JPH07170066A - Additive process printed wiring board adhesive agent and manufacture of wiring board by use thereof - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing an additive wiring board adhesive agent high in adhesive power to plated copper and an adhesive sheet and a laminated board by the use of it. CONSTITUTION:Adhesive agent is composed of 100 parts by weight of composition mainly formed of epoxy resin, acrylonitrile-butadien rubber, alkylphenol resin, and inorganic filler and 0.05 to 1.0 part by weight of internal releasing agent formed of long chain-phosphate tri- or di- or monoester having an alkyl group whose number of carbon atoms ranges from 6 to 18, and it is applied to a releasing support and dried up. Obtained adhesive agent sheets are provided sandwiching a prepreg impregnated with thermosetting resin between them, and the laminate is thermocompressed into one piece for the formation of an insulating board provided with adhesive agent, or base material formed of inorganic material or organic material or composite composed of inorganic and organic material is impregnated with thermosetting resin for the formation of prepreg, and a required number of prepregs are laminated and thermocompressed into an insulating board, and adhesive agent is applied onto the insulating board through a dip method or a curtain coating method and dried up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for an additive printed wiring board excellent in adhesive strength to copper deposited by electroless plating and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board by an additive method is one in which a necessary wiring pattern is formed on an insulating base material with an adhesive by electroless plating. For example, an adhesive layer containing a plating catalyst is formed on an insulating base material containing a plating catalyst by a dipping method or curtain coating, and the temperature is set to 150 ° C.
It is cured by heating at a temperature of 190 ° C for 30 minutes to 60 minutes. Next, mask the parts other than the circuit forming part with a plating resist, and selectively chemistry of the adhesive surface of the circuit forming part with an oxidizing etchant such as chromic sulfuric acid as a pretreatment to improve adhesion with electroless plated copper. Roughen. After that, it is immersed in an electroless copper plating solution through a neutralization and washing process to deposit copper in the circuit portion to form a wiring pattern.

Examples of such adhesives for printed wiring boards of the additive method include those disclosed in Japanese Patent Publication Nos. 48-24250, 45-9843, 55-16391, and 1-53910. As disclosed, in general, acrylonitrile butadiene rubber having good adhesion to plated copper is the main component, and in order to ensure heat resistance, the acrylonitrile butadiene rubber is cross-linked with an alkylphenol resin, and in order to ensure electrical properties. It is known to compound an epoxy resin. Further, an adhesive containing an inorganic filler has been proposed in order to reinforce the adhesive coating film and increase the unevenness of the adhesive during chemical roughening (improve the adhesiveness due to the anchoring effect with plated copper).

Recently, as a method of manufacturing a laminated board with an adhesive, a method of forming an adhesive layer at the same time as molding an insulating substrate from a conventional starting method using an insulating substrate (hereinafter, referred to as
It is called the one-step method. ) Is being reviewed from the viewpoints of manufacturing cost, uniform film thickness, low surface roughness, etc.

[0005]

By the way, in recent years, with the miniaturization and multi-functionalization of electronic devices, it has become necessary to increase the wiring density of printed wiring boards, and the wiring width has rapidly become thinner. ing. Specifically, 150μ 2-3 years ago
The wiring width of m was the mainstream, but now 100 μm is becoming the mainstream, and soon 75 μm or 50 μm.
There is a possibility that it will develop to the wiring width of. From such a background, it goes without saying that the adhesive force with the plated copper is important in the additive wiring board manufactured by the conventional manufacturing method or the one-step method.

However, when this one-step method is used, when the prepreg of the thermosetting resin and the adhesive are integrally molded, the thermosetting resin contained in the prepreg is mixed during heating and pressurization (hereinafter , Abbreviated as migration)
Occurs, which causes a decrease in the adhesive strength with the electroless plated copper. Therefore, a method of preliminarily curing the adhesive sheet and applying prepreg, heating, and pressure may be adopted. However,
Roughening is less likely to occur as the curing of the adhesive progresses, and the adhesive strength with the electroless plated copper is about 70% to 8% as compared with the case where a laminated plate with an adhesive produced by a usual method is used as a starting source. There is a problem that it will drop relatively.

The present invention provides an adhesive for an additive wiring board having a high adhesive strength with plated copper and a method for producing the same.

