JP2602992B2 - Manufacturing method of adhesive composition for chemical plating, adhesive film for chemical plating and printed wiring board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive composition for chemical plating, an adhesive film for chemical plating, and a method for producing a printed wiring board.

(Prior Art) Conventionally, in a method of manufacturing a printed wiring board in which a circuit is formed by electroless plating on the surface of an insulating substrate, a base adhesive for electroless plating is previously formed on the surface of the insulating substrate. Methods are known. As this adhesive,
-9843, JP-A-58-57776, JP-A-59-626
No. 83, JP-A-62-248291, and the like, those whose main components consist of an epoxy resin, a synthetic rubber, and a phenol resin are known. Also, Japanese Patent Publication No. 58-30760, Japanese Patent Publication No. 60-5079,
JP-A-3-213676, JP-A-63-213677 and the like disclose an adhesive containing a synthetic rubber and a phenol resin as main components. In these, known thermosetting catalysts such as imidazoles, amines, acid anhydrides and novolak phenolic resins are used as curing agents for epoxy resins, and vulcanization of synthetic rubbers is carried out by vulcanization of resole phenols, sulfur compounds and the like. Zinc oxide, magnesium oxide, and the like are used as auxiliaries.
On the other hand, these adhesives include calcium carbonate, calcium silicate, silicon oxide, zirconium silicate, and the like for the purpose of improving the roughening efficiency in a chromic sulfuric acid mixed solution, the peel strength with the plating film, and the soldering heat resistance. An inorganic filler such as titanium oxide is used.

The above adhesive component is dissolved in a solvent and dipped,
The adhesive film obtained by coating and drying on an insulating substrate by a roll coating method, a curtain coating method, or the like, or by applying and drying the film on a support film in advance, and laminating the adhesive film on the insulating substrate side, Thereafter, a method of heat curing is used. As described in the above-mentioned Japanese Patent Application Laid-Open No. 62-248291, the curing conditions of the adhesive described above are as follows.
It is 30-120 minutes at a temperature of 50-200 ° C. But 150
Under conditions of 30 ° C for 30 minutes, the thermosetting components do not react sufficiently, so the cured adhesive has low insulation resistance and the adhesive film blisters due to the deposition stress during electroless plating. And the peel strength with the plating film and the solder heat resistance are reduced. For this reason, generally, as described in the above-mentioned embodiment of JP-A-62-248291, 1
Curing conditions of 60 ° C or more and 60 minutes or more are performed.

In recent years, the thickness of printed wiring boards has become thinner year by year, and the insulating base material used is 0.8 to 1.0 mm thick paper phenol board.
For glass epoxy plates, 0.5-1.0 mm thickness has come to be used.

If the above-mentioned adhesive is formed on a thin insulating substrate and cured at 160 ° C or more for 60 minutes or more, the insulating substrate will be warped and twisted. In the forming process, a problem occurs in printing of the resist ink and formation of the plating resist using the dry film, which causes a problem that a fine circuit cannot be formed.

(Problems to be Solved by the Invention) The present invention is intended to solve the above-mentioned problems of the prior art, that is, warping, twisting and thermal deterioration of a paper phenol board when a thin insulating base material is used. An adhesive composition for chemical plating that cures in a short time, an adhesive film for chemical plating using the same, and a method for producing a printed wiring board.

(Means for Solving the Problems) The present invention relates to an adhesive for chemical plating comprising an epoxy resin, a synthetic rubber, a phenol resin, a noble metal compound serving as a catalyst for chemical plating, and a photosensitive aromatic onium salt. The present invention relates to a composition, an adhesive film for chemical plating in which a layer of the adhesive composition is formed on a transparent support film, and a method for producing a printed wiring board using the adhesive composition or the adhesive film.

The present invention is preferably applied to a thin laminate having a thickness of 0.6 mm or less as a laminate.

The adhesive composition for chemical plating and the adhesive film for chemical plating of the present invention will be described in detail below.

The photo-sensitive aromatic onium salt used in the present invention includes:
Aromatic onium salts of Group VIIa elements described in JP-B-52-14277, aromatic onium salts of Group VIa elements described in JP-B-52-14278, and OH-groups described in JP-B-52-14279. V
An aromatic onium salt of a group a element or the like can be used. Specifically, triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, and the like can be used. The amount of the light-sensitive aromatic onium salt is preferably 0.2 to 5% by weight as a solid content in the composition from the viewpoint of curing of the epoxy resin.

