JP6710955B2 - Prepreg - Google Patents

Description

The present invention relates to prepreg. Furthermore, the present invention relates to a printed wiring board using a prepreg and a semiconductor device.

As a method of manufacturing a wiring board (printed wiring board), a build-up method of alternately stacking conductor layers and insulating layers on which circuits are formed is widely used, and the insulating layer is formed by curing a prepreg. , And those formed by curing a resin composition are known (see, for example, Patent Document 1).

JP, 2005-82535, A

In recent years, in the production of printed wiring boards, there has been an increasing demand for improvement in handling properties, embedding properties, peel strength and the like of prepregs. In addition, there is an increasing demand for suppressing warpage that occurs when an insulating layer is formed using a prepreg.

The object of the present invention is to solve the above problems, handleability, embeddability, and copper plating peel strength is improved, further warp or the like prepreg does not occur, a printed wiring board using the same. And to provide a semiconductor device.

That is, the present invention includes the following contents.
[1] A sheet-shaped fiber base material, and a resin composition impregnated in the sheet-shaped fiber base material,
The resin composition contains (a) an elastomer, (b) a thermosetting resin having an aromatic structure, and (c) an inorganic filler,
A prepreg in which the average maximum length of domains contained in a cured product obtained by thermosetting a resin composition is 15 μm or less.
[2] The prepreg according to [1], wherein the resin composition contains (d) organic particles.
[3] The component (a) is one or more selected from resins having a glass transition temperature of 25° C. or lower or a liquid at 25° C. and having a functional group capable of reacting with the component (b), [1] ] Or the prepreg as described in [2].
[4] The component (a) is a butadiene structural unit, a polysiloxane structural unit, a (meth)acrylate structural unit, an alkylene structural unit, an alkyleneoxy structural unit, an isoprene structural unit, an isobutylene structural unit, a chloroprene structural unit, a urethane structural unit, The prepreg according to any one of [1] to [3], having one or more structural units selected from polycarbonate structural units.
[5] The prepreg according to any one of [1] to [4], which contains a solid epoxy resin at a temperature of 20° C. as the component (b).
[6] As the component (b), a liquid epoxy resin at a temperature of 20° C. and a solid epoxy resin at a temperature of 20° C. are included, and the liquid epoxy resin:solid epoxy resin mass ratio is 1:0.3 to. The prepreg according to any one of [1] to [5], which is 1:10.
[7] The prepreg according to [5] or [6], which does not contain a resin having a naphthalene skeleton and a molecular weight of 400 or more as a solid epoxy resin at a temperature of 20°C.
[8] When the mass of the component (a) in the resin composition is A and the mass of the component (b) is B, (A/(A+B))×100 is 20 to 70, [1] to [1]. 7] The prepreg according to any one of 7).
[9] The prepreg according to any one of [1] to [8], wherein the content of the component (c) is 25 to 70 mass% when the nonvolatile component in the resin composition is 100 mass %.
[10] When the mass of the component (a) in the resin composition is A, the mass of the component (b) is B, and the mass of the component (d) is D, (D/(A+B+D))×100 is 10 or less. The prepreg according to any one of [2] to [9].
[11] The prepreg according to any one of [1] to [10], which is for forming an insulating layer of a printed wiring board.
[12] The prepreg according to any one of [1] to [11], which is for forming a buildup layer of a printed wiring board.
[13] A printed wiring board including an insulating layer formed by the prepreg according to any one of [1] to [12].
[14] A semiconductor device comprising the printed wiring board according to [13].

According to the present invention, it is possible to provide a prepreg in which handling property, embedding property, and copper plating peel strength are improved, and further, warpage or the like does not occur, a printed wiring board using the same, and a semiconductor device.

FIG. 1 is a cross-sectional photograph of a cured product of the prepreg of Example 1. FIG. 2 is a cross-sectional photograph of a cured product of the prepreg of Example 2. FIG. 3 is a cross-sectional photograph of a cured product of the prepreg of Comparative Example 1.

Hereinafter, the prepreg, the printed wiring board, and the semiconductor device of the present invention will be described in detail.

[Prepreg]
The prepreg of the present invention includes a sheet-shaped fiber base material and a resin composition impregnated in the sheet-shaped fiber base material, and the resin composition is (a) an elastomer and (b) a thermosetting resin having an aromatic structure. A resin and (c) an inorganic filler are contained, and the average maximum length of domains contained in a cured product obtained by thermosetting a resin composition is 15 μm or less.

From the viewpoint of improving the handling property, embedding property, and copper plating peel strength of the prepreg, the average maximum length of the domains contained in the cured product obtained by thermosetting the resin composition is preferably 15 μm or less and 10 μm or less, It is more preferably 5 μm or less, and further preferably not confirmed (domain does not exist). By setting the average maximum length of the domain to 15 μm or less, the embedding property of the prepreg can be improved.

The average maximum length of a domain can be measured as follows. The prepreg thermally cured under the conditions of 100° C. for 30 minutes and then 170° C. for 30 minutes was subjected to cross-sectional observation using a FIB-SEM composite device (“SMI3050SE” manufactured by SII Nano Technology Co., Ltd.). .. Specifically, a cross section in a direction perpendicular to the surface of the prepreg was carved by FIB (focused ion beam), and a cross-sectional SEM image (observation width 60 μm, observation magnification 2,000 times) was acquired. SEM images of cross-sections randomly selected at 5 sites were observed, the largest domain existing in the SEM image of cross-section was selected, the maximum length of each selected domain was measured, and the average value was taken as the average maximum length. The maximum length is the length of the longest straight line that can be drawn in the domain region. In the cured product obtained by thermosetting the resin composition, the components of the resin composition may not be uniformly mixed and may be unevenly distributed. When observing a cross-sectional SEM image of a cured product in which such constituent components are unevenly distributed, a sea-island structure due to the uneven distribution of constituent components is observed. In the present invention, the domain means an island portion of such a sea-island structure.

Although details will be described later, when manufacturing a wiring board, the wiring layer is embedded in the prepreg of the present invention, thereby forming an embedded wiring layer. The prepreg of the present invention has improved handling properties, embedding properties, and copper plating peel strength, and from the viewpoint of suppressing the occurrence of warpage, the resin composition has a (a) elastomer and (b) an aromatic structure. It contains a curable resin and (c) an inorganic filler. The resin composition further contains additives such as (d) organic particles, (e) curing agent, (f) curing accelerator, (g) thermoplastic resin, and (h) flame retardant, if necessary. You may stay. Hereinafter, each component contained in the resin composition will be described in detail.

(Resin composition)
<(a) Elastomer>
The resin composition contains the component (a). By including the soft resin such as the component (a), the handling property, the embedding property, and the copper plating peel strength of the prepreg are improved, and the occurrence of warpage and the like can be suppressed.

The component (a) is not particularly limited as long as it is a flexible resin, but preferably has a functional group capable of reacting with the component (b) described later. Above all, a resin which is liquid at a glass transition temperature of 25° C. or lower or 25° C. and is one or more selected from resins having a functional group capable of reacting with the component (b) is preferable.

The glass transition temperature of the resin having a glass transition temperature (Tg) of 25° C. or lower is preferably 20° C. or lower, more preferably 15° C. or lower. The lower limit of the glass transition temperature is not particularly limited, but it may be usually -15°C or higher. The resin which is liquid at 25° C. is preferably a resin which is liquid at 20° C. or lower, more preferably a resin which is liquid at 15° C. or lower.

In a preferred embodiment, the functional group capable of reacting with the component (b) is at least one selected from the group consisting of a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group and a urethane group. It is a functional group. Among them, the functional group is preferably a hydroxyl group, an acid anhydride group, an epoxy group or a phenolic hydroxyl group, more preferably a hydroxyl group, an acid anhydride group or an epoxy group. However, when an epoxy group is included as a functional group, a thermosetting resin having an aromatic structure is not included as the component (a) in order to distinguish it from the component (b).

The component (a) is a butadiene structural unit such as polybutadiene and hydrogenated polybutadiene, a polysiloxane structural unit such as silicone rubber, a (meth)acrylate structural unit, and the number of carbon atoms from the viewpoint of improving the handling property of the prepreg of the present invention. 2 to 15 alkylene structural units (preferably 3 to 10 carbon atoms, more preferably 5 to 6 carbon atoms), 2 to 15 alkyleneoxy structural units (preferably 3 to 10 carbon atoms, more It is preferable to have one or more structural units selected from 5 to 6 carbon atoms, isoprene structural units, isobutylene structural units, chloroprene structural units, urethane structural units, and polycarbonate structural units. Butadiene structural units, urethane It is more preferable to have one or more structural units selected from structural units and (meth)acrylate structural units. In addition, "(meth)acrylate" refers to methacrylate and acrylate.

