general formula (A1-4), a divalent group represented by the following general formula (A1-5), and a divalent group represented by the following general formula (A1-6).

（式中、Ｒ^Ａ１１は、炭素数１～５の脂肪族炭化水素基又はハロゲン原子である。ｎ^Ａ１１は０～４の整数である。＊は結合部位を表す。）

(In the formula, R ^A11 is an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. n ^A11 is an integer of 0 to 4. * represents a bonding site.)

Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R ^A11 in general formula (A1-2) above include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, and n-pentyl groups; 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 the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In the above general formula (A1-2), n ^A11 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. When n ^A11 is an integer of 2 or more, multiple R ^A11 may be the same or different.

（式中、Ｒ^Ａ１２及びＲ^Ａ１３は、各々独立に、炭素数１～５の脂肪族炭化水素基又はハロゲン原子である。Ｘ^Ａ１２は炭素数１～５のアルキレン基、炭素数２～５のアルキリデン基、エーテル基、スルフィド基、スルホニル基、カルボニルオキシ基、ケト基、単結合、又は下記一般式（Ａ１－３－１）で表される２価の基である。ｎ^Ａ１２及びｎ^Ａ１３は、各々独立に、０～４の整数である。＊は結合部位を表す。）

(In the formula, R ^A12 and R ^A13 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. X ^A12 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, a single bond, or a divalent group represented by the following general formula (A1-3-1). n ^A12 and n ^A13 each independently represent an integer of 0 to 4. * represents a bonding site.)

Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R ^A12 and R ^A13 in general formula (A1-3) above include the same as those for R ^A11 above.

Examples of the alkylene group having 1 to 5 carbon atoms represented by X ^A12 in the above general formula (A1-3) 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 alkylidene group having 2 to 5 carbon atoms represented by X ^A12 in the above general formula (A1-3) include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group.

In the above general formula (A1-3), n ^A12 and n ^A13 each independently represent an integer of 0 to 4. When n ^A12 or n ^A13 is an integer of 2 or greater, a plurality of R ^A12 's or a plurality of R ^A13's may be the same or different.

The divalent group represented by X ^A12 in the above general formula (A1-3) and represented by general formula (A1-3-1) is as follows.

（式中、Ｒ^Ａ１４及びＲ^Ａ１５は、各々独立に、炭素数１～５の脂肪族炭化水素基又はハロゲン原子である。Ｘ^Ａ１３は炭素数１～５のアルキレン基、炭素数２～５のアルキリデン基、エーテル基、スルフィド基、スルホニル基、カルボニルオキシ基、ケト基又は単結合である。ｎ^Ａ１４及びｎ^Ａ１５は、各々独立に、０～４の整数である。＊は結合部位を表す。）

(In the formula, R ^A14 and R ^A15 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. X ^A13 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. n ^A14 and n ^A15 each independently represent an integer of 0 to 4. * represents a bonding site.)

Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R ^A14 and R ^A15 in general formula (A1-3-1) above include the same as those for R ^A11 above.
Examples of the alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms represented by X ^A13 in the above general formula (A1-3-1) include the same as those for X ^A12 above. Among these, X ^A13 is preferably an alkylidene group having 2 to 5 carbon atoms, more preferably an alkylidene group having 2 to 4 carbon atoms, and even more preferably an isopropylidene group.

In the above general formula (A1-3-1), n ^A14 and n ^A15 are each independently an integer of 0 to 4, and from the viewpoint of availability, each is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. When n ^A14 or n ^A15 is an integer of 2 or greater, multiple R ^A14s or multiple R ^A15s may be the same or different.

（式中、ｎ^Ａ１６は０～１０の整数である。＊は結合部位を表す。）

(In the formula, n ^A16 is an integer of 0 to 10. * represents a binding site.)

In the above general formula (A1-4), n ^A16 is preferably an integer of 0 to 5, more preferably an integer of 0 to 4, and even more preferably an integer of 0 to 3, from the viewpoint of availability.

（式中、ｎ^Ａ１７は０～５の数である。＊は結合部位を表す。）

(In the formula, n ^A17 is a number from 0 to 5. * represents a binding site.)

（式中、Ｒ^Ａ１６及びＲ^Ａ１７は、各々独立に、水素原子又は炭素数１～５の脂肪族炭化水素基である。ｎ^Ａ１８は１～８の整数である。＊は結合部位を表す。）

(In the formula, R ^A16 and R ^A17 each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms; n ^A18 represents an integer of 1 to 8; * represents a bonding site.)

Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R ^A16 and R ^A17 in general formula (A1-6) above include the same as those for R ^A11 above.
When n ^A18 is an integer of 2 or greater, a plurality of R ^A16 or a plurality of R ^A17 may be the same or different.

Examples of the maleimide resin (A1) include aromatic bismaleimide resins, aromatic polymaleimide resins, and aliphatic maleimide resins.
Examples of the maleimide resin (A1) 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, biphenyl aralkyl maleimide, aromatic bismaleimide resins having an indane skeleton, etc. Among these, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane is preferred.

(Structure derived from siloxane compound (A2))
An example of the structure derived from the siloxane compound (A2) is a structure formed by a Michael addition reaction between one or both of the two primary amino groups contained in the siloxane compound (A2) and an N-substituted maleimide group contained in the maleimide resin (A1).

The content of the structure derived from the siloxane compound (A2) in the siloxane-modified maleimide resin (A) is not particularly limited, but from the viewpoints of dielectric properties, heat resistance, flame retardancy, and glass transition temperature, it is preferably 5 to 95 mass%, more preferably 7 to 70 mass%, and even more preferably 10 to 40 mass%.

The siloxane compound (A2) is not particularly limited as long as it is a siloxane compound having two or more primary amino groups.

The siloxane compound (A2) preferably contains a divalent group represented by the following general formula (A2-1), and more preferably contains a divalent group represented by the following general formula (A2-2).

（式中、Ｒ^Ａ２１及びＲ^Ａ２２は、各々独立に、炭素数１～５の脂肪族炭化水素基、フェニル基又は置換フェニル基である。＊は結合部位を表す。）

(In the formula, R ^A21 and R ^A22 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms, a phenyl group, or a substituted phenyl group. * represents a bonding site.)

（式中、Ｒ^Ａ２１及びＲ^Ａ２２は、上記一般式（Ａ２－１）中のものと同じであり、Ｒ^Ａ２３及びＲ^Ａ２４は、各々独立に、炭素数１～５の脂肪族炭化水素基、フェニル基又は置換フェニル基である。Ｘ^Ａ２１及びＸ^Ａ２２は、各々独立に、２価の有機基であり、ｎ^Ａ２１は、２～１００の整数である。＊は結合部位を表す。）

(In the formula, R ^A21 and R ^A22 are the same as those in the above general formula (A2-1), R ^A23 and R ^A24 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms, a phenyl group or a substituted phenyl group. X ^A21 and X ^A22 each independently represent a divalent organic group, and n ^A21 is an integer of 2 to 100. * represents a bonding site.)

Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R ^A21 to R ^A24 in the above general formulae (A2-1) and (A2-2) include an alkyl group having 1 to 5 carbon atoms such as 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; an alkenyl group having 2 to 5 carbon atoms; and an alkynyl group having 2 to 5 carbon atoms. The aliphatic hydrocarbon group having 1 to 5 carbon atoms may be either linear or branched. As the aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aliphatic hydrocarbon group having 1 to 3 carbon atoms is preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and a methyl group is even more preferable.
Examples of the substituent that the phenyl group in the substituted phenyl group represented by R ^A21 to R ^A24 has include the above-mentioned aliphatic hydrocarbon groups having 1 to 5 carbon atoms.

Examples of the divalent organic group represented by X ^A21 and X ^A22 include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, --O--, or a divalent linking group formed by combining these groups.
Examples of the alkylene group include alkylene groups having 1 to 10 carbon atoms, such as a methylene group, an ethylene group, and a propylene group.
The alkenylene group includes, for example, alkenylene groups having 2 to 10 carbon atoms.
The alkynylene group includes, for example, alkynylene groups having 2 to 10 carbon atoms.
Examples of the arylene group include arylene groups having 6 to 20 carbon atoms, such as a phenylene group and a naphthylene group.
Among these, X ^A21 and X ^A22 are preferably an alkylene group or an arylene group, and more preferably an alkylene group.

n ^A21 is an integer of 2 to 100, preferably an integer of 2 to 50, more preferably an integer of 3 to 40, and further preferably an integer of 5 to 30. When n ^A21 is an integer of 2 or greater, a plurality of R ^A21s or a plurality of R ^A22s may be the same or different.

