JPH06244556A - Manufacture of multilayered printed wiring board - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing a wiring board used by cleaning with an alkali permanganate solution before an inner layer board is treated for interlayer adhesion. CONSTITUTION:A method for manufacturing a title wiring board which uses an inner layer printed wiring board comprising the surface of a copper foil cleaned with an alkalipermanganate solution before the copper foil is surface- treated for interlayer adhesion after an inner layer printed wiring network is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inner layer printed wiring board used as an intermediate layer of a multilayer board, and more completely removes resist and the like remaining on the inner layer printed wiring network. This makes it possible to manufacture a multilayer printed wiring board having more reliable interlayer adhesion by making the surface treatment for interlayer adhesion more uniform.

[0002]

2. Description of the Related Art As an inner layer printed wiring board, a double-sided copper-clad laminate is usually subjected to mechanical polishing such as buffing, and appropriately treated with a chemical polishing liquid.
It is manufactured by exposing, developing, etching, removing photoresist, forming a brown or black fine uneven copper oxide film, or performing surface treatment for interlayer adhesion such as a method of reducing it while maintaining fine unevenness. .

Recently, with the miniaturization of components and the surface mounting thereof, it is necessary to reduce the diameter of through holes, to form a more precise printed wiring pattern, and to use a thinner printed wiring board for inner layers. It is said that. In particular, with the development of smaller diameter through-holes, the through-hole plating solution penetrates into the minute fracture surfaces and cracks that occur during drilling,
There is a problem that haloing is likely to occur.

As a solution to this problem, by forming a copper oxide film and then reducing it to metallic copper, the occurrence of fracture surfaces and cracks at the time of drilling is suppressed and the metallic copper also dissolves in the plating solution. Methods have been developed to take advantage of the difficulty. However, this method has problems in terms of equipment and running cost, and it is necessary to make the copper oxide film before reduction more uniform.

[0005]

DISCLOSURE OF THE INVENTION The present invention enables uniform oxidation treatment by completely removing organic substances such as residue of resist peeling from the surface of the printed wiring copper foil for inner layer after etching. The purpose is to find an inner layer plate in which the haloing size is greatly reduced compared to the conventional case only by the oxidation treatment.

[0006]

That is, according to the present invention, in a method for producing a multilayer printed wiring board, after forming a printed wiring network for an inner layer and prior to a copper foil surface treatment for interlayer adhesion, an alkaline permanganate is used. A method for producing a multilayer printed wiring board, which comprises using an inner layer printed wiring board obtained by cleaning the surface of a copper foil with an aqueous salt solution. In a preferred embodiment of the present invention, the alkaline permanganate aqueous solution is potassium permanganate or sodium permanganate 10 to 70 g / liter, sodium hydroxide 5 to 70.
It is an aqueous solution containing g / liter and is a method for producing a multilayer printed wiring board in which the treatment is carried out at 40 to 80 ° C. for 2 to 7 minutes.

The structure of the present invention will be described below. The multilayer printed wiring board of the present invention, as an inner layer printed wiring board used as an intermediate layer, after forming an inner layer printed wiring network,
After cleaning with an alkaline permanganate aqueous solution and then using the inner layer printed wiring board made by performing the copper foil surface for interlayer adhesion, multilayer prepreg for adhesion, copper foil for outer layer or single-sided copper clad Conventionally known materials such as a laminated material such as a laminated plate and a method for forming a multilayered laminate thereof can be used.

Prepreg for single-sided or double-sided copper-clad laminate,
The multi-layered adhesive prepreg uses a base material having excellent drilling properties and is impregnated with a thermosetting resin composition and dried. As a base material, E-glass, S-
Glass, SII-glass, T-glass, C-glass, A-glass,
Woven cloth, non-woven cloth using various glass fibers such as D-glass,
Inorganic fiber non-woven fabric such as alumina paper; liquid crystalline polyester, wholly aromatic polyamide, polyimide, fluororesin, polyphenylene sulfide, polyether ether ketone, polyether imide, and other woven and non-woven fabrics using heat-resistant fibers Mixed woven fabrics, mixed non-woven fabrics and the like.

As the thermosetting resin used for impregnation, bisphenol A type, novolac type, halogenated bisphenol A type, halogenated novolak type, and other polyfunctional epoxy resins having three or more functional groups; cyanato resin, cyanic acid Cyanate ester resins such as ester-epoxy resin, cyanate ester-maleimide-epoxy resin; bismaleimide, and other polyfunctional maleimides having two or more maleimide groups and bis (4-aminophenyl)
Examples thereof include a maleimide-based resin containing a polyfunctional amine such as methane as a main component; and a heat-resistant thermoplastic resin or a composition of a thermoplastic resin and a thermosetting resin.

Examples of the copper foil include rolled copper foil and electrolytic copper foil. Examples of the lamination molding method include hot plate press, hot plate vacuum press, and autoclave molding. Moreover, as the surface treatment for the interlayer adhesion of the inner layer printed wiring network copper foil, a conventionally known method and a method of reducing the same can be mentioned.

