JP6653065B2 - Resin sheet and printed wiring board - Google Patents

Description

  The present invention relates to a resin sheet and a printed wiring board useful as a material for an insulating layer of the printed wiring board.

  In recent years, miniaturization and high performance of electronic devices have been advanced. In the multilayer printed wiring board, in order to increase the mounting density of electronic components, finer conductor wiring has been advanced, and a wiring forming technique is desired. As a method of forming high-density fine wiring on the insulating layer, there are an additive method of forming a conductor layer only by electroless plating, and a conductor layer formed by electrolytic plating after forming a thin copper layer on the entire surface by electroless plating Then, a semi-additive method of flash etching a thin copper layer is known.

  The roughness of the surface of the insulating layer is desirably made as small as possible because plating in the deep portion of the physical anchor cannot be removed in a flash etching process in a later step. On the other hand, because the roughness of the surface of the insulating layer is small, the adhesion strength between the conductor layer and the insulating layer tends to be small. Therefore, there is a demand for an insulating layer resin composition having a high interface adhesion strength to a conductor layer even if the surface roughness of the insulating layer is small.

  Also, due to the miniaturization and high density of the multilayer printed wiring board, studies to reduce the thickness of the laminated board used for the multilayer printed wiring board have been actively conducted. As the thickness of the multilayer printed wiring board has been reduced, the thickness of the insulating layer has also been required to be reduced. On the other hand, problems such as a decrease in mounting reliability and an increase in warpage of the multilayer printed wiring board arise. Therefore, a resin composition used as a material of the insulating layer is required to have high adhesion and low thermal expansion.

  Various efforts have been made for this. For example, Patent Document 1 discloses an arithmetic average of the surface of an insulating layer after a wet roughening process by using a resin composition containing an epoxy resin, a curing agent, and an inorganic filler surface-treated with aminobis (alkoxysilane). A technique is described which not only has a low roughness but also has a small root-mean-square roughness and can form a plated conductor layer having a sufficient peel strength thereon.

  In Patent Document 2, a roughening treatment is performed with a resin composition containing an epoxy resin (A), a curing agent (B), and a silica component (C) in which silica particles are surface-treated with a silane coupling agent. There is described a technique capable of forming a fine rough surface on a cured product and increasing the adhesive strength between the cured product and a metal layer.

  Patent Literature 3 discloses a thermosetting resin, a curing agent, a first inorganic filler surface-treated with a first silane coupling agent, and a second inorganic filler surface-treated with a second silane coupling agent. By the resin composition containing the material, the surface roughness of the cured product after roughening can be reduced, and when a metal layer is formed on the surface of the cured product, the adhesion strength between the cured product and the metal layer is increased. Techniques that can be used are described.

JP 2014-15606 A Japanese Patent No. 4868750 WO 2014/038534 pamphlet

  However, in the method described in Patent Document 1, the surface roughness and the adhesion to the conductor layer formed by plating are not satisfactory.

  Also, with the method described in Patent Document 2, the surface roughness and the adhesion to the conductor layer formed by plating were not satisfactory.

  Furthermore, even in the method described in Patent Document 3, fine irregularities were not formed by changing the silane coupling agent, and the surface roughness and the adhesion to the conductor layer formed by plating were not satisfactory.

  The present invention has been made in view of the above problems, the purpose thereof, when used for an insulating layer in a printed wiring board material, excellent adhesion between the insulating layer and a conductive layer plated on the surface thereof, An object of the present invention is to obtain a resin sheet having a low coefficient of thermal expansion when completely cured, and to provide a printed wiring board using the resin sheet.

The present inventors have conducted intensive studies and found that a polymer sheet, a metal foil and a metal sheet selected from the group consisting of any one of an outer layer and a resin sheet including an insulating layer laminated on the outer layer. The insulating layer is made of a resin sheet containing an epoxy compound (A), a cyanate ester compound (B), an aminosilane-treated silica (C), and an acid-soluble inorganic filler (D). The inventors have found that the problem is solved and arrived at the present invention.
[1] A resin sheet including an outer layer of any one kind selected from the group consisting of a polymer film, a metal foil and a metal film, and an insulating layer laminated on the outer layer,
A resin sheet in which the insulating layer contains an epoxy compound (A), a cyanate ester compound (B), an aminosilane-treated silica (C), and an acid-soluble inorganic filler (D).
[2] The resin sheet according to [1], wherein the content of the aminosilane-treated silica (C) in the insulating layer is 50 to 350 parts by mass based on 100 parts by mass of the resin solid content.
[3] The content according to [1] or [2], wherein the content of the acid-soluble inorganic filler (D) in the insulating layer is 20 to 150 parts by mass with respect to 100 parts by mass of the resin solid content. Resin sheet.
[4] The resin sheet according to any one of [1] to [3], wherein the inorganic filler (D) soluble in an acid is magnesium hydroxide or magnesium oxide.
[5] The resin sheet according to any one of [1] to [4], wherein the resin composition further includes a maleimide compound (E).
[6] The resin sheet according to any one of [1] to [5], wherein the polymer film is any one selected from the group consisting of polyester, polyimide and polyamide.
[7] The insulating layer is obtained by applying a composition containing the components (A) to (D) on an outer layer, drying the composition under heating or reduced pressure, and solidifying the composition. 6] The resin sheet according to any one of the above.
[8] A printed wiring comprising the insulating layer according to any one of [1] to [7], which is laminated on a circuit board having a core substrate and a conductor circuit formed on the core substrate. Board.
[9] The printed wiring board according to [8], wherein the insulating layer has been subjected to a surface treatment, and includes a conductor layer patterned on the surface.
[10] The printed wiring board according to [9], wherein the surface treatment is a desmear treatment including a roughening treatment with a swelling agent and an alkaline oxidizing agent, and a neutralization treatment with an acidic reducing agent.
[11] The printed wiring board according to [9] or [10], wherein the conductor layer includes a conductor layer formed by a semi-additive method or a conductor layer formed by a subtractive method.
[12] The printed wiring board according to [9] or [10], wherein the conductor layer includes a conductor layer obtained by etching an outer layer made of the metal foil or metal film according to [1].

The sheet of the present invention exhibits at least one, and preferably all of the following effects (1) to (3).
(1) Excellent adhesion between the insulating layer and the conductor layer formed on the surface of the insulating layer.
(2) The surface roughness of the substrate is small.
(3) It has a low coefficient of thermal expansion.

  One embodiment of the present invention is a resin sheet including an outer layer of any one kind selected from the group consisting of a polymer film, a metal foil and a metal film, and an insulating layer laminated on the outer layer, The insulating layer is a resin sheet containing an epoxy compound (A), a cyanate ester compound (B), an aminosilane-treated silica (C), and an acid-soluble inorganic filler (D).