This light-sensitive aromatic onium salt decomposes when irradiated with ultraviolet light (approximately 0.5 to 3.0 J / cm ² with a 365 nm sensor), releasing a Lewis acid, which is a hardening species of the epoxy resin, and subsequently or by simultaneous heating. It cures the epoxy resin. This effect allows low temperature curing at 100-150 ° C.

As the epoxy resin used in the present invention, an epoxy resin of a bisphenol type, a novolak type, a cresol novolak type alicyclic type or the like can be used. Epoxy equivalent is 450 ~ 2,1
A bisphenol A type epoxy resin of 00 g / eq is more preferable in terms of heat resistance and insulation properties. The compounding amount is 15 to 40% by weight as a solid content in the composition from the viewpoint of insulation resistance and peel strength of the adhesive film. % Is preferred.

Examples of the synthetic rubber used in the present invention include acrylonitrile butadiene rubber, isoprene-containing acrylonitrile butadiene rubber, carboxyl-containing acrylonitrile butadiene rubber, and styrene butadiene rubber. The compounding amount is 40 to 60% by weight as the solid content of the composition from the viewpoint of the peel strength of the plating film and the insulation resistance of the obtained printed wiring board.
Is preferred. The insulation resistance of the cured adhesive film tends to be as low as 10 ¹² Ω or less.

Examples of the phenolic resin used in the present invention include a resol type phenolic resin, a pure phenolic resin, an alkyl-modified phenolic resin, and a cashew-modified phenolic resin. The compounding amount of the phenol resin is preferably 20 to 40% by weight as the solid content of the composition from the viewpoint of the reactivity with the synthetic rubber and the peel strength of the plating film.

Examples of the noble metal compound used as a catalyst for chemical plating used in the present invention include a palladium compound such as palladium chloride and a rhodium compound such as rhodium chloride, which are dispersed in a fine particle adsorbed on an inorganic filler or a resin solution. It can be used as a solution. As a product, for example, there is PEC-8 manufactured by Hitachi Chemical Co., Ltd. As the compounding amount,
From the viewpoint of the deposition property of the plating film and the insulation resistance of the obtained printed wiring board, it is preferably 0.01 to 2% by weight in the solid content of the composition. If necessary, two or more kinds of epoxy resin, synthetic rubber, phenol resin, noble metal compound serving as a catalyst for chemical plating, and light-sensitive aromatic onium salt can be used.

In the present invention, known synthetic rubber vulcanization aids such as zinc oxide, magnesium oxide, and cobalt oxide can be used.
Silicon oxide with a large surface area as a run-off inhibitor during coating,
Fine powder fillers such as calcium carbonate, calcium silicate and zirconium silicate which have an effect of facilitating roughening during chemical roughening can also be used. Other additives, coloring agents, thermosetting catalysts and the like can also be used.

The adhesive composition of the present invention can be produced by a conventional method using a known apparatus such as a two-roller or a kneader. The inorganic material is dispersed in synthetic rubber or the like using these devices, and the organic material is dissolved in a solvent such as ketones or cellosolves to obtain a solution of the adhesive composition of the present invention.

As a method of applying the solution of the adhesive composition on the laminate, a known method such as a roll printing method, a curtain coating method, a dipping method, and a screen printing method is used. On this occasion,
The coating amount can be adjusted by the adhesive solution concentration and the coating method, but the thickness of the adhesive composition layer after drying is 20 to 20 from the viewpoint of the peel strength of the plating film and the curing of the epoxy resin.
A thickness of 70 μm is preferred.

The adhesive film of the present invention can be produced by a conventional method. For example, a solution of the adhesive composition described above is used to support a polypropylene film, a polyethylene film, a triacetate film, a vinyl fluoride film, a silicone release treated polyester film, an olefin release treated polyester film, an unstretched polymethylpentene film, or the like. The coating is performed on the body film by a knife coating method, a roll coating method or the like, followed by drying. As the support film, an olefin release-treated polyester film is preferable in terms of heat resistance during coating, release properties, and non-transfer properties of the release agent.

When manufacturing a long adhesive film, the adhesive film is wound into a roll at the final stage of the manufacturing. In this case, a protective film having a smaller adhesive strength with the adhesive layer than the support film is formed on the exposed surface of the adhesive composition layer (opposite the support) by a known method in the production of a pressure-sensitive adhesive tape or the like. It is preferred to coat with. By covering the adhesive composition layer with a protective film, it is possible to prevent the adhesive composition layer from being transferred to the back surface of the support film when wound up in a roll form, and also to prevent dust from adhering. Can also be prevented. As a protective film, for example,
There are polyethylene film, polypropylene film, Teflon film and the like.