The siloxane compound (A2) is preferably a polydimethylsiloxane having primary amino groups at both ends, and more preferably a polydimethylsiloxane having primary amino groups only at both ends.
The primary amino group equivalent of the siloxane compound (A2) is not particularly limited, but is preferably 300 to 2,000 g/mol, more preferably 400 to 1,500 g/mol, and even more preferably 500 to 1,000 g/mol.

The weight average molecular weight (Mw) of the siloxane compound (A2) is not particularly limited, but from the viewpoint of ease of handling and moldability, it is preferably 400 to 10,000, more preferably 1,000 to 5,000, even more preferably 1,500 to 4,000, and particularly preferably 2,000 to 3,000.

((A) Method for Producing Siloxane-Modified Maleimide Resin)
The siloxane-modified maleimide resin (A) can be produced, for example, by reacting a maleimide resin (A1) with a siloxane compound (A2) in an organic solvent.
By reacting the maleimide resin (A1) with the siloxane compound (A2), a siloxane-modified maleimide resin (A) is obtained by a Michael addition reaction between the N-substituted maleimide group of the maleimide resin (A1) and the primary amino group of the siloxane compound (A2).
The reaction temperature of the Michael addition reaction is, for example, 50 to 160° C. from the viewpoints of workability such as reaction rate, suppression of gelation of the product during the reaction, etc. The reaction time of the Michael addition reaction is, for example, 0.5 to 10 hours from the viewpoints of productivity and allowing the reaction to proceed sufficiently.

((A) Content of Siloxane-Modified Maleimide Resin)
In the resin composition of the present embodiment, the content of the (A) siloxane-modified maleimide resin is not particularly limited, but is preferably 20 to 90 mass%, more preferably 30 to 80 mass%, and even more preferably 40 to 70 mass%, relative to the total amount (100 mass%) of the resin components in the resin composition of the present embodiment.
When the content of the siloxane-modified maleimide resin (A) is equal to or greater than the above lower limit, a cured product having better moldability, heat resistance, and conductor adhesion tends to be obtained. When the content of the siloxane-modified maleimide resin (A) is equal to or less than the above upper limit, a cured product having better dielectric properties tends to be obtained.

In this specification, the term "resin component" refers to a resin and a compound that forms a resin through a curing reaction. For example, components (A) and (B) correspond to the resin component. Furthermore, when the resin composition 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. Optional resin components include components (E) and (F), which will be described later. On the other hand, components (C), (D), and (G) are not included in the resin component.

The content of the resin component in the resin composition of the present embodiment is not particularly limited, but is preferably 20 to 90 mass%, more preferably 30 to 70 mass%, and even more preferably 40 to 60 mass%, relative to the total solid content (100 mass%) in the resin composition.
When the content of the resin component is equal to or more than the lower limit, the moldability of the resin composition tends to be improved, whereas when the content of the resin component is equal to or less than the upper limit, a cured product having excellent low thermal expansion tends to be obtained.

<(B) Polyphenylene Ether Resin>
The polyphenylene ether resin (B) is not particularly limited as long as it is a resin having a polyphenylene ether chain and a functional group containing an ethylenically unsaturated bond.
By containing the polyphenylene ether resin (B), the resin composition of the present embodiment tends to easily give a cured product having more excellent dielectric properties.
The polyphenylene ether resin (B) may be used alone or in combination of two or more kinds.

(B) Polyphenylene ether resin has a phenylene ether bond and preferably has a structural unit represented by the following general formula (B-1).

（式中、Ｒ^Ｂ１は、炭素数１～５の炭化水素基又はハロゲン原子である。ｎ^Ｂ１は、０～４の整数である。）

(In the formula, R ^B1 is a hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. n ^B1 is an integer of 0 to 4.)

Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R ^B1 in the above general formula (B-1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. The hydrocarbon group having 1 to 5 carbon atoms may be either linear or branched. As the hydrocarbon group having 1 to 5 carbon atoms, a hydrocarbon group having 1 to 3 carbon atoms is preferable, and a methyl group is more preferable.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the above general formula (B-1), n ^B1 is an integer of 0 to 4, preferably 1 or 2, and more preferably 2. When n ^B1 is 1 or 2, the substitution position of R ^B1 is preferably the ortho position on the benzene ring based on the substitution position of the oxygen atom. When n ^B1 is an integer of 2 or more, multiple R ^B1 may be the same or different.
The phenylene ether unit represented by the above general formula (B-1) is preferably a phenylene ether unit represented by the following general formula (B-1').