  Hereinafter, the present invention will be described in detail. In the present invention, “X to Y” includes the end values X and Y. “X or Y” means either X or Y, or both.

  In the present invention, a composition containing the components (A) to (D) and, if necessary, other components described below is referred to as a “resin composition”. A layer provided on the outer layer and containing a resin composition and having no fluidity at room temperature is referred to as an “insulating layer”. As described later, the insulating layer may include a solvent. In addition, the insulating layer needs to be curable because it is used by being bonded to another material. Specifically, the curable resin in the insulating layer is uncured, or partially cured but in a curable state. A liquid containing the resin composition and a solvent and having fluidity that can be applied to the outer layer at room temperature is referred to as “varnish”. Hereinafter, each component will be described.

[I-1. Epoxy compound (A)]
The epoxy compound (A) used in the present invention is an organic compound having at least one epoxy group. The number of epoxy groups per molecule of the epoxy compound (A) is one or more. More preferably, the number of the epoxy groups is two or more.

  As the epoxy compound (A), a conventionally known epoxy resin can be used. As the epoxy compound (A), only one type may be used, or two or more types may be used in combination.

  Examples of the epoxy compound (A) include a biphenyl aralkyl type epoxy compound (epoxy group-containing biphenyl aralkyl resin), a naphthalene type epoxy compound (an epoxy group-containing compound having a naphthalene skeleton: a naphthalene bifunctional epoxy compound), and a bisnaphthalene type epoxy compound Compound (epoxy group-containing compound having bisnaphthalene skeleton: naphthalene tetrafunctional epoxy compound), aromatic hydrocarbon formaldehyde type epoxy compound (epoxy group-containing aromatic hydrocarbon formaldehyde resin), anthraquinone type epoxy compound (epoxy having anthraquinone skeleton) Group-containing compound), naphthol aralkyl type epoxy compound (epoxy group-containing naphthol aralkyl resin), ziloc type epoxy compound (epoxy group-containing zyloc resin), Phenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A novolak type epoxy resin, trifunctional phenol type epoxy compound (epoxy group-containing compound having trifunctional phenol skeleton), tetrafunctional phenol type epoxy compound (tetrafunctional phenol skeleton An epoxy group-containing compound having), a biphenyl type epoxy resin (an epoxy group-containing compound having a biphenyl skeleton), an aralkyl novolak type epoxy resin, a triazine skeleton epoxy compound (an epoxy resin having a triazine skeleton), an alicyclic epoxy resin, a polyol type epoxy resin, Compounds obtained by epoxidizing double bonds of double bond-containing compounds such as glycidylamine, glycidyl ester, and butadiene, and those obtained by reacting hydroxyl-containing silicone resins with epichlorohydrin. Compounds, and the like.

  In addition, as described in the above examples, in this specification, an epoxy compound having a structure obtained by epoxidizing a certain resin or compound is given a description of "-type epoxy compound" in the name of the resin or compound. May be represented.

  Among them, epoxy compounds (A) include biphenyl aralkyl type epoxy compounds, naphthalene type epoxy compounds, bisnaphthalene type epoxy compounds, and aromatic compounds from the viewpoints of adhesion between the insulating layer and the plated conductor layer and flame retardancy. Hydrocarbon formaldehyde type epoxy compound (preferably, aromatic hydrocarbon formaldehyde resin obtained by polymerizing aromatic hydrocarbon such as benzene, toluene, xylene and the like with formaldehyde is converted to a hydroxyl group-containing aromatic hydrocarbon such as phenol and xylenol. Compounds which are modified with hydrogen and further epoxidized the hydroxyl groups, and compounds in which the hydroxyl groups of an aromatic hydrocarbon formaldehyde resin obtained by polymerizing a hydroxyl group-containing aromatic hydrocarbon such as phenol and xylenol with formaldehyde are epoxidized. ), Anthraquinone type Epoxy compounds, naphthol aralkyl-type epoxy compounds, and xylok type epoxy compound is preferably one or more members selected from the group consisting of.

  As the biphenylaralkyl type epoxy compound, a compound represented by the formula (1) is preferable. The use of this preferred biphenyl aralkyl type epoxy compound resin can improve the combustion resistance of the insulating layer.

（式中、Ｒ^１は各々独立に、水素原子又はメチル基を表す。ｎ^１は１以上の整数を示す。）

(In the formula, R ¹ each independently represents a hydrogen atom or a methyl group. N ¹ represents an integer of 1 or more.)

  The content of the epoxy compound (A) in the present invention is not particularly limited, but is preferably in the range of 20 to 80 parts by mass, and more preferably 30 to 70 parts by mass with respect to 100 parts by mass of the resin solid content of the insulating layer from the viewpoint of heat resistance and curability. The range of parts by weight is particularly preferred. Here, the “resin solid content of the insulating layer” is a component excluding the solvent, the aminosilane-treated silica (C), and the acid-soluble inorganic filler (D) in the insulating layer. As described below, when the insulating layer is manufactured using varnish, the insulating layer may include a solvent. In this case, the resin solid content in the insulating layer is a component excluding the silica (C), the inorganic filler (D), and the solvent. Therefore, the resin solid content of 100 parts by mass is the sum of the aminosilane-treated silica (C) and the acid-soluble inorganic filler (D) in the insulating layer, and the component excluding the solvent when the solvent is contained. Means 100 parts by mass.

  As the epoxy compound (A), ready-made products having various structures are commercially available, and these can be appropriately obtained and used. Moreover, you may manufacture an epoxy compound (A) using various well-known manufacturing methods. Examples of such a production method include a method of obtaining or synthesizing a hydroxyl group-containing compound having a desired skeleton, modifying the hydroxyl group by a known method, and epoxidizing (introducing an epoxy group).

[I-2. Cyanate compound (B)]
The cyanate ester compound (B) used in the present invention is not particularly limited as long as it has a cyanato group (cyanate ester group). Specifically, naphthol aralkyl type cyanate compound (cyanato group-containing naphthol aralkyl resin), aromatic hydrocarbon formaldehyde type cyanate compound (cyanato group-containing aromatic hydrocarbon formaldehyde resin), biphenyl aralkyl type cyanate compound (Cyanato group-containing biphenyl aralkyl resin), and novolak type cyanate compound (cyanato group-containing novolak resin).

  Since these cyanate ester compounds (B) impart excellent properties such as high chemical resistance, high glass transition temperature, and low thermal expansion property to the insulating layer of the present invention, they are suitable as components of the resin composition of the present invention. Can be used for

  As described in the above examples, in this specification, a cyanate ester compound (B) having a structure obtained by cyanating a certain resin or compound (cyanate esterification) is referred to as the resin or compound name. In some cases, the description may be given with a description of “-type cyanate compound”.