[0008]

The adhesive provided on the circuit-forming surface of the insulating substrate of the present invention has a composition of 100 parts by weight of a composition containing an epoxy resin, acrylonitrile butadiene rubber, an alkylphenol resin, and an inorganic filler as main components. 0.05 to 5.0% by weight of an internal release agent consisting of a tri-, di- or mono-long-chain phosphoric acid ester having 6 to 18 carbon atoms in the alkyl group and an amine salt with respect to parts. And

This internal release agent is an end plate (stainless end plate) when a paper phenol laminated plate is manufactured by hot press bonding.
For the purpose of releasing from the resin, a resin added by several% to the resin constituting the paper phenol laminate can be used. With this internal release agent, a release agent having a different molecular weight can be obtained depending on the number of carbon atoms in the alkyl group and the number of alkyl groups in the ester bond with phosphoric acid. Examples thereof include monostearyl phosphate triethanolamine salt, dioctyl phosphate monoethanolamine salt, and trilauryl phosphate triethylamine salt. The amount of the internal mold release agent added is 0.05 to 5 with respect to the composition containing the epoxy resin, the acrylonitrile butadiene rubber, the alkylphenol resin, and the inorganic filler as the main components.
This is because the range of 0% by weight is preferable, and if it is less than 0.05% by weight, the effect of improving the adhesive strength with the plated copper is small, and if it is 5.0% by weight or more, the heat resistance decreases.

The epoxy resin used in the present invention includes bisphenol A type, novolac type and bisphenol F type.
Although there are molds, alicyclic molds and the like, bisphenol A type or novolac type is preferable from the viewpoint of heat resistance and plating solution resistance, and the compounding amount thereof is preferably 10 to 65% by weight. 1
If it is less than 0% by weight, the heat resistance is lowered, and if it exceeds 65% by weight, the adhesive force with the plated copper is lowered. As a curing agent for this epoxy resin, a general curing agent for an epoxy resin such as an imidazole-based, amine-based, phenol-based or latent curing agent-based curing agent such as dicyandiamide can be used and is not particularly limited.

The acrylonitrile butadiene rubber is not particularly limited as long as the content of acrylonitrile is in the range of 15 to 50% by weight, and acrylonitrile butadiene rubber containing a carboxyl group can also be used. When the content of acrylonitrile is less than 15% by weight, the compatibility as an adhesive mixture is lowered, and 5
When it exceeds 0% by weight, water is easily absorbed, so that the insulating property is deteriorated. The blending amount is preferably 10 to 60% by weight, and when it is less than 10% by weight, coating film forming property and roughening property are deteriorated, and when it exceeds 60% by weight, heat resistance is decreased.

In the present invention, the alkylphenol resin is used to thermally crosslink the acrylonitrile butadiene rubber. As such an alkylphenol resin, there are various kinds depending on the kind of alkyl group, kind of reactive group and molecular weight distribution, but paratertiary butylphenol, paratertiary amylphenol, paraphenylphenol, para-secondary butylphenol and the like can be used. The blending amount is preferably in the range of 2 to 30% by weight, and when it is less than 2% by weight, heat resistance is not sufficient, and when it exceeds 30% by weight, roughening cannot be sufficiently performed and adhesiveness to plated copper is not sufficient. Is low.

As the inorganic filler, calcium carbonate, magnesium silicate, aluminum silicate, aluminum hydroxide, calcined hydrotalcite, silica oxide and the like can be used, and one kind or a mixture of two or more kinds may be used. The blending amount is preferably 10 to 50% by weight, and when it is less than 10% by weight, the roughening property and the heat resistance are both insufficient, and when it exceeds 50% by weight, the roughening property and the heat resistance are not improved, It is economically meaningless.

In the present invention, the adhesive may contain a plating catalyst which becomes a precipitation nucleus of electroless copper plating.
As the plating catalyst, 8, 1B and 2B in the periodic table of the elements are used.
A metal salt or oxide of a genus metal can be used. For example, compounds such as platinum, palladium, and tin are used, and they can be mixed in the adhesive in the form of a solution in which they are dissolved in solid particles or an organic solvent or dissolved and dispersed with another resin.
The content of the plating catalyst in the adhesive is preferably in the range of 2 to 15% by weight, and when it is less than 2% by weight, copper does not deposit due to electroless plating. Deteriorating and not economical.

The respective components of the adhesive are kneaded and mixed in an organic solvent to prepare a solution-like mixture. The organic solvent is toluene, methyl ethyl ketone, acetone, methyl isobutyl ketone, xylene, diethylene glycol monomethyl ether, diethylene glycol monomethyl. One or more of ether acetate and ethyl acetate can be used.

