TW201728456A - Resin sheet capable of reducing the bending of the substrate and having excellent part embedding property - Google Patents

Abstract

To provide a resin sheet capable of reducing the bending of the substrate and excellent in the parts embedding property is excellent. A resin sheet having a support and a hardened resin composition layer arranged on the support. The hardened resin composition layer comprises inorganic fillers. The hardened resin composition layer includes 74mass% or more of inorganic filler. The average particle diameter of the inorganic filler is 1.6 micrometers or less. The product of the specific surface area [m2/g] and the true density [g/cm3] of the inorganic filler is 6 to 8. The minimum melt viscosity of the hardened resin composition layer is lower than 12000 poise.

Description

Resin sheet

The present invention relates to a resin sheet, a wiring board, and a semiconductor device.

In recent years, there is a growing demand for small high-performance electronic devices for smart phones and tablet PCs. Along with this, further improvement in the functionality and miniaturization of printed wiring boards used in such small electronic devices is being sought.

In the printed wiring board, components such as a bare chip, a wafer capacitor, and a wafer inductor are mounted. In the past, such a component is only mounted on the surface circuit of the printed wiring board, but the mounting amount is limited, and it is difficult to further increase the functionality and size of the printed wiring board in recent years.

In order to solve the problem, it is proposed to incorporate a circuit board in which a component is housed in an inner layer circuit board, and to increase the number of components to be mounted, and to reduce the size (thin-thickness) of the component (see, for example, Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4114629

However, the component embedding property of the concave portion (cavity) of the component in which the component board is placed is excellent, and the resin flow is emphasized, and the content of the inorganic filler in the resin composition used for the component embedding is suppressed, and Although it is considered to use a resin having a relatively small molecular weight, the thermal expansion rate increases the bending of the substrate easily. On the other hand, in order to reduce the bending of the substrate of the component-embedded circuit board, it is considered that the content of the inorganic filler in the resin composition is increased, but there is a problem in that the melt viscosity is improved to easily reduce the embedding property of the hole.

Therefore, the problem to be solved by the present invention is to provide a resin sheet which is excellent in part embedding property while reducing the curvature of the substrate.

As a result of intensive studies on the above-mentioned problems, the present inventors have found that the average particle diameter is 1.6 μm or less and the specific surface area [m ² /g] by the curable resin composition in which the curable resin composition layer is to be formed. The inorganic filler having a product of 6 to 8 in the true density [g/cm ³ ] is contained in an amount of 74% by mass or more, and the lowest melt viscosity of the curable resin composition layer is set to 12,000 poise or less. The invention is finally completed. The present invention has been completed in accordance with the novel teachings.

That is, the present invention includes the following contents.

[1] A resin sheet comprising a support and a resin sheet of a curable resin composition layer provided on a support, wherein the curable resin composition layer contains an inorganic filler, and the curable resin composition The content of the inorganic filler in the layer is 74% by mass or more, and the average particle diameter of the inorganic filler is 1.6 μm or less, and the product of the specific surface area [m ² /g] of the inorganic filler and the true density [g/cm ³ ] is 6 to 8, the lowest melt viscosity of the curable resin composition layer is 12,000 poise or less.

[2] The resin sheet according to [1], wherein the inorganic filler is cerium oxide.

[3] The resin sheet according to [1] or [2], wherein the curable resin composition layer comprises (a) an epoxy resin comprising a liquid epoxy resin, and a curable resin composition layer The content of the liquid epoxy resin is 1% by mass or more.

[4] The resin sheet according to [3], wherein (a) the epoxy resin further comprises a solid epoxy resin, and the mass M _S of the solid epoxy resin is relative to the liquid ring in the curable resin composition layer The ratio (M _S /M _L ) of the mass M _L of the oxygen resin is 0.6 to 10.

[5] The resin sheet according to [3] or [4] wherein (a) the epoxy resin is an epoxy resin having an (a') aromatic structure.

[6] The resin sheet according to any one of [3], wherein the curable resin composition layer further comprises (d) a component selected from the group consisting of a resin having a functional group having a glass transition temperature of 25 ° C or lower. And one or more resins having a resin having a functional group at 25 ° C.

[7] The resin sheet according to [6], wherein the component (d) has one or more functional groups selected from the group consisting of a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and an urethane group. And having an alkyl group structure selected from Unit, alkoxy structural unit, butadiene structural unit, isoprene structural unit, isobutylene structural unit, chloroprene structural unit, urethane structural unit, polycarbonate structural unit, (methyl And one or more structural units of the acrylate structural unit and the polyoxyalkylene structural unit.

[8] The resin sheet according to any one of [1] to [7], which is for use in a circuit board.

[9] A wiring board comprising an insulating layer and a conductor layer obtained by curing a layer of a curable resin composition of the resin sheet according to any one of [1] to [8].

[10] A semiconductor device comprising the wiring board of [9].

According to the present invention, it is possible to provide a resin sheet which is excellent in part embedding while reducing the curvature of the substrate.

1‧‧‧ circuit substrate

2‧‧‧Substrate

2a‧‧‧ Hole

3‧‧‧Conductor layer (circuit wiring)

4‧‧‧Materials temporarily attached

5‧‧‧ parts

10‧‧‧Resin sheet (first resin sheet)

11‧‧‧Support (1st support)

12‧‧‧ hardened resin composition layer

12'‧‧‧ hardened resin composition layer (heat treatment body)

12"‧‧‧Insulation

20‧‧‧2nd resin sheet

21‧‧‧2nd support

22‧‧‧2nd hardened resin composition layer

22'‧‧‧Second hardening resin composition layer (heat treatment body)

22"‧‧‧Insulation

100‧‧‧Wiring board (with built-in circuit board)

1A] Fig. 1A is a schematic view (1) showing a process of preparing a circuit board for temporarily attaching a component to be used in a method of manufacturing a circuit board in which a resin sheet of the present invention is used.

1B] Fig. 1B is a schematic view (2) showing a process of preparing a circuit board for temporarily attaching a component to be used in a method of manufacturing a circuit board in which a resin sheet of the present invention is used.

[Fig. 1C] Fig. 1C shows the zero of the resin sheet used in the present invention. A method of manufacturing a built-in circuit board, and a schematic diagram (3) of a process for preparing a circuit board for temporarily attaching a component.

[Fig. 1D] Fig. 1D is a schematic view (4) showing a process of preparing a circuit board for temporarily attaching a component to be used in a method of manufacturing a circuit board in which a resin sheet of the present invention is used.

Fig. 2 is a schematic view showing an aspect of a resin sheet of the present invention.

3A] Fig. 3A is a schematic view (1) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

3B] Fig. 3B is a schematic view (2) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

3C] Fig. 3C is a schematic view (3) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

3D] Fig. 3D is a schematic view (4) for explaining a method of manufacturing a built-in circuit board using the resin sheet of the present invention.

3E] Fig. 3E is a schematic view (5) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

3F] Fig. 3F is a schematic view (6) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

3G] Fig. 3G is a schematic view (7) for explaining a method of manufacturing a built-in circuit board using a resin sheet of the present invention.

Before the detailed description of the resin sheet of the present invention, In the resin sheet of the present invention, a curable resin composition (also referred to as a "resin composition") used for forming a curable resin composition layer (also referred to as a "resin composition layer") will be described.

<Curable resin composition>

The curable resin composition forming the curable resin composition layer has an average particle diameter of 1.6 μm or less, and the product of the specific surface area [m ² /g] and the true density [g/cm ³ ] is 6-8. The inorganic filler is not particularly limited, and the cured product (insulating layer) may have sufficient hardness and insulation properties. Examples of the curable resin composition include a composition containing a curable resin and a curing agent together with the inorganic filler. As the curable resin, a conventionally known curable resin used in forming an insulating layer of a printed wiring board can be used, and among them, an epoxy resin is preferable. Accordingly, in one embodiment, the curable resin composition includes (a) an epoxy resin, (b) a curing agent, and (c) an inorganic filler. Further, in a preferred embodiment, the curable resin composition comprises: (a') an epoxy resin having an aromatic structure, (b) a curing agent, (c) an inorganic filler, and (d) selected from the group consisting of One or more resins selected from the group consisting of a resin having a functional group of a glass transition temperature of 25° C. or lower and a resin having a functional group having a liquidity at 25° C. In the present invention, the curable resin composition may further contain an additive such as a thermoplastic resin, a curing accelerator, a flame retardant, and rubber particles, if necessary.

In the following, (a) an epoxy resin, (b) a curing agent, (c) an inorganic filler, and (d) are used as a material which can be used as a material of a curable resin composition, and are selected from functional groups having a glass transition temperature of 25 ° C or lower. Resin, and have One or more resins and (e) additives of a resin having a liquid functional group at 25 ° C will be described.

(a) Epoxy resin

Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AF epoxy resin, dicyclopentadiene epoxy resin, and ginseng. Phenolic epoxy resin, naphthol novolak epoxy resin, phenol novolak epoxy resin, tert-butyl-catechol epoxy resin, naphthalene epoxy resin, naphthol epoxy resin, Onion type epoxy resin, bisphenol type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear fat Group epoxy resin, epoxy resin with butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, epoxy resin with spiral ring, cyclohexane dimethanol epoxy resin, naphthalene ether type Epoxy resin, trimethylol epoxy resin, tetraphenylethane epoxy resin, and the like. Epoxy resins may be used alone or in combination of two or more.

As the epoxy resin, it is preferably selected from the group consisting of a bisphenol type epoxy resin, a fluorine type epoxy resin (for example, a bisphenol AF type epoxy resin), a dicyclopentadiene type epoxy resin, a naphthalene type epoxy resin, and a combination. One or more epoxy resins of the group consisting of a benzene type epoxy resin and a mixture of such epoxy resins.

In a preferred embodiment, the (a) epoxy resin is preferably an epoxy resin (a') having an aromatic structure. The epoxy resin (a') having an aromatic structure is not particularly limited as long as it has an aromatic structure. Examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol type epoxy resin, bisphenol type epoxy resin, and dicyclopentadiene type ring. Oxygen resin, phenolic epoxy resin, naphthol novolac epoxy resin, phenol novolak epoxy resin, tert-butyl-catechol epoxy resin, naphthalene epoxy resin, naphthol type Epoxy resin, onion type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, naphthalene ether type epoxy resin, tetraphenylethane type epoxy resin, bisphenol type epoxy Resin, etc.

The epoxy resin is preferably contained in a liquid-like epoxy resin (hereinafter referred to as "liquid epoxy resin") from the viewpoint of reducing the minimum melt viscosity of the curable resin composition layer. Further, in the present specification, the term "normal temperature" means 25 ° C.

Further, the epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the non-volatile content of the epoxy resin is 100% by mass, it is preferably at least 50% by mass or more of an epoxy resin having two or more epoxy groups in one molecule. In particular, it is preferably a liquid epoxy resin having two or more epoxy groups in one molecule, and an epoxy resin having three or more epoxy groups in one molecule and being solid at room temperature (hereinafter referred to as It is a "solid epoxy resin"). As the epoxy resin, a liquid epoxy resin and a solid epoxy resin are used in combination to obtain a resin composition having excellent flexibility. Further, the breaking strength of the cured product (insulating layer) of the curable resin composition is also increased.

As the liquid epoxy resin (a1), a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AF type epoxy resin, a naphthalene type is preferable. Epoxy resin, glycidyl ester type epoxy resin, phenol novolak type epoxy resin, alicyclic epoxy resin having an ester skeleton, and epoxy resin having a butadiene structure, more preferably bisphenol A type ring Oxygen resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin and naphthalene type epoxy resin. In particular, an epoxy resin containing an aromatic skeleton is preferred because it can lower the average linear thermal expansion rate. Specific examples of the liquid epoxy resin include "HP4032", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC Co., Ltd., "828US" manufactured by Mitsubishi Chemical Corporation, and "jER828EL". "(Bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolak type epoxy resin), "ZX1059" made by Nippon Steel & Sumitomo Chemical Co., Ltd. (A mixture of bisphenol A epoxy resin and bisphenol F epoxy resin), "EX-721" (glycidyl ester epoxy resin) manufactured by Nagase ChemteX Co., Ltd., and "Daicel" Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton) and "PB-3600" (epoxy resin having a butadiene structure). These may be used alone or in combination of two or more.