The thickness of the adhesive composition layer of the adhesive film of the present invention is as follows.
Although not particularly limited, 20 to 70 μm is preferable as described above.

A solution of the adhesive composition for chemical plating of the present invention is applied on a laminate, and then the adhesive composition is cured, and a plating resist is coated on portions other than the wiring pattern forming portion. The printed wiring board is manufactured by depositing the plating on the pattern forming portion.

The adhesive film for chemical plating according to the present invention is laminated on a laminate by heating and pressing with the adhesive composition layer facing the laminate, and then the adhesive composition is cured to be applied to portions other than the wiring pattern forming portion. A resist is coated, and then a plating is formed on the wiring pattern forming portion by chemical plating to produce a printed wiring board.

A method of laminating the adhesive film for chemical plating of the present invention on a laminate will be described.

These steps are described in JP-A-50-15876 and JP-A-63
This is performed by a known method described in, for example, Japanese Patent Application Laid-Open No.
It is easy to laminate the adhesive film on a laminate, such as a phenolic resin laminate on a paper substrate. In other words, if there is no protective film such as polyethylene, and if there is a protective film, peel off the protective film or, while peeling off, make the adhesive side the laminate side, and apply heat and pressure lamination on both sides or the other side of the laminate. I do. Heat and pressure lamination is performed by a hot-roll laminator under normal pressure, which is well known to a printed wiring board manufacturer, Japanese Patent Application Laid-Open No. 52-52703, and Japanese Patent Publication No. 55-1.
It can be performed using a laminator under reduced pressure or under vacuum described in JP-A-3341.

The laminate on which the adhesive film has been laminated is then cured with the adhesive composition layer by peeling the support film or without peeling it, if necessary. The adhesive film obtained by applying the adhesive composition to the substrate is cured as it is. Curing is performed at the same time as the step of irradiating with ultraviolet rays or thereafter by heating at 100 to 150 ° C.

Next, a plating resist is formed on a portion other than the chemically plated portion of the laminate on which the adhesive film has been formed, and the adhesive is chemically roughened, and plating nuclei are precipitated and activated. Either the roughening of the adhesive for forming the plating resist, the deposition of the plating nucleus, or the activation may be performed first.

Next, a chemical plating film is deposited on a portion to be chemically plated by electroless plating by a conventional method.

Since the laminate having the adhesive layer of the present invention does not warp or twist, printing of plating resist or lamination of dry film plating resist is facilitated, and a fine circuit can be stably formed.

(Examples) Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In the examples, "parts" indicates "parts by weight" unless otherwise specified.

Examples 1 and 2 and Comparative Example As shown in Table 1 using a knife coater, a polyester film which was subjected to an olefin release treatment as a support film, Tetron Film RO2 (38) manufactured by Teijin Limited.
An adhesive composition solution having the composition shown in Table 1 was applied to the release surface having a thickness of 30 μm on the release surface having a thickness of 30 μm and then dried (60 to 110 ° C. for 5 minutes). , A protective film, a polyethylene film (30 μm thick), and an adhesive film for chemical plating that was wound into a roll. Next, roll two adhesive films (500m wide)
m, length of 100 m) paper-based epoxy resin laminate (Hitachi Chemical Industries, Ltd., trade name LE-144, 0.8 mm thickness, A hot roll laminator (HLM-1 manufactured by Hitachi Chemical Co., Ltd.) while peeling off the polyethylene film on both surfaces of 500 mm x 500 mm)
The adhesive film was cut to a laminate size (a hot roll temperature of 150 ° C., a hot roll pressure of 4 kgf / cm ² , and a laminating speed of 1 m / min). Next, 80W /
Using a 365nm sensor using an ultraviolet irradiator with two cm high-pressure mercury lamps (Oak Seisakusho Co., Ltd., trade name: HMW-514)
Irradiation with ultraviolet rays of 1.2 J / cm ² was performed. In Comparative Example 1, this ultraviolet irradiation step was not performed. Next, the polyester film was peeled off and heated for 30 minutes in a curing furnace having an ambient temperature of 150 ° C.

Further, as Comparative Example 2, another substrate was heated for 60 minutes in a curing furnace having an ambient temperature of 160 ° C. without performing ultraviolet irradiation.