In the present invention, the following two methods can be used to form the adhesive on the surface of the insulating substrate. First, an adhesive is applied to a release support, dried, and the obtained adhesive sheet is placed on both sides of a prepreg impregnated with a thermosetting resin, and heated and pressed to integrally mold the insulating substrate with the adhesive. Is manufactured. As the release support, in addition to release-treated aluminum foil, metal foil such as copper foil, a release-treated film such as a polypropylene film, a polyethylene film, a triacetate film, a polyester film, or a vinyl fluoride film is used. Can be used. An adhesive, for example, having a film thickness of 20 to 1 is applied to the release support.
It is applied in the range of 20 μm, and dried and preliminary cured at a temperature of 120 ° C. to 180 ° C. for 2 minutes to 20 minutes. The obtained adhesive sheet is arranged so as to be a circuit forming surface, and a thermosetting resin (eg, epoxy resin, phenol resin, polyimide resin, etc.) is used as a base material made of an inorganic material or an organic material or a composite material of an inorganic material and an organic material. The impregnated prepreg and the whole are heated,
It is manufactured by applying pressure. The conditions of heating, pressurization and time at this time are a temperature of 140 ° C. to 200 ° C. and a pressure of 20 to 100 k.
Molding is preferably performed at g / cm ² for 30 to 120 minutes. If the temperature is 140 ° C or lower, moldability is insufficient, and if the temperature is 200 ° C or higher, problems such as warpage and discoloration occur.
Similarly, if the pressure is less than 20 kg / cm ² , the moldability is insufficient, and if it exceeds 100 kg / cm ² , problems such as warpage and discoloration occur. Further, if the time is 30 minutes or less, the moldability is insufficient, and if it is 90 minutes or more, the curing is excessively promoted and roughening is less likely to occur.

The second method is to stack a predetermined number of prepregs in which a thermosetting resin (eg, epoxy resin, phenol resin, polyimide resin, etc.) is impregnated into a base material made of an inorganic material or an organic material or a composite material of an inorganic material and an organic material. The adhesive is applied to an insulating substrate produced by heating and pressurizing the whole with a dipping method or curtain coating, followed by drying to produce a laminate with an adhesive. Drying after applying the adhesive,
It is produced by performing the curing at a temperature of 100 ° C. to 150 ° C. for 15 minutes to 45 minutes and the curing at a temperature of 150 ° C. to 200 ° C. for 30 minutes to 90 minutes. The film thickness of the adhesive is preferably 20 to 50 μm. When the film thickness is 20 μm or less, the adhesive force with the plated copper is reduced, and when it exceeds 50 μm, the amount of the adhesive used is increased, which is not economical.

The insulating substrate of the present invention may also contain an electroless plating catalyst similar to the adhesive. The content is preferably in the range of 2 to 15% by weight, and the reason is the same as that of the adhesive.

When depositing the electroless plating, the surface of the adhesive is chemically roughened to a shape suitable for adhesion.
As the treatment liquid used for the chemical roughening, chromic acid-sulfuric acid, chromic acid-sulfuric acid-sodium fluoride, borofluoric acid-dichromic acid, alkaline permanganate, or the like can be used.

As the electroless plating bath, a bath capable of forming general copper as a plating film is used.

Holes for mounting electronic parts on the wiring board and holes for conduction are formed using a punch press or an NC drill machine.

The pattern is formed by screen-printing a plating resist or UV-curing and developing a photomask. The formation of these plating resists is performed before or after the chemical roughening treatment step.

[0023]

[Function] As an additive method printed wiring board having high adhesion to plated copper, a composition containing epoxy resin, acrylonitrile butadiene rubber, alkylphenol resin, and an inorganic filler as a main component and having an alkyl group having 6 to 18 carbon atoms It has been found that it is effective to use an adhesive containing an internal mold release agent for paper phenol laminates consisting of tri-, di- or mono-phosphate ester and amine salt.

Although the principle of the improvement of the adhesive force by the internal release agent is not clear, the action of the release agent which transfers the hydrophilic group to the resin surface side at the time of high temperature during curing is caused by the additive method printed wiring board. It is presumed that the chemical bonding force between the hydrophilic group appearing on the surface of the adhesive and the plated copper deposited on the surface of the adhesive for use in the adhesive increased.

[0025]

[Example] Bisphenol A type epoxy resin Epicoat 1001 (manufactured by Yuka Shell Epoxy Co., Ltd.,
Product name): 15 parts by weight-Acrylonitrile butadiene rubber Nipol 1031 (manufactured by Nippon Zeon Co., Ltd., product name)-
・ ・ ・ ・: 50 parts by weight ・ Alkylphenol resin Hitanol 2400 (manufactured by Hitachi Chemical Co., Ltd., product name) ・ ・ ・: 10 parts by weight ・ Inorganic additive (zirconium silicate) Micropax (manufactured by Shiramizu Chemical Co., Ltd., product) Name)···
・ ・ ・ ・: 20 parts by weight ・ Curing agent for epoxy resin 2 Ethyl 4 methyl imidazole
・ ・ ・ ・: 0.1 parts by weight ・ Catalyst for electroless plating Palladium chloride resin mixture ・ ・ ・
···: To 4 parts by weight, as shown in Table 1, 0.5 parts by weight of internal release agents having different carbon numbers of the alkyl groups of the phosphoric acid ester were added, and kneading was performed using a kneader. And was dissolved in methyl ethyl ketone to prepare an adhesive having a concentration of 20%. Using this adhesive, a laminated board with an adhesive produced by the one-step method and a laminated board with an adhesive produced by the dipping method were produced.