The polyphenylene ether resin (B) has a functional group containing an ethylenically unsaturated bond (hereinafter, may be referred to as an "ethylenically unsaturated bond-containing group").
In this specification, the term "ethylenically unsaturated bond" means a carbon-carbon double bond capable of undergoing an addition reaction, and does not include a double bond in an aromatic ring.

Examples of the ethylenically unsaturated bond-containing group include a vinyl group, an allyl group, a 1-methylallyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a styryl group, a maleimide group, and a group represented by the following general formula (B-2).

（式中、Ｒ^Ｂ２は、水素原子又は炭素数１～２０のアルキル基である。）

(In the formula, R ^B2 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)

The number of carbon atoms in the alkyl group having 1 to 20 carbon atoms represented by R ^B2 in the above general formula (B-2) is preferably 1 to 10, more preferably 1 to 3, and even more preferably 1. That is, R ^B2 is more preferably a methyl group. The group represented by the above general formula (B-2) in which R ^B2 is a hydrogen atom corresponds to an acryloyl group, and the group represented by the above general formula (B- ² ) in which R B2 is a methyl group corresponds to a methacryloyl group.

Among the above, from the viewpoint of dielectric properties, the ethylenically unsaturated bond-containing group possessed by the polyphenylene ether resin (B) is preferably a group represented by the above general formula (B-2), more preferably a (meth)acryloyl group, and even more preferably a methacryloyl group.

The number of ethylenically unsaturated bond-containing groups that the polyphenylene ether resin (B) has in one molecule is not particularly limited, but is preferably 1 to 5, more preferably 2 to 3, and even more preferably 2.
When the number of ethylenically unsaturated bond-containing groups is equal to or greater than the above lower limit, a cured product having better heat resistance tends to be obtained. When the number of ethylenically unsaturated bond-containing groups is equal to or less than the above upper limit, the flowability and moldability of the resin composition tends to be improved.

The polyphenylene ether resin (B) preferably has an ethylenically unsaturated bond-containing group at a terminal, and more preferably at both terminals.
The (B) polyphenylene ether resin may have an ethylenically unsaturated bond-containing group in a position other than the terminal, but it preferably has an ethylenically unsaturated bond-containing group only at the terminal, and more preferably has an ethylenically unsaturated bond-containing group only at both terminals.

The weight average molecular weight (Mw) of the polyphenylene ether resin (B) is not particularly limited, but is preferably 500 to 7,000, more preferably 800 to 5,000, and even more preferably 1,000 to 3,000.
When the weight average molecular weight (Mw) of the polyphenylene ether resin (B) is equal to or greater than the lower limit, a cured product having excellent dielectric properties and heat resistance tends to be obtained. When the weight average molecular weight (Mw) of the polyphenylene ether resin (B) is equal to or less than the upper limit, the moldability of the resin composition tends to be improved.

(B) The method for synthesizing polyphenylene ether resin is not particularly limited and may be any known method for synthesizing and modifying polyphenylene ether.

((B) Content of polyphenylene ether resin)
The content of the polyphenylene ether resin (B) in the resin composition of the present embodiment is not particularly limited, but is preferably 1 to 30 mass %, more preferably 5 to 25 mass %, and even more preferably 10 to 20 mass %, relative to the total amount (100 mass %) of the resin components in the resin composition of the present embodiment.
When the content of the polyphenylene ether resin (B) is equal to or greater than the lower limit, a cured product having excellent dielectric properties tends to be obtained. When the content of the polyphenylene ether resin (B) is equal to or less than the upper limit, the moldability of the resin composition tends to be improved.

<(C) Phosphorus-based flame retardant having a phosphorus atom content of 12% by mass or more>
The (C) phosphorus-based flame retardant is not particularly limited so long as the phosphorus atom content is 12 mass % or more, but metal phosphates are preferred, and metal salts of di-substituted phosphinic acids are more preferred.
Examples of the metal salt of a disubstituted phosphinic acid include a metal salt of a dialkylphosphinic acid, a metal salt of a diallylphosphinic acid, a metal salt of a divinylphosphinic acid, and a metal salt of a diarylphosphinic acid.
Examples of metal salts of disubstituted phosphinic acids include lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, aluminum salts, titanium salts, zinc salts, etc. Among these, aluminum salts are preferred, and aluminum trisdiethylphosphinate is more preferred.
The phosphorus-based flame retardant (C) may be used alone or in combination of two or more kinds.