  Among these, as the cyanate ester compound (B), naphthol aralkyl cyanide is preferred from the viewpoint of providing the insulating layer of the present invention having excellent flame retardancy, high curability, and high glass transition temperature of the cured product. Acid ester compound, aromatic hydrocarbon formaldehyde-type cyanate ester compound (preferably, aromatic hydrocarbon formaldehyde resin obtained by polymerizing aromatic hydrocarbon such as benzene, toluene, xylene and the like with phenol, phenol, Compounds obtained by denaturing with a hydroxyl group-containing aromatic hydrocarbon such as xylenol and further converting the hydroxyl group to a cyanate, or phenol or a hydroxyl group-containing aromatic hydrocarbon formaldehyde obtained by polymerizing a hydroxyl group-containing aromatic hydrocarbon such as xylenol with formaldehyde. Compounds in which the hydroxyl group of the resin is cyanated , And one or more members selected from the group consisting of biphenyl aralkyl type cyanate ester compounds are particularly preferred.

  As the naphthol aralkyl cyanate compound, a compound represented by the formula (2) is preferable.

（式中、Ｒ^２は各々独立に水素原子又はメチル基を表し、中でも水素原子が好ましい。ｎ^２は１以上の整数を示す。）

(In the formula, R ² each independently represents a hydrogen atom or a methyl group, and among them, a hydrogen atom is preferable. N ² represents an integer of 1 or more.)

  As the novolak type cyanate compound, a compound represented by the formula (3) or (4) is preferable.

（式中、Ｒ^３は水素原子又はメチル基を表し、中でも水素原子が好ましい。ｎ^３は１以上の整数を示す。）

(In the formula, R ³ represents a hydrogen atom or a methyl group, and among them, a hydrogen atom is preferable. N ³ represents an integer of 1 or more.)

（式中、Ｒ^４は水素原子又はメチル基を表し、中でも水素原子が好ましい。ｎ^４は１以上の整数を示す。）

(In the formula, R ⁴ represents a hydrogen atom or a methyl group, and among them, a hydrogen atom is preferable. N ⁴ represents an integer of 1 or more.)

  The content of the cyanate ester compound (B) in the present invention is not particularly limited, but is preferably in the range of 20 to 40 parts by mass with respect to 100 parts by mass of the resin solid content of the insulating layer from the viewpoint of heat resistance and curability. A range from 25 to 35 parts by weight is particularly preferred.

  As the cyanate ester compound (B), ready-made products having various structures are commercially available, and can be appropriately obtained and used. Moreover, you may manufacture a cyanate ester compound (B) using various well-known manufacturing methods. Examples of such a production method include a method of obtaining or synthesizing a hydroxyl group-containing compound having a desired skeleton, modifying the hydroxyl group by a known method, and converting the compound to a cyanate. As a technique for cyanating a hydroxyl group, for example, a technique described in Ian Hamerton, "Chemistry and Technology of Cyanate Ester Resins," Blackie Academic & Professional.

[I-3. Aminosilane treated silica (C)]
The aminosilane-treated silica (C) in the present invention can be obtained by treating silica particles with an aminosilane-based silane coupling agent. The details will be described below.

[I-3-1. Silica particles in aminosilane-treated silica (C)]
The silica particles in the aminosilane-treated silica (C) used in the present invention are not particularly limited, and examples include natural silica, fused silica, amorphous silica, and hollow silica. Among them, fused silica is particularly preferable from the viewpoint of low thermal expansion. Specific examples of the fused silica include SFP-130MC manufactured by Denki Kagaku Kogyo Co., Ltd. and SC2050, SC2500, SC4500 manufactured by Admatechs Co., Ltd.

  The average particle diameter of the silica is not limited, but is preferably 0.01 to 5.0 μm, more preferably 0.2 to 2.0 μm, from the viewpoint of improving the productivity of the resin sheet. In this specification, the “average particle diameter” of the aminosilane-treated silica (C) means a median diameter of the silica. Here, the median diameter means that when the particle size distribution of the powder is divided into two based on a certain particle size, the mass of the larger particle size and the mass of the smaller particle size are all It means a particle diameter that occupies 50% of each of the powders. The average particle size (median size) of the aminosilane-treated silica (C) is measured by a wet laser diffraction / scattering method.

[I-3-2. Silane coupling agent in aminosilane-treated silica (C)]
Examples of the aminosilane-based silane coupling agent include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, phenylaminosilane, and the like. In particular, phenylaminosilane (KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.) is particularly preferable from the viewpoint of improving moisture absorption heat resistance.

  Although the content is not limited, the ratio of the silane coupling agent to silica is preferably 0.05 to 5% by mass, and 0.1 to 3% by mass from the viewpoint of improving the heat resistance to moisture absorption. Is more preferable. When two or more silane coupling agents are used in combination, the total amount thereof preferably satisfies the above ratio. One of these silicas (C) treated with aminosilane may be used alone, or two or more thereof may be used in any combination and in any ratio.

  Examples of a method for producing the above-mentioned aminosilane-treated silica (C) include the following method.

  The first method includes a dry method. Examples of the dry method include a method of directly attaching the optional silane coupling agent to the optional silica particles. A silica particle is charged into a mixer, and an alcohol solution or an aqueous solution of a silane coupling agent is dropped or sprayed with stirring, and then the mixture is further stirred and classified by a sieve. Thereafter, the silane coupling agent and the silica particles are dehydrated and condensed by heating to obtain the aminosilane-treated silica (C).

  The second method is a wet method. In the wet method, an optional silane coupling agent is added while stirring untreated slurry silica, and after stirring, filtration, drying, and classification by sieving are performed. Next, aminosilane-treated silica (C) can be obtained by dehydrating and condensing the silane coupling agent and the silica particles by heating.

  As a third method, an aminosilane-treated silica (C) is obtained by adding an arbitrary silane coupling agent while stirring untreated slurry silica and then proceeding dehydration condensation by heating and refluxing. Method.

  As a fourth method, when preparing a varnish for producing an insulating layer, silica and an aminosilane-based silane coupling agent are added together with other components, and silica that has been subjected to aminosilane treatment in the step of forming an insulating layer. There is a method of generating (C).

  As the aminosilane-treated silica (C) used in the resin composition of the present invention, a commercially available product can be used in addition to the above-mentioned production method. Commercially available products include slurry silica (SC2050-MTX, manufactured by Admatechs Co., Ltd.) treated with phenylaminosilane (KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.).

  Among these, the first to third methods are preferred from the viewpoint of obtaining high plating peel strength while reducing the coefficient of thermal expansion of the insulating layer. It is presumed that in these methods, the silica is preliminarily treated with aminosilane, so that the amino group concentration on the silica surface is increased, and the adhesion of the insulating layer to the matrix is improved. However, since the insulating layer is usually cured, it is not practical to determine the concentration.