(Production Method 1) The one-step method was carried out by the following method.
That is, a thickness of 75 μ obtained by subjecting the adhesive to a release treatment on both sides.
A film having a thickness of 40 μm was applied to one surface of a polyester film having a thickness of m and heat-treated at 170 ° C. for 15 minutes to obtain an adhesive film. Next, a 0.2 mm thick glass cloth was impregnated with an epoxy resin containing a plating catalyst to be semi-cured prepreg G.
E-168 (manufactured by Hitachi Chemical Co., Ltd., trade name) was produced, a predetermined number of the layers were laminated, and the above adhesive films were laminated so as to be on both outer sides of the prepreg, and then, through an end plate, 17
Molding was carried out under the conditions of 0 ° C.-50 kg / cm ² -60 minutes to obtain a laminated plate with an adhesive.

(Production method 2) The immersion method was carried out by the following method. That is, the adhesive is adjusted to have a predetermined viscosity. Then, a 0.2 mm glass cloth was impregnated with an epoxy resin containing a plating catalyst to be semi-cured prepreg GE-
168 (manufactured by Hitachi Chemical Co., Ltd., trade name)
After stacking a specified number of sheets, 170 ° C through the end plate and release film
Molded under the condition of 50 kg / cm ² -60 minutes to obtain a laminated plate L
E-168 (manufactured by Hitachi Chemical Co., Ltd., trade name) was obtained. This laminate is dipped in the adhesive and the speed is 10 mm.
The coating film was pulled up at a speed of about 1 / min to apply a film thickness of 25 μm. Then 12
After heat treatment at 0 ° C. for 30 minutes, it was cured at 170 ° C. for 60 minutes to obtain a laminated board with an adhesive.

Then, SR-3000 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a resist for plating, was laminated on the insulating substrate with the adhesive, exposed to ultraviolet rays and developed to prepare a test pattern.

Then, 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 10 minutes to form an adhesive. Only the exposed part was chemically roughened, then neutralized and washed with water. Furthermore, after pouring into CC-41 liquid (made by Hitachi Chemical Co., Ltd., trade name) which is an electroless copper plating bath to deposit 35 μm of plated copper, 160 ° C.-
Annealing was performed for 60 minutes to obtain an additive method printed wiring board.

A test pattern was prepared in the same manner as in the above-mentioned examples, except that, as a comparative example, a release agent for a paper phenol laminate was not added as a comparative example. The results of Examples and Comparative Examples are shown in Table 1.

[0031]

[Table 1]

[0032]

As described above, the epoxy resin,
Acrylonitrile butadiene rubber, alkylphenol resin, by adding an internal mold release agent to the inorganic filler-based adhesive composition, without impairing heat resistance and electrical characteristics,
It is possible to provide an adhesive for an additive-type printed wiring board, which has an excellent adhesion to plated copper.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Kagaya 4133 No. 4133 Kushita, Ninomiya-machi, Haga-gun, Tochigi Prefecture Hitachi AIC Corporation Ninomiya Factory

Claims (6)

[Claims] 1. An adhesive formed on the surface of an insulating substrate, the composition of which includes an epoxy resin, an acrylonitrile butadiene rubber, an alkylphenol resin, and an inorganic filler as a main component, and an alkyl group carbon. The number is 6
0.05 to 5.0% by weight of an internal release agent consisting of a tri-, di- or mono-long-chain phosphoric acid ester up to 18 and an amine salt
An adhesive for an additive method printed wiring board, characterized by containing. 2. An adhesive sheet in which the adhesive of claim 1 is applied to a release support and dried. 3. A laminated board provided with the adhesive of claim 1 on a circuit forming surface. 4. The adhesive sheet according to claim 2 is placed on both sides of a prepreg impregnated with a thermosetting resin, and the temperature is 140 ° C. to 200 ° C.
30 to 12 at a temperature of ℃ and pressure of 20 to 100 kg / cm ² .
A laminated board with an adhesive in which an adhesive layer obtained by integrally molding for 0 minutes is provided on a circuit forming surface. 5. A laminated board with an adhesive, wherein the adhesive according to claim 1 is formed on a circuit forming surface of an insulating substrate by a dipping method or a curtain coating method. 6. A method for producing a printed wiring board, which comprises punching, forming a plating resist, roughening, and electroless plating the laminate with an adhesive according to any one of claims 3, 4, and 5.