The phosphorus atom content in the phosphorus-based flame retardant (C) is 12 mass% or more. By having the phosphorus atom content in the phosphorus-based flame retardant (C) be 12 mass% or more, excellent circuit embedding properties can be obtained while effectively suppressing the resin flow of the resin composition.
From the same viewpoint, the content of phosphorus atoms in component (C) is preferably from 13 to 50 mass %, more preferably from 15 to 40 mass %, and even more preferably from 20 to 30 mass %.

(C) Content of phosphorus-based flame retardant
The content of the phosphorus-based flame retardant (C) in the resin composition of the present embodiment 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 4 to 10 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 (C) phosphorus-based flame retardant is at least the above lower limit, flame retardancy, resin flow, and circuit embedding properties tend to be more improved.
The content of the phosphorus-based flame retardant (C) in the resin composition of the present embodiment is not particularly limited, but is preferably 0.5 to 15 mass%, more preferably 1 to 10 mass%, and even more preferably 2 to 5 mass%, relative to the total amount of solids in the resin composition of the present embodiment (100 mass%).
When the content of the (C) phosphorus-based flame retardant is at least the above lower limit, flame retardancy, resin flow, and circuit embedding properties tend to be more improved.

<(D) Inorganic filler>
The resin composition of the present embodiment preferably further contains (D) an inorganic filler.
By containing the inorganic filler (D), the resin composition of the present embodiment tends to easily give a cured product that has low thermal expansion properties, heat resistance, and flame retardancy.
The inorganic filler (D) may be used alone or in combination of two or more kinds.

(D) Examples of inorganic fillers 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, etc. Among these, from the viewpoints of low thermal expansion, heat resistance, and flame retardancy, silica, alumina, mica, and talc are preferred, silica and alumina are more preferred, and silica is even more preferred. As for silica, fused silica is preferred from the viewpoints of dispersibility and moldability.

The average particle size of the inorganic filler (D) is not particularly limited, but from the viewpoint of dispersibility and fine wiring property of the inorganic filler (D), it 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.
In this specification, the average particle size of the inorganic filler (D) refers to the particle size at the point corresponding to 50% volume when a cumulative frequency distribution curve of particle sizes is calculated assuming the total volume of the particles to be 100%. The average particle size of the inorganic filler (D) can be measured, for example, by a particle size distribution measuring device using a laser diffraction scattering method.
The shape of the inorganic filler (D) may be, for example, spherical or crushed, with spherical being preferred.

((D) Content of inorganic filler)
When the resin composition of the present embodiment contains an inorganic filler (D), the content of the inorganic filler (D) is not particularly limited, but is preferably 20 to 90 mass%, more preferably 30 to 70 mass%, and even more preferably 40 to 60 mass%, relative to the total amount of solids in the resin composition (100 mass%).
When the content of the (D) inorganic filler is equal to or more than the above lower limit, a cured product having excellent low thermal expansion, heat resistance, and flame retardancy tends to be obtained. When the content of the (D) inorganic filler is equal to or less than the above upper limit, the moldability of the resin composition tends to be improved.

<(E) Maleimide resin>
It is preferable that the resin composition of the present embodiment further contains (E) a maleimide resin.
The maleimide resin (E) may be used alone or in combination of two or more kinds.
Examples of the maleimide resin (E) include the same maleimide resin (A1) as described in the section <(A) Siloxane-modified maleimide resin>.

((E) Maleimide resin content)
When the resin composition of the present embodiment contains a maleimide resin (E), the content of the maleimide resin (E) in the resin composition of the present embodiment is not particularly limited, but is preferably 5 to 40 mass%, more preferably 10 to 30 mass%, and even more preferably 15 to 25 mass%, relative to the total amount (100 mass%) of the resin components in the resin composition of the present embodiment.
When the content of the (E) maleimide resin is equal to or greater than the above lower limit, a cured product having better moldability, heat resistance, and conductor adhesion tends to be obtained. When the content of the (E) maleimide resin is equal to or less than the above upper limit, a cured product having better dielectric properties tends to be obtained.

<(F) Styrene-based elastomer>
The resin composition of the present embodiment preferably further contains (F) a styrene-based elastomer.
The resin composition of the present embodiment tends to have better dielectric properties by containing the styrene-based elastomer (F).
The styrene-based elastomer (F) may be used alone or in combination of two or more kinds.

(F) The styrene-based elastomer has a structural unit derived from a styrene-based compound (hereinafter, may be referred to as a "styrene-based unit").
Examples of the styrene-based compound include styrene; and alkyl-substituted styrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. The number of carbon atoms in the alkyl group of the alkyl-substituted styrene is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2.