The solid epoxy resin (a2) is preferably a naphthalene type tetrafunctional epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a phenol type epoxy resin, or a naphthol type ring. Oxygen resin, biphenyl type epoxy resin, naphthalene ether type epoxy resin, onion type epoxy resin, bisphenol A type epoxy resin, tetraphenylethane type epoxy resin, more preferably naphthalene type 4 functional epoxy Resin, naphthol type epoxy resin, and biphenyl type epoxy resin. In particular, a polyfunctional epoxy resin has an increased cross-linking point and is preferred because it lowers the average linear thermal expansion rate. Specific examples of the solid epoxy resin include DIC (shares). "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type 4-functional epoxy resin), "N-690" (cresol novolac type epoxy resin), "N -695" (cresol novolac type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200L", (dicyclopentadiene type epoxy resin), "EXA7311", "EXA7311-G3" "EXA7311-G4", "EXA7311-G4S", "HP6000" (naphthyl ether type epoxy resin), "EPPN-502H" (phenolic epoxy resin) made by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolac epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), "ESN475V" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (naphthol) Epoxy resin), "ESN485" (naphthol novolac type epoxy resin), "YX4000H" manufactured by Mitsubishi Chemical Corporation, "YL6121" (biphenyl type epoxy resin), "YX4000HK" (dimethyl) "Phenol type epoxy resin", "YX8800" (onion type epoxy resin), "PG-100" made by Osaka Gas Chemical Co., Ltd., "CG-500", "YL7800" made by Mitsubishi Chemical Corporation (茀) Type epoxy resin), Mitsubishi Chemical Co., Ltd. "JER1010" (bisphenol A type solid epoxy resin), "jER1031S" (tetraphenyl ethane epoxy resin), "YL7760" (bisphenol AF type epoxy resin) and the like.

When the epoxy resin and the solid epoxy resin are used together, the ratio (M _S /M _L ) of the mass M _S of the solid epoxy resin to the mass M _L of the liquid epoxy resin is preferably The range of 0.6~10. By setting M _S /M _L in this range, i) gives a moderate adhesiveness when used in the form of a resin sheet, and ii) sufficient flexibility when used in the form of a resin sheet, and improves workability. And iii) an effect of obtaining a cured product (insulating layer) having sufficient breaking strength.

The content of the (a) epoxy resin in the curable resin composition is preferably 0.1% by mass or more, and more preferably 1% by mass or more from the viewpoint of obtaining an insulating layer having good mechanical strength and exhibiting insulating reliability. More preferably, it is 5% by mass or more. The upper limit of the content of the epoxy resin is not particularly limited as long as the effect of the present invention is exerted, but is preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 30% by mass or less.

Accordingly, the content of the (a) epoxy resin in the curable resin composition is preferably from 0.1 to 50% by mass, more preferably from 10 to 45% by mass, still more preferably from 20 to 42% by mass. In the present invention, the content of each component in the curable resin composition is a value at which the nonvolatile content in the curable resin composition is 100% by mass unless otherwise specified.

The epoxy equivalent of the epoxy resin is preferably from 50 to 5,000, more preferably from 50 to 3,000, still more preferably from 80 to 2,000, still more preferably from 110 to 1,000. By setting it as such a range, it is possible to provide an insulating layer in which the crosslinking density of the cured product is sufficient and the surface roughness is small. Further, the epoxy equivalent can be measured in accordance with JIS K7236 and is a mass of a resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of the epoxy resin is preferably from 100 to 5,000, more preferably from 250 to 3,000, still more preferably from 400 to 1,500. 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.

(b) hardener

The curing agent is not particularly limited as long as it has a function of curing the 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 ester. A hardener, a carbodiimide-based hardener, and the like. The curing agent may be used alone or in combination of two or more.

The phenolic curing agent and the naphthol-based curing agent are preferably a phenolic curing agent having a novolak structure or a naphthol-based curing agent having a novolac structure from the viewpoint of heat resistance and water resistance. Moreover, from the viewpoint of adhesion to the conductor layer (circuit wiring), a nitrogen-containing phenol-based curing agent is preferable, and a phenol resin having a triazine structure and an alkylphenol resin having a triazine structure are more preferable. Among them, from the viewpoint of satisfying heat resistance, water resistance, and adhesion to the conductor layer (peeling strength), it is preferred to use a phenol-based curing agent containing a triazine structure.

Specific examples of the phenolic curing agent and the naphthol-based curing agent include "MEH-7700", "MEH-7810", "MEH-7851", and Nippon Chemical Co., Ltd., manufactured by Megumi Kasei Co., Ltd. "SNN", "SNH", "SN190", "SN190", "SN485", "SN495", "SN375", "SN395", "NHN", "CBN", "GPH", and Dongdu Chemicals Co., Ltd. "LA7052", "LA7054", "LA3018", etc. by DIC (share) system.

The active ester-based curing agent is not particularly limited, but is generally preferably a phenolic ester having two or more compounds in one molecule, a thiophenol ester, an N-hydroxyamine ester, or a heterocyclic hydroxy compound. An ester group having a high reactivity such as an ester. The active ester-based hardener is preferably a carboxylic acid A condensation reaction of a compound and/or a thiocarboxylic acid compound with a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester-based curing agent derived from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester system derived from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. hardener. 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 the naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, and 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, phloroglucinol, benzenetriol, dicyclopentadiene Diphenol compounds, phenol novolacs, and the like.

Specifically, it is preferably an active ester compound containing a dicyclopentadiene diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetal of a phenol novolak, and a benzamidine group containing a phenol novolak. The active ester compound of the compound is more preferably an active ester compound containing a naphthalene structure or an active ester compound containing a dicyclopentadiene type diphenol structure.

As a commercial product of the active ester-based curing agent, examples of the active ester compound containing a dicyclopentadiene diphenol structure include "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" (DIC). )) as an active ester compound containing a naphthalene structure The "EXB9416-70BK" (manufactured by DIC Co., Ltd.), and the active ester compound containing the acetal of the phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation) can be used as the phenol novolac. Examples of the active ester compound of the benzamidine compound include "YLH1026" (manufactured by Mitsubishi Chemical Corporation).

Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa Polymer Co., Ltd., and "P-d" and "F-a" manufactured by Shikoku Chemical Industries Co., Ltd.

Examples of the cyanate-based curing agent include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylenecyanate), and 4,4'- Methylene bis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-double (4-cyanate) phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3 - bis(4-cyanate phenyl-1-(methylethylidene)) benzene, bis(4-cyanate phenyl) sulfide, and bis(4-cyanate phenyl) ether A polyfunctional cyanate resin derived from a bifunctional cyanate resin, a phenol novolac, a cresol novolak or the like, a prepolymer which is partially triazineated with such a cyanate resin, and the like. Specific examples of the cyanate-based curing agent include "PT30" and "PT60" (all phenol novolac type polyfunctional cyanate resins) manufactured by Lonza Japan Co., Ltd., and "BA230" (becoming bisphenol A II) a prepolymer of a partially or fully triazineated trimer of a cyanate ester or the like.

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

In the present invention, (b) the hardener preferably comprises a phenolic group selected from the group consisting of One or more of a curing agent cyanate-based curing agent and an active ester-based curing agent, more preferably a phenol-based resin containing a triazine structure, an alkylphenol-based resin containing a triazine structure, or a cyanate-based curing agent. And one or more of the active ester-based curing agents.

The content of the (b) curing agent in the curable resin composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably from the viewpoint of obtaining an insulating layer having high peel strength and low dielectric tangent. It is 0.5% by mass or more, and more preferably 1% by mass or more. (b) The upper limit of the content of the curing agent is not particularly limited as long as the effect of the present invention is exerted, and is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less.

Accordingly, the content of the (b) hardener in the curable resin composition is preferably from 0.1 to 30% by mass, more preferably from 0.5 to 25% by mass, still more preferably from 1 to 20% by mass.

(a) the ratio of the epoxy resin to the (b) hardener, in the ratio of [(a) the total number of epoxy groups of the epoxy resin]: [(b) the total number of reactive groups of the hardener] Preferably, the range is 1:0.2 to 1:2, more preferably 1:0.3 to 1:1.5, and even more preferably 1:0.4 to 1:1. Here, the reactive group of the curing agent includes an active hydroxyl group, an active ester group, and the like, and differs depending on the type of the curing agent. Further, the total number of epoxy groups of the epoxy resin is a value obtained by dividing the solid content of each epoxy resin by the value of the epoxy equivalent for all the epoxy resins, and the total number of reactive groups of the curing agent is Is the total value of all the hardeners by dividing the solid content of each hardener by the value of the reactive base equivalent. By setting the ratio of the epoxy resin to the hardener to the range, The heat resistance of the cured product (insulating layer) of the curable resin composition is further improved.

(c) Inorganic filler

When the average particle diameter is 1.6 μm or less, the product of the specific surface area [m ² /g] and the true density [g/cm ³ ] (specific surface area × true density) is 6 to 8 as an inorganic filler, although it is not particularly Qualified, but specifically, cerium oxide, aluminum oxide, glass, cordierite, cerium oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, hydrogen Alumina, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, barium carbonate, barium titanate, calcium titanate, magnesium titanate, barium titanate, Titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium tungstate, and the like. Among these, cerium oxide is particularly suitable. Further, as the cerium oxide, spherical cerium oxide is preferred. The inorganic filler may be used singly or in combination of two or more. As a commercial item of the cerium oxide used as the inorganic filler, for example, "ADMAFINE" manufactured by Admatechs, "SFP series" manufactured by Electrochemical Industry Co., Ltd., and "SP" manufactured by Nippon Steel & Metals Materials Co., Ltd. H) Series, "Sciqas Series" by the Chemical Industry Co., Ltd., "Sea Hoster Series" by the Japanese catalyst system, etc. As a commercial item of alumina, the company is listed in the Nippon Steel & Metals Material Co., Ltd. "AZ, AX series" and so on.

In the present invention, the inorganic filler has an average particle diameter of 1.6 μm or less. The average particle diameter of the inorganic filler is preferably 1.5 μm or less, and more preferably 1.4 μm or less. On the other hand, when a resin varnish is formed using a curable resin composition, a resin having an appropriate viscosity and good handleability is obtained. The average particle diameter of the inorganic filler is preferably 0.5 μm or more, more preferably 0.6 μm or more, and still more preferably 0.7 μm or more, from the viewpoint of the varnish and the viewpoint of preventing the increase in the melt viscosity of the curable resin composition layer. .

The average particle size of the inorganic filler can be determined by laser diffraction and scattering according to the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis by a laser diffraction scattering type particle size distribution measuring apparatus, and can be measured by using the median diameter as an average particle diameter. It is preferable to use a sample in which the inorganic filler is dispersed in water by ultrasonic waves. As the laser diffraction scattering type particle size distribution measuring apparatus, "SALD-2200" manufactured by Shimadzu Corporation can be used.

The specific surface area of the inorganic filler can be determined by the BET method. For the measurement of the specific surface area, a BET fully automatic specific surface area measuring device (manufactured by Mountech, Macsorb HM-1210) or the like can be used. The true density of inorganic fillers can be used micro. Super pycnometer (MUPY-21T manufactured by Kanta Chrome Instruments Japan).

According to the present invention, when the product of the specific surface area [m ² /g] of the inorganic filler and the true density [g/cm ³ ] is 6 or more, the inflow of the pores of the curable resin composition is good. By setting the total to 8 or less, the average linear thermal expansion rate can be lowered. The lower limit of the product of the specific surface area to the true density of the inorganic filler is preferably 6.1 or more, more preferably 6.3 or more. Further, the product of the specific surface area of the inorganic filler and the true density is preferably 7.7 or less, more preferably 7.5 or less.

The inorganic filler is preferably an amine-based decane coupling agent, an epoxy decane coupling agent, or a hydrazine from the viewpoint of improving moisture resistance and dispersibility. One or more kinds of surface treatment agents such as a quinone-based coupling agent, a decane-based coupling agent, an alkoxy decane compound, an organic decazane compound, and a titanate coupling agent are treated. For example, "KBM403" (3-glycidoxypropyltrimethoxydecane) manufactured by Shin-Etsu Chemical Co., Ltd., and "KBM803" manufactured by Shin-Etsu Chemical Co., Ltd. (3) are commercially available as a surface treatment agent. "Methyl propyl trimethoxy decane", "KBE903" (3-aminopropyltriethoxy decane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-based) manufactured by Shin-Etsu Chemical Co., Ltd. "3-Aminopropyltrimethoxydecane", "SZ-31" (hexamethyldioxane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM103" (phenyltrimethoxy) manufactured by Shin-Etsu Chemical Co., Ltd.矽 )), "KBM-4803" (long-chain epoxy type decane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and still more preferably 0.2 from the viewpoint of improving the dispersibility of the inorganic filler. Mg/m ² or more. In addition, from the viewpoint of preventing the melt viscosity of the resin varnish or the increase in the melt viscosity of the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, still more preferably 0.5 mg/m. ² or less.