  The content of the aminosilane-treated silica (C) in the present invention is not particularly limited, but from the viewpoint of obtaining high plating peel strength while reducing the coefficient of thermal expansion of the insulating layer, the resin solid content of the insulating layer is 100 parts by mass. Is preferably 50 to 350 parts by mass, more preferably 70 to 300 parts by mass. When two or more aminosilane-treated silicas (C) are used in combination, the total amount thereof preferably satisfies the above ratio.

[I-4. Inorganic filler soluble in acid (D)]
The component (D) used in the present invention is not particularly limited as long as it is an inorganic filler soluble in an acid, and examples thereof include magnesium hydroxide and magnesium oxide. Preferably, the acid is hydrochloric acid or sulfuric acid. These are eluted into the neutralizing solution during the desmear treatment of the surface of the insulating layer, and have the effect of forming a uniform roughened surface and improving the plating peel strength. Specifically, as magnesium hydroxide, Echomag Z-10 and Echomag PZ-1 manufactured by Tateho Chemical Industry Co., Ltd .; Examples include MGZ-1, MGZ-3, and MGZ-6R manufactured by Chemical Industry Co., Ltd., and Kisuma 5, Kisuma 5A, and Kisuma 5P manufactured by Kyowa Chemical Industry Co., Ltd. Examples of magnesium oxide include FNM-G manufactured by Tateho Chemical Industry Co., Ltd., and SMO, SMO-0.1, SMO-S-0.5 manufactured by Sakai Chemical Industry Co., Ltd. As the inorganic filler (D) soluble in these acids, one kind may be used alone, or two or more kinds may be used in optional combination and ratio.

  The average particle diameter of the acid-soluble inorganic filler (D) is preferably from 0.1 to 2.0 μm from the viewpoint of obtaining a uniform surface roughness after the desmear treatment. The average particle diameter is a median diameter as described above.

  The content of the inorganic filler (D) soluble in the acid is determined based on 100 parts by mass of the resin solid content of the insulating layer from the viewpoint of obtaining uniform surface roughness after desmearing and obtaining high plating peel strength. , Preferably from 20 to 150 parts by mass, more preferably from 30 to 130 parts by mass.

  Moreover, it is preferable that the inorganic filler (D) soluble in the acid is surface-treated from the viewpoints of moisture absorption heat resistance and chemical resistance. As the surface treatment agent, a silane coupling agent is preferable. Specific examples of the silane coupling agent include aminosilanes such as γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Epoxysilanes, vinylsilanes such as γ-methacryloxypropyltrimethoxysilane, cationic silanes such as N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride, and phenylsilanes And the like, and one or more of them can be used in an appropriate combination. Specifically, those treated with epoxysilane (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) are preferable.

  When a silane coupling agent is used, its content is not limited, but from the viewpoint of improving moisture absorption heat resistance, the ratio of the silane coupling agent to the component (D) is set to 0.05 to 5% by mass. And more preferably 0.1 to 3% by mass. When two or more silane coupling agents are used in combination, the total amount thereof preferably satisfies the above ratio.

[I-5. Maleimide compound (E)]
In the present invention, it is preferable to use a maleimide compound (E) in order to improve the moisture absorption and heat resistance of the insulating layer of the printed wiring board. The maleimide compound (E) used is not particularly limited as long as it has a maleimide group. Specifically, bis (4-maleimidophenyl) methane, 2,2-bis {4- (4-maleimide) Phenoxy) -phenyl} propane, bis (3,5-dimethyl-4-maleimidophenyl) methane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, bis (3,5-diethyl-4-maleimide) Phenyl) methane, tris (4-maleimidophenyl) methane, a maleimide compound represented by the formula (5), a long-chain alkylbismaleimide represented by the formula (6), and the like.

  Among them, the maleimide compound represented by the formula (5) is preferable from the viewpoints of moisture absorption heat resistance and flame resistance. As the compound, a commercially available product can be used, and examples of such a compound include BMI-2300 manufactured by K-I Kasei Corporation.

（式中、Ｒ^５は各々独立に、水素原子又はメチル基を表す。ｎ^５は平均値として１〜１０の範囲である。）

(In the formula, R ⁵ each independently represents a hydrogen atom or a methyl group. N ⁵ ranges from 1 to 10 as an average value.)

  From the viewpoint of obtaining high plating peel strength, it is preferable to use a long-chain alkyl bismaleimide represented by the formula (6). As the compound, a commercially available product can be used, and examples of such a compound include BMI-1000P manufactured by K-I Kasei Corporation.

（式中ｎ^６は、１以上３０以下の整数を示す。）

(In the formula, n ⁶ represents an integer of 1 or more and 30 or less.)

  It is to be noted that these may be blended in the form of a prepolymer of a maleimide compound or a prepolymer of a maleimide compound and an amine compound, and one or more of them may be used as appropriate.

  The content of the maleimide compound (E) in the present invention is preferably 5 to 50 parts by mass based on 100 parts by mass of the total of the epoxy compound (A), the cyanate ester compound (B) and the maleimide compound (E). Preferably, it is 5 to 20 parts by mass. When the amount of the maleimide compound is in the range of 5 to 50 parts by mass, good heat resistance to moisture absorption can be obtained.

[I-6. Other components)
In the present invention, in addition to the epoxy compound (A), the cyanate ester compound (B), the silica (C) treated with aminosilane, the inorganic filler (D) soluble in acid and the maleimide compound (E), May contain one or more other components.

  Rubber may be added to the insulating layer of the present invention from the viewpoint of improving the handleability of the resin sheet. The rubber is not limited as long as it is a commonly used rubber. Specific examples include natural rubber (NR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), and ethylene. -Propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), urethane rubber (U), silicone rubber, fluorine rubber (FKM). One type of these rubbers may be used alone, or two or more types may be used in any combination and in any ratio. In particular, acrylonitrile butadiene rubber (NBR) is preferable from the viewpoint of uniformity.

  The resin sheet of the present invention may contain a wet dispersant from the viewpoint of improving the productivity of the resin sheet. The wetting and dispersing agent is not limited as long as it is a wetting and dispersing agent generally used for paints and the like. Specific examples include Disperbyk-110, -111, -180, -161, BYK-W996, -W9010, and -W903 manufactured by Big Chemie Japan KK. One of these wetting and dispersing agents may be used alone, or two or more thereof may be used in an optional combination and ratio.

  When a wetting and dispersing agent is used, its content is not limited, but from the viewpoint of improving the productivity of the resin sheet, the total amount of the aminosilane-treated silica (C) and the acid-soluble inorganic filler (D) is preferably On the other hand, the proportion of the wetting and dispersing agent is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass. When two or more types of wet dispersants are used in combination, it is preferable that the total amount thereof satisfies the above ratio.