The (F) styrene-based elastomer 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 are structural units in which ethylene units and butylene units are mixed, and the isoprene-derived structural units are structural units in which ethylene units and propylene units are mixed.

Examples of the styrene-based elastomer (F) include hydrogenated styrene-butadiene-styrene block copolymers, hydrogenated styrene-isoprene-styrene block copolymers, and styrene-maleic anhydride copolymers.
Examples of hydrogenated styrene-butadiene-styrene block copolymers include SEBS obtained by completely hydrogenating the carbon-carbon double bonds in the butadiene block, and SBBS obtained by partially hydrogenating the carbon-carbon double bonds at the 1,2-bond sites in the butadiene block. Hydrogenated 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, adhesion to conductors, heat resistance, glass transition temperature, and low thermal expansion.

In (F) the styrene elastomer, the content of styrene units (hereinafter sometimes referred to as "styrene content") is preferably 5 to 60% by mass, more preferably 7 to 40% by mass, and even more preferably 10 to 20% by mass, from the viewpoints of dielectric properties, conductor adhesion, heat resistance, and low thermal expansion.

The (F) styrene-based elastomer may be acid-modified with maleic anhydride, etc. The acid value of the (F) acid-modified styrene-based elastomer is preferably 2 to 20 mg CH ₃ ONa/g, more preferably 5 to 15 mg _{CH 3} ONa/g, and even more preferably 7 to 13 mg _{CH 3} ONa/g.

The number average molecular weight (Mn) of the (F) styrene-based elastomer is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and even more preferably 100,000 to 200,000.

When the resin composition of the present embodiment contains a (F) styrene-based elastomer, the content of the (F) styrene-based elastomer in the resin composition of the present embodiment is preferably 1 to 30 mass%, more preferably 3 to 20 mass%, and even more preferably 5 to 10 mass%, relative to the total amount (100 mass%) of resin components in the resin composition.
When the content of the (F) styrene-based elastomer is equal to or greater than the lower limit, the dielectric properties tend to be improved. When the content of the (F) styrene-based elastomer is equal to or less than the upper limit, the heat resistance and flame retardancy tend to be improved.

<(G) Curing Accelerator>
The resin composition of the present embodiment preferably further contains (G) a curing accelerator.
By including the curing accelerator (G), the resin composition of the present embodiment has improved curability, and tends to have better dielectric properties, heat resistance, and conductor adhesion.
The curing accelerator (G) may be used alone or in combination of two or more kinds.

Examples of the curing accelerator (G) include acid catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, tributylamine, pyridine, and dicyandiamide; imidazole compounds such as methylimidazole, phenylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-phenylimidazolium trimellitate; isocyanate mask imidazole compounds such as an addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; quaternary ammonium compounds; and phosphorus compounds such as triphenylphosphine and quaternary phosphonium compounds which are addition reaction products of p-benzoquinone and tri-n-butylphosphine. 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; inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile); carboxylates such as manganese, cobalt, and zinc; and acid catalysts such as p-toluenesulfonic acid.
Among these, from the viewpoints of the curing acceleration effect and storage stability, organic peroxides, imidazole compounds, and phosphorus-based compounds are preferred, and it is more preferred to use these in combination.

When the resin composition of the present embodiment contains a curing accelerator (G), the content of the curing accelerator (G) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, and even more preferably 0.5 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 curing accelerator (G) is equal to or more than the lower limit, a sufficient curing acceleration effect tends to be easily obtained, and when the content of the curing accelerator (G) is equal to or less than the upper limit, storage stability tends to be more easily improved.

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

(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 kinds.
Examples of the organic solvent 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 dimethylsulfoxide; and ester-based solvents such as γ-butyrolactone.
Among these, from the viewpoint of solubility, alcohol solvents, ketone solvents, nitrogen atom-containing solvents, and aromatic hydrocarbon solvents are preferred, ketone solvents are more preferred, and methyl ethyl ketone is even more preferred.

<Method of producing resin composition>
The resin composition of the present embodiment can be produced by mixing each component by a known method. At this time, each component may be dissolved or dispersed while stirring. The conditions such as the mixing order, temperature, and time are not particularly limited and may be set arbitrarily depending on the type of raw material, etc.

[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.

As the sheet-like fiber base material contained in the prepreg of this embodiment, for example, a known sheet-like fiber base material used in various laminates for electrical insulating materials can be used.
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; mixtures of these; etc. These sheet-like fiber substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat.