The surface-treated inorganic filler can be measured by washing with a solvent (for example, methyl ethyl ketone (MEK)) with respect to the amount of carbon per unit surface area of the inorganic filler. Specifically, as a solvent, ultrasonic cleaning was performed at 25 ° C for 5 minutes, except that a sufficient amount of MEK was surface-treated with an inorganic filler. Removed After the clear liquid is dried, the amount of carbon per unit surface area relative to the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by Horiba Ltd. can be used.

The content of the (c) inorganic filler in the curable resin composition is 74% by mass or more, preferably 76% by mass or more, and more preferably 78% by mass or more. (c) The upper limit of the content of the inorganic filler is preferably 90% by mass or less, and more preferably 85% by mass or less from the viewpoint of forming a fine wiring to obtain an insulating layer.

(d) One or more resins ((d) component) selected from the group consisting of a resin having a functional group having a glass transition temperature of 25 ° C or lower and a resin having a functional group at 25 ° C.

In a preferred embodiment, the curable resin composition contains the component (d) together with the epoxy resin (a') ((a') component) having an aromatic structure. By the soft resin containing the component (d), the elastic modulus and the thermal expansion coefficient of the cured product (insulating layer) of the thermosetting resin composition layer can be lowered, and the wiring obtained by using the resin sheet of the present invention can be suppressed. The bending of the board occurs.

The glass transition temperature of the resin having a functional group having a glass transition temperature (Tg) of 25 ° C or less (d) is preferably 20 ° C or lower, more preferably 15 ° C or lower. Although the lower limit of the glass transition temperature of the component (d) is not particularly limited, it is usually -15 ° C or higher.

When the resin having a functional group which is liquid at 25 ° C is liquid at 25 ° C, the Tg of the resin is of course 25 ° C or less.

The functional group which the (d) component has is preferably a functional group which can react with the component (a) or (a'). In a suitable embodiment, (d) The functional group of the component 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 an aminocarboxylate group. In particular, the functional group is preferably a hydroxyl group, an acid anhydride group, an epoxy group or a phenolic hydroxyl group, and more preferably a hydroxyl group, an acid anhydride group or an epoxy group. However, when the functional group contains an epoxy group, the component (d) does not have an aromatic structure.

The component (d) preferably has an alkylene structural unit selected from the group consisting of carbon atoms of 2 to 15 (preferably having a carbon number of 3 to 10, from the viewpoint of obtaining a curable resin composition layer having a low modulus of elasticity. More preferably, it is a structural unit of alkoxy groups having 5 to 6 carbon atoms and 2 to 15 carbon atoms (preferably having 3 to 10 carbon atoms, more preferably 5 to 6 carbon atoms), butadiene structure. Unit, isoprene structural unit, isobutylene structural unit, chloroprene structural unit, urethane structural unit, polycarbonate structural unit, (meth) acrylate structural unit, and polyoxyalkylene structural unit More preferably, one or more structural units have one or more structural units selected from the group consisting of a butadiene structural unit, an urethane structural unit, and a (meth) acrylate structural unit. In addition, "(meth) acrylate" means methacrylate and acrylate.

A suitable embodiment of the component (d) is a saturated and/or unsaturated butadiene resin containing a functional group which is liquid at 25 °C. The saturated and/or unsaturated butadiene resin containing a functional group which is liquid at 25 ° C is preferably selected from the group consisting of saturated and/or butadiene resins containing an acid anhydride group which is liquid at 25 ° C. 25 ° C is a saturated phenolic hydroxyl group and / or butadiene resin, saturated and / or butyl containing liquid epoxy at 25 ° C An olefin resin, a saturated and/or butadiene resin containing a liquid isocyanate group at 25 ° C, and a saturated and/or butadiene resin containing a liquid urethane group at 25 ° C. More than one resin in the group. Here, the term "saturated and/or unsaturated butadiene resin" means a resin containing a saturated butadiene skeleton and/or an unsaturated butadiene skeleton, and among these resins, a saturated butadiene skeleton and The unsaturated butadiene skeleton may be included in the main chain or may be included in the side chain.

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

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

The saturated and/or unsaturated butadiene resin containing a liquid epoxy group at 25 ° C is preferably an epoxy resin containing a saturated and/or butadiene skeleton at 25 ° C, more preferably It is an epoxy resin containing a polybutadiene skeleton which is liquid at 25 ° C, an epoxy resin containing a hydrogenated polybutadiene skeleton which is liquid at 25 ° C, and more preferably contains a liquid at 25 ° C. An epoxy resin having a polybutadiene skeleton and an epoxy resin containing a hydrogenated polybutadiene skeleton which is liquid at 25 ° C. Here, the so-called "hydrogenated polybutadiene" The epoxy resin of the skeleton refers to an epoxy resin in which at least a part of the polybutadiene skeleton is hydrogenated, and an epoxy resin which does not require a complete hydrogenation of the polybutadiene skeleton. Specific examples of the resin containing a polybutadiene skeleton which is liquid at 25 ° C and a hydrogenated polybutadiene skeleton which is liquid at 25 ° C include "PB3600" manufactured by Daicel. PB4700" (polybutadiene skeleton epoxy resin), "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin) manufactured by Nagase Chemical Co., Ltd.

The saturated and/or unsaturated butadiene resin containing an acid anhydride group in a liquid state at 25 ° C is preferably an acid anhydride resin containing a saturated and/or unsaturated butadiene skeleton at 25 ° C in a liquid state. The saturated and/or unsaturated butadiene resin containing a phenolic hydroxyl group which is liquid at 25 ° C is preferably a phenol resin containing a saturated and/or unsaturated butadiene skeleton at 25 ° C in a liquid state. The saturated and/or unsaturated butadiene resin containing a liquid isocyanate group at 25 ° C is preferably an isocyanate resin containing a saturated and/or unsaturated butadiene skeleton at 25 ° C in a liquid state. As the saturated and/or unsaturated butadiene resin containing a urethane group which is liquid at 25 ° C, an amine having a saturated and/or unsaturated butadiene skeleton which is liquid at 25 ° C is preferred. Ethyl carbamate resin.

Another suitable embodiment of the component (d) is an acrylic resin containing a functional group having a Tg of 25 ° C or lower. The acrylic resin containing a functional group having a Tg of 25 ° C or lower is preferably selected from an acrylic resin containing an acid anhydride group having a Tg of 25 ° C or lower, an acrylic resin containing a phenolic hydroxyl group having a Tg of 25 ° C or less, and a Tg of 25 An acrylic resin having a carboxyl group of lower than ° C, an acrylic resin containing an isocyanate group having a Tg of 25 ° C or lower, At least one or more of the group consisting of an acrylic resin having a Tg of 25 ° C or less and an acrylic resin containing an epoxy group having a Tg of 25 ° C or less.

The number average molecular weight (Mn) of the acrylic resin containing a functional group having a Tg of 25 ° C or less 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 by GPC (gel permeation chromatography).

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

The acryl resin containing an epoxy group having a Tg of 25 ° C or less is preferably an acrylate copolymer resin containing an epoxy group having a Tg of 25 ° C or lower. Specific examples thereof include "SG" manufactured by Nagase Chemical Co., Ltd. -80H" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn: 350,000 g/mol, epoxy price: 0.07 eq/kg, Tg11 °C)), "SG-P3" manufactured by Nagase Chemical Co., Ltd. (Epoxy group-containing acrylate copolymer resin (number average molecular weight Mn: 850,000 g/mol, epoxy price 0.21 eq/kg, Tg 12 ° C)).

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

The acrylic resin containing a phenolic hydroxyl group having a Tg of 25 ° C or less is preferably an acrylate copolymer resin containing a phenolic hydroxyl group having a Tg of 25 ° C or less, and specific examples thereof include a product of Nippon Chemical Co., Ltd. "SG-790" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn: 500,000 g/mol, hydroxyl value: 40 mgKOH/kg, Tg-32 ° C)).

Further, a suitable embodiment of the component (d) is a polyimine resin having a butadiene structural unit, an urethane structural unit, and a quinone imine structural unit in the molecule, and the polyimine. The resin preferably has a phenolic structure at the molecular end.

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

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

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

The details of the polyimine resin can be incorporated into the present specification by reference to International Publication No. 2008/153208.

From the viewpoint of enhancing the breaking strength, the component (d) preferably has a higher compatibility with components other than the component (d). That is, it is preferred to disperse the component (d) in the curable resin composition layer.

The content of the component (d) in the curable resin composition is not particularly limited, but is preferably 14% by mass or less, more preferably 13% by mass or less, still more preferably 12% by mass or less. Further, the lower limit is preferably 2% by mass or more, more preferably 3% by mass or more, and still more preferably 4% by mass or more.

The curable resin composition may contain an additive (e) such as a thermoplastic resin, a curing accelerator, a flame retardant, and rubber particles in addition to the above (a), (b), (c), and (d).

(e) Additives

- thermoplastic resin -

Examples of the thermoplastic resin include a phenoxy resin, a polyvinyl acetal resin, a polyolefin resin, a polybutadiene resin, a polyimine resin, a polyamidimide resin, a polyether phthalimide resin, and a poly A thermoplastic resin such as an anthracene resin, a polyether oxime resin, a polyphenylene ether resin, a polycarbonate resin, a polyether ether ketone resin or a polyester resin, among these, a phenoxy resin is preferred. One type of the thermoplastic resin may be used alone or two or more types may be used in combination.

The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 5,000 to 100,000, more preferably in the range of 10,000 to 60,000, still 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 a gel permeation chromatography (GPC) method. Specifically, the weight average molecular weight of the thermoplastic resin in terms of polystyrene is determined by using LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P/K-804L manufactured by Showa Denko Co., Ltd. /K-804L is used as a column, and chloroform is used as the movement equivalent. The column temperature is measured at 40 ° C, and can be calculated using a standard polystyrene calibration line.

The phenoxy resin may, for example, be selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a novolac skeleton, a biphenyl skeleton, an anthracene skeleton, and a dicyclopentadiene bone. A phenoxy resin having one or more kinds of skeletons in the group consisting of a shelf, a norbornene skeleton, a naphthalene skeleton, an onion skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be a functional group of any one of 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 phenoxy resins containing a bisphenol A skeleton) and "YX8100" (including a bisphenol S skeleton) manufactured by Mitsubishi Chemical Corporation. "Phenoxy resin" and "YX6954" (phenoxy resin containing bisphenol acetophenone skeleton), among others, "FX280" and "FX293" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., Mitsubishi "YX6954BH30", "YX7553", "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482", etc., which are produced by the company.

Examples of the polyvinyl acetal resin include a polyvinyl formal resin and a polyvinyl butyral resin, and a polyvinyl butyral resin is preferable. Specific examples of the polyvinyl acetal resin include "electrodinated butyral 4000-2", "electricated butyral 5000-A", and "electrodinated butyral 6000-C" manufactured by the Electrochemical Industry Co., Ltd. "Electrified butyral 6000-EP", S-LEC BH series, BX series, KS series, BL series, BM series, etc., manufactured by Sekisui Chemical Industry Co., Ltd.

Specific examples of the polyimine resin include "RIKACOAT SN20" and "RIKACOAT PN20" manufactured by Nippon Chemical and Chemical Co., Ltd.

Specific examples of the polyamidoximine resin include the east "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Yangfang Performance Co., Ltd.

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

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

Specific examples of the polyphenylene ether resin include oligophenyl ether manufactured by Mitsubishi Gas Chemical Co., Ltd. Styrene resin "OPE-2St 1200" and the like.

In the combination with other components, from the viewpoint of obtaining an insulating layer which further reduces the surface roughness and is more excellent in adhesion to the conductor layer, the thermoplastic resin is preferably a phenoxy resin or a polyethylene. Acetal resin. According to one embodiment, the thermoplastic resin component contains one or more selected from the group consisting of a phenoxy resin and a polyvinyl acetal resin.

The content of the thermoplastic resin in the curable resin composition is preferably from 0% by mass to 20% by mass, more preferably from 0.5% by mass to 10% by mass, from the viewpoint of appropriately adjusting the melt viscosity of the curable resin composition layer. More preferably, it is 0.6% by mass to 8% by mass.

