JP2004074799A - Insulating substrate to which copper is bonded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate on which a coating film, excellent in the strength of bonding with a plated copper and used for an additive-method wiring board, is formed without spoiling the insulating property. <P>SOLUTION: The insulating substrate is configured with the state of bonding each other using the bond which contains the particles of an acrylonitrile-butadiene rubber crosslinked with an epoxy resin. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an insulating substrate, and more particularly, to an insulating substrate bonded to copper by an adhesive containing epoxy resin and crosslinked acrylonitrile butadiene rubber particles.

As is well known, an additive printed wiring board forms a necessary wiring pattern on an insulating base material with an adhesive by electroless plating.

(4) For example, an adhesive layer containing a plating catalyst is formed on an insulating substrate containing a plating catalyst and the like, and cured by heating at a temperature of 140 to 190 ° C. for 20 to 90 minutes. Next, the portions other than the circuit forming portion are masked with a plating resist, and as a pretreatment for improving the adhesive force with electroless plated copper, the adhesive surface of the circuit forming portion is selectively treated with an oxidizing etching solution such as chromium-sulfuric acid. To be chemically roughened. Then, after a neutralization and water washing process, it is immersed in an electroless plating solution, and copper is deposited on a circuit portion to form a wiring pattern.

Such an additive method printed wiring board adhesive generally has acrylonitrile butadiene rubber as a main component having good adhesion to plated copper, and crosslinks acrylonitrile butadiene rubber with an alkylphenol resin to ensure heat resistance, and Epoxy resin is blended to ensure electrical characteristics. Further, an adhesive compounded with an inorganic filler or the like has been proposed to reinforce the adhesive coating film or increase the adhesive unevenness during chemical roughening. Patent Literatures 1 to 4 disclose techniques relating to such an adhesive.
JP-B-48-24250 Japanese Patent Publication No. 45-9843 Japanese Patent Publication No. 55-16391 Japanese Patent Publication No. 1-53910

In recent years, as electronic devices have become smaller and more multifunctional, it has become necessary to increase the wiring density of printed wiring boards, and wiring widths have been rapidly reduced. Against this background, the adhesive coating supporting the circuit conductor is becoming an important property in terms of insulation.

Therefore, in general, the amount of acrylonitrile-butadiene rubber, whose insulation is inferior to that of epoxy resin, is reduced, and the amount of epoxy resin is increased. However, in this case, in order to increase the epoxy resin whose solubility of the roughening solution is significantly lower than that of the acrylonitrile-butadiene rubber, the roughness of the roughening is reduced, and therefore, the adhesive strength with the plated copper is reduced to a level that cannot be used practically. Resulting in. It goes without saying that the thinner the wire, the more advantageous it is that the adhesive strength to the plated copper becomes higher.

An object of the present invention is to provide an insulating base material that is in an adhesion state with copper by an adhesive having excellent adhesion to plated copper without impairing insulation properties.

絶 縁 The insulating base material of the present invention is characterized in that the adhesive applied to the surface of the insulating base material contains acrylonitrile-butadiene rubber particles crosslinked with an epoxy resin.

The crosslinked acrylonitrile-butadiene rubber particles used in the present invention are crosslinked rubber particles of fine polymer particles having a primary average particle diameter of about 50 to 500 nm obtained by cross-linking acrylonitrile-butadiene rubber in an emulsion state after emulsion polymerization. Any of the acrylonitrile butadiene rubbers can be used.

The compounding amount is preferably 2 to 40% by weight in the adhesive. The reason is that if it is less than 2% by weight, there is no effect in improving the adhesive strength with the plated copper, and if it exceeds 40% by weight, the tackiness of the surface of the adhesive increases, and problems such as adhesion of dust in a later step occur. To come.

As the basic resin composition containing this crosslinked NBR, a general resin composition used for an additive method wiring board can be applied, and in consideration of plating solution resistance, coating film forming property, roughening property, etc., epoxy resin is used. And preferably a mixture containing acrylonitrile butadiene rubber, a resol type phenol resin, an inorganic filler and the like.

ビ ス As the epoxy resin, a bisphenol A type epoxy resin is exemplified.

に お い て In the present invention, the adhesive may contain a plating catalyst that serves as a deposition nucleus for electroless plating. As the plating catalyst, salts or oxides of metals of Groups 8 and 4B of the periodic table can be used. For example, a compound such as platinum, palladium, tin or the like is used, and can be dissolved in solid particles or an organic solvent, or can be mixed with an adhesive in a solution state of being dissolved and dispersed together with another resin. If the amount of the plating catalyst in the adhesive is in the range of 2 to 15% by weight, copper is deposited by electroless plating.

各 Each component of the adhesive is prepared as a solution mixture kneaded and mixed in an organic solvent. As the organic solvent to be used, a single or mixed system of toluene, methyl ethyl ketone, acetone, methyl isobutyl ketone, xylene, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, and propylene glycol monomethyl ether can be used.

基材 As the insulating base material according to the present invention, a base material made of a phenol resin or epoxy resin, or an inorganic or organic composite can be used.

接着 The adhesive is applied to the insulating base material in a thickness of 10 to 50 μm, and is heated and cured at a temperature of 140 to 190 ° C. for 30 to 90 minutes.

析出 When depositing electroless plating, the surface of the adhesive is chemically roughened to a shape suitable for bonding. As a roughening solution used for chemical roughening, a chromium-sulfuric acid system, a chromium-sulfuric acid-sodium fluoride system, an alkali-permanganate system, a borofluoric acid-bichromic system system, and the like can be used. The pattern is formed by screen-printing a plating resist or by curing and developing a photomask with ultraviolet rays. These plating resists are performed before or after the chemical roughening process.