One suitable embodiment of the component (a) is a functional group-containing saturated and/or unsaturated butadiene resin which is liquid at 25°C. The functional group-containing saturated and/or unsaturated butadiene resin which is liquid at 25° C. is an acid anhydride group-containing saturated and/or butadiene resin which is liquid at 25° C., and the phenolic hydroxyl group-containing saturated and/or butadiene which is liquid at 25° C. Resin, a saturated epoxy group-containing and/or butadiene resin which is liquid at 25° C., an isocyanate group-containing saturated and/or butadiene resin which is liquid at 25° C., and a urethane group-containing saturated and/or butadiene resin which is liquid at 25° C. One or more resins selected from are preferred. Here, the “saturated and/or unsaturated butadiene skeleton” means a resin containing a saturated butadiene skeleton and/or an unsaturated butadiene skeleton, and in these resins, the saturated butadiene skeleton and/or the unsaturated butadiene skeleton are main chains. Or may be contained in the side chain.

The number average molecular weight (Mn) of the functional group-containing saturated and/or unsaturated butadiene resin which is liquid at 25° C. is preferably 500 to 50,000, more preferably 1,000 to 10,000. Here, the number average molecular weight (Mn) of the resin is a polystyrene equivalent number average molecular weight measured using GPC (gel permeation chromatography).

The functional group equivalent of the functional group-containing saturated and/or unsaturated butadiene resin which is liquid at 25° C. is preferably 100 to 10,000, more preferably 200 to 5,000. The functional group equivalent is the mass of the resin containing 1 equivalent of the functional group. For example, the epoxy equivalent of the resin can be measured according to JIS K7236.

As the epoxy group-containing saturated and/or unsaturated butadiene resin which is liquid at 25° C., a saturated and/or butadiene skeleton-containing epoxy resin which is liquid at 25° C. is preferable, and a polybutadiene skeleton-containing epoxy resin which is liquid at 25° C. A liquid hydrogenated polybutadiene skeleton-containing epoxy resin is more preferable, a liquid polybutadiene skeleton-containing epoxy resin which is liquid at 25° C., and a hydrogenated polybutadiene skeleton-containing epoxy resin which is liquid at 25° C. are further preferable. Here, the "hydrogenated polybutadiene skeleton-containing epoxy resin" means an epoxy resin in which at least a part of the polybutadiene skeleton is hydrogenated, and it is not always necessary that the polybutadiene skeleton is completely hydrogenated. Specific examples of the polybutadiene skeleton-containing resin that is liquid at 25° C. and the hydrogenated polybutadiene skeleton-containing resin that is liquid at 25° C. include “PB3600” and “PB4700” (polybutadiene skeleton epoxy resin) manufactured by Daicel Corporation, Nagase Chemtex. "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin) manufactured by K.K.

The acid anhydride group-containing saturated and/or unsaturated butadiene resin which is liquid at 25° C. is preferably a saturated and/or unsaturated butadiene skeleton-containing acid anhydride resin which is liquid at 25° C. The saturated and/or unsaturated butadiene resin containing a phenolic hydroxyl group which is liquid at 25° C. is preferably a saturated and/or unsaturated butadiene skeleton-containing phenol resin which is liquid at 25° C. The saturated and/or unsaturated butadiene resin containing an isocyanate group which is liquid at 25° C. is preferably an isocyanate resin containing a saturated and/or unsaturated butadiene skeleton which is liquid at 25° C. As the urethane group-containing saturated and/or unsaturated butadiene resin which is liquid at 25°C, a saturated and/or unsaturated butadiene skeleton-containing urethane resin which is liquid at 25°C is preferable.

Another suitable embodiment of the component (a) is a functional group-containing acrylic resin having Tg of 25° C. or lower. Examples of the functional group-containing acrylic resin having Tg of 25° C. or lower include acid anhydride group-containing acrylic resin having Tg of 25° C. or lower, phenolic hydroxyl group-containing acrylic resin having Tg of 25° C. or lower, and isocyanate group containing Tg of 25° C. or lower. One or more resins selected from the group consisting of acrylic resins, urethane group-containing acrylic resins having Tg of 25° C. or lower, and epoxy group-containing acrylic resins having Tg of 25° C. or lower are preferable.

The number average molecular weight (Mn) of the functional group-containing acrylic resin having a Tg of 25° C. or lower is preferably 10,000 to 1,000,000, more preferably 30,000 to 900,000. Here, the number average molecular weight (Mn) of the resin is a polystyrene equivalent number average molecular weight measured using GPC (gel permeation chromatography).

The functional group equivalent of the functional group-containing acrylic resin having Tg of 25° C. or lower is preferably 1,000 to 50,000, more preferably 2,500 to 30,000.

The epoxy group-containing acrylic resin having a Tg of 25° C. or lower is preferably an epoxy group-containing acrylic ester copolymer resin having a Tg of 25° C. or lower, and specific examples thereof include “SG- manufactured by Nagase Chemtex Co., Ltd.” 80H" (epoxy group-containing acrylic acid ester copolymer resin (number average molecular weight Mn: 350,000 g/mol, epoxy value 0.07 eq/kg, Tg 11°C)), "SG-P3" manufactured by Nagase Chemtex Co., Ltd. ( Examples thereof include epoxy group-containing acrylic ester copolymer resin (number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg, Tg 12° C.).

The acid anhydride group-containing acrylic resin having a Tg of 25° C. or lower is preferably an acid anhydride group-containing acrylic acid ester copolymer resin having a Tg of 25° C. or lower.

As the phenolic hydroxyl group-containing acrylic resin having a Tg of 25° C. or lower, a phenolic hydroxyl group-containing acrylic acid ester copolymer resin having a Tg of 25° C. or lower is preferable, and specific examples thereof include “Nagase Chemtex Co., Ltd.”. SG-790" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn: 500000 g/mol, hydroxyl value 40 mgKOH/kg, Tg-32°C)).

Further, a preferred embodiment of the component (a) is a polyimide resin having a butadiene structural unit, a urethane structural unit, and an imide structural unit in the molecule, and the polyimide resin preferably has a phenol structure at the molecular end. ..

The number average molecular weight (Mn) of the polyimide resin is preferably 1,000 to 100,000, more preferably 10,000 to 15,000. Here, the number average molecular weight (Mn) of the resin is a polystyrene equivalent number average molecular weight measured using GPC (gel permeation chromatography).

The acid value of the polyimide resin is preferably 1 KOH/g to 30 KOH/g, more preferably 10 KOH/g to 20 KOH/g.

The content of the butadiene structure in the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass.

For details of the polyimide resin, the description in International Publication No. 2008/153208 can be referred to, and the contents thereof are incorporated herein.

The content of the component (a) in the resin composition is not particularly limited, but is preferably 80% by mass or less, more preferably 50% by mass or less, and further preferably 45% by mass or less. Further, the lower limit is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 25% by mass or more.

In the present invention, the content of each component in the resin composition is a value when the nonvolatile component in the resin composition is 100% by mass, unless otherwise specified.

<(b) Thermosetting Resin Having Aromatic Structure>
(B) As the thermosetting resin having an aromatic structure, a conventionally known thermosetting resin used when forming an insulating layer of a wiring board can be used, and among them, an epoxy resin having an aromatic structure is used. More preferable.

The epoxy resin having an aromatic structure (hereinafter, also simply referred to as “epoxy resin”) is not particularly limited as long as it has an aromatic structure. The aromatic structure is a chemical structure generally defined as aromatic, and includes polycyclic aromatic and aromatic heterocyclic rings. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, Phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidyl amine type epoxy resin having aromatic structure, glycidyl ester type epoxy having aromatic structure Resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having aromatic structure, epoxy resin having butadiene structure having aromatic structure, alicyclic epoxy resin having aromatic structure, heterocycle Type epoxy resin, spiro ring-containing epoxy resin having aromatic structure, cyclohexanedimethanol type epoxy resin having aromatic structure, naphthylene ether type epoxy resin, trimethylol type epoxy resin having aromatic structure, tetraphenylethane type epoxy resin Resin etc. are mentioned. The epoxy resins may be used alone or in combination of two or more. The component (b) is preferably one or more selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the nonvolatile component of the epoxy resin is 100% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Above all, it is preferable to include a solid epoxy resin at a temperature of 20° C. (hereinafter referred to as “solid epoxy resin”), and further to include a liquid epoxy resin at a temperature of 20° C. (hereinafter referred to as “liquid epoxy resin”). May be.