- hardening accelerator -

Examples of the curing accelerator include a phosphorus-based curing accelerator, an amine-based curing accelerator, an imidazole-based curing accelerator, and an oxime-based curing accelerator. Preferred examples are a phosphorus-based curing accelerator, an amine-based curing accelerator, and an imidazole-based curing agent. Hardening promotion The agent is more preferably an amine-based hardening accelerator or an imidazole-based hardening accelerator. The curing accelerator may be used alone or in combination of two or more.

Examples of the phosphorus-based hardening accelerator include triphenylphosphine, bismuth borate compound, tetraphenylphosphonium tetraphenyl borate, n-butyl phosphotetraphenyl borate, and tetrabutyl decanoic acid. a salt, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc., preferably triphenylphosphine, tetrabutyl Sulfate.

Examples of the amine-based curing accelerator include a trialkylamine such as triethylamine or tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6, and a ginseng. (dimethylaminomethyl) phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc., preferably 4-dimethylaminopyridine, 1,8- Diaza-heterocyclic (5,4,0)-undecene.

Examples of the imidazole-based hardening accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-ethyl-4-methyl group. Imidazole, 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 benzene Triester, 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-phenylimidazolium isocyanide Urea acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrole [1 , 2-a] imidazolium, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, etc., imidazole compounds and imidazole compounds The adduct with epoxy resin is preferably 2-ethyl-4-methylimidazole or 1-benzyl-2-phenylimidazole.

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

Examples of the oxime-based hardening accelerator include dicyandiamide, 1-methyl hydrazine, 1-ethyl hydrazine, 1-cyclohexyl hydrazine, 1-phenyl fluorene, 1-(o-methylphenyl) fluorene, and dimethyl Base, diphenyl hydrazine, trimethyl hydrazine, tetramethyl hydrazine, pentamethyl hydrazine, 1,5,7-triazabicyclo[4.4.0]non-5-ene, 7-methyl-1 , 5,7-triazabicyclo[4.4.0]non-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allyl biguanide, 1-phenylbiguanide, 1-(o-methylphenyl)biguanide, etc., preferably It is dicyandiamide, 1,5,7-triazabicyclo[4.4.0]non-5-ene.

The content of the curing accelerator in the curable resin composition is not particularly limited, but is preferably in the range of 0.05% by mass to 3% by mass.

- Flame retardant -

The curable resin composition may contain a flame retardant. Examples of the flame retardant include an organic phosphorus-based flame retardant, a phosphorus compound containing organic nitrogen, and nitridation. Compound, antimony-based flame retardant, metal hydroxide, and the like. One type of the flame retardant may be used alone or two or more types may be used in combination.

Commercially available products can be used as the flame retardant, and examples thereof include "HCA-HQ" manufactured by Sanko Corporation and "PX-200" manufactured by Daiba Chemical Industry Co., Ltd.

The content of the flame retardant in the curable resin composition is not particularly limited, but is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, even more preferably 1.5% by mass. 10% by mass is better.

-Organic filler -

The curable resin composition may further comprise an organic filler. As the organic filler, any organic filler which can be used in forming the insulating layer of the printed wiring board can be used, and examples thereof include rubber particles, polyamide fine particles, and xenon particles, and rubber particles are preferable.

Commercially available products can be used as the rubber particles, and examples thereof include "EXL 2655" manufactured by Dow Chemical Co., Ltd., and "AC3816N" manufactured by AICA Industries Co., Ltd., and the like.

The content of the organic filler in the curable resin composition is preferably from 0.5% by mass to 20% by mass, more preferably from 0.7% by mass to 10% by mass.

The curable resin composition may contain a flame retardant and other additives other than the organic filler, and examples of the other additives include an organic copper compound, an organic zinc compound, and an organic cobalt compound. The organometallic compound, and an organic filler, a tackifier, an antifoaming agent, a leveling agent, a tackifier, and a resin additive such as a coloring agent.

- Liquid amino resin -

The curable resin composition can be further contained in a liquid-like amine-based resin (liquid amine-based resin) from the viewpoint of setting the minimum melt viscosity of the curable resin composition layer to 12,000 poise or less. The liquid amino resin is substituted for the liquid epoxy resin or may be used together with the liquid epoxy resin. The liquid amine-based resin may, for example, be an alkylated melamine resin such as methyl melamine. The alkylated melamine resin, for example, reacts melamine with formaldehyde, and after a part or all of the hydrogen atom of the amine group is substituted with a methylol group, and then reacts with the alcohol compound to convert a part or all of the methylol group into an alkane. Obtained from oxymethyl.

[resin sheet]

Hereinafter, the resin sheet of the present invention will be described.

The resin sheet of the present invention comprises a support and a curable resin composition layer formed of a curable resin composition, and the curable resin composition layer has a minimum melt viscosity of 12,000 poise or less. Further, it is preferable that the insulating layer (cured material) obtained by curing the curable resin composition layer has an average linear thermal expansion coefficient of from 25 ° C to 150 ° C of 17 ppm / ° C or less.

One of the resin sheets of the present invention is illustrated in Fig. 2 . In FIG. 2, the resin sheet 10 is provided with a support 11 and a support body 11 The upper curable resin composition layer 12.

<Support>

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material or a metal foil is preferable.

When a film made of a plastic material is used as the support, examples of the plastic material include polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter, Polyester, polycarbonate (hereinafter sometimes abbreviated as "PC"), polymethyl methacrylate (PMMA), etc., etc., may be referred to as "PEN", etc. Ethyl phthalocyanine (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among them, polyethylene terephthalate or polyethylene naphthalate is preferred, and polyethylene terephthalate is particularly preferred.

When a metal foil is used as the support, examples of the metal foil include a copper foil, an aluminum foil, and the like, and a copper foil is preferable. As the copper foil, a foil composed of a single metal of copper may be used, and a foil composed of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, hafnium, titanium, or the like) may be used.

The support can be subjected to a matte treatment or a corona treatment on the surface joined to the curable resin composition layer.

Further, as the support, a support having a release layer having a release layer can be used on the surface to be bonded to the curable resin composition layer. As The release agent to be used in the release layer of the support to which the release layer is attached may, for example, be one selected from the group consisting of an alkyd resin, a polyolefin resin, a urethane resin, and a silicone resin. The above release agent. A commercially available product can be used as the support for the mold release layer, and for example, a PET film having a release layer containing an alkyd resin release agent as a main component, that is, "Lumilar T6AM" manufactured by Toray Industries Co., Ltd., Lintec "Stock" system "SK-1", "AL-5", "AL-7", etc.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When the support having the release layer is used, the thickness of the entire support having the release layer is preferably in the above range.

<Curable resin composition layer>

In the present invention, the lowest melt viscosity of the curable resin composition layer is preferably 12,000 poise or less, preferably 10,000 poise from the viewpoint of achieving good embedding property of the inside of the hole when manufacturing the circuit board in the component. Below, it is better to be 8000 poise or less. The lower limit of the minimum melt viscosity of the curable resin composition layer is not particularly limited, and may be usually 500 poise or more, 1000 poise or more.

Here, the "minimum melt viscosity" of the curable resin composition layer means a resin having a melt-hardenable resin composition layer, and the curable resin composition layer exhibits the lowest viscosity. Specifically, when the resin is melted by heating the curable resin composition layer at a constant temperature increase rate, the initial stage melt viscosity decreases with temperature rise, and then when the temperature exceeds a certain course When the degree is increased, the melt viscosity is increased together with the temperature rise. The term "minimum melt viscosity" refers to the melt viscosity of the minimum point. The lowest melt viscosity of the curable resin composition layer can be measured by a dynamic viscoelastic method. Specifically, the lowest melt viscosity of the curable resin composition layer can be obtained by dynamic viscoelasticity measurement at a measurement start temperature of 60 ° C, a temperature increase rate of 5 ° C / min, a vibration number of 1 Hz, and a distortion of 1 deg. Examples of the dynamic viscoelasticity measuring device include ("Rheosol-G3000" manufactured by UBM).

In the present invention, the average linear thermal expansion coefficient of the insulating layer obtained by hardening the curable resin composition layer from 25 ° C to 150 ° C is 17 ppm / from the viewpoint of realizing the built-in circuit board for the part which suppresses the bending problem. Below °C, it is preferably 16 ppm/° C. or less, more preferably 15 ppm/° C. or less. The lower limit of the average linear thermal expansion coefficient is not particularly limited, but may be usually 1 ppm/° C. or higher, 2 ppm/° C. or higher, or 3 ppm/° C. or higher. The average linear thermal expansion coefficient can be measured, for example, by a known method such as thermomechanical analysis. As the thermomechanical analysis device, for example, "Thermo Plus TMA8310" manufactured by Rigaku Corporation can be cited. In the present invention, the average linear thermal expansion coefficient of the insulating layer is an average linear thermal expansion coefficient of 25 to 150 ° C in the plane direction at the time of thermomechanical analysis by the tensile weighting method.

In the present invention, the thickness of the curable resin composition layer composed of the curable resin composition is preferably 300 μm or less, and more preferably 200 μm or less. The lower limit of the thickness of the curable resin composition layer is not particularly limited, but from the viewpoint of obtaining an insulating layer which exhibits excellent peel strength for the conductor layer after the roughening treatment, and the ease of production of the resin sheet, usually It may be 10 μm or more, 20 μm or more, or the like.

The resin sheet 10 of the present invention may further include a protective film on a surface that is not bonded to the support 11 of the curable resin composition layer 12 (that is, a surface opposite to the support). The protective film contributes to the prevention of adhesion or scratches to the surface of the curable resin composition layer 12, such as garbage. As the material of the protective film, the same material as that described for the support 11 can be used. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the printed wiring board 10 is manufactured, the resin sheet 10 can be used by peeling off a protective film.

The resin sheet of the present invention is capable of realizing good embedding of parts inside the hole while manufacturing the circuit board built in the part, and at the same time, realizing the built-in circuit board of the part which suppresses the bending problem. Accordingly, the resin sheet of the present invention is particularly suitable for use in a part for embedding a hole (for hole embedding) in the manufacture of a built-in circuit board of a part, even if it is Mold underfill (sealed) at the bottom of the mold. The use can also be used. The resin sheet of the present invention can be used also for an insulating layer (for an insulating layer of a printed wiring board) for forming a printed wiring board. The resin sheet of the present invention can be suitably used for forming an insulating layer (printed wiring board) because it produces an insulating layer capable of forming fine wiring thereon, and is manufactured by a build-up printed wiring board. For the accumulation of the insulating layer, it is more suitably used for forming a conductor layer by plating (a conductive insulating layer for a printed wiring board in which a conductor layer is formed by plating).

<Method for Producing Resin Sheet>

Hereinafter, an example of a method for producing a resin sheet of the present invention will be described. to A curable resin composition layer composed of a curable resin composition is formed on the support.

The method of forming the curable resin composition layer is, for example, a method in which a support is applied to a curable resin composition, and a coating film is dried to provide a curable resin composition layer.

In this method, the curable resin composition layer can be prepared by applying a resin varnish which dissolves the curable resin composition to an organic solvent, and the resin varnish is applied onto a support by a die coater or the like, and the resin varnish is dried. To make.

Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol. Acetate such as acetate, cellosolve, carbitol such as butyl carbitol, aromatic hydrocarbon such as toluene and xylene, dimethylformamide, dimethylacetamide, and A guanamine-based solvent such as N-methylpyrrolidone. The organic solvent may be used alone or in combination of two or more.

The resin varnish drying can be carried out by a known drying method such as heating, blowing hot air or the like. Although it varies depending on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing 30% by mass to 60% by mass of an organic solvent is used, it is dried at 50 ° C to 150 ° C for 3 minutes to 10 minutes. A layer of a curable resin composition can be formed on the support.

Further, in the present invention, for example, a curable resin composition layer can be formed on the protective film, and then the laminate can be laminated on the curable resin composition layer to form a resin sheet.

<Wiring board>

The wiring board of the present invention includes an insulating layer and a conductor layer obtained by curing a layer of a curable resin composition of the resin sheet of the present invention. Hereinafter, a component-embedded circuit board which is one embodiment of the wiring board of the present invention will be described.