  The insulating layer of the present invention may contain a curing accelerator for the purpose of adjusting the curing speed and the like. The curing accelerator is known as a curing accelerator such as an epoxy compound or a cyanate ester compound, and is not particularly limited as long as it is generally used. Specific examples include organic metal salts containing metals such as copper, zinc, cobalt, nickel and manganese (eg, zinc octylate, cobalt naphthenate, nickel octylate, manganese octylate), imidazoles and derivatives thereof (eg, -Ethyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 2,4,5-triphenylimidazole and the like, and tertiary amines (for example, triethylamine, tributylamine and the like). One of these curing accelerators may be used alone, or two or more thereof may be used in an optional combination and ratio.

  When using a curing accelerator, the content is not limited, but from the viewpoint of obtaining a high glass transition temperature, the ratio of the curing accelerator to 0.01 to 5 parts by mass with respect to 100 parts by mass of the resin solid content of the insulating layer. Part by mass, more preferably 0.05 to 4 parts by mass. When two or more curing accelerators are used in combination, the total amount thereof preferably satisfies the above ratio.

  The insulating layer of the present invention may contain other various polymer compounds or flame-retardant compounds as long as the desired properties are not impaired. The polymer compound and the flame retardant compound are not limited as long as they are commonly used. Examples of the polymer compound include various thermosetting resins and thermoplastic resins, and oligomers and elastomers thereof. Examples of the flame-retardant compound include a phosphorus-containing compound (for example, phosphate ester, melamine phosphate, phosphorus-containing epoxy resin, etc.), a nitrogen-containing compound (for example, melamine, benzoguanamine, etc.), an oxazine ring-containing compound, a silicone compound, and the like. No. One of these polymer compounds or flame retardant compounds may be used alone, or two or more thereof may be used in any combination and in any ratio.

  Further, the insulating layer of the present invention may contain various additives for various purposes as long as the desired properties are not impaired. Examples of additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, And a brightener. One of these additives may be used alone, or two or more thereof may be used in an optional combination and ratio.

[I-7. varnish〕
The components (A) to (D) and, if necessary, the other components described above can be dissolved or dispersed in a solvent to form a varnish. Such a varnish can be suitably used as a varnish for producing a resin sheet of the present invention described below. The solvent is not limited as long as it can suitably dissolve or disperse each of the above-mentioned components and does not impair the intended effect of the present invention. Specific examples include alcohols (methanol, ethanol, propanol, etc.), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), amides (eg, dimethylacetamide, dimethylformamide, etc.), aromatic hydrocarbons (eg, toluene , Xylene, etc.). One of these organic solvents may be used alone, or two or more thereof may be used in an optional combination and ratio.

[II-1. Resin sheet)
The resin sheet of the present invention has the above-described insulating layer of the present invention on an outer layer. When a printed wiring board is manufactured using the resin sheet, the outer layer may be separated or etched from the resin sheet as necessary.

  The outer layer is not particularly limited, but may be a polymer film, a metal foil or a metal film. Specific examples of the polymer film include polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, polyurethane, ethylene-vinyl oxide copolymer, polyethylene terephthalate, polyester such as polyethylene naphthalate and polybutylene terephthalate, polyethylene, polypropylene, ethylene -Propylene copolymer, polymethylpentene, films containing at least one resin selected from the group consisting of polyimide and polyamide, and release films coated with a release agent on the surface of these films, Among these, polyester, polyimide and polyamide are particularly preferred, and among them, polyethylene terephthalate, which is a kind of polyester, is particularly preferred.

  The thickness of the polymer film is not particularly limited, and may be, for example, 0.002 to 0.1 mm. Specific examples of the metal foil or the metal film include a foil or a film made of a metal such as copper or aluminum, among which a copper foil or a copper film is preferable, and particularly, an electrolytic copper foil, a rolled copper foil, and a copper alloy film are preferable. Can be used for A known surface treatment such as a nickel treatment or a cobalt treatment may be applied to the metal foil or the metal film. The thickness of the metal foil or metal film can be appropriately adjusted depending on the intended use, but is preferably, for example, in the range of 5 to 70 μm.

  The method for producing the resin sheet of the present invention by forming the insulating layer of the present invention on the outer layer described above is not limited. As an example, a method of applying the above-described varnish to the surface of the above-mentioned outer layer, drying under heating or reduced pressure, and removing the solvent to solidify the varnish may be mentioned. Drying conditions are not particularly limited, but drying is performed so that the content ratio of the solvent to the total amount of the insulating layer thus formed is usually 10 parts by mass or less, preferably 5 parts by mass or less. The conditions for achieving such drying vary depending on the amount of the organic solvent in the varnish. It should be done. The thickness of the insulating layer in the resin sheet of the present invention is not limited, but from the viewpoint of better removal of light volatile components during drying, and from the viewpoint of more effectively and reliably exhibiting the function as a resin sheet, 0.1 to 500 μm. Is suitable. When the resin composition has fluidity without containing a solvent, the resin composition may be used like a varnish to form an insulating layer.

  When comparing an insulating layer formed from a varnish or a resin composition having fluidity with a method formed by a different method (such as melting and pressing a resin), the former is better in the layer. Excellent in uniformity and adhesion to the outer layer.

  The resin sheet of the present invention can be used as a build-up material for a printed wiring board. In a printed wiring board formed using the resin sheet of the present invention, the insulating layer of the present invention constitutes an insulating layer in the printed wiring board. The insulating layer in the printed wiring board is usually hardened. The printed wiring board will be described in detail below.

[II-2. (Printed wiring board)
The printed wiring board of the present invention can be obtained by using the resin sheet of the present invention as a build-up material for a core base material. The core substrate is a substrate serving as a core in the build-up method, and is a metal foil-clad laminate in which the resin insulating layer is completely cured. On the surface of the core substrate, a conductor circuit is formed by a metal foil of a metal foil-clad laminate generally used in the art or a conductor layer obtained by peeling and plating the metal foil.

  The core substrate is mainly formed of a patterned conductor layer (circuit) on one or both surfaces of a substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. What was done. Further, when a multilayer printed wiring board is manufactured, an inner layer circuit board of an intermediate product on which an insulating layer or a conductor layer is to be further formed is also included in the circuit board according to the present invention. The surface of the conductor layer (circuit) is preferably subjected to a roughening treatment in advance by a blackening treatment or the like from the viewpoint of the adhesion of the insulating layer to the circuit board.

  The insulating layer of the resin sheet of the present invention is cured to form the insulating layer in the printed wiring board.

  Specifically, when the resin sheet of the present invention is used as a build-up material, the surface of the insulating layer of the resin sheet is treated by a conventional method, and a wiring pattern (conductor layer) is formed on the surface of the insulating layer by plating. Thus, the printed wiring board of the present invention is obtained.