Next, on the surface of the substrate on which the adhesive layer was formed,
Except for the peel strength measurement pattern of mx 10cm in length and the 260 ° C solder heat resistance measurement pattern of 2.5cm in width x 2.5cm in length,
An ultraviolet-curable plating resist ink (trade name: RI-510, manufactured by Nippon Soda Co., Ltd.) was printed and irradiated with ultraviolet rays at 1.5 J / cm ² to cure the plating resist ink. Both of the above pattern portions where the adhesive layer is exposed are coated with chromic anhydride 65 g /
, Roughening 7 minutes at 50 ° C. in a chemical roughening solution comprising concentrated sulfuric acid 250ml / and, after washing with _{water, CuSO 4 · 5H 2 O150g /} , ethylenediaminetetraacetic acid 30 g /, 37% HCHO aqueous solution 10 ml /, sodium cyanide 25 mg / Was immersed in an electroless copper plating solution adjusted to pH 12.5 with NaOH at 70 ° C. for 15 hours to form a copper plating film having a thickness of about 30 μm on each pattern forming portion. Next, after washing with water,
Dry at 50 ° C. for 30 minutes.

Using the obtained printed wiring board, the peel strength and solder heat resistance of the copper-plated film at the pattern forming portion were measured according to the JIS-C6481 method. The results are summarized in Table 2.

The peel strength was indicated by the peel strength of a 1cm-wide coated film with a rheometer at a speed of 50mm / min at a tension of 90 ° to the laminate.

Solder heat resistance was expressed as the time until the surface of the printed wiring board was brought into contact with a flow solder bath at 260 ° C and blistering and peeling of the plating film occurred.

In both Examples 1 and 2, curing at a low temperature of 150 ° C using ultraviolet light was possible, and the substrate warpage and twist were less than 1.0 mm, and there were no problems in printing, etc., peel strength of plated copper, solder heat resistance, etc. A good printed wiring board was obtained. on the other hand,
In the curing at 150 ° C. in the comparative example, the curing of the epoxy resin was insufficient, and the warpage and twist were small, but there were problems in peel strength and solder heat resistance. Heat cured at 160 ° C for 60 minutes has peel strength and solder heat resistance.
Although there was almost no problem, the warpage was severe, and it was necessary to correct the warpage before printing the racist ink.

(Effect of the Invention) The adhesive composition for chemical plating and the adhesive film for chemical plating according to the present invention can reduce the warping and twisting of the substrate, and provide a printed film having high peel strength and solder heat resistance. A wiring board is obtained.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C09J 121/00 JEB C09J 121/00 JEB C23C 18/20 C23C 18/20 H05K 3/18 6921-4E H05K 3/18 E (72) Inventor Mineo Kawamoto 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (56) References JP-A-2-167381 (JP, A) JP-A-60-226582 ( JP, A) JP-A-60-199024 (JP, A) JP-A-60-124622 (JP, A) JP-A-57-118553 (JP, A)

Claims (6)

(57) [Claims] 1. An adhesive composition for chemical plating comprising an epoxy resin, a synthetic rubber, a phenol resin, a noble metal compound serving as a catalyst for chemical plating, and a photosensitive aromatic onium salt. 2. An epoxy resin having a solid content of 15% in the composition.
-40% by weight, 40-60% by weight of synthetic rubber, 20-40% by weight of phenolic resin, 0.01-2% by weight of a noble metal compound serving as a catalyst for chemical plating, and 0.1% by weight of a photo-sensitive aromatic onium salt.
The adhesive composition for chemical plating according to claim 1, wherein the amount is 2 to 5% by weight. 3. An adhesive film for chemical plating formed on a transparent support film of the adhesive composition layer for chemical plating according to claim 1. 4. The adhesive film for chemical plating according to claim 3, wherein the transparent support film is an olefin release-treated polyester film. 5. A solution of the adhesive composition for chemical plating according to claim 1 or 2 is coated on a laminate, and then the adhesive composition is cured to form a plating resist on portions other than the wiring pattern forming portion. A method of manufacturing a printed wiring board that coats and then deposits plating on the wiring pattern formation part by chemical plating. 6. An adhesive film for chemical plating according to claim 3 or 4 is laminated on a laminate by heating and pressurizing with the adhesive composition layer facing the laminate, and then the adhesive composition is cured. A method of manufacturing a printed wiring board in which a plating resist is coated on portions other than a wiring pattern forming portion, and then plating is deposited on the wiring pattern forming portion by chemical plating.