The component-embedded circuit board includes (A) a circuit board having first and second main faces, a hole penetrating through the first and second main faces, and a second main surface joined to the circuit board. The temporarily attached material and the component temporarily attached to the inside of the hole of the circuit board by the temporarily attached material, the circuit board temporarily attached to the component can be obtained by a manufacturing method including the following sequence a circuit in which the resin sheet of the present invention is laminated to the first main surface of the circuit board, and the first lamination step of vacuum lamination is performed, and (B) heat treatment is performed to laminate the resin sheet. After the step of heat-treating the substrate and (C) peeling off the temporarily-attached material from the second main surface of the circuit board, the second resin sheet is bonded to the second main surface of the circuit board by the curable resin composition layer And a step of performing a second lamination step of vacuum lamination, and D) thermally curing the curable resin composition layer of the resin sheet and the curable resin composition layer of the second resin sheet. Before the description of each step, a description will be given of a "circuit board for temporarily attaching a component" using the resin sheet 10 of the present invention.

(The circuit board with the parts temporarily attached)

Circuit board with temporary parts attached (hereinafter, also referred to as "temporary attachment" The circuit board and the "hole substrate" of the component include a circuit board having first and second main faces and forming a hole penetrating between the first and second main faces, and bonding to the second main surface of the circuit board The temporarily attached material and the part temporarily attached to the inside of the hole of the circuit board by the temporarily attached material.

The circuit board on which the parts are temporarily attached can be prepared in any order known in the art when manufacturing the circuit board built in the parts. Hereinafter, an example of the procedure for preparing a circuit board for temporarily attaching components will be described with reference to FIGS. 1A to 1D, but the present invention is not limited to the following procedure.

First, a circuit board is prepared (Fig. 1A). The "circuit board" refers to a plate-like substrate having a first or second main surface facing the first and second main surfaces of the first and second main surfaces. In FIG. 1A, the end surface of the circuit board 1 is schematically shown, and the circuit board 1 includes a circuit board 3 including a substrate 2, a via wiring, and a surface wiring. In the following description, for convenience of explanation, the first main surface of the circuit board is shown as the upper main surface of the circuit board shown in the drawing, and the second main surface of the circuit board is the lower main surface of the circuit board shown in the drawing. .

Examples of the substrate 2 used for the circuit board 1 include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like, and preferably a glass epoxy. Substrate. Further, when the printed wiring board is manufactured, the inner layer circuit board in which the intermediate layer of the insulating layer and/or the conductor layer is formed is also included in the "circuit board".

The thickness of the substrate 2 of the circuit substrate 1 is built in from the parts From the viewpoint of thinning of the road plate, it is preferably less than 400 μm, more preferably 350 μm or less, still more preferably 300 μm or less, still more preferably 250 μm or less, and particularly preferably 200 μm or less, 180 μm. Hereinafter, it is 170 μm or less, 160 μm or less, or 150 μm or less. The lower limit of the thickness of the substrate 2 is not particularly limited, but is preferably 50 μm or more, more preferably 80 μm or more, and still more preferably 100 μm or more from the viewpoint of improving workability during transportation.

The size of the circuit wiring 3 included in the circuit board 1 can be determined in accordance with desired characteristics. For example, the thickness of the surface wiring is preferably 40 μm or less, more preferably 35 μm or less, still more preferably 30 μm or less, and still more preferably 25 μm or less, from the viewpoint of reducing the thickness of the component-embedded circuit board. 20 μm or less, 19 μm or less, or 18 μm or less. The lower limit of the thickness of the surface wiring is not particularly limited, but is usually 1 μm or more, 3 μm or more, and 5 μm or more.

Next, a hole (recess) for accommodating the component is placed on the circuit board (Fig. 1B). As schematically shown in FIG. 1B, a hole 2a penetrating between the first and second main faces of the circuit board can be provided at a predetermined position of the substrate 2. The hole 2a can be formed by considering a characteristic of the substrate 2 by, for example, a well-known method using a drill, a laser, a plasma, an etching medium, or the like.

Although only one hole 2a is shown in Fig. 1B, the holes 2a may be plurally arranged at a predetermined interval from each other. The distance between the holes 2a is suitable for a short period of view from the viewpoint of miniaturization of the built-in circuit board. The distance between the holes 2a varies depending on the opening size of the hole 2a itself, but is preferably 10 mm or less, more preferably 9 mm or less, still more preferably 8 mm or less, and even better. It is 7 mm or less, and particularly preferably 6 mm or less. According to the method of the present invention, even in the case where the holes are provided at the shorter interval, the occurrence of the bending of the substrate can be suppressed. The lower limit of the distance between the holes 2a varies depending on the opening size of the hole 2a itself, but is usually 1 mm or more and 2 mm or more. The pitch between the holes 2a does not need to be the same for the entire circuit board, and may be different.

The shape of the opening of the hole 2a is not particularly limited, and may be any shape such as a rectangle, a circle, a rectangle, or a circle. Further, although the opening size of the hole 2a varies depending on the design of the circuit wiring, for example, when the opening shape of the hole 2a is rectangular, it is preferably 5 mm × 5 mm or less, more preferably 3 mm × 3 mm or less, or 2 mm × 2 mm or less. . The lower limit of the opening size varies depending on the size of the components to be housed, but is usually 0.5 mm × 0.5 mm or more. The opening shape and the opening size of the hole 2a need not be the same as the entire circuit board, and may be different.

Next, a material temporarily attached to the second main surface of the circuit board on which the holes are provided is laminated (FIG. 1C). The material to be temporarily attached is not particularly limited as long as it has an adhesive surface indicating sufficient adhesion, and any conventionally-prepared material that has been conventionally known can be used for the production of the built-in circuit board. In the aspect schematically shown in Fig. 1C, the material 4 temporarily attached in a film form is laminated such that the adhesive surface of the temporarily attached material 4 is joined to the second main surface of the circuit board. Thereby, the through-hole 2a becomes the adhesive surface of the material 4 temporarily attached.

For example, the UC series (UV tape for wafer cutting) manufactured by Furukawa Electric Co., Ltd. can be cited as a material to be temporarily attached to the film.

Next, the adhesive surface of the temporarily attached material exposed through the hole is temporarily attached to the part (Fig. 1D). In the aspect schematically shown in Fig. 1D, the component 5 is temporarily attached to the adhesive surface of the temporarily attached material 4 through the hole 2a.

As the component 5, an appropriate electric component may be selected in accordance with desired characteristics, and examples thereof include a passive component such as a capacitor, an inductor, and a resistor, and a current component such as a semiconductor bare wafer. The same part 5 can be used for all holes, and different parts 5 can be used for each hole.

When the circuit board for temporarily attaching the component is manufactured, in addition to the above method, for example, after the hole 2a is formed in the substrate 2, the circuit wiring 3 can be provided, and the temporarily attached material 4 can be laminated on the second main surface of the circuit board. A hole 2a is formed.

A method of manufacturing a circuit board in a part will be described using the resin sheet of the present invention. In the following description, the resin sheets of the present invention which are laminated on the first main surface and the second main surface of the component-embedded circuit board are described as "first resin sheet 10" and "second resin sheet 20", respectively. Happening. The same may be used as the first resin sheet 10 and the second resin sheet 20, and a different one may be used. In the following description, in order to distinguish the first resin sheet 10 from the second resin sheet 20, the support 11 of the first resin sheet 10 may be referred to as the first support 11.

<(A) First Lamination Step (Lamination of First Resin Sheet)>

First, the resin sheet (first resin sheet 10) of the present invention is laminated on a circuit board on which components are temporarily attached (first lamination step). In detail, for the time being In the circuit board 1' to which the component is attached, the first resin sheet 10 is vacuum-laminated so that the curable resin composition layer 12 is bonded to the first main surface of the circuit board (see FIG. 3A). In the case where the protective film of the first resin sheet 10 is coated with the curable resin composition layer 12, the protective film is peeled off, and then the circuit board is laminated.

The vacuum lamination of the first resin sheet 10 of the circuit board 1' to which the components are temporarily attached is, for example, under the reduced pressure, from the side of the support 11, by heating the first resin sheet 10 to the temporarily attached parts. The circuit board 1' is performed. A member (not shown; hereinafter also referred to as "heating and pressing member") for heating and pressing the first resin sheet 10 on the circuit board 1' to which the components are temporarily attached is, for example, a heated metal plate (SUS) Mirror plate, etc.) or metal roll (SUS roll). In addition, it is preferable that the heating and pressing member is not directly pressed into the first resin sheet 10, but the unevenness of the circuit wiring 3 or the hole 2a of the circuit board 1' due to the temporary attachment of the component is preferably sufficient for the first resin sheet 10. In the following way, it is punched through an elastic material such as heat-resistant rubber.

The heating and pressing temperature is preferably from 80 ° C to 160 ° C, more preferably from 100 ° C to 140 ° C, and the heating pressing pressure is preferably from 0.098 MPa to 1.77 MPa, more preferably from 0.29 MPa to 1.47 MPa, and heating pressure. The time is preferably from 20 seconds to 400 seconds, more preferably from 30 seconds to 300 seconds. The vacuum lamination is preferably carried out under reduced pressure of 26.7 hPa or less.

Vacuum lamination can be carried out by means of a commercially available vacuum laminator. As a commercially available vacuum laminator, for example, the true name of the machine can be listed. An air pressure laminator, a vacuum applicator manufactured by Nichigo-Morton Co., Ltd., a two-stage accumulation laminator made of Nichigo-Morton Co., Ltd., and the like.

After the first laminating step, the smoothing treatment of the laminated first resin sheet 10 is performed by, for example, pressing the heating and pressing member from the side of the first support 11 under normal pressure (atmospheric pressure). good. The pressing conditions of the smoothing treatment may be the same conditions as the heating and pressing conditions of the vacuum lamination described above.

The smoothing step can be carried out by a commercially available laminator. Still, the first lamination step and the smoothing step can be carried out using the commercially available vacuum laminator continuity described above.

After the first lamination step, the curable resin composition layer 12 is filled in the hole 2a, and the component 5 temporarily attached to the hole 2a is fitted into the curable resin composition layer 12 (see FIG. 3B).

<(B) Heat treatment step>

Next, the circuit board of the first resin sheet 10 is laminated by heat treatment (heat treatment step). The heating temperature in this step is preferably 155 ° C or lower, more preferably 150 ° C or lower, still more preferably 145 ° C or lower, and still more preferably 140 ° C or lower. The lower limit of the heating temperature is preferably 110 ° C or more, more preferably 115 ° C or more, still more preferably 120 ° C or more, and still more preferably 125 ° C or more.

Although the heating time in the heat treatment step varies depending on the heating temperature, it is preferably 10 minutes or longer, more preferably 15 minutes or longer, and still more preferably 20 minutes or longer. Although the upper limit of the heating time is not particularly limited, it is usually 60 minutes or less.

The heat treatment of the curable resin composition layer 12 in the heat treatment step is preferably carried out under atmospheric pressure (at normal pressure).

The heat treatment of the curable resin composition layer 12 in the heat treatment step may be carried out in a state where the first support 11 is attached to the curable resin composition layer 12, or the first support 11 may be peeled off to form a curable resin composition layer. 12 is implemented after exposure. In a preferred embodiment, the heat treatment of the curable resin composition layer 12 is carried out in a state in which the first support 11 is attached to the first curable resin composition layer 12. Thereby, it is advantageous from the viewpoint of preventing adhesion of foreign matter and preventing damage of the curable resin composition layer.

In the case where the heat treatment of the curable resin composition layer 12 in the heat treatment step is performed in the state in which the first support 11 is attached, the first support 11 is an insulating layer obtained by curing the curable resin composition layer 12. (The cured product) may be peeled off before the step of providing the conductor layer (circuit wiring), for example, may be peeled off between the first heat treatment step and the second lamination step described later, or may be in the second lamination step and the thermal hardening step. Peeling between (described later) may also be performed after the thermal hardening step. In a preferred embodiment, the first support 11 is peeled off after the thermal curing step. When a metal foil such as a copper foil is used as the first support 11, as will be described later, since the conductor layer (circuit wiring) can be provided using the metal foil, the first support 11 may not be peeled off.

In a preferred embodiment, the circuit substrate can be cooled to room temperature (room temperature) between the first lamination step and the heat treatment step.

In a suitable embodiment, by heating the step The curable resin composition layer 12 is a curable resin composition layer (heat treatment body) 12' (see Fig. 3C). In addition, Fig. 3C shows a state in which the curable resin composition layer (heat treatment body) 12' is obtained by heat treatment in a state in which the first support 11 is attached.