As the solid epoxy resin, naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin having an aromatic structure, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene Ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, tetraphenylethane type epoxy resin are preferable, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin, and biphenyl type epoxy resin, naphthi A lenether type epoxy resin is more preferable, and a naphthalene type tetrafunctional epoxy resin and a naphthylene ether type epoxy resin are more preferable. Specific examples of the solid epoxy resin include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), and "N-690" manufactured by DIC Corporation. (Cresol novolac type epoxy resin), "N-695" (cresol novolac type epoxy resin), "HP-7200", "HP-7200L", "HP-7200HH", "HP-7200H", "HP-7200HHH". "(Dicyclopentadiene type epoxy resin), "EXA7311", "EXA7311-G3", "EXA7311-G4", "EXA7311-G4S", "HP6000" (naphthylene ether type epoxy resin), Nippon Kayaku Co., Ltd. "EPPN-502H" (trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), Nippon Steel & Sumikin Chemicals "ESN475V" (naphthol type epoxy resin), "ESN485" (naphthol novolac type epoxy resin), Mitsubishi Chemical Corporation "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" "(Bixylenol type epoxy resin), "YL7760" (bisphenol AF type epoxy resin), "YX8800" (anthracene type epoxy resin), "PG-100", "CG-500" manufactured by Osaka Gas Chemicals, Inc. "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1031S" (tetraphenylethane type epoxy resin), " 157S70" (bisphenol novolac type epoxy resin), "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "YX8800" (anthracene type epoxy resin), "PG-100" manufactured by Osaka Gas Chemicals Co., Ltd. , "CG-500", "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation, and the like. These may be used alone or in combination of two or more.

From the viewpoint that the average maximum length of the domain is 15 μm or less, it is preferable that the solid epoxy resin does not include a resin having a naphthalene skeleton and a molecular weight of 400 or more (do not include a resin having a naphthalene skeleton and a molecular weight of 350 or more). Is more preferable, and it is more preferable that the resin having a naphthalene skeleton is not contained). The solid epoxy resin preferably does not contain a resin having a triphenyl skeleton. Furthermore, it is preferable that the solid epoxy resin does not contain a bisphenol novolac resin. Further, the solid epoxy resin preferably does not contain an epoxy resin having a biphenyl skeleton and having a molecular weight of 1000 or more (more preferably does not contain a resin having a biphenyl skeleton).
Further, the solid epoxy resin is selected from an epoxy resin having an alicyclic structure (for example, a dicyclopentadiene type epoxy resin), a resin containing a xylene skeleton, a cresol novolac type epoxy resin, and a tetraphenylethane type epoxy resin. It is preferable to contain one or more kinds, and it is more preferable to contain an epoxy resin having an alicyclic structure.

The liquid epoxy resin includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin having an aromatic structure, and glycidyl amine type epoxy resin having an aromatic structure. , A phenol novolac type epoxy resin, an alicyclic epoxy resin having an ester skeleton having an aromatic structure, a cyclohexanedimethanol type epoxy resin having an aromatic structure and an epoxy resin having a butadiene structure having an aromatic structure are preferable, and bisphenol A is preferable. Type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin and naphthalene type epoxy resin are more preferable, and bisphenol A type epoxy resin and bisphenol F type epoxy resin are further preferable. Specific examples of the liquid epoxy resin include “HP4032”, “HP4032D” and “HP4032SS” (naphthalene type epoxy resin) manufactured by DIC Corporation, “828US” and “jER828EL” (bisphenol A) manufactured by Mitsubishi Chemical Corporation. Type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "630", "630LSD" (glycidylamine type epoxy resin), manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. "ZX1059" (mixed product of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" manufactured by Nagase Chemtex Co., Ltd. (glycidyl ester type epoxy resin), "Ceroxide 2021P" manufactured by Daicel Corporation (Alicyclic epoxy resin having an ester skeleton), “ZX1658” and “ZX1658GS” (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical Co., Ltd. These may be used alone or in combination of two or more.

The liquid epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule and having a liquid aromatic ring structure at a temperature of 20°C, and the solid epoxy resin is three or more epoxies in one molecule. An epoxy resin having a group and having a solid aromatic ring structure at a temperature of 20° C. is preferable.

By using the liquid epoxy resin, the handling property and the resin flow of the prepreg can be improved, and by using the solid epoxy resin, the heat resistance and the electrical characteristics can be improved while suppressing the tack of the prepreg. When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin in order to impart both effects of the liquid epoxy resin and the solid epoxy resin, the quantity ratio (liquid epoxy resin:solid epoxy resin) is The mass ratio is preferably in the range of 1:0.1 to 1:20. From the viewpoint of obtaining the above effect, the amount ratio of the liquid epoxy resin and the solid epoxy resin (liquid epoxy resin:solid epoxy resin) is more preferably in the range of 1:0.3 to 1:10 by mass ratio, and 1 : 0.6 to 1:9 is more preferable.

The content of the epoxy resin in the resin composition is preferably 4% by mass or more, more preferably 5% by mass or more, further preferably 6% by mass from the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulation reliability. That is all. The upper limit of the content of the epoxy resin is not particularly limited as long as the effects of the present invention are exhibited, but is preferably 50% by mass or less, more preferably 30% by mass or less.

From the viewpoint of suppressing the warp of the prepreg, when the mass of the component (a) is A and the mass of the component (b) is B, A/(A+B)×100 is preferably 20 to 70, and more preferably 30 to 68. 35 to 65 are more preferable. By setting A/(A+B)×100 to 20 to 70, the warp can be effectively suppressed.

The epoxy equivalent of the epoxy resin is preferably 50 to 5000, more preferably 50 to 3000, even more preferably 80 to 2000, and even more preferably 110 to 1000. Within this range, the cross-linking density of the cured product will be sufficient and an insulating layer with a small surface roughness can be provided. The epoxy equivalent can be measured according to JIS K7236 and is the mass of the resin containing 1 equivalent of epoxy group.

The weight average molecular weight of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and further preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a polystyrene equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method. The molecular weight of 1000 or less can be measured by GC/MS (gas chromatography mass spectrometry).

<(c) Inorganic filler>
The material of the inorganic filler is not particularly limited, for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, water. Aluminum oxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide , Zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium phosphate tungstate, and the like. Among these, silica is particularly preferable. Spherical silica is preferable as the silica. The inorganic fillers may be used alone or in combination of two or more.

The average particle size of the inorganic filler is preferably 2 μm or less, more preferably 1.5 μm or less, further preferably 1.2 μm or less, more preferably 1 μm or less from the viewpoint of good embedding property. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more. Examples of commercially available inorganic fillers having such an average particle diameter include "YC100C", "YA050C", "YA050C-MJE", "YA010C" manufactured by Admatechs Co., Ltd., manufactured by Denki Kagaku Kogyo Co., Ltd. "UFP-30", "Silfill NSS-3N" manufactured by Tokuyama Corp., "Silfill NSS-4N", "Silfill NSS-5N", "SOC4", "SOC2", "SOC1" manufactured by Admatechs Co., Ltd., "BMB-05" manufactured by Kawai Lime Industry Co., Ltd. and the like can be mentioned.

The average particle diameter of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction/scattering particle size distribution measuring device, and the median diameter can be used as the average particle diameter for measurement. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction/scattering particle size distribution measuring device, "LA-500" manufactured by Horiba, Ltd. or the like can be used.

The inorganic filler is an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an organosilazane compound, a titanate coupling agent, from the viewpoint of enhancing moisture resistance and dispersibility. It is preferably treated with one or more surface treatment agents such as Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. and "KBM803" (3-mercaptopropyltrimethoxy manufactured by Shin-Etsu Chemical Co., Ltd.). Silane), Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. Ltd. "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd. "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM-4803" (long-chain epoxy type) Silane coupling agent) and the like.

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. Carbon content per unit surface area of the inorganic filler, from the viewpoint of improving dispersibility of the inorganic filler is preferably 0.02 mg / ^{m 2} or more, 0.1 mg / ^{m 2} or more preferably, 0.2 mg / ^{m 2} The above is more preferable. On the other hand, 1 mg/m ² or less is preferable, 0.8 mg/m ² or less is more preferable, and 0.5 mg/m ² or less is further preferable from the viewpoint of preventing the melt viscosity of the resin varnish and the melt viscosity in a sheet form from increasing. preferable.

The amount of carbon per unit surface area of the inorganic filler can be measured after cleaning the surface-treated inorganic filler with a solvent (for example, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent, and ultrasonic cleaning is performed at 25° C. for 5 minutes. After removing the supernatant and drying the solid content, the carbon amount per unit surface area of the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by Horiba Ltd. or the like can be used.

The content of the inorganic filler in the resin composition is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 25% by mass or more from the viewpoint of obtaining an insulating layer having a low coefficient of thermal expansion. The upper limit of the content of the inorganic filler in the resin composition is preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 65% by mass or less from the viewpoint of mechanical strength of the insulating layer, particularly elongation. is there.

<(d) Organic particles>
As the resin composition, any organic particles (also referred to as organic fillers) that can be used when forming an insulating layer of a printed wiring board may be used, and examples thereof include rubber particles, polyamide fine particles, and silicone particles. .. The component (d) preferably does not have the functional group in the component (a). The component (d) preferably has a solubility in methyl ethyl ketone of less than 5 (g/100 g) at 25°C.

The average particle diameter of the organic particles may be preferably 2 μm or less, more preferably 1 μm or less, and further preferably 0.5 μm or less. The lower limit is not particularly limited, but is 0.01 μm or more. The average particle size is an average value obtained by measuring each organic particle 50 times using a laser diffraction/scattering type particle size distribution measuring device or the like.