(4) The crosslinked NBR used in the present invention is in the form of fine particles, and by dissolving the crosslinked NBR in the roughening liquid, it is possible to form, on the surface of the adhesive, fine irregularities suitable for bonding. In addition, since it is a crosslinked NBR, there is no decrease in insulation in proportion to the blending amount.

Hereinafter, the present invention will be described in more detail with reference to examples.

The adhesive component shown below was applied to LE-168 (trade name, manufactured by Hitachi Chemical Co., Ltd.), a glass cloth epoxy laminate, by dip coating to form an adhesive layer having a thickness of 25 μm on both surfaces.
(Adhesive composition)
・ Cross-linked NBR,
XER-91 (Nippon Synthetic Rubber Co., Ltd., trade name) 20 parts by weight Bisphenol A type epoxy resin,
Epicoat 1001 (trade name, manufactured by Yuka Shell Co., Ltd.): 20 parts by weight ・ Acrylonitrile butadiene rubber,
Nipol 1031 (trade name, manufactured by Zeon Corporation) ... 50 parts by weight-Alkyl phenol resin,
Hitanol 2400 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 5 parts by weight
2E4MZ (Shikoku Chemicals Co., Ltd., trade name) 0.1 parts by weight Filler (zirconium silicate)
Micropacks (trade name, manufactured by Hakusui Chemical Co., Ltd.) 10 parts by weight ・ Catalyst for electroless plating (resin mixture of palladium chloride)
PEC-8 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 4 parts by weight

Next, the insulating substrate on which the adhesive layer was formed was cured by heating at 170 ° C. for 60 minutes. Further, a plating resist SR-3000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) was laminated, exposed to ultraviolet light through a circuit-forming photomask, and developed. Next, it is immersed in a roughening solution of chromium-sulfuric acid-sodium fluoride (chromic acid 40 g / l, concentrated sulfuric acid 300 ml / l, sodium fluoride 10 g / l) at 40 ° C. for 5 minutes, and only the exposed portion of the adhesive is selected. Chemically roughened, then neutralized and washed with water. Further, the solution was put into a CC-41 solution (trade name, manufactured by Hitachi Chemical Co., Ltd.) as an electroless copper plating bath to precipitate 35 μm of plated copper, and then annealed at 160 ° C. for 60 minutes to obtain an additive method. A printed wiring board was manufactured.

As the adhesive composition, the following composition was used as a composition in which the insulating property was improved as compared with Example 1, that is, as a compounding system in which an epoxy resin was increased. Except for this, the additive method printed wiring board was manufactured in the same manner as in Example 1.
(Adhesive composition)
・ Cross-linked NBR,
XER-91 (Nippon Synthetic Rubber Co., Ltd., trade name) 20 parts by weight Bisphenol A type epoxy resin,
Epicoat 1001 (trade name, manufactured by Yuka Shell Co., Ltd.): 50 parts by weight ・ Acrylonitrile butadiene rubber,
Nipol 1031 (manufactured by Nippon Zeon Co., Ltd., trade name) 20 parts by weight alkylphenol resin,
Hitanol 2400 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 5 parts by weight
2E4MZ (Shikoku Chemicals Co., Ltd., trade name) 0.1 parts by weight Filler (zirconium silicate)
Micropacks (trade name, manufactured by Hakusui Chemical Co., Ltd.) 10 parts by weight ・ Catalyst for electroless plating (resin mixture of palladium chloride)
PEC-8 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 4 parts by weight

In the adhesive composition of Example 2, the amount of the crosslinked NBR was increased. Otherwise, in the same manner as in Example 2, an additive method printed wiring board was manufactured.
(Adhesive composition)
・ Cross-linked NBR,
XER-91 (Nippon Synthetic Rubber Co., Ltd., trade name) 35 parts by weight Bisphenol A type epoxy resin,
Epicoat 1001 (trade name, manufactured by Yuka Shell Co., Ltd.): 50 parts by weight ・ Acrylonitrile butadiene rubber,
Nipol 1031 (manufactured by Nippon Zeon Co., Ltd., trade name) 15 parts by weight Alkyl phenol resin,
Hitanol 2400 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 5 parts by weight
2E4MZ (Shikoku Chemicals Co., Ltd., trade name) 0.1 parts by weight Filler (zirconium silicate)
Micropacks (trade name, manufactured by Hakusui Chemical Co., Ltd.): 10 parts by weight

Comparative Examples 1-2
In Examples 1 and 2, the composition was such that the crosslinked NBR in the adhesive was not used. Otherwise, an additive method printed wiring board was manufactured in the same manner as in each example.

Table 1 shows the characteristic results of the additive printed wiring board manufactured as described above.

As described above, by using acrylonitrile-butadiene rubber particles cross-linked in the adhesive composition, insulation, an adhesive capable of improving the adhesive strength with plated copper without impairing the heat resistance, the adhesive state with copper. A certain insulating substrate can be provided.

Claims (3)

(4) An insulating base material which is in an adhesive state with copper by an adhesive containing an epoxy resin and crosslinked acrylonitrile butadiene rubber particles. 2. The insulating base material according to claim 1, wherein the adhesive contains 2 to 40% by weight of crosslinked acrylonitrile butadiene rubber particles. 3. The insulating substrate according to claim 1, wherein the crosslinked acrylonitrile butadiene rubber particles have an average particle size of 50 to 100 nm.