<(C) Second Lamination Step (Lamination of Second Resin Sheet)>

After the heat treatment step, the temporarily attached material 4 is peeled off from the second main surface of the circuit board, and the second main surface of the circuit board 2 is exposed. Further, the second resin sheet 20 is vacuum-laminated so that the curable resin composition layer 22 is bonded to the second main surface (lower side surface) of the circuit board 2 (see FIG. 3D). Here, the second resin sheet includes a support 21 (also referred to as a second support) and a curable resin composition layer 22 (also referred to as a second curable resin composition layer) bonded to the support. As the second resin sheet, the resin sheet of the present invention is preferably used. The structure of the second support or the second curable resin composition layer is the same as that of the above-described support sheet of the resin sheet of the present invention and the curable resin composition layer. Further, as the second resin sheet, a resin sheet having a different constitution from the first resin sheet (for example, a resin sheet having a plurality of curable resin composition layers having different compositions or having a minimum melting ratio which is not satisfactory in the present invention) can be used. Viscosity condition, the average linear thermal expansion rate of the curable resin composition layer).

The peeling of the temporarily attached material 4 can be carried out according to a conventionally known method depending on the type of the material 4 to be temporarily attached. For example, when the UV tape for wafer cutting such as the UC series manufactured by Kawasaki Electric Co., Ltd. is used as the material 4 to be temporarily attached, the UV irradiation temporarily supplies the material. After the material 4, the temporarily attached material 4 can be peeled off. The conditions such as the amount of UV irradiation can be well-known conditions generally used in the manufacture of a circuit board in which a part is built.

By the heat treatment step, even when a circuit board having a high hole density or a circuit board having a small thickness is used, the occurrence of bending of the substrate can be suppressed, and the step from the heat treatment step to the second lamination step is not disturbed. The substrate is conveyed, and the second lamination step can be smoothly performed. Further, since the curable resin composition layer is subjected to heat treatment under specific conditions, the vacuum lamination in the second lamination step can suppress the positional change (offset) of the component, and the placement accuracy of the component can be achieved with good yield. Excellent parts contain built-in boards.

In the vacuum lamination of the second resin sheet 20 in the second lamination step, the same method and conditions as in the vacuum lamination of the first resin sheet 10 in the first lamination step can be employed.

In a preferred embodiment, the circuit substrate can be cooled to room temperature (room temperature) between the heat treatment step and the second lamination step.

In the second laminating step, the second curable resin composition layer 22 and the second support 21 are laminated on the second main surface of the circuit board 2 (see FIG. 3E).

The second support 21 may be peeled off before the step of providing the conductor layer (circuit wiring) in the insulating layer obtained by curing the second curable resin composition layer 22, and may be, for example, a second lamination step and a later description. Peeling between the hardening steps may also be performed after the hardening step. In a suitable In the embodiment, the second support 21 is peeled off after the hardening step. In the case where a metal foil such as a copper foil is used as the second support 21, a conductor layer (circuit wiring) may be provided by using the metal foil, and the second support 21 may not be peeled off.

<(D) hardening step>

In the curing step, the curable resin composition layer 12 of the first resin sheet 10 and the second curable resin composition layer 22 of the second resin sheet 20 are thermally cured. Thereby, on the first main surface of the circuit board 2, the curable resin composition layer (heat treatment body) 12' forms the insulating layer 12" (cured material) on the second main surface of the circuit board 2, and the second hardening property The resin composition layer 22 forms an insulating layer 22" (cured material) (refer to FIG. 3F).

The conditions of the thermosetting are not particularly limited, and the conditions generally employed in forming the insulating layer of the circuit board built in the part can be used.

The thermosetting conditions of the curable resin composition layers 12 and 22 of the first and second resin sheets 10 and 20 are different depending on the composition of the curable resin composition used for each curable resin composition layer, and the like. However, the hardening temperature may be in the range of 120 ° C to 240 ° C (preferably in the range of 150 ° C to 210 ° C, more preferably in the range of 170 ° C to 190 ° C), and the hardening time may be in the range of 5 minutes to 90 minutes (preferably) It is 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes).

Before the thermosetting, the curable resin composition layer 12 and the second curable resin composition layers 12 and 22 may be preheated at a temperature lower than the curing temperature. For example, before thermal hardening, it can be above 50 °C The curable resin composition layers 12 and 22 are preheated for 5 minutes or longer (preferably 5 minutes) at a temperature of less than 120 ° C (preferably 60 ° C or more and 110 ° C or less, more preferably 70 ° C or more and 100 ° C or less). 150 minutes, more preferably 15 minutes to 120 minutes). In the case of preliminary heating, the preliminary heating is also included in the hardening step.

The thermal hardening of each of the curable resin composition layers in the hardening step is preferably carried out under atmospheric pressure (at normal pressure).

In a preferred embodiment, the circuit substrate can be cooled to room temperature (room temperature) between the second lamination step and the hardening step.

In the present invention, the insulating layer 12", 22" obtained by curing the curable resin composition layer 12 and the second curable resin composition layer 22 has an average linear thermal expansion coefficient from 25 ° C to 150 ° C, and the substrate is lowered. From the viewpoint of bending, it is preferably 17 ppm/° C. or less, more preferably 15 ppm/° C. or less.

Although the embodiment using the temporarily attached material has been described in detail above, the resin-made sheet can be used instead of the temporarily-attached material to manufacture the component-embedded circuit board. The resin sheet which can be used instead of the temporarily attached material can be similar to the above-mentioned second resin sheet, and can be the resin sheet of the present invention or another resin sheet. In the case where the material to be temporarily attached is used instead of the resin sheet, the peeling step of the material to be temporarily attached is not required.

<other steps>

When manufacturing a built-in circuit board for a part, it can be further included and then drilled a step of the edge layer (drilling step), a step of roughening the surface of the insulating layer (roughening step), a step of forming a conductor layer on the surface of the roughened insulating layer (conductor layer forming step). These steps can be carried out in accordance with various methods well known to those skilled in the art for the manufacture of the built-in circuit boards of the parts. When the support sheets 11 and 21 of the resin sheets 10 and 20 are peeled off after the hardening step, the peeling of the supports 11 and 21 can be performed between the hardening step and the drilling step, the drilling step and the roughening step. Interposed between, or between the roughening step and the conductor layer forming step.

The drilling step is a step of drilling the insulating layers 12", 22" (hardened), whereby holes such as through holes, through holes, and the like can be formed in the insulating layers 12", 22". For example, a hole can be formed using a drill, a laser (carbon gas laser, a YAG laser, etc.), and a plasma equal to the insulating layers 12", 22". In the built-in circuit board of the part, the insulating layers 12", 22" are generally turned on by the through holes.

The roughening step is a step of roughening the insulating layers 12", 22". The order and conditions of the roughening treatment are not particularly limited, and a well-known sequence and conditions which are generally used when forming the insulating layers 12" and 22" of the circuit board in the component can be employed. For example, the roughening treatment of the insulating layers 12", 22" can be performed by the swelling treatment of the swelling liquid, the roughening treatment by the oxidizing agent, and the neutralization treatment by the neutralization liquid, and the insulating layer can be roughened. 12", 22". The swelling solution is not particularly limited, and examples thereof include an alkali solution and a surfactant solution, and an alkali solution is preferred. The alkali solution is more preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of the commercially available swelling liquid include Swelling Dip Securiganth P, Swelling Dip Securiganth SBU, and the like manufactured by Atotech Japan Co., Ltd. Swelling by swelling liquid Although the treatment is not particularly limited, it can be carried out, for example, by immersing the insulating layer 12" and 22" for 1 minute to 20 minutes by a swelling liquid at 30 ° C to 90 ° C. From the viewpoint of suppressing the swelling of the resin of the insulating layers 12" and 22" at an appropriate level, it is preferable that the insulating layer 12" and 22" are immersed in the swelling liquid at 40 ° C to 80 ° C for 5 seconds to 15 minutes. The oxidizing agent is not particularly limited, and examples thereof include an alkaline permanganic acid solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganic acid solution is preferably carried out by immersing the first and second insulating layers in an oxidizing agent solution heated to 60 to 80 ° C for 10 minutes to 30 minutes. Further, the concentration of the permanganate in the alkaline permanganic acid solution is preferably 5% by mass to 10% by mass. Examples of the commercially available oxidizing agent include an alkaline permanganic acid solution such as Concentrate Compact P manufactured by Atotech Japan Co., Ltd., and Dozing Solusion Securiganth P. In addition, as a neutralizing liquid, an acidic aqueous solution is preferable, and as a commercial item, the reduction solution Securiganth P by Atotech Japan Co., Ltd. is mentioned, for example. The treatment with the neutralizing solution can be carried out by immersing the surface of the treatment with the roughening treatment of the oxidizing agent solution at 30 ° C to 80 ° C for 5 minutes to 30 minutes. From the viewpoint of workability and the like, it is preferred that the object to be roughened by the oxidizing agent is immersed in a liquid at 40 ° C to 70 ° C for 5 minutes to 20 minutes.

The conductor layer forming step is a step of forming a conductor layer (circuit wiring) on the surface of the roughened insulating layer.

The conductor material used for the conductor layer is not particularly limited. In a suitable embodiment, the conductor layer comprises a layer selected from the group consisting of gold, platinum, palladium, silver, One or more metals selected from the group consisting of copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of the alloy layer include alloys of two or more metals selected from the group (for example, nickel, chromium alloy, copper, nickel alloy, copper, titanium). The layer formed by the alloy). Among them, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper is preferred from the viewpoints of versatility, cost, and ease of pattern formation of the conductor layer. Or nickel. Chrome alloy, copper. Nickel alloy, copper. The alloy layer of titanium alloy is more preferably a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel. The alloy layer of chrome alloy is more preferably a single metal layer of copper.

The conductor layer may have a single layer structure, or may be a single metal layer formed of different kinds of metals or alloys or a laminated structure of two or more alloy layers laminated. When the conductor layer is a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc or titanium, or nickel. Alloy layer of chrome alloy.

Although the thickness of the conductor layer varies depending on the desired design of the built-in circuit board, it is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

The method of forming the conductor layer is not particularly limited as long as it can form a conductor layer (circuit wiring) having a desired pattern. In a suitable embodiment, the conductor layer can be formed by plating. For example, a conductor layer (circuit wiring) having a desired pattern can be formed by plating on the surfaces of the first and second insulating layers by a conventional technique such as a semi-additive method or a full-addition method. Hereinafter, an example in which the conductor layer is formed by a semi-additive method will be described.

First, on the surface of the two insulating layers 12", 22" Electroless plating forms a plating seed layer. Next, a mask pattern for exposing a portion of the plating seed layer to the desired wiring pattern is formed on the formed plating seed layer. After the metal layer is formed by electrolytic plating on the exposed plated seed layer, the mask pattern is removed. Then, the unnecessary seed plating layer is removed by etching or the like to form a conductor layer having a desired pattern.

By this step, a conductor (through-hole wiring) is also formed in the through hole, and the circuit wiring 3 provided on the surface of the insulating layers 12" and 22" and the circuit wiring of the circuit substrate are electrically connected to obtain a built-in circuit board of the component. 100 (refer to Fig. 3G).

When a metal foil such as a copper foil is used as the first support 11 and the second support 21, the conductor layer can be formed by subtracting the metal foil or the like. Further, by using a metal foil as a plating seed layer, a conductor layer can be formed by electrolytic plating.

The manufacturing method of the built-in circuit board of the part may further include the step of singulating the built-in circuit board of the part.

In the singulation step, for example, it can be ground by a conventionally known cutting device having a rotary blade, and the obtained structure is formed into individual pieces of the built-in circuit board unit.

[semiconductor device]

The semiconductor device of the present invention includes the wiring board of the present invention (for example, the component-embedded circuit board described above).

As the semiconductor device, an electrical product can be cited (for example) Various semiconductor devices such as computers, mobile phones, digital cameras, and televisions, and vehicles (such as motorcycles, automobiles, trams, ships, and airplanes).

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

<Production of Resin Sheet>

The resin varnish of the examples and the comparative examples was produced using the resin varnish (curable resin composition) prepared by the following procedure.

(Preparation of inorganic filler)

As the cerium oxide 1~6, "ADMAFINE" made by Admatechs, "SFP series" made by Electrochemical Industry Co., Ltd., "SP(H) series" made by Nippon Steel & Metals Materials Co., Ltd., 堺After the surface treatment of the "Sciqas series" manufactured by the Chemical Industry Co., Ltd. and the "Sea Hoster series" manufactured by Nippon Shokubai Co., Ltd., the particle size distribution and specific surface area were measured by the following methods, and used in Examples and Comparative Examples.