The prepreg of the present embodiment can be produced, for example, by impregnating or coating a sheet-like fiber substrate with the resin composition of the present embodiment, and then heating and drying to bring it to a B-stage.
The temperature and time for heat drying are not particularly limited, but from the viewpoint of productivity and appropriately bringing the resin composition of the present embodiment into the B-stage, the temperature and time for heat drying can be, for example, 50 to 200° C. and 1 to 30 minutes.

The amount of the resin composition contained in the prepreg of this embodiment is not particularly limited, but from the viewpoint of obtaining better moldability when made into a laminate, it is preferably 20 to 90% by mass, more preferably 40 to 85% by mass, and even more preferably 50 to 80% by mass.

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

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

[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.
Incidentally, a laminate having a metal foil is sometimes called a metal-clad laminate.

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

The laminate of this embodiment can be produced, for example, by arranging metal foil on one or both sides of the prepreg of this embodiment and then molding it under heat and pressure.
Usually, the B-staged prepreg is cured by this hot press molding to obtain the laminate of this embodiment.
When the heat and pressure molding is performed, only one prepreg may be used, or two or more prepregs may be laminated and used.
For the hot pressure 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 the hot pressing are not particularly limited, but may 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.

[Printed wiring board]
The printed wiring board of the present embodiment is a printed wiring board having a cured product of the resin composition of the present embodiment.
The printed wiring board of the present embodiment can be manufactured, for example, by forming a conductor circuit on one or more selected from the group consisting of the cured product of the prepreg of the present embodiment, the cured product of the resin film of the present embodiment, and a laminated board by a known method. In addition, a multilayer printed wiring board can be manufactured by further performing a multilayer adhesive process as necessary. The conductor circuit can be formed, for example, by appropriately performing a hole drilling process, a metal plating process, an etching process of a metal foil, or the like.

[Semiconductor package]
The semiconductor package of this embodiment is a semiconductor package that includes 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, and the like on the printed wiring board of this embodiment by a known method.

The present embodiment will be specifically described below with reference to examples. However, the present embodiment is not limited to the following examples.

In each example, the weight average molecular weight (Mw) was measured by the following method.
The values were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a third-order equation using standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, product name]. The measurement conditions for GPC are shown below.
·Device:
Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation]
Detector: L-3300 RI [manufactured by Hitachi High-Technologies Corporation]
Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation]
Column: Guard column: TSK Guardcolumn 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: 20μL
・Flow rate: 1.00mL/min ・Measurement temperature: 40℃

Production Example 1: Production of siloxane-modified maleimide resin In a 5-liter reaction vessel equipped with a thermometer, a stirrer, and a moisture content meter with a reflux condenser, capable of heating and cooling, 100 parts by mass of 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 5.6 parts by mass of a silicone compound having primary amino groups at both ends (primary amino group equivalent: 750 g/mol), 7.9 parts by mass of 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 171 parts by mass of propylene glycol monomethyl ether were added and reacted for 2 hours under reflux. This was concentrated at the reflux temperature for 3 hours to produce a solution of siloxane-modified maleimide resin with a solid content concentration of 65% by mass. The weight average molecular weight (Mw) of the obtained siloxane-modified maleimide resin was about 2,700.

Examples 1 to 5, Comparative Examples 1 to 5
(Production of resin composition)
A resin composition having a solid content concentration of 55% by mass was prepared by stirring and mixing at room temperature each of the components shown in Table 1 together with methyl ethyl ketone according to the formulation shown in Table 1. In Table 1, the unit of the blend amount of each component is parts by mass, and in the case of a solution, it means parts by mass converted into solid content.

(Prepreg Production)
The resin composition obtained above was applied to a glass cloth having a thickness of 0.02 mm, and then dried for 5 minutes at the drying temperature shown in Table 1 to prepare a prepreg. The content of the resin composition in the prepreg obtained in each example is shown in Table 1.

[Evaluation method]
The evaluations were carried out according to the following methods, and the results are shown in Table 1.