  Other various steps (for example, a hole processing for forming a via hole, a through hole, and the like) may be added as necessary.

  Hereinafter, each process for manufacturing the printed wiring board of the present invention will be described.

1) Surface treatment The surface treatment of the insulating layer is performed from the viewpoint of improving the adhesion between the insulating layer and the plated conductor layer, removing smear, and the like. Examples of the surface treatment include desmear treatment and silane coupling treatment. The desmear treatment preferably includes swelling, surface roughening and smear dissolution, and neutralization treatment. Preferably, the roughening treatment is performed with a swelling agent and an alkaline oxidizing agent, and the neutralization treatment is performed with an acidic reducing agent. In the present invention, by using silica treated with an aminosilane-based coupling agent, a collapse mark can be reduced and a low surface roughness can be achieved.

  More preferably, the roughening treatment also serves to remove smears generated in the drilling step. In this case, since the roughening state is different depending on the degree of curing of the insulating layer, it is preferable to select the optimum conditions for the lamination molding described later in combination with the subsequent roughening treatment conditions and plating conditions.

  In a preferred embodiment, the roughening treatment first swells the surface insulating layer using a swelling agent. The swelling agent is not limited as long as it improves the wettability of the surface insulating layer and can swell the surface insulating layer to the extent that oxidative decomposition is promoted in the next surface roughening and smear dissolution treatment. . Examples include alkaline solutions, surfactant solutions and the like.

  Next, the swollen surface is treated with an oxidizing agent to oxidatively decompose and roughen the surface. At this time, smear generated in the processing is also removed. Examples of the oxidizing agent include an alkaline permanganate solution, and specific examples thereof include a potassium permanganate aqueous solution and a sodium permanganate aqueous solution. Such an oxidizing agent treatment is called wet desmearing. In addition to the wet desmearing, dry desmearing by plasma treatment or UV treatment, mechanical polishing by buff, etc., and other known roughening treatments such as sand blasting are appropriately combined and performed. May be.

  Further, by the neutralization treatment, the oxidizing agent used in the pretreatment is neutralized with the reducing agent. Examples of the reducing agent include an amine-based reducing agent, and specific preferred examples thereof include an acidic aqueous solution such as an aqueous solution of hydroxylamine sulfate, an aqueous solution of ethylenediaminetetraacetic acid, and an aqueous solution of nitrilotriacetic acid.

  In forming a fine wiring pattern, it is preferable that the surface unevenness of the insulating layer after the roughening treatment is small. Specifically, the Rz value is preferably 4.0 μm or less, more preferably 2.0 μm or less. Since the surface irregularities after the roughening treatment are determined according to the degree of hardening of the insulating layer, the conditions of the roughening treatment, and the like, it is preferable to select optimal conditions for obtaining desired surface irregularities. In particular, the insulating layer of the present invention can secure the adhesion to the plated conductor layer even if the surface roughness is low, and is extremely suitable.

2) Formation of Conductive Layer As a method of forming a wiring pattern (conductive layer) by plating, a semi-additive method, a full-additive method, a subtractive method, and the like can be given. Among them, the semi-additive method is preferable from the viewpoint of forming a fine wiring pattern.

  As an example of a method of forming a pattern by the semi-additive method, a thin conductor layer is formed on an insulating layer surface by electroless plating or the like, and then selectively electrolytically plated using a plating resist (pattern plating), and then a plating resist is formed. And a method of forming a wiring pattern by etching the whole by an appropriate amount.

  As an example of a method of forming a pattern by the full additive method, there is a method of forming a wiring pattern by previously forming a pattern on a surface of an insulating layer using a plating resist and selectively attaching electroless plating or the like.

  As an example of a method of forming a pattern by a subtractive method, a method of forming a wiring pattern by forming a conductive layer on a surface of an insulating layer by plating and then selectively removing the conductive layer using an etching resist is cited. Can be Alternatively, when the outer layer of the resin sheet is a metal foil or a metal film, these may be etched to form a wiring pattern.

  When a wiring pattern is formed by plating, it is preferable to perform drying after plating, from the viewpoint of improving the adhesion strength between the insulating layer and the conductor layer. In the pattern formation by the semi-additive method, the electroless plating and the electrolytic plating are performed in combination. In this case, it is preferable to perform drying after the electroless plating and after the electrolytic plating, respectively. Drying after electroless plating is preferably performed at, for example, 80 to 180 ° C for 10 to 120 minutes, and drying after electrolytic plating is preferably performed at, for example, 130 to 220 ° C for 10 to 120 minutes. . Since the electroless plating layer has better layer uniformity than the electroplating layer, the two can be distinguished.

3) Others In order to manufacture a printed wiring board, the resin sheet of the present invention may be subjected to hole processing. This processing is performed to form via holes, through holes, and the like. The hole processing is performed using any one of known methods such as an NC drill, a carbon dioxide laser, a UV laser, a YAG laser, and plasma, or a combination of two or more as necessary.

  The printed wiring board of the present invention can be a multilayer printed wiring board. For example, after forming a laminated board of the present invention that has been subjected to a plating process, an inner layer circuit is formed thereon, and a blackening process is performed on the obtained circuit to obtain an inner layer circuit board. On one or both sides of the inner layer circuit board thus obtained, the resin sheet of the present invention is arranged, and further a metal foil (eg, copper or aluminum) or a release film (polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, Multilayered printed wiring by repeatedly laminating and forming a film having a release agent applied to the surface thereof, such as an ethylene tetrafluoroethylene copolymer film, a polyester film, a polyimide film, or a polyamide film. A board is manufactured.

Lamination molding is a method generally used for lamination molding of a normal printed wiring board laminate, for example, using a multi-stage press, a multi-stage vacuum press, a laminator, a vacuum laminator, an autoclave molding machine, and the like. The temperature and the pressure are, for example, 0.1 to 100 kgf / cm ² (about 9.8 kPa to about 38 MPa), and the heating time is appropriately selected, for example, in the range of 30 seconds to 5 hours. If necessary, post-curing may be performed at a temperature of, for example, 150 to 300 ° C. to adjust the degree of curing.

  Hereinafter, the present invention will be described in detail with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited thereto.

(Production of cyanate compound)
Synthesis Example 1: Synthesis of α-naphthol aralkyl cyanate compound (7)

（式中、ｎ^７は平均値として３から４までの範囲である。）

(Where n ⁷ ranges from 3 to 4 as an average)

  The reactor equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser was previously cooled to 0 to 5 ° C. with a saline solution, and 7.47 g (0.122 mol) of cyanogen chloride and 35% hydrochloric acid were added thereto. 75 g (0.0935 mol), 76 ml of water and 44 ml of methylene chloride were charged.