The aluminum oxide was subjected to surface treatment using "AZ series" and "AX series" manufactured by Nippon Steel & Co., Ltd., and the particle size distribution and specific surface area were measured by the following methods, and used in Example 4.

(1) Determination of average particle size

100 mg of powder of cerium oxide 1 to 6 or 100 mg of alumina, 0.1 g of a dispersing agent ("SN9228" manufactured by San Nopco Co., Ltd.), and 10 g of methyl ethyl ketone were weighed in a container bottle, and dispersed in ultrasonic waves. 20 minutes. The particle size distribution was measured by a batch type of SALD-2200 manufactured by Shimadzu Corporation using a laser diffraction type particle size distribution measuring apparatus (batch cell), and the average particle diameter was calculated and shown in Table 2.

(2) Determination of specific surface area

The specific surface area of cerium oxide 1 to 6 and alumina was measured using a BET fully automatic specific surface area measuring apparatus (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and shown in Table 2.

(3) Determination of true density

The true density of cerium oxide 1~6 and alumina is reduced by micro. A super pycnometer (MUPY-21T manufactured by Kanta Chrome Instruments Japan) was measured and shown in Table 2.

(Modulation of Resin Varnish 1)

A bisphenol type epoxy resin (ZX1059, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., an epoxy equivalent of about 169, a 1:1 mixture of bisphenol A and bisphenol F), and a naphthalene ether ring. Oxygen resin ("EXA-7311-G4" manufactured by DIC Co., Ltd., epoxy equivalent: 213) 10 parts, bisphenol type epoxy resin ("XX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 185) 6 parts, biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 272), 10 parts, and flame retardant ("PX-200" manufactured by Daiwa Chemical Industry Co., Ltd.) 4 The mixture was heated and dissolved while stirring in a solvent mixture of 20 parts of solvent naphtha and 10 parts of cyclohexanone. After cooling to room temperature, a cresol novolak-based hardener containing a triazine skeleton ("LA-3018-50P" manufactured by DIC Co., Ltd., 2-hydroxyl group having a hydroxyl equivalent of about 151 and a solid content of 50%) was mixed. Propanol solution) 10 parts, phenol novolac-based curing agent containing triazine skeleton ("LA-7054" manufactured by DIC Co., Ltd., MEK solution having a hydroxyl equivalent of about 125 and a solid content of 60%) 4 parts, naphthol-based hardening 10 parts of "SN-495V" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., MEK solution with a hydroxyl equivalent of about 231 and a solid content of 60%), and an amine hardening accelerator (4-dimethylaminopyridine (DMAP)) 1 part, a solid quinone-based coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.), spherical cerium oxide 1 (average particle diameter 1.47 μm, specific surface area) 3.07 m ² /g, the amount of carbon per unit surface area is 0.30 mg/m ² ), 220 parts, and uniformly dispersed by a high-speed rotary mixer, and then filtered with a cartridge filter ("SHP050" manufactured by ROKITECHNO Co., Ltd.) to prepare a resin varnish. 1.

(modulation of resin varnish 2)

Glycidylamine type liquid epoxy resin ("630LSD" manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent: 95), 6 parts, and bisphenol type epoxy resin ("XX4000HK" manufactured by Mitsubishi Chemical Corporation) Oxygen equivalent: 185) 6 parts, bisphenol AF type epoxy resin (Mitsubishi Chemical Co., Ltd. "YL7760", epoxy equivalent of about 238) 6 parts, naphthalene type epoxy resin (Nippon Steel & Sumitomo Chemical Co., Ltd. "ESN475V", epoxy equivalent of about 330 parts, 15 parts, and phenoxy resin ("XX7553BH30" manufactured by Mitsubishi Chemical Corporation, 30% by mass of cyclohexanone: methyl ethyl ketone (MEK) 1: (1 solution) 8 parts, and dissolved by heating while stirring a solvent mixture of 20 parts of solvent naphtha and 5 parts of cyclohexanone. After cooling to room temperature, a cresol novolak-based hardener containing a triazine skeleton ("LA-3018-50P" manufactured by DIC Co., Ltd., 2-hydroxyl group having a hydroxyl equivalent of about 151 and a solid content of 50%) was mixed. 12 parts of propanol solution, active ester-based curing agent ("EXB-8000L-65M" manufactured by DIC Co., Ltd., MEK solution having an active base equivalent of about 220 and a nonvolatile content of 65 mass%) 12 parts, an amine-based hardening accelerator (4-dimethylaminopyridine (DMAP), solid content of 5% by mass of MEK solution) 1 part, flame retardant (Sanko (HQ-HQ), 10-(2,5-dihydroxybenzene) Base) 10-hydrogen-9-oxa-10-phosphonium phenanthrene (Phosphaphenanthrene-10-oxide, average particle size 2 μm) 2 parts, rubber particles (Dow Chemical Co., Ltd., EXL 2655) 2 parts Phenyltrimethoxydecane ("KBM103" manufactured by Shin-Etsu Chemical Co., Ltd.)) spherical cerium oxide 2 (average particle diameter 1.33 μm, specific surface area 3.38 m ² /g, carbon per unit surface area) 190 parts of the amount of 0.28 mg/m ² ) was uniformly dispersed in a high-speed rotary mixer, and then filtered through a cartridge filter ("SHP050" manufactured by ROKITECHNO Co., Ltd.) to prepare a resin varnish 2.

(Modulation of Resin Varnish 3)

A bisphenol type liquid epoxy resin (ZX1059, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., an epoxy equivalent of about 169, a 1:1 mixture of bisphenol A and bisphenol F), and a naphthalene type. 4 parts of liquid epoxy resin ("HP4032SS" manufactured by DIC Co., Ltd., epoxy equivalent: 144), and 3 parts of naphthalene type epoxy resin ("HP-4710" manufactured by DIC Co., Ltd., epoxy equivalent: about 170). Biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 272) 12 parts, and phenoxy resin ("XX7553BH30" manufactured by Mitsubishi Chemical Corporation, 30% by mass of solid content) Hexanone: a 1:1 solution of methyl ethyl ketone (MEK), 5 parts, and dissolved by heating while stirring a mixture of 20 parts of solvent naphtha and 5 parts of cyclohexanone. After cooling to room temperature, a phenol novolak-based curing agent containing a triazine skeleton ("LA-7054" manufactured by DIC Co., Ltd., a MEK solution having a hydroxyl equivalent of about 125 and a solid content of 60%) was mixed with 8 parts of naphthol. A sclerosing agent ("SN-485" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., a MEK solution with a hydroxyl equivalent of about 212 and a solid content of 60%), 12 parts, and an imidazole-based hardening accelerator (manufactured by Shikoku Chemicals Co., Ltd.) 1B2PZ"1-benzyl-2-phenylimidazole, 5% MEK solution in solid form) 1 part, flame retardant ("HCA-HQ", 10-(2,5-dihydroxyphenyl) manufactured by Sanguang Co., Ltd. )-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 4 parts, amine decane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) 140 parts of spherical cerium oxide 3 (having an average particle diameter of 1.06 μm, a specific surface area of 3.01 m ² /g, and a carbon content per unit surface area of 0.31 mg/m ² ), and uniformly dispersed in a high-speed rotary mixer, followed by a tube A filter ("SHP050" manufactured by ROKITECHNO Co., Ltd.) was filtered to prepare a resin varnish 3.

(Modulation of Resin Varnish 4)

50 parts of component (d) prepared as follows, bisphenol epoxy resin (ZX1059 manufactured by Nippon Steel Chemical Co., Ltd.), 1:1 mixture of bisphenol A and bisphenol F, epoxy Equivalent 169) 3 parts, bisphenol AF type epoxy resin ("YL7760" manufactured by Mitsubishi Chemical Corporation, epoxide equivalent: 238) 2 parts, and flame retardant ("H-HQ-HQ", 10" -(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 2 parts, 15 parts of solvent naphtha and ring A mixed solvent of 5 parts of ketone was dissolved by heating while stirring. 2 parts of an active ester-based curing agent ("EXB-8000L-65M" manufactured by DIC Co., Ltd., a MEK solution having an active base equivalent of about 220 and a nonvolatile content of 65 mass%), and an imidazole-based hardening accelerator (Four Nations) Industrial (stock) "1B2PZ" 1-benzyl-2-phenylimidazole, solid solution 5% MEK solution) 1 part, and phenylamino decane coupling agent (made by Shin-Etsu Chemical Co., Ltd., " spherical alumina KBM573 ") surface treatment (average particle diameter 1.52 m, specific surface area 1.70m ² / g, carbon content per unit surface area of 0.11mg / m ²⁾ 190 parts of a high speed rotary stirrer uniformly dispersed, and then to tube A filter ("SHP050" manufactured by ROKITECHNO Co., Ltd.) was filtered to prepare a resin varnish 4.

[Manufacture of component (d)]

Mixing G-3000 (bifunctional hydroxyl terminated polybutadiene, number average molecular weight = 5047 (GPC method), hydroxyl equivalent = 1798 g/eq., solid content 100% by mass, manufactured by Nippon Soda Co., Ltd.) 50 g 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 uniformly dissolved. When the temperature was 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 while stirring, and the reaction was carried out for about 3 hours. Next, after cooling the reaction mixture to room temperature, benzophenonetetracarboxylic dianhydride (anhydride equivalent = 161.1 g/eq.) of 8.96 g, triethylenediamine 0.07 g, and ethyl diangan were added thereto. 40.4 g of an alcohol acetate (manufactured by Daicel) was heated to 130 ° C while stirring, and the reaction was carried out for about 4 hours. Confirmation of disappearance of the NCO peak at 2250 cm ^{-1 was} performed by FT-IR. The confirmation that the NCO peak disappeared was regarded as the end point of the reaction, and after the reaction product was cooled to room temperature, it was filtered through a 100-mesh filter cloth to obtain a quinone imine skeleton, a urethane skeleton, and a butadiene skeleton. Polymer resin A.

Viscosity: 7.5Pa. s (25 ° C, E-type viscometer)

Acid value: 16.9 mgKOH/g

Solid content: 50% by mass

Number average molecular weight: 13723

Glass transfer temperature: -10 ° C

The content of the polybutadiene structural part: 50 / (50 + 4.8 + 8.96) × 100 = 78.4% by mass

(Modulation of Resin Varnish 5)

In addition to replacing the cerium oxide ¹ , 220 parts of the resin varnish 1, 220 parts of cerium oxide 4 (average particle diameter of 1.73 μm, specific surface area of 2.71 m ² /g, and carbon content per unit surface area of 0.26 mg/m ² ) were used. The resin varnish 5 was prepared in the same manner as the resin varnish 1 except for the cartridge filter ("SHP100" manufactured by ROKITECHNO Co., Ltd.).

(modulation of resin varnish 6)

In addition to replacing 2,190 parts of cerium oxide 2 of resin varnish 2, 190 parts of cerium oxide 5 (average particle diameter 1.11 μm, specific surface area 2.66 m ² /g, carbon amount per unit surface area 0.22 mg/m ² ) were used instead. Other than the resin varnish 2, the resin varnish 6 was prepared.

(Modulation of Resin Varnish 7)

In addition to replacing 3,140 parts of cerium oxide of resin varnish 3, cerium oxide 6 (average particle diameter 0.77 μm, specific surface area 5.76 m ² /g, carbon content per unit surface area 0.35 mg/m ² ) was used instead of 120 parts. Other than the resin varnish 3, the resin varnish 7 was prepared.

(modulation of resin varnish 8)

A naphthalene type epoxy resin ("ESN475V" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., an epoxy equivalent of about 330) of 10 parts, a naphthalene type epoxy resin ("HP-4710" manufactured by DIC), and an epoxy equivalent. 170) 5 parts, biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 272) 12 parts, and phenoxy resin ("XX7553BH30" manufactured by Mitsubishi Chemical Corporation), solid content 30% by mass of cyclohexanone: a 1:1 solution of methyl ethyl ketone (MEK)) 5 parts of a mixed solvent of 20 parts of solvent naphtha and 10 parts of cyclohexanone were heated and dissolved while stirring. After cooling to room temperature, a phenol novolak-based curing agent containing a triazine skeleton ("LA-7054" manufactured by DIC Co., Ltd., a MEK solution having a hydroxyl equivalent of about 125 and a solid content of 60% by weight) was mixed with 8 parts of naphthalene. Phenolic curing agent ("SN-485" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., MEK solution with a hydroxyl equivalent of about 212 and a solid content of 60%) 12 parts, and an imidazole-based hardening accelerator (Shikoku Chemical Industry Co., Ltd.) "1B2PZ" 1-benzyl-2-phenylimidazole, solid solution 5% MEK solution) 1 part, flame retardant (Sanguang (share) "HCA-HQ", 10-(2,5-dihydroxybenzene Base) 10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 4 parts, amino decane-based coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) Surface-treated spherical cerium oxide 3 (average particle diameter 1.06 μm, specific surface area 3.01 m ² /g, carbon content per unit surface area 0.31 mg/m ² ) 140 parts, uniformly dispersed in a high-speed rotary mixer, in a barrel type A filter ("SHP050" manufactured by ROKITECHNO Co., Ltd.) was filtered to prepare a resin varnish 8.