As the rubber particles, commercially available products may be used, and examples thereof include “EXL-2655” manufactured by Dow Chemical Japan Co., Ltd. and “AC3816N” manufactured by Ganz Kasei Co., Ltd.

When the resin composition contains organic particles, the content of the organic particles is preferably 0.1% by mass to 20% by mass, more preferably 0.2% by mass to 10% by mass, and further preferably 0.3% by mass. % To 5% by mass, or 0.5% to 4% by mass.

When the mass of the component (a) in the resin composition is A, the mass of the component (b) is B, and the mass of the component (d) is D, (D/(A+B+D))×100 is preferably 10 or less. , 8 or less are more preferable, and 5 or less are still more preferable. By setting (D/(A+B+D))×100 to 10 or less, phase separation of each component is suppressed, and the average maximum length of domains can be set to 15 μm or less. When the component (d) is blended (that is, when D is not 0), the lower limit of (D/(A+B+D))×100 is preferably 1 or more.

<(e) Curing agent>
The curing agent is not particularly limited as long as it has a function of curing a thermosetting resin such as an epoxy resin, and examples thereof include a phenol curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, and a cyanate. Examples thereof include ester-based curing agents and carbodiimide-based curing agents. The curing agents may be used alone or in combination of two or more. The component (e) is preferably one or more selected from a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent and a cyanate ester-based curing agent.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolac structure or a naphthol-based curing agent having a novolac structure is preferable from the viewpoint of heat resistance and water resistance. Also, from the viewpoint of adhesion to the wiring layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent is more preferable. Of these, a triazine skeleton-containing phenol novolac curing agent is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion to a wiring layer.

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., manufactured by Nippon Kayaku Co., Ltd. "NHN", "CBN", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495V", "SN375", "SN395" manufactured by Nippon Steel & Sumitomo Metal Corporation. , "IC-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", "EXB-9500", "HPC-9500" manufactured by DIC Corporation. Etc.

From the viewpoint of obtaining an insulating layer having excellent adhesion to the wiring layer, an active ester curing agent is also preferable. The active ester-based curing agent is not particularly limited, but in general, an ester group having a high reaction activity such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds is contained in one molecule. Compounds having two or more of them are preferably used. The active ester type curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxy compound and/or a thiol compound. Particularly, from the viewpoint of improving heat resistance, an active ester type curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester type curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid and pyromellitic acid. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Examples thereof include benzenetriol, dicyclopentadiene type diphenol compound, and phenol novolac. Here, the "dicyclopentadiene type diphenol compound" means a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoylated product of phenol novolac are preferable. Of these, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene type diphenol structure are more preferable. The "dicyclopentadiene type diphenol structure" represents a divalent structural unit composed of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-" as active ester compounds containing a dicyclopentadiene type diphenol structure. 65TM", "EXB-8000L-65TM" (manufactured by DIC Corporation), "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, and an active ester compound containing an acetylated product of phenol novolac. "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester compound containing a benzoylation product of phenol novolac, and "DC808" as an active ester curing agent which is an acetylated product of phenol novolac. (Manufactured by Mitsubishi Chemical Co., Ltd.), “YLH1026” (manufactured by Mitsubishi Chemical Co., Ltd.), “YLH1030” (manufactured by Mitsubishi Chemical Co., Ltd.), and “YLH1048” as an active ester type curing agent which is a benzoylation product of phenol novolac. (Manufactured by Mitsubishi Chemical Co., Ltd.) and the like.

Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa Highpolymer Co., Ltd., "Pd" and "Fa" manufactured by Shikoku Chemicals Co., Ltd.

Examples of the cyanate ester-based curing agent include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4′-methylenebis(2,6-dimethylphenyl cyanate), 4,4. '-Ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenyl propane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethyl) Phenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bifunctional cyanate resin such as bis(4-cyanatephenyl)ether, phenol Examples thereof include polyfunctional cyanate resins derived from novolac and cresol novolac, and prepolymers obtained by partially converting these cyanate resins into triazine. Specific examples of the cyanate ester-based curing agent include “PT30” and “PT60” manufactured by Lonza Japan Co., Ltd. (both are phenol novolac type polyfunctional cyanate ester resins), “BA230”, and “BA230S75” (of bisphenol A dicyanate). Prepolymers) which are partially or wholly triazined to form trimers, and the like.

Specific examples of the carbodiimide-based curing agent include "V-03" and "V-07" manufactured by Nisshinbo Chemical Inc.

The content of the curing agent in the resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, and further preferably 20% by mass or less. The lower limit is not particularly limited, but is preferably 2% by mass or more.

<(f) Curing accelerator>
Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like, phosphorus-based curing accelerators, amine-based curing accelerators. A curing accelerator, an imidazole curing accelerator and a metal curing accelerator are preferable, and an amine curing accelerator, an imidazole curing accelerator and a metal curing accelerator are more preferable. The curing accelerator may be used alone or in combination of two or more.

Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , Tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, and the like, and triphenylphosphine and tetrabutylphosphonium decanoate are preferable.

Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6,-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo. Examples include (5,4,0)-undecene, and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferable.

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-Phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecyl Imidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4- Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline , 2-phenylimidazoline and other imidazole compounds, and adducts of imidazole compounds and epoxy resins are mentioned, and 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferable.

A commercially available product may be used as the imidazole-based curing accelerator, and examples thereof include "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, Tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0] Deca-5-ene, 1-methyl biguanide, 1-ethyl biguanide, 1-n-butyl biguanide, 1-n-octadecyl biguanide, 1,1-dimethyl biguanide, 1,1-diethyl biguanide, 1-cyclohexyl biguanide, 1 Examples thereof include allyl biguanide, 1-phenyl biguanide, 1-(o-tolyl) biguanide, and dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

Examples of the metal-based curing accelerator include organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organic metal complex include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. And the like, organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate and the like.

The content of the curing accelerator in the resin composition is not particularly limited, but 0.01% by mass to 3% by mass is preferable when the total amount of the nonvolatile components of the thermosetting resin and the curing agent is 100% by mass.

<(g) Thermoplastic resin>
Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyether. Ether ketone resins, polyester resins, among them, preferably a thermoplastic resin having an aromatic structure, for example, a phenoxy resin having an aromatic structure, a polyvinyl acetal resin having an aromatic structure, a polyimide resin having an aromatic structure, Polyamideimide resin having aromatic structure, polyetherimide resin having aromatic structure, polysulfone resin having aromatic structure, polyethersulfone resin having aromatic structure, polyphenylene ether resin having aromatic structure, aromatic structure The polyether ether ketone resin and the polyester resin having an aromatic structure are preferable, and the phenoxy resin having an aromatic structure is more preferable. The thermoplastic resins may be used alone or in combination of two or more.

The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and even more preferably in the range of 20,000 to 60,000. The polystyrene equivalent weight average molecular weight of the thermoplastic resin is measured by gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight average molecular weight of the thermoplastic resin is LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P/K-manufactured by Showa Denko KK as a column. 804L/K-804L can be calculated by using chloroform as a mobile phase, measuring the column temperature at 40° C., and using a calibration curve of standard polystyrene.

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene. Examples include phenoxy resins having one or more skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group and an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both are bisphenol A skeleton-containing phenoxy resins) manufactured by Mitsubishi Chemical Corporation, "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" ( Bisphenol acetophenone skeleton-containing phenoxy resin), and in addition, "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., "YX6954BH30", "YX7553", "YX7553BH30" manufactured by Mitsubishi Chemical Corporation, "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482" and the like can be mentioned.

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferable. Specific examples of the polyvinyl acetal resin include, for example, "Electrical butyral 4000-2", "Electrical butyral 5000-A", "Electrical butyral 6000-C", and "Electrical butyral 6000-EP" manufactured by Denki Kagaku Kogyo Co., Ltd. , Sekisui Chemical Co., Ltd. S-REC BH series, BX series (eg BX-5Z), KS series (eg KS-1), BL series, BM series and the like.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika Co., Ltd. Specific examples of the polyimide resin also include linear polyimide obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compound and tetrabasic acid anhydride (polyimide described in JP 2006-37083 A), polysiloxane skeleton. Modified polyimides such as contained polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-319386) can be mentioned.

Specific examples of the polyamide-imide resin include “Vylomax HR11NN” and “Vylomax HR16NN” manufactured by Toyobo Co., Ltd. Specific examples of the polyamideimide resin also include modified polyamideimides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamideimide) manufactured by Hitachi Chemical Co., Ltd.

Specific examples of the polyether sulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. and the like.

Specific examples of the polysulfone resin include polysulfone "P1700" and "P3500" manufactured by Solvay Advanced Polymers Co., Ltd.

Among them, phenoxy resin and polyvinyl acetal resin are preferable as the thermoplastic resin. Therefore, in a preferred embodiment, the thermoplastic resin includes at least one selected from the group consisting of a phenoxy resin and a polyvinyl acetal resin.