  The α-naphthol aralkyl resin represented by the following formula (8) (SN485, OH equivalent weight: 214 g / eq. Softening) is stirred and maintained at a temperature in the reactor of -5 to + 5 ° C. and a pH of 1 or less. Point: 86 ° C., a solution of 20 g (0.0935 mol) of Nippon Steel Chemical Co., Ltd. and 14.16 g (0.14 mol) of triethylamine dissolved in 92 ml of methylene chloride was added dropwise using a dropping funnel over 1 hour. After completion of the dropwise addition, 4.72 g (0.047 mol) of triethylamine was further added dropwise over 15 minutes.

（式中、ｎ^８は平均値として３から４までの範囲である。）

(Wherein, n ⁸ ranges from 3 as an average value up to 4.)

  After completion of the dropwise addition, the mixture was stirred at the same temperature for 15 minutes, then, the reaction solution was separated, and the organic phase was separated. After the obtained organic phase was washed twice with 100 ml of water, methylene chloride was distilled off under reduced pressure by an evaporator, and finally, it was concentrated and dried at 80 ° C. for 1 hour to obtain α- represented by the above-mentioned compound 7. 23.5 g of a cyanate ester of an naphthol aralkyl resin (α-naphthol aralkyl-type cyanate compound) was obtained.

(Preparation of resin composition and resin sheet)
Example 1
As the epoxy compound (A), 85.7 parts by mass of a MEK solution of a biphenylaralkyl type epoxy compound (NC-3000-FH, epoxy equivalent: 320 g / eq., Manufactured by Nippon Kayaku Co., Ltd.) (nonvolatile content: 70% by mass) (60 parts by mass in terms of non-volatile content) and methyl ethyl ketone (hereinafter referred to as “MEK”) of the α-naphthol aralkyl-type cyanate ester compound (cyanate equivalent: 261 g / eq.) Obtained in Synthesis Example 1 as the cyanate ester compound (B). The solution may be abbreviated.) 60 parts by mass of the solution (nonvolatile content 50% by mass) (30 parts by mass in terms of nonvolatile content), and as the aminosilane-treated silica (C), phenylaminosilane-treated silica MEK slurry (SC2050-MTX, 107, manufactured by Admatechs Co., Ltd., average particle diameter 0.5 μm, nonvolatile component 70 mass%) 1 part by mass (75 parts by mass in terms of nonvolatile content), as an inorganic filler (D) soluble in acid, magnesium oxide MEK slurry (SMO-0.4, manufactured by Sakai Chemical Industry Co., Ltd .; As a maleimide compound (E), a novolak-type maleimide compound (BMI-2300, silicon carbide) represented by the following formula (5) was used. 5.0 parts by mass of bismaleimide compound (BMI-1000P, manufactured by K-I Kasei Corporation), 5.0 parts by mass of 2,4,5-triphenylimidazole as a curing accelerator 15 parts by mass of DMAc solution (manufactured by Wako Pure Chemical) (3% by mass in terms of nonvolatile content) and 0.8 parts by mass of MEK solution of zinc octylate (10% by mass in nonvolatile content) In conversion The .08 parts by weight) was added to the MEK solution. After the addition, the mixture is stirred for 30 minutes using a high-speed stirrer to obtain an epoxy compound (A), a cyanate ester compound (B), aminosilane-treated silica (C), an acid-soluble inorganic filler (D), A varnish containing the maleimide compound (E) was obtained. The varnish was applied to a 38 μm-thick polyethylene terephthalate film (TR1-38, manufactured by Unitika Ltd.) having a surface coated with a release agent, and heated and dried at 100 ° C. for 3 minutes to form an insulating layer. A resin sheet having a terephthalate film as an outer layer was obtained.

（式中、Ｒ^５は各々独立に、水素原子又はメチル基を表す。ｎ^５は平均値として１〜１０の範囲である。）

(In the formula, R ⁵ each independently represents a hydrogen atom or a methyl group. N ⁵ ranges from 1 to 10 as an average value.)

(Preparation of inner layer circuit board)
Both sides of a glass cloth base material BT resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.2 mm, CCL-HL832NX type A, manufactured by Mitsubishi Gas Chemical Co., Ltd.) on which an inner layer circuit is formed are manufactured by Mec Corporation. The copper layer was roughened by etching at 1 μm with CZ8100 to obtain an inner circuit board.

[Production of printed wiring board]
After placing the insulating layer surface of the obtained resin sheet on the inner layer circuit board and performing evacuation (5.0 MPa or less) for 30 seconds using a vacuum laminator (manufactured by Nichigo Morton), a pressure of 10 kgf / cm ^{2 was applied} . Laminate molding was performed at a temperature of 100 ° C. for 30 seconds. Further, a laminate was formed at a pressure of 10 kgf / cm ^{2 at} a temperature of 100 ° C. for 60 seconds to obtain a printed wiring board. By drying the obtained printed wiring board at 180 ° C. for 60 minutes, curing was sufficiently advanced to obtain a printed wiring board.

Example 2
A varnish was prepared in the same manner as in Example 1 except that the amount of the magnesium oxide MEK slurry (SMO-0.4, nonvolatile content: 70% by mass) was changed to 42.9 parts by mass (30.0 parts by mass in terms of nonvolatile content). (Solution of resin composition) was prepared to obtain a resin sheet and a printed wiring board using the same.

Example 3
A varnish was prepared in the same manner as in Example 1, except that the amount of the magnesium oxide MEK slurry (SMO-0.4, nonvolatile content: 70% by mass) was changed to 85.7 parts by mass (60.0 parts by mass in terms of nonvolatile content). (Solution of resin composition) was prepared to obtain a resin sheet and a printed wiring board using the same.

Example 4
A varnish was prepared in the same manner as in Example 1 except that the amount of the magnesium oxide MEK slurry (SMO-0.4, nonvolatile content: 70% by mass) was changed to 178.6 parts by mass (125.0 parts by mass in terms of nonvolatile content). (Solution of resin composition) was prepared to obtain a resin sheet and a printed wiring board using the same.

Example 5
The amount of magnesium oxide MEK slurry (SMO-0.4, nonvolatile content 70% by mass) used was 85.7 parts by mass (60.0 parts by mass in terms of nonvolatile content), and phenylaminosilane-treated silica MEK slurry (SC2050-MTX, nonvolatile content) A varnish (resin of a resin composition) was prepared in the same manner as in Example 1 except that the amount of the active component (70% by mass) was changed to 285.7 parts by mass (200 parts by mass in terms of nonvolatile components), and a resin sheet was prepared. And a printed wiring board using the same.