The materials used for the production of each resin varnish and the blending amount thereof (parts by mass of nonvolatile matter) are shown in Table 1. With respect to (a1) liquid epoxy resin and (c) inorganic filler, the content (% by mass) of the nonvolatile matter is also shown in Table 1.

[Table 1]

(Examples 1 to 4 and Comparative Examples 1 to 4: Production of Resin Sheet)

A PET film (Lumilar T6AM, manufactured by Toray Industries, Ltd.) having a thickness of 38 μm and a softening point of 130 ° C, which was released from an alcohol resin-based release agent ("AL-5" manufactured by Lintec Co., Ltd.), was prepared as a support. Demoulding PET").

Each of the resin varnishes was varnished on the release PET, and uniformly coated in a die coater so that the thickness of the cured curable resin composition layer was 25 μm, and dried by drying at 80 ° C to 110 ° C for 4 minutes. A layer of a curable resin composition was obtained on the mold PET. Next, a polypropylene film ("Alfan MA-430" manufactured by Prince Ftex, thickness: 20 μm) and a curable resin composition were used as a protective film on the surface which was not bonded to the support of the curable resin composition layer. Lamination is carried out in the form of layer bonding. Thereby, a resin sheet composed of a support, a curable resin composition layer, and a protective film in this order is obtained.

(Measurement of the lowest melt viscosity of the curable resin composition layer)

(1) Determination of the lowest melt viscosity

The particles for measurement (diameter: 18 mm, 1.2 g to 1.3 g) were produced by peeling only the curable resin composition layer from the release PET and compressing it with a mold.

Using a pellet for measurement, a dynamic viscoelasticity measuring apparatus ("Rheosol-G3000" manufactured by UBM) was used, and a parallel plate having a diameter of 18 mm was used for 1 g of the sample resin composition, and the temperature was raised at a temperature of 5 ° C / min from the starting temperature of 60 ° C. The temperature was raised to 200 ° C, and the dynamic viscoelasticity was measured under the measurement conditions of a measurement temperature interval of 2.5 ° C, a vibration number of 1 Hz, and a twist of 1 deg, and the lowest melt viscosity was calculated, which is shown in Table 2.

(The average line thermal expansion of the cured product (insulating layer) of the curable resin composition layer Determination of the expansion ratio)

A copper-clad laminate (R5715ES, manufactured by Matsushita Electric Works Co., Ltd.) and a thickness of an untreated surface of a release film of a PET film ("501010", a thickness of 38 μm, and a width of 240 mm) and a glass cloth base material epoxy resin. The contact pattern of 0.7 mm, 255 mm square) was set on the copper-clad laminate of the glass cloth substrate epoxy resin, and the four sides of the release PET film were fixed with polyimide and tape (width: 10 mm).

Each of the adhesive films (200 mm square) prepared in the examples and the comparative examples was a batch type vacuum press laminator (manufactured by Nichigo-Morton, a two-stage accumulation laminator CVP700) to form a curable resin composition layer. The lamination treatment is carried out at the center in such a manner as to be in contact with the release surface of the release PET film. In the lamination treatment, the pressure was reduced to 13 hPa or less after depressurizing for 30 seconds, and then it was carried out by pressing at 100 ° C and a pressure of 0.74 MPa for 30 seconds.

Next, it was placed in an oven at 100 ° C for 30 minutes at a temperature of 100 ° C, and then transferred to an oven at 175 ° C for 30 minutes at a temperature of 175 ° C to thermally harden it. Then, the substrate was taken out at room temperature, and the release PET (support) was peeled off from the resin sheet, and then the curable resin composition layer was thermally cured by a curing condition of 90 minutes after the 190 ° C oven was placed.

After the heat curing, the polyimide and the tape were peeled off, and the curable resin composition layer was taken out from the glass cloth substrate epoxy double-sided copper-clad laminate. Further, a release PET film ("501010" manufactured by Lintec Co., Ltd.) of the laminate-hardenable resin composition layer was peeled off to obtain a flaky cured product. Will The obtained cured product was cut into a test piece having a width of 5 mm and a length of 15 mm, and subjected to thermomechanical analysis by a tensile weighting method using a thermomechanical analyzer ("Thermo Plus TMA8310"). Specifically, after the test piece was attached to the above-described thermomechanical analysis device, the test piece was continuously measured twice under the measurement conditions of a load of 1 g and a temperature increase rate of 5 ° C /min. Further, in the second measurement, the average linear thermal expansion coefficient (ppm/° C.) in the plane direction from 30 ° C to 150 ° C was calculated and shown in Table 2.

<evaluation test>

1. Evaluation of part embedding

Using the resin sheets produced in the examples and the comparative examples, the circuit board of the temporarily attached parts was produced in the following order to evaluate the component embedding property.

(1) Preparation of circuit board (hole substrate) for temporarily attaching parts

On the glass cloth substrate BT resin double-sided copper clad laminate (copper foil thickness 18μm, substrate thickness 0.15mm, Mitsubishi Gas Chemical Co., Ltd. "HL832NSF LCA") 255*340mm size, 0.7mm × 1.1mm The holes and conductor patterns are formed by the design of the attachment. Then, the surface of the microetching agent ("CZ8100" manufactured by MEC Co., Ltd.) was etched at 1 μm to roughen the copper surface, and further rust-proof treatment ("CL8300" manufactured by MEC Co., Ltd.) was carried out, and dried at 180 ° C. 30 minutes.

(2) Production of circuit board with temporary attached parts

On the single side of the substrate obtained in (1), a 25 μm thick adhesive is deposited. A bismuth imide film (polyimide 38 μm thick, manufactured by Azawa Seisakusho Co., Ltd., "PFDKE-1525TT") using a batch type vacuum pressure laminator (a 2-phase accumulation laminator made by Nichigo-Morton) The CVP700") is disposed such that the adhesive is bonded to the substrate and laminated on one side. The laminating system was subjected to a pressure reduction of 30 seconds to reduce the gas pressure to 13 hPa or less, and then it was pressed at 80 ° C and a pressure of 0.74 MPa for 30 seconds. Next, laminated ceramic capacitor parts (1005=1*0.5 mm size, thickness 0.14 mm) were temporarily attached to the holes one by one, and a circuit board (hole substrate) for temporarily attaching the parts was produced.

(3) Evaluation test of part embedding

The batch type vacuum pressure laminator ("CVP700" manufactured by Nichigo-Morton Co., Ltd.) was used to bond the cured film exposed from the resin sheets produced in the examples and the comparative examples to reveal the curability. The resin composition layer is laminated so as to face the surface of the circuit board (hole substrate) of the temporarily attached component produced in (2) on the side opposite to the surface on which the polyimide film is disposed. The laminating system was subjected to a pressure reduction of 30 seconds to reduce the gas pressure to 13 hPa or less, and then pressed at 120 ° C under a pressure of 0.74 MPa for 30 seconds. Next, the laminated resin sheet was subjected to hot stamping under normal pressure at 120 ° C and a pressure of 0.5 MPa for 60 seconds to be smoothed. The evaluation substrate A was produced by peeling off the adhesive polyimide-based polyimide film from the circuit board on which the components were temporarily cooled to room temperature. The surface of the polyimine film of the substrate A for evaluation was peeled off, and the resin in the hole was observed by an optical microscope (150 times) (10 holes), and the part embedding property was evaluated by the following criteria, and the results were shown in Table 2.

Judged as

○: The periphery of the laminated ceramic capacitor component was covered with a resin in all the holes.

×: Even if a hole is formed, voids or voids are not embedded in the periphery of the laminated ceramic capacitor component.

2. Evaluation of the amount of bending

(1) Hardening of resin sheets

The evaluation substrate A prepared in 1. (3) was placed in an oven at 100 ° C under a temperature of 100 ° C, and then heat-treated for 30 minutes. After cooling to room temperature, the surface of the polyimide film was peeled off from the adhesive. The resin sheet was also bonded under the same conditions as in 1. (3). Then, it was placed in an oven at 100 ° C for 30 minutes at a temperature of 100 ° C, and then transferred to an oven at 175 ° C under a temperature of 175 ° C for 30 minutes and then thermally cured to form an insulating layer on both surfaces of the substrate. Then, the substrate on which the insulating layer is formed on both sides is taken out at room temperature, and the release PET on both sides is peeled off, and the hardened resin composition layer is heated by the hardening condition of 90 minutes after the 190 ° C oven is put into the oven at 190 ° C. Hardening, making the built-in circuit board of the part as the evaluation substrate B.

(2) Evaluation test of bending amount

After the evaluation substrate B is cut out of a piece of 45 mm square (n=5), the reflow device that reproduces the reflow soldering temperature at a peak temperature of 260 ° C at one time (Japan) ANTOM (shares) "HAS-6116") (reflow temperature file according to IPC/JEDEC J-STD-020C). Next, using a shadow moire apparatus ("TherMoire AXP" manufactured by Akrometrix Co., Ltd.), the substrate was heated under the substrate according to the reflow temperature profile of IPC/JEDEC J-STD-020C (peak temperature: 260 ° C), and the center of the substrate was measured. The displacement (μm) of the square portion of 10 mm is shown in Table 2.

In the same manner as in the evaluation results, the types of the resin varnish used in the formation of the respective curable resin composition layers of the resin sheets of the examples and the comparative examples, the types and contents (% by mass) of the inorganic filler, and the average are shown in Table 2 Particle size (μm), specific surface area (m ² /g), true density (g/cm ³ ), product of true density and specific surface area, lowest melt viscosity of the curable resin composition layer, average of the insulating layer Line thermal expansion rate (ppm / ° C).

[Table 2]

10‧‧‧Resin sheet (first resin sheet)

11‧‧‧Support (1st support)

12‧‧‧ hardened resin composition layer

Claims (10)

A resin sheet comprising a support and a resin sheet of a curable resin composition layer provided on a support, wherein the curable resin composition layer contains an inorganic filler, and the curable resin composition layer The content of the inorganic filler is 74% by mass or more, the average particle diameter of the inorganic filler is 1.6 μm or less, and the product of the specific surface area [m ² /g] of the inorganic filler and the true density [g/cm ³ ] is 6-8. The curable resin composition layer has a minimum melt viscosity of 12,000 poise or less. The resin sheet of claim 1, wherein the inorganic filler is cerium oxide. The resin sheet according to claim 1, wherein the curable resin composition layer comprises (a) an epoxy resin comprising a liquid epoxy resin, and a liquid epoxy resin in the curable resin composition layer The content is 1% by mass or more. The resin sheet of claim 3, wherein (a) the epoxy resin further comprises a solid epoxy resin, and the mass M _S of the solid epoxy resin is relative to the liquid epoxy resin in the curable resin composition layer. The ratio of mass M _L (M _S /M _L ) is 0.6-10. The resin sheet of claim 3, wherein (a) the epoxy resin is an epoxy resin having an (a') aromatic structure. The resin sheet of claim 3, wherein the curable resin is composed The material layer further contains the component (d): one or more resins selected from the group consisting of a resin having a functional group having a glass transition temperature of 25 ° C or lower and a resin having a functional group at 25 ° C. The resin sheet of claim 6, wherein the component (d) has one or more functional groups selected from the group consisting of a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and an urethane group, and has Selected from alkylene structural unit, alkylene structural unit, butadiene structural unit, isoprene structural unit, isobutylene structural unit, chloroprene structural unit, urethane structural unit, polycarbonate One or more structural units of a structural unit, a (meth) acrylate structural unit, and a polyoxyalkylene structural unit. The resin sheet of claim 1 is for use in a circuit board. A wiring board comprising an insulating layer and a conductor layer obtained by curing a layer of a curable resin composition of the resin sheet according to any one of claims 1 to 8. A semiconductor device comprising the wiring board of claim 9.