When the resin composition contains a thermoplastic resin, the content of the thermoplastic resin is preferably 0.5% by mass to 60% by mass, more preferably 3% by mass to 50% by mass, and further preferably 5% by mass. It is 40 mass %.

<(h) Flame retardant>
Examples of the flame retardant include organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, metal hydroxides, and the like. The flame retardants may be used alone or in combination of two or more.

As the flame retardant, a commercially available product may be used, and examples thereof include "HCA-HQ" manufactured by Sanko Co., Ltd.

When the resin composition contains a flame retardant, the content of the flame retardant is not particularly limited, but preferably 0.5% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and further preferably 0.5% by mass to 10% by mass is more preferable.

<Other ingredients>
The resin composition may further contain other additives, if necessary, and as such other additives, for example, organocopper compounds, organozinc compounds and organometallic compounds such as organocobalt compounds, In addition, a resin additive such as a thickener, a defoaming agent, a leveling agent, an adhesion-imparting agent, and a coloring agent can be used.

(Sheet-like fiber base material)
The sheet-shaped fiber base material used for the prepreg of the present invention is not particularly limited, and those commonly used as a base material for prepreg such as glass cloth, aramid nonwoven fabric, liquid crystal polymer nonwoven fabric and the like can be used.

Specific examples of the glass cloth that can be used as the sheet-shaped fiber base material include “Style 1027MS” manufactured by Asahi Schebel Co., Ltd. (warp density 75/25 mm, weft density 75/25 mm, cloth weight 20 g/m ² , Thickness 19 μm), “Style 1037MS” manufactured by Asahi Schebel Co., Ltd. (warp density 70 threads/25 mm, weft density 73 threads/25 mm, cloth weight 24 g/m ² , thickness 28 μm), manufactured by Arisawa Manufacturing Co., Ltd. "1078" (warp density 54/25 mm, weft density 54/25 mm, cloth weight 48 g/m ² , thickness 43 μm), "1037NS" manufactured by Arisawa Manufacturing Co., Ltd. (warp density 72/25 mm, weft density 69 threads/25 mm, cloth weight 23 g/m ² , thickness 21 μm, “1027NS” manufactured by Arisawa Manufacturing Co., Ltd. (warp density 75 threads/25 mm, weft density 75 threads/25 mm, cloth weight 19.5 g/m ^{2 ).} , Thickness 16 μm), “1015NS” manufactured by Arisawa Seisakusho Co., Ltd. (warp density 95 threads/25 mm, weft density 95 threads/25 mm, cloth weight 17.5 g/m ² , thickness 15 μm), Arisawa Manufacturing Co., Ltd. "1000NS" (warp density 85/25 mm, weft density 85/25 mm, cloth weight 11 g/m ² , thickness 10 μm) and the like. Specific examples of the liquid crystal polymer non-woven fabric include “Vecrus” (weight per unit area: 6 g/m ^{2 to} 15 g/m ² ) and “Vectran” manufactured by Kuraray Co., Ltd. by an aromatic polyester non-woven fabric by a melt blow method.

The thickness of the prepreg is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, still more preferably 20 μm or less, from the viewpoint of reducing the thickness of the printed wiring board.

The prepreg of the present invention may be laminated with a protective film or a metal foil, if necessary.

Examples of the protective film include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), polyethylene naphthalate (hereinafter sometimes abbreviated as “PEN”), polycarbonates (hereinafter referred to as “PC”). Abbreviated), acrylic such as polymethylmethacrylate (PMMA), cyclic polyolefin, triacetylcellulose (TAC), polyether sulfide (PES), polyetherketone, polyimide, and the like. A support with a release layer may be used as the protective film. Examples of the release agent used in the release layer of the support with release layer include one or more release agents selected from the group consisting of alkyd resin, polyolefin resin, urethane resin, and silicone resin. .. As the support with a release layer, a commercially available product may be used, for example, "SK-1" manufactured by Lintec Co., Ltd., which is a PET film having a release layer containing an alkyd resin release agent as a main component. , "AL-5", "AL-7", "Lumirror T6AM" manufactured by Toray Industries, Inc., and the like.

The metal foil includes at least one metal selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. The metal foil may be a single metal layer or an alloy layer, and as the alloy layer, for example, an alloy of two or more kinds of metals selected from the above group (for example, nickel chromium alloy, copper nickel alloy). And a copper/titanium alloy). Among them, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or a nickel-chromium alloy, copper-nickel, from the viewpoint of versatility of forming a metal foil, cost, easiness of patterning, and the like. Alloy, preferably an alloy layer of copper-titanium alloy, more preferably a chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper single metal layer, or a nickel-chromium alloy alloy layer, a copper single metal layer is More preferable. Further, the metal foil may be a laminate of a plurality of metal foils.

[Prepreg manufacturing method]
The prepreg of the present invention can be manufactured by a known method such as a hot melt method or a solvent method. In the hot-melt method, the resin composition is not dissolved in an organic solvent and once coated on a release paper having good releasability from the resin composition and then laminated on a sheet-shaped fiber base material, or in a sheet form by a die coater. Prepregs are manufactured by directly coating on fiber base materials. In the solvent method, the sheet-shaped fiber base material is impregnated with the sheet-shaped fiber base material by immersing the sheet-shaped fiber base material in a varnish obtained by dissolving the resin composition in an organic solvent, and then dried to produce a prepreg. There is. Further, the prepreg can also be produced by sandwiching a sheet-shaped fiber base material from both sides of two resin sheets made of a resin composition and continuously thermally laminating it under heating and pressurizing conditions.

The prepreg may be produced by a roll-to-roll method or a batch method using a long sheet-shaped fiber base material.

The prepreg of the present invention exhibits the characteristic that the occurrence of warpage is suppressed. The magnitude of the warp is preferably less than 1.5 cm, more preferably 1.3 cm or less or -1 cm or less, and more preferably 0 cm. The warpage can be measured according to the method described in <Evaluation of Warpage> described later.

The prepreg of the present invention exhibits good handleability. In one embodiment, even if the prepreg is peeled off after the prepreg is once stacked on the substrate, there is no deposit such as resin on the substrate. The handling property can be measured according to the method described in <Evaluation of handling property> described later.

The prepreg of the present invention exhibits good embeddability. In one embodiment, the prepreg can be laminated on the wiring layer without voids when the prepreg is laminated on the substrate with the wiring layer. The embedding property can be measured according to the method described in <Evaluation of pattern embedding property> in Examples described later.

The prepreg of the present invention exhibits good copper peeling strength (copper plating peel strength). In one embodiment, it is preferably 1.5 kgf/cm or less, more preferably 1.3 kgf/cm or less, and even more preferably 1.0 kgf/cm or less. The lower limit is not particularly limited, but is 0.4 kgf/cm or more. The copper peeling strength can be measured according to the method described in <Measurement of copper peeling strength (copper plating peel strength)> in Examples described later.

[Printed wiring board and manufacturing method thereof]
The printed wiring board of the present invention can be manufactured using the above prepreg by a method including the following steps (I) and (II).
(I) A step of laminating a prepreg on the inner layer substrate so as to be bonded to the inner layer substrate (II) A step of thermosetting the prepreg to form an insulating layer

The "inner layer substrate" used in the step (I) is mainly a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate or the like, or one or both sides of the substrate. A circuit board on which a patterned conductor layer (circuit) is formed. In addition, an inner layer circuit board of an intermediate product in which an insulating layer and/or a conductor layer is to be formed when manufacturing a printed wiring board is also included in the "inner layer board" in the present invention. When the printed wiring board is a circuit board with built-in components, an inner layer board with built-in components may be used.

The lamination of the inner layer substrate and the prepreg can be performed, for example, by thermocompression bonding the prepreg to the inner layer substrate. Examples of the member that heat-bonds the prepreg to the inner layer substrate (hereinafter, also referred to as “heat-bonding member”) include a heated metal plate (SUS end plate or the like), metal roll (SUS roll), or the like. It is preferable that the thermocompression bonding member is not directly pressed to the prepreg, but is pressed via an elastic material such as heat resistant rubber so that the prepreg sufficiently follows the surface irregularities of the inner layer substrate.

The lamination of the inner layer substrate and the prepreg may be performed by a vacuum laminating method. In the vacuum laminating method, the thermocompression bonding temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, and the thermocompression bonding pressure is preferably 0.098 MPa to 1.77 MPa, more preferably 0. It is in the range of 0.29 MPa to 1.47 MPa, and the thermocompression bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably performed under reduced pressure conditions with a pressure of 26.7 hPa or less.

Lamination can be performed by a commercially available vacuum laminator. Examples of the commercially available vacuum laminator include a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd. and a vacuum applicator manufactured by Nichigo Morton Co., Ltd.