Example 6
The amount of magnesium oxide MEK slurry (SMO-0.4, nonvolatile content 70% by mass) used was 85.7 parts by mass (60.0 parts by mass in terms of nonvolatile content), and phenylaminosilane-treated silica MEK slurry (SC2050-MTX, nonvolatile content) A varnish (resin of a resin composition) was prepared in the same manner as in Example 1 except that the amount of the active ingredient (70% by mass) was changed to 428.6 parts by mass (300 parts by mass in terms of nonvolatile components). And a printed wiring board using the same.

Example 7
Aminosilane-treated silica (SC2050-MTX, non-volatile content 70 parts by mass) was completely replaced with untreated silica MEK slurry (SO-C2, non-volatile content 70 parts by mass), and phenylaminosilane (KBM-573, Shin-Etsu Chemical Co., Ltd.) was contained in the varnish. A varnish (solution of a resin composition) was prepared in the same manner as in Example 1 except that was added later, to obtain a resin sheet and a printed wiring board using the same.

Comparative Example 1
A varnish (solution of a resin composition) was prepared in the same manner as in Example 1 except that the amount of magnesium oxide MEK slurry (SMO-0.4, nonvolatile content: 70% by mass) was changed to 0 parts by mass, and a resin sheet was prepared. And a printed wiring board using the same.

Comparative Example 2
The amount of magnesium oxide MEK slurry (SMO-0.4, nonvolatile content 70% by mass) used was 178.6 parts by mass (125.0 parts by mass in terms of nonvolatile content), and phenylaminosilane-treated silica MEK slurry (SC2050-MTX, nonvolatile content) Varnish (solution of the resin composition) was prepared in the same manner as in Example 1 except that the amount of the active ingredient (70% by mass) was changed to 0 parts by mass, to obtain a resin sheet and a printed wiring board using the same. .

Comparative Example 3
The varnish was prepared in the same manner as in Example 1 except that the aminosilane-treated silica MEK slurry (SC2050-MTX, nonvolatile content 70% by mass) was completely replaced with the epoxysilane-treated silica MEK slurry (SC2050-MB, nonvolatile content 70% by mass). A solution of the resin composition) was prepared to obtain a resin sheet and a printed wiring board using the same.

Comparative Example 4
A varnish (resin) was prepared in the same manner as in Example 1 except that the aminosilane-treated silica MEK slurry (SC2050-MTX, nonvolatile content: 70 parts by mass) was completely replaced with the vinylsilane-treated silica MEK slurry (SC2050-MNU, nonvolatile content: 70 parts by mass). A solution of the composition) was prepared to obtain a resin sheet and a printed wiring board using the same.

[Evaluation of printed wiring boards]
Wet roughening treatment of printed wiring boards and conductor layer plating:
The printed wiring board outer layers obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were peeled off. The exposed insulating layer is subjected to an electroless copper plating process manufactured by Uemura Kogyo (chemical name: MCD-PL, MDP-2, MAT-SP, MAB-4-C, MEL-3-APEA ver. 2). And about 0.8 μm of electroless copper plating, and dried at 130 ° C. for 1 hour. Subsequently, electrolytic copper plating was performed so that the thickness of the plated copper became 18 μm, and drying was performed at 180 ° C. for 1 hour. Thus, a sample in which a conductor layer (plated copper) having a thickness of 18 μm was formed on the insulating layer was prepared and subjected to the following evaluation.
(1) Adhesive strength of plated copper Using the sample prepared by the above procedure, the adhesive strength of plated copper was measured three times according to JIS C6481, and an average value was obtained. For samples that had swelled by drying after electrolytic copper plating, the swelling after plating was “Yes”, and for samples that did not swell, the swelling after plating was “No”. With respect to the sample having “swelling” of plating, evaluation was performed using a portion that did not swell. The results are shown in Table 1.
(2) Surface Roughness After etching the surface-plated copper of the sample prepared by the above procedure, using a laser microscope (VK-9500, manufactured by KEYENCE), the Rz (10-point average roughness) of the surface of the insulating layer was determined by a 3000-fold image. ) And Ra (arithmetic average roughness). The results are shown in Table 1.
(3) Thermal expansion coefficient (CTE)
Using a resin sheet having an insulating layer thickness of 0.05 mm cured at 180 ° C. for 2 hours, the temperature was raised from 25 ° C. to 250 ° C. at a rate of 10 ° C. per minute by a thermomechanical analyzer (Q400 manufactured by TA Instruments). The coefficient of thermal expansion was measured at a temperature between 150C and 150C. The results are shown in Table 1.

As described above, the resin sheet of the present invention, when used as a material for the insulating layer of a printed wiring board, has various effects such as excellent handling properties of the resin sheet and excellent adhesion between the insulating layer and the plated conductor layer. Is extremely useful as a material for an insulating layer of a printed wiring board.

Claims (12)

Polymer film, selected from the group consisting of metal foil and metal film, an outer layer of any one type, and a resin sheet including an insulating layer laminated on the outer layer,
A resin sheet in which the insulating layer contains an epoxy compound (A), a cyanate ester compound (B), an aminosilane-treated silica (C), and an acid-soluble inorganic filler (D).   The resin sheet according to claim 1, wherein the content of the aminosilane-treated silica (C) in the insulating layer is 50 to 350 parts by mass with respect to 100 parts by mass of the resin solid content.   The resin sheet according to claim 1, wherein the content of the acid-soluble inorganic filler (D) in the insulating layer is 20 to 150 parts by mass with respect to 100 parts by mass of the resin solid content.   The resin sheet according to any one of claims 1 to 3, wherein the acid-soluble inorganic filler (D) is magnesium hydroxide or magnesium oxide.   The resin sheet according to any one of claims 1 to 4, wherein the resin composition further includes a maleimide compound (E).   The resin sheet according to any one of claims 1 to 5, wherein the polymer film is any one selected from the group consisting of polyester, polyimide, and polyamide.   7. The insulating layer according to claim 1, wherein the insulating layer is obtained by applying a resin composition containing the components (A) to (D) on an outer layer, followed by drying under heating or reduced pressure and solidification. 8. The resin sheet according to claim 1.   A printed wiring board comprising the insulating layer according to any one of claims 1 to 7, laminated on a circuit board having a core substrate and a conductor circuit formed on the core substrate.   9. The printed wiring board according to claim 8, wherein the insulating layer is surface-treated, and includes a conductor layer patterned on the surface.   The printed wiring board according to claim 9, wherein the surface treatment is a desmear treatment including a roughening treatment with a swelling agent and an alkaline oxidizing agent, and a neutralization treatment with an acidic reducing agent.   The printed wiring board according to claim 9, wherein the conductor layer includes a conductor layer formed by a semi-additive method or a conductor layer formed by a subtractive method. The printed wiring board according to claim 9, wherein the conductor layer includes a conductor layer obtained by etching an outer layer made of the metal foil or the metal film according to claim 1.