(Method of evaluating resin flow)
Resin flow was evaluated by the following method in accordance with IPC TM-650.
The prepreg obtained in each example was cut into a 102 mm square, and four of the prepregs were stacked to prepare a test piece, and the weight of the test piece was measured. The measured weight was designated as W1.
Next, the test piece was placed in a press machine set to a temperature of 171±3° C., a pressure of 1.38±0.07 MPa, and a time of 5±0.5 minutes, and pressed. After that, a disk having a diameter of 81.1 mm was punched out from the center of the test piece, and the weight was measured. The measured weight was designated as W2.
Using W1 and W2 obtained above, the resin flow was calculated according to the following formula.
Resin flow (%) = {[W1-2 x W2]/W1} x 100

(Method of evaluating circuit embedding properties)
The prepreg and copper foil obtained above were placed in this order on a circuit board having a circuit for an embedding test (a total of six rectangular areas of 70 mm × 115 mm, each having a thickness of 12 μm and a pattern with dot-shaped openings and a residual copper ratio of 50 volume %, arranged in two rows and three columns with slits of 2 mm width between them), and press molding was performed under the following conditions.
<Press molding conditions>
・Heating temperature (maximum temperature reached): 230℃
Press pressure: 3 MPa
Press time: 3 hours After press molding, the copper foil on both sides was removed by etching, and the area near the circuit was observed visually and with a fluorescent microscope, and the circuit embeddability of the prepreg was evaluated according to the following criteria.
A: There are no unfilled portions in the circuit pattern or slits.
B: There are no unfilled parts in the circuit pattern, but there are some unfilled parts in the slits.
C: There are some parts that are not filled in both the circuit pattern and the slits.

The details of each material in Table 1 are as follows.
[Component (A)]
Siloxane-modified maleimide resin: Siloxane-modified maleimide resin obtained in Production Example 1

[(B) Component]
Polyphenylene ether resin having methacryloyl groups: polyphenylene ether having methacryloyl groups at both ends (weight average molecular weight (Mw) 1,700)

[(C) Component]
Phosphorus-based flame retardant 1: aluminum dialkylphosphinate, metal salt of disubstituted phosphinic acid, phosphorus atom content: 23.5% by mass

[Comparative ingredients]
Phosphorus-based flame retardant 2: 4,4'-biphenylene-bis(di-2,6-dimethylphenylphosphate), phosphorus atom content: 8.1% by mass

[(D) Component]
Silica: Spherical fused silica with an average particle size of 0.5 μm

[(E) component]
Maleimide resin: polyphenylmethane maleimide (manufactured by Daiwa Chemical Industry Co., Ltd., product name "BMI-2300")

[Component (F)]
SEBS: Carboxylic acid modified hydrogenated styrene-butadiene copolymer resin (manufactured by Asahi Kasei Chemicals Corporation, product name "Tuftec (registered trademark) M1913", styrene content 30 mass%, acid value 10 mgCH ₃ ONa/g)

[(G) component]
α,α'-di(t-butylperoxy)diisopropylbenzene, 2-undecylimidazole, and p-benzoquinone reacted with tri-n-butylphosphine

From the results shown in Table 1, it can be seen that the prepregs formed from the resin compositions of Examples 1 to 5 of this embodiment have excellent suppression of resin flow while improving circuit embedding properties.

Claims (12)

(A) a siloxane-modified maleimide resin including a structure derived from a maleimide resin (A1) having one or more N-substituted maleimide groups and a structure derived from a siloxane compound (A2) having two or more primary amino groups;
(B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond;
(C) a phosphorus-based flame retardant having a phosphorus atom content of 12 mass% or more;
A resin composition comprising: The resin composition according to claim 1, wherein the component (C) is a metal phosphate. The resin composition according to claim 1 or 2, wherein the content of the (C) component is 1 to 30 parts by mass relative to the total amount (100 parts by mass) of the resin components in the resin composition. The resin composition according to claim 1 or 2, wherein the component (B) has a functional group containing the ethylenically unsaturated bond at its terminal. The resin composition according to claim 1 or 2, wherein the functional group containing an ethylenically unsaturated bond in component (B) is a (meth)acryloyl group. The resin composition according to claim 1 or 2, further comprising (D) an inorganic filler. The resin composition according to claim 6, wherein the content of the (D) component is 20 to 90 mass% relative to the total amount of solids in the resin composition (100 mass%). A prepreg containing the resin composition according to claim 1 or 2 or a semi-cured product of said resin composition. A laminate comprising a cured product of the resin composition according to claim 1 or 2 and a metal foil. A resin film containing the resin composition according to claim 1 or 2 or a semi-cured product of the resin composition. A printed wiring board having a cured product of the resin composition according to claim 1 or 2. A semiconductor package comprising the printed wiring board according to claim 11 and a semiconductor element.