After laminating, the smoothing treatment of the laminated prepreg may be performed under normal pressure (under atmospheric pressure), for example, by pressing a thermocompression bonding member from the support side. The pressing conditions for the smoothing treatment can be the same as the above-mentioned thermocompression bonding conditions for the lamination. The smoothing treatment can be performed with a commercially available laminator. The lamination and smoothing treatment may be continuously performed using the above-mentioned commercially available vacuum laminator.

In step (II), the prepreg is thermoset to form an insulating layer.

The heat curing conditions of the prepreg are not particularly limited, and the conditions usually adopted when forming the insulating layer of the printed wiring board may be used.

For example, the thermosetting conditions of the prepreg vary depending on the type of the resin composition and the like, but the curing temperature is in the range of 120°C to 240°C (preferably 150°C to 220°C, more preferably 170°C to 200°C). Range), and the curing time can be in the range of 5 minutes to 120 minutes (preferably 10 minutes to 100 minutes, more preferably 15 minutes to 90 minutes).

Before heat-curing the prepreg, the prepreg may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the prepreg, the prepreg is kept at a temperature of 50° C. or higher and lower than 120° C. (preferably 60° C. or higher and 110° C. or lower, more preferably 70° C. or higher and 100° C. or lower) for 5 minutes or longer (preferably Preheating may be performed for 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes.

In manufacturing a printed wiring board, (III) a step of forming a hole in the insulating layer, (IV) a step of roughening the insulating layer, and (V) a step of forming a conductor layer may be further performed. These steps (III) to (V) may be performed according to various methods known to those skilled in the art, which are used for manufacturing a printed wiring board.

The step (III) is a step of forming a hole in the insulating layer, which allows formation of holes such as via holes and through holes in the insulating layer. The step (III) may be carried out by using, for example, a drill, a laser, plasma or the like depending on the composition of the resin composition used for forming the insulating layer. The size and shape of the holes may be appropriately determined according to the design of the printed wiring board.

Step (IV) is a step of roughening the insulating layer. The procedure and conditions of the roughening treatment are not particularly limited, and known procedures and conditions usually used when forming an insulating layer of a printed wiring board can be adopted. For example, the insulating layer can be roughened by performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid in this order. The swelling liquid is not particularly limited, and examples thereof include an alkaline solution and a surfactant solution, preferably an alkaline solution, and the alkaline solution is more preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of commercially available swelling liquids include “Swelling Dip Securigans P” and “Swelling Dip Securigans SBU” manufactured by Atotech Japan Co., Ltd. The swelling treatment with the swelling liquid is not particularly limited, but can be performed, for example, by immersing the insulating layer in the swelling liquid at 30° C. to 90° C. for 1 minute to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the cured product in a swelling liquid at 40° C. to 80° C. for 5 minutes to 15 minutes. The oxidizing agent is not particularly limited, and examples thereof include an alkaline permanganate solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the insulating layer in the oxidizing agent solution heated to 60°C to 80°C for 10 minutes to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotech Japan Co., Ltd. The neutralizing solution is preferably an acidic aqueous solution, and examples of commercially available products include “Reduction Solution Securigant P” manufactured by Atotech Japan Co., Ltd. The treatment with the neutralizing solution can be performed by immersing the treated surface, which has been roughened with an oxidizing agent, in the neutralizing solution at 30°C to 80°C for 5 minutes to 30 minutes. From the viewpoint of workability and the like, it is preferable to immerse the object roughened with the oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

In one embodiment, the arithmetic mean roughness Ra of the insulating layer surface after the roughening treatment is preferably 400 nm or less, more preferably 350 nm or less, further preferably 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. Is. The arithmetic average roughness (Ra) of the surface of the insulating layer can be measured using a non-contact surface roughness meter. A specific example of the non-contact type surface roughness meter is “WYKO NT3300” manufactured by Bee Coin Instruments.

Step (V) is a step of forming a conductor layer.

The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Including metal. The conductor layer may be a single metal layer or an alloy layer. As the alloy layer, for example, an alloy of two or more kinds of metals selected from the above group (for example, nickel-chromium alloy, copper. Layers formed from nickel alloys and copper-titanium alloys). Among them, from the viewpoint of versatility of conductor layer formation, cost, easiness of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, copper. A nickel alloy or an alloy layer of copper/titanium alloy is preferable, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of nickel/chromium alloy is more preferable, and a single layer of copper is preferable. Metal layers are more preferred.

The conductor layer may have a single layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different kinds of metals or alloys are laminated. When the conductor layer has a multilayer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc or titanium or an alloy layer of nickel-chromium alloy.

The thickness of the conductor layer depends on the desired design of the printed wiring board, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

In one embodiment, the conductor layer may be formed by plating. For example, the conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer by a conventionally known technique such as a semi-additive method or a full-additive method. Hereinafter, an example of forming the conductor layer by the semi-additive method will be described.

First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern that exposes a part of the plating seed layer corresponding to a desired wiring pattern is formed on the formed plating seed layer. After forming a metal layer on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. After that, the unnecessary plating seed layer can be removed by etching or the like to form a conductor layer having a desired wiring pattern.

The printed wiring board of the present invention may be in a mode including an insulating layer, which is a cured product of the prepreg of the present invention, and an embedded wiring layer embedded in the insulating layer.
As a method of manufacturing such a printed wiring board,
(1) a step of preparing a base material with a wiring layer having an inner layer substrate and a wiring layer provided on at least one surface of the base material;
(2) A step of laminating the prepreg of the present invention on a substrate with a wiring layer so that the wiring layer is embedded in the prepreg, and thermosetting to form an insulating layer,
(3) A step of connecting the wiring layers to each other, and (4) a step of removing the base material.

It is preferable to have a metal layer made of copper foil or the like on both surfaces of the inner layer substrate used in this manufacturing method, and it is more preferable that the metal layer has a structure in which two or more metal layers are laminated. For details of the step (1), a dry film (photosensitive resist film) is laminated on the inner layer substrate and exposed and developed under a predetermined condition using a photomask to form a patterned dry film. After the wiring layer is formed by the electrolytic plating method using the developed patterned dry film as a plating mask, the patterned dry film is peeled off.

The conditions for laminating the inner layer substrate and the dry film are the same as the conditions for the step (II) described above, and the preferable ranges are also the same.

After the dry film is laminated on the inner layer substrate, the dry film is exposed and developed under predetermined conditions using a photomask to form a desired pattern.

The line (circuit width)/space (width between circuits) ratio of the wiring layer is not particularly limited, but is preferably 20/20 μm or less (that is, the pitch is 40 μm or less), more preferably 18/18 μm or less (pitch 36 μm or less), More preferably, it is 15/15 μm or less (pitch 30 μm or less). The lower limit of the line/space ratio of the wiring layer is not particularly limited, but is preferably 0.5/0.5 μm or more, more preferably 1/1 μm or more. The pitch need not be the same throughout the wiring layer.

After forming the dry film pattern, a wiring layer is formed and the dry film is peeled off. Here, the wiring layer can be formed by a plating method using a dry film having a desired pattern as a plating mask.

The conductor material used for the wiring layer is not particularly limited. In a preferred embodiment, the wiring layer is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Including metal. The wiring layer may be a single metal layer or an alloy layer. As the alloy layer, for example, an alloy of two or more kinds of metals selected from the above group (for example, nickel-chromium alloy, copper Those formed from nickel alloys and copper/titanium alloys).

The thickness of the wiring layer depends on the desired design of the printed wiring board, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, still more preferably 10 to 20 μm, or 15 μm.

After forming the wiring layer, the dry film is peeled off. The peeling of the dry film can be carried out by a known method. If necessary, an unnecessary wiring pattern can be removed by etching or the like to form a desired wiring pattern.

Step (2) is a step of laminating the prepreg of the present invention on a substrate with a wiring layer so that the wiring layer is embedded in the prepreg, and thermosetting to form an insulating layer. The conditions for laminating the base material with a wiring layer and the prepreg are the same as the conditions for the step (II) described above, and the preferable ranges are also the same.

The step (3) is not particularly limited as long as the wiring layers can be interconnected, but a step of forming a via hole in the insulating layer to form a conductor layer, and a step of polishing or grinding the insulating layer to expose the wiring layer. It is preferable that it is at least one of the steps. The process of forming the via hole in the insulating layer and forming the conductor layer is as described above.

The polishing method or grinding method for the insulating layer is not particularly limited as long as the printed wiring layer can be exposed and the polishing or grinding surface is horizontal, and a conventionally known polishing method or grinding method can be applied. For example, a chemical mechanical polishing method using a chemical mechanical polishing apparatus, a mechanical polishing method such as buffing, and a surface grinding method by rotating a grindstone can be cited.

Step (4) is a step of removing the inner layer substrate to form the printed wiring board of the present invention. The method for removing the inner layer substrate is not particularly limited. In a preferred embodiment, the inner layer substrate is separated from the printed wiring board at the interface of the metal layer provided on the inner layer substrate, and the metal layer is removed by etching with, for example, an aqueous copper chloride solution.

[Semiconductor device]
A semiconductor device of the present invention includes the printed wiring board of the present invention. The semiconductor device of the present invention can be manufactured using the printed wiring board of the present invention.