In the present invention, the above-mentioned single-sided or double-sided copper-clad laminate is used, and after the etching resist is attached, exposed, developed, etched, and the resist is peeled off, the copper foil surface is cleaned with an alkaline permanganate aqueous solution. After that, a surface treatment for interlayer adhesion is performed to obtain an inner layer printed wiring board. The alkaline permanganate aqueous solution and the treatment therewith include potassium permanganate or sodium permanganate.
~ 70 g / liter, preferably 40-60 g / liter, sodium hydroxide 5-70 g / liter, preferably 40-60 g / liter in an aqueous solution containing 40 to 80 ° C, preferably 60 to 80 ° C, 2 to 7 minutes, preferably in the range of 3 to 7 minutes; a method of performing the treatment in concentrated sulfuric acid having a concentration of 85% by weight or more at a temperature of 20 to 45 ° C. for 2 to 7 minutes.

The concentration of the aqueous alkaline permanganate solution,
The optimum temperature is selected according to the surface condition of the printed wiring board to be treated. If the concentration is low, if the treatment temperature is low, the treatment takes too much time, or the removal of oil and fat is insufficient, which is not preferable. It is not preferable because self-decomposition occurs and it takes time to prepare the solution.

The apparatus or method used for treating the inner layer printed wiring board with the above alkaline permanganate aqueous solution of the present invention includes a solution dipping method by dipping,
Examples include a method using a spray-type conveyor belt type soft-etching machine.

[0014]

EXAMPLES The present invention will be described below with reference to examples. Example 1 A double-sided copper clad laminate having an insulation layer thickness of 0.8 mm and a copper foil thickness of 70 μm was a buff brush with a # 1000 alumina abrasive (footprint 10 mm, cutting speed 9 m / sec, oscillation 250 times / min, conveyor speed 3 m). / min), buffed and dried, then dry film (AQ306 manufactured by Asahi Kasei Corp.)
5) was laminated on both sides. The both surfaces were exposed to ultraviolet light using a UV exposure machine (HMW301, manufactured by Oak Co.), and then treated with a 3 wt% sodium hydroxide aqueous solution at 40 ° C. for 1 minute to remove the dry film.

This was cleaned with an aqueous solution of 50 g / l (liter) of potassium permanganate and 50 g / l of sodium hydroxide by strong oxidation at 60 ° C. for 3 minutes, then pickled with 10% by weight sulfuric acid and washed with water. Sodium chlorite 30g / l, sodium hydroxide 15g
/ l, an aqueous solution of 5 g / l sodium phosphate at 80 ° C for 4 minutes to oxidize the surface of the copper foil to enhance adhesion, and then wash and dry to obtain an inner layer printed wiring board.

A glass epoxy prepreg with a resin amount of 52% and a thickness of 0.1 mm was placed on each side of the printed wiring board for the inner layer, three sheets on each side, and an electrolytic copper foil of 18 μm was placed on the outside of the printed wiring board for a temperature of 175 ° C. Then, lamination molding was performed at a pressure of 40 kg / cm ² for 2 hours to obtain a four-layer board having a thickness of 1.6 mm. Two of the obtained 4-layer boards are stacked, a 0.1 mm aluminum board is placed on the upper surface, and a paper phenol laminated board of 1.5 mm is placed on the lower surface. A 0.4 mmφ drill bit is used, and the rotation speed is 80 krpm and the feed rate is 1.6 m / min. Total 2500
I made a hole.

The four-layer plate perforated as described above was added to 4N hydrochloric acid to form 5
After dipping for a minute, remove the outer layer 18μm copper foil by polishing,
The maximum amount of haloing that occurred was determined. As a result, the maximum amount of haloing was 230 μm. Comparative Example 1 The same procedure was performed as in Example 1 except that the strong oxidation treatment with the mixed solution of potassium permanganate and sodium hydroxide was not performed. As a result, the maximum amount of haloing is 400 μm
Met.

[0018]

As is clear from the detailed description of the invention, the examples, etc., the printed wiring board according to the present invention suppresses the amount of haloing generated, and makes it possible to manufacture a more reliable printed wiring board. Therefore, its industrial significance is high.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Nakano 6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory

Claims (2)

[Claims] 1. A method for manufacturing a multilayer printed wiring board, comprising:
After forming the inner layer printed wiring network, prior to the copper foil surface treatment for interlayer adhesion, the inner layer printed wiring board formed by cleaning the copper foil surface with an alkaline permanganate aqueous solution is used. Manufacturing method of multilayer printed wiring board 2. The alkaline permanganate aqueous solution,
Potassium permanganate or sodium permanganate
The method for producing a multilayer printed wiring board according to claim 1, wherein the treatment is an aqueous solution containing 10 to 70 g / liter and 5 to 70 g / liter of sodium hydroxide, and the treatment is carried out at 40 to 80 ° C. for 2 to 7 minutes.