Examples of the semiconductor device include various semiconductor devices used for electric products (for example, computers, mobile phones, digital cameras and televisions) and vehicles (for example, motorcycles, automobiles, trains, ships and aircrafts).

The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. The "conducting portion" is a "portion for transmitting an electric signal in the printed wiring board", and the location may be a surface or an embedded portion. The semiconductor chip is not particularly limited as long as it is an electric circuit element made of a semiconductor.

The semiconductor chip mounting method for manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively. Specifically, the wire bonding mounting method, the flip chip mounting method, and the bumpless method are used. Examples thereof include a mounting method using a build-up layer (BBUL), a mounting method using an anisotropic conductive film (ACF), and a mounting method using a non-conductive film (NCF). Here, the "mounting method using a bump-free build-up layer (BBUL)" is a "mounting method in which a semiconductor chip is directly embedded in a recess of a printed wiring board to connect the semiconductor chip and wiring on the printed wiring board". Is.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following description, "part" and "%" mean "part by mass" and "% by mass", respectively, unless otherwise specified.

First, the measurement method and evaluation method in the physical property evaluation will be described.

[Preparation of measurement/evaluation substrate]
(1) Preparation of inner layer circuit board Glass cloth substrate epoxy resin double-sided copper clad laminate (copper foil thickness 35 μm, substrate thickness 0.8 mm, “R5715ES” manufactured by Matsushita Electric Works, Ltd.), and IPC MULTI- PURPOSE TEST BOARD NO. A pattern of IPC C-25 (comb-tooth pattern (line/space ratio=600/660 μm, residual copper ratio 48%)) was formed. Then, both surfaces of the substrate were roughened with a microetching agent (“CZ8100” manufactured by MEC Co., Ltd.) to prepare an inner layer circuit board.

(2) Lamination of prepreg The prepreg prepared in the following Examples and Comparative Examples and a carrier-added copper foil (“MT-Ex” manufactured by Mitsui Mining & Smelting Co., Ltd., copper foil thickness 3 μm) were placed so that the copper foil was on the outside. The laminate was placed above and below the inner layer circuit board and pressed at a pressure of 20 kgf/cm ² at a temperature of 190° C. for 90 minutes to obtain a laminate.

[Evaluation]
<Evaluation of pattern embeddability>
After peeling the carrier copper from the laminate obtained in (2) above, the remaining copper was dipped in an iron chloride solution to peel off the copper, and the surface 3 cm ^{2 of the} insulating layer was covered with a microscope (manufactured by KEYENCE CO., LTD. It was observed using a microscope VK-8510"), and when there were no wrinkles or voids, it was designated as "O", and when there were wrinkles or voids, it was designated as "x".

<Measurement of copper peeling strength (copper plating peel strength)>
After peeling the carrier copper from the laminate obtained in (2) above, electrolytic copper plating was performed to form a conductor layer (copper layer) having a total thickness of 30 μm. A notch surrounding a partial area of 10 mm in width and 100 mm in length is made on the obtained substrate with a conductor layer, one end side of the notch is peeled off, and a grasping tool (TSE, Autocom type tester AC- 50 C-SL), and the load (kgf/cm (N/cm)) when 35 mm was peeled off in the vertical direction at a speed of 50 mm/min at room temperature (25° C.) was measured. When the peeling strength was 0.4 kgf/cm or more, it was designated as "○", and when it was less than 0.4 kgf/cm, it was designated as "x".

<Evaluation of warpage>
The prepregs produced in the following examples and comparative examples were placed on one surface of a copper foil (“JTC foil” manufactured by JX Nippon Mining & Metals Corporation, copper foil thickness 70 μm), and a pressure of 20 kgf/cm and a temperature of 190° C. It was pressed for 90 minutes to obtain an evaluation sample. Of the four sides of the obtained copper foil with prepreg, two sides were fixed to a SUS plate with a polyimide tape, and the height of the highest point was determined from the SUS plate to determine the warpage value. And, when the size of the warp is 0 cm or more and less than 1.5 cm, it is "○", -1 cm or more and less than 0 cm, or 1.5 cm or more and less than 3 cm is "△", and when it is less than -1 cm, or 3.5 cm or more, it is "X". Regarding the magnitude of warpage, "+" was given when the prepreg was warped toward the prepreg side when the prepreg was placed upward, and "-" was given when the prepreg was warped toward the copper foil side.

<Evaluation of prepreg handling>
The prepregs produced in the following examples were superposed on the substrate obtained in (1) above at atmospheric pressure and then peeled off, and the surface 3 cm ² was used with a microscope (“Microscope VK-8510” manufactured by KEYENCE Co., Ltd.). When the resin did not adhere to the substrate, it was evaluated as “◯”, and when the resin adhered to the substrate, it was evaluated as “x”.

<Measurement of average maximum length of domain>
An FIB-SEM composite device (“SMI3050SE” manufactured by SII Nano Technology Co., Ltd.) was used as the average maximum length of the domains. A cross-section in a direction perpendicular to the surface of the prepreg heat-cured under conditions of 100° C. for 30 minutes and 170° C. for 30 minutes was carved by FIB (focused ion beam), and a sectional SEM image (observation width 60 μm, observation magnification 2 1,000 times). SEM images of cross-sections randomly selected at 5 sites were observed, the largest domain existing in the SEM image of cross-section was selected, the maximum length of each selected domain was measured, and the average value was taken as the average maximum length.

[Example 1]
28 parts of a butadiene-based elastomer produced as described below, 5 parts of a dicyclopentadiene type epoxy resin (“HP-7200L” manufactured by DIC Corporation, epoxy equivalent 245), and a bisphenol type epoxy resin (Nippon Steel Chemical Co., Ltd. )) "ZX1059", a 1:1 mixture of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and an epoxy equivalent of about 169) 3 parts were heated and dissolved in 15 parts of methyl ethyl ketone (MEK) with stirring. There, 1 part of a curing accelerator (1B2PZ manufactured by Shikoku Kasei Co., Ltd., 1-benzyl-2-phenylimidazole, a MEK solution containing 5% by mass of non-volatile components) and organic particles (Aika Kogyo Co., Ltd., Staphyloid AC3816N). 1 part) and a spherical silica (“SOC4” manufactured by Admatex Co., Ltd.) surface-treated with a phenylaminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) as an inorganic filler, having an average particle size of 1. (0 μm) and 11 parts were mixed and uniformly dispersed by a high speed rotation mixer to prepare a resin varnish 1.

<Preparation of prepreg>
The resin varnish 1 was impregnated into Nitto Boseki Co., Ltd. style WEA2013 (warp density 46 yarns/25 mm, weft yarn density 44 yarns/25 mm, cloth mass 81 g/m ² , thickness 71 μm), and 135 in a vertical drying oven. A prepreg was prepared by drying at 5°C for 5 minutes. The resin composition content in the prepreg was 48% by mass, and the thickness of the prepreg was 90 μm. The length of the prepreg in the vertical direction was 30 cm, and the length in the horizontal direction was 20 cm.

<Synthesis of butadiene elastomer>
50 g of G-3000 (bifunctional hydroxyl group-terminated polybutadiene, number average molecular weight = 5047 (GPC method), hydroxyl group equivalent = 1798 g/eq., solid content 100% by mass: Nippon Soda Co., Ltd.) in a reaction vessel, 23.5 g of Ipsol 150 (aromatic hydrocarbon-based mixed solvent: manufactured by Idemitsu Petrochemical Co., Ltd.) and 0.005 g of dibutyltin laurate were mixed and uniformly dissolved. When the temperature became uniform, the temperature was raised to 50° C., and 4.8 g of toluene-2,4-diisocyanate (isocyanate group equivalent=87.08 g/eq.) was added with stirring, and the reaction was carried out for about 3 hours. Then, this reaction product was cooled to room temperature, and then 8.96 g of benzophenonetetracarboxylic dianhydride (acid anhydride equivalent=161.1 g/eq.), 0.07 g of triethylenediamine, and ethyldiglycol were added. 40.4 g of acetate (manufactured by Daicel Chemical Industries, Ltd.) was added, the temperature was raised to 130° C. with stirring, and the reaction was carried out for about 4 hours. The disappearance of the NCO peak at 2250 cm ^-1 was confirmed by FT-IR. The confirmation of the disappearance of the NCO peak was regarded as the end point of the reaction, and the reaction product was cooled to room temperature and filtered with a 100-mesh filter cloth to obtain a butadiene-based elastomer.
Properties of butadiene elastomer:
Viscosity: 7.5 Pa·s (25°C, E type viscometer)
Acid value: 16.9 mg KOH/g
Solid content: 50 mass%
Number average molecular weight: 13723
Content of polybutadiene structure portion: 50×100/(50+4.8+8.96)=78.4 mass %.

[Example 2]
Instead of 11 parts of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm), diamond shaped boehmite (“BMB-05” manufactured by Kawai Lime Industry Co., Ltd., average particle size 0.5 μm) 15 A resin varnish 2 and a prepreg 2 were produced in the same manner as in Example 1 except that the parts were used.

[Example 3]
55 parts of epoxy group-containing acrylic ester copolymer (“SG-P3” manufactured by Nagase Chemtex Co., Ltd., number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg) and bisphenol type epoxy resin (new Nippon Steel Chemical Co., Ltd. "ZX1059", 1:1 mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, epoxy equivalent of about 169) 1 part, and bisphenol novolac type epoxy resin (Mitsubishi Chemical Co., Ltd.) "157S70" manufactured by Epoxy Co., Ltd. and 3.5 parts of epoxy equivalent 210) were heated and dissolved while stirring. There, 4 parts of a triazine skeleton-containing cresol novolac-based curing agent (“LA3018-50P” manufactured by DIC Corporation, hydroxyl equivalent 151, 1-methoxy-2-propanol solution containing 50% of non-volatile components) and a curing accelerator (Shikoku Kasei Co., Ltd. 1B2PZ, 1-benzyl-2-phenylimidazole, a non-volatile component 5 mass% MEK solution 0.1 part, and organic particles (Aika Kogyo KK, Staphyroid AC3816N) 0.8 part, 10 parts of diamond-shaped boehmite (“BMB-05” manufactured by Kawai Lime Industry Co., Ltd., average particle size 0.5 μm) as an inorganic filler was mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 3. .. A prepreg 3 was produced in the same manner as in Example 1 except that the resin varnish 3 was used instead of the resin varnish 1.

[Example 4]
A resin varnish 4 and a prepreg 4 were produced in the same manner as in Example 1 except that the addition amount of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm) was changed to 40 parts.

[Example 5]
Addition amount of butadiene-based elastomer is 10 parts, addition amount of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm) is 7 parts, and organic particles (Aika Kogyo Co., Ltd., Staphyloid AC3816N) Resin varnish 5 and prepreg 5 were produced in the same manner as in Example 1 except that the addition amount of) was changed to 0.6 part.

[Example 6]
5 parts of the butadiene-based elastomer produced as described above, 9 parts of a dicyclopentadiene type epoxy resin (“HP-7200L” manufactured by DIC Corporation, epoxy equivalent 245), and a bisphenol type epoxy resin (Nippon Steel Chemical Co., Ltd. )) "ZX1059", a 1:1 mixture of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and an epoxy equivalent of about 169) 4 parts were heated and dissolved in 15 parts of methyl ethyl ketone (MEK) with stirring. There, as a curing accelerator (1B2PZ manufactured by Shikoku Kasei Co., Ltd., a MEK solution containing 5% by mass of non-volatile components), 1 part of organic particles (Staffloid AC3816N manufactured by Aika Kogyo Co., Ltd.), and as an inorganic filler. 10 parts of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm) surface-treated with a phenylaminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed. Then, the resin varnish 6 was prepared by uniformly dispersing it with a high-speed rotary mixer. A prepreg 6 was produced in the same manner as in Example 1 except that the resin varnish 6 was used instead of the resin varnish 1.

[Example 7]
A resin varnish 7 and a prepreg 7 were produced in the same manner as in Example 1 except that the addition amount of the butadiene-based elastomer was changed to 40 parts.

[Example 8]
A resin varnish 8 and a prepreg 8 were produced in the same manner as in Example 1 except that the addition amount of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm) was changed to 5 parts.

[Example 9]
A resin varnish 9 and a prepreg 9 were produced in the same manner as in Example 1 except that the addition amount of spherical silica (“SOC4” manufactured by Admattex Co., Ltd., average particle size 1.0 μm) was changed to 60 parts.

[Comparative Example 1]
28 parts of the butadiene-based elastomer produced as described above, bisphenol type epoxy resin (“ZX1059” manufactured by Nippon Steel Chemical Co., Ltd., 1:1 mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, epoxy 2.5 parts by weight of about 169) and 5 parts by weight of bisphenol novolac type epoxy resin (“157S70” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 210) were dissolved in 15 parts of methyl ethyl ketone (MEK) with heating. There, 1 part of a curing accelerator (1B2PZ manufactured by Shikoku Kasei Co., Ltd., 1-benzyl-2-phenylimidazole, a MEK solution containing 5% by mass of non-volatile components) and organic particles (Aika Kogyo Co., Ltd., Staphyloid AC3816N). 1 part) and a spherical silica (“SOC4” manufactured by Admatex Co., Ltd.) surface-treated with a phenylaminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) as an inorganic filler, having an average particle size of 1. (0 μm) 11 parts were mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 10. A prepreg 10 was produced in the same manner as in Example 1 except that the resin varnish 10 was used instead of the resin varnish 1.

[Comparative example 2]
A resin varnish 11 and a prepreg 11 were produced in the same manner as in Example 1 except that the addition amount of organic particles (Staffloid AC3816N, manufactured by Aika Kogyo Co., Ltd.) was changed to 4 parts.

[Comparative Example 3]
A resin varnish 12 and a prepreg 12 were produced in the same manner as in Example 1 except that the butadiene elastomer was not added.

From the table, it can be seen that the prepregs of Examples 1 to 9 have improved handleability, embeddability, and copper plating peel strength, and no warpage has occurred. In addition, the prepregs of Comparative Examples 1 and 2 in which the average maximum length of the domain exceeds 15 μm and Comparative Example 3 not containing the component (a) have any one of handling property, embedding property, copper plating peel strength, and warpage. It turns out that it is inferior to the prepreg of 1-9. In the measurement of the copper plating peel strength of Comparative Example 1, it was not possible to measure the copper plating peel strength because the copper foil partly swelled only by heating the prepreg and the copper foil peeled off thereafter.

Further, as shown in FIG. 1, in Example 1, the average maximum length of the domain was 7.2 μm. As shown in FIG. 2, it can be seen that in Example 2, the average maximum length of the domains was so small that it could not be confirmed, and the respective components such as the inorganic filler were dispersed. On the other hand, as shown in FIG. 3, Comparative Example 1 is considered to be inferior to Examples 1 to 9 in embedding property and copper plating peel strength because the average maximum length of the domain is 18.0 μm. .

In Example 6 and Example 7, since (A/(A+B))×100 is outside the range of 20 to 70, (A/(A+B))×100 is within the range of 20 to 70. Although the warpage was inferior to that of the example, it was in a level that there was no actual harm in use.

In Examples 8 and 9, since the content of the inorganic filler is outside the range of 25 to 70% by mass, another example in which the content of the inorganic filler is within the range of 25 to 70% by mass. The warpage was inferior to that of the above, but there was no actual harm in use.

Claims (12)

A sheet-shaped fiber base material, and a resin composition impregnated in the sheet-shaped fiber base material,
The resin composition contains (a) an elastomer, (b) a thermosetting resin having an aromatic structure, and (c) an inorganic filler,
The component (a) is one or more selected from resins having a glass transition temperature of 25° C. or lower or a liquid at 25° C., and having a functional group capable of reacting with the component (b),
The content of the component (c) is 25 to 70 mass% when the nonvolatile component in the resin composition is 100 mass%,
A prepreg in which the average maximum length of domains contained in a cured product obtained by thermosetting a resin composition is 15 μm or less. The prepreg according to claim 1, wherein the resin composition contains (d) organic particles. Component (a) is a butadiene structural unit, a polysiloxane structural unit, a (meth)acrylate structural unit, an alkylene structural unit, an alkyleneoxy structural unit, an isoprene structural unit, an isobutylene structural unit, a chloroprene structural unit, a urethane structural unit, a polycarbonate structural unit. The prepreg according to claim 1 or 2 , which has one or more structural units selected from the following. (B) as a component, it contains a solid epoxy resin at a temperature 20 ° C., the prepreg according to any one of claims 1-3. As the component (b), a liquid epoxy resin at a temperature of 20° C. and a solid epoxy resin at a temperature of 20° C. are included, and the liquid epoxy resin:solid epoxy resin mass ratio is 1:0.3 to 1:10. in it, prepreg according to any one of claims 1-4. The prepreg according to claim 4 or 5 , which does not include a resin having a naphthalene skeleton and having a molecular weight of 400 or more as a solid epoxy resin at a temperature of 20°C. When the mass of the component (a) in the resin composition was A, and B on the weight of component (b), (A / (A + B )) × 100 is 20 to 70, claim 1-6 The prepreg according to item 1. When the mass of the component (a) in the resin composition is A, the mass of the component (b) is B, and the mass of the component (d) is D, (D/(A+B+D))×100 is 10 or less, The prepreg according to any one of claims 2 to 8 . A insulating layer formed of a printed wiring board prepreg according to any one of claims 1-8. It is for build-up layer formed of a printed wiring board prepreg according to any one of claims 1-9. Comprising an insulating layer formed by the prepreg according to any one of claims 1 to 1 0, the printed wiring board. It comprises a printed wiring board according to claim 1 1, the semiconductor device.