JPH05160567A - Method of manufacturing wiring board - Google Patents

Abstract

PURPOSE:To improve the copper plating deposition property of the inner wall of a through hole by a method wherein more than one kind of metals are mixed in glass particles, which are soluble in a fluorine compound, and a liquid, which consists of a chromic acid compound, a sulfuric acid and sodium fluoride or a chromic acid compound and borofluoride, is used as a chemically roughening liquid. CONSTITUTION:A bonding agent layer containing a catalyst for electroless plating use is formed on the surface of an insulating board containing a catalyst for electroless plating use, which is obtained by adding 0.05 to 1% of more than one kind of metals, such as palladium, gold, platinum or silver, to glass particles, which are soluble in a fluorine compound. Then, a hole which is used as a through hole is bored in the board. Then, a resist for electroless plating use is formed on a part other than the hole and a part to be used as a circuit part of the board. Then, the board is dipped in a chemically roughening liquid, which consists of a chromic acid compound, a sulfuric acid and sodium fluoride or a chromic acid and a borofluoric acid, and the surfaces of the parts, on which the resist is not formed, are selectively roughened. Then, copper plating is applied to the hole and the circuit part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a high density additive printed wiring board.

[0002]

2. Description of the Related Art As a wiring board, an adhesive layer containing a catalyst for electroless plating such as palladium is formed on the surface in order to deposit electroless plating as an economical method for producing electroless plating. Where the electroless plating resist is provided on the insulating plate containing the catalyst for electroless plating other than the place to be the circuit part, and the resist is not formed by dipping it in a chemical roughening solution such as chromic acid Selectively roughens the surface of
There is a so-called additive method of forming a circuit pattern by immersing it in an electroless plating solution.

[0003]

At present, in the manufacturing method which is industrially performed, in the immersion step in the chemical roughening solution,
As the electroless plating catalyst palladium dissolves in the roughening solution and falls off, and the catalytic activity of palladium deteriorates,
It takes about 2 hours to start the deposition of the wet copper on the inner wall of the hall (Teiquim). As a wiring board, if it is immersed in an alkaline plating bath having a pH of about 12 for a long time,
The phenomenon of copper pretend is frequently generated, and the heat resistance and the insulating property of the insulating portion are deteriorated. The present invention provides an electroless plating method which is excellent in suppressing such a decrease in plating deposition rate.

[0004]

The electroless plating catalyst of the present invention comprises a glass particle soluble in a fluorine compound and one or more metals such as palladium, gold, platinum or silver in a total amount of 0.05 to 0.05. 1%, and as the chemical roughening liquid, one containing a chromic acid compound, sulfuric acid, and a sodium fluoride system or a chromic acid compound and borofluoric acid was used, and glass particles were produced by the above chemical roughening acid. Is dissolved and a catalytic metal such as palladium, gold, platinum or silver is exposed on the surface, which is a process for producing a wiring board comprising the following steps.

A. Manufacturing process of insulating resin laminated board with catalyst. The electroless plating catalyst used in the present invention is obtained by kneading finely pulverized glass particles that can be dissolved in a fluorine-based compound with powder of chloride such as palladium, gold, platinum or silver, sulfuric acid compound, fluoride or nitric acid compound. After that, the mixed solution is heated in an electric furnace at 1000 ° C. for 1 hour to sublimate chlorine ions, sulfate ions, fluorine ions or nitrate ions. The generated glass particles were cooled and crushed at room temperature, and the glass particles were melted again in an electric furnace at 1000 ° C. for 1 hour, then cooled and crushed to obtain an electroless plating catalyst. The diameter of the glass particles is preferably 20 μm or less, 2
If it is larger than 0 μm, the dispersibility in the resin solution decreases. Here, the content of palladium is set to 0.05 to 1%, but if it is 0.05% or less, the active sites of the catalyst are reduced and the plating depositability is lowered. Further, even when the content is 1% or more, the dispersibility decreases and good plating depositability is not observed. Therefore, the palladium content is 0.05 to
1% is preferable.

B. Manufacturing process of insulating resin laminated board with catalyst. Glass cloth or cloth or paper made of organic fibers such as aramid, tetron, nylon, glass paper, ceramic paper mixed with the above electroless plating catalyst epoxy resin, polyester resin, polyamide resin, phenol resin, polyamideimide resin A prepreg characterized by being coated with a polytetrafluoroethylene resin, a polyethylene resin, or the like, and a laminated plate integrated with pressure and heating are produced using the prepreg.

C. A step of applying a catalyst-containing adhesive to a catalyst-containing insulating resin laminated plate. The plating catalyst-containing adhesive described above is applied to both sides of the plating catalyst-containing insulating resin laminated plate so that the adhesive film thickness after drying is about 25 μm.
This is a manufacturing process in which dip coating is performed so that As the adhesive, a synthetic rubber such as acrylonitrile butadiene rubber having glycidyl methacrylate, a cross-linking agent such as a boron trifluoride amine complex compound that simultaneously cross-links an alkylphenol resin and an epoxy resin, and silicic acid as a filler. Zirconium, silica, calcium carbonate, aluminum hydroxide or the like may be used as a component, and a photoinitiator may be added for photocuring.

D. Make a hole that will be a whole hole. As the holes serving as through holes, any device such as a punch or a drill, which is generally used for boring a wiring board, can be used. e. A resist for electroless plating is formed on a portion other than the through-hole and the circuit portion which is to be the circuit portion. Examples of the plating resist include a UV-curable resist film formed by photo-curing a resin into a film, a UV-curable resist ink, and a thermosetting resist ink that can be applied by screen printing. Electroless nickel plating Solution, copper plating solution, chemical solution used in the process of pretreatment, posttreatment, etc. and its usage conditions must not cause peeling.

F. The surface of the part where the resist is not formed is selectively roughened by immersing it in a chemical roughening liquid. As the chemical roughening liquid, it is preferable to use an aqueous solution containing a chromic acid compound, sulfuric acid and sodium fluoride, or an aqueous solution containing a chromic acid compound and borofluoric acid. For example, when roughening with an aqueous solution of alkaline permanganate, the plating deposition start time becomes extremely slow.

G. Dip in an electroless copper plating solution to apply copper plating to the circuit section. The electroless copper plating solution is not particularly limited, and a normal electroless copper plating solution such as CC-41 plating solution (trade name, manufactured by Hitachi Chemical Co., Ltd.) can be used. In order to reduce the take time of the inner wall of the through hole, dip it in a reducing aqueous solution such as formalin / sodium hydroxide or dimethylamine borane / sodium hydroxide before dipping in the electroless copper plating solution. Good.

[0011]

EXAMPLES Example 1 As an electroless plating catalyst, first, A-glass (trade name, manufactured by Toshiba Ballotini) which can be dissolved in a fluorine compound was used.
0 g and 0.04 g of palladium chloride were kneaded and ground. Then, the mixture is heated to 1000 ° C. in an electric furnace.
After heating for 1 hour to sublimate the hydrochloric acid ions, the palladium-containing glass is cooled and crushed at room temperature, and the glass particles are melted again in an electric furnace at 1000 ° C. for 1 hour. afterwards,
It was cooled at room temperature and pulverized to obtain an electroless plating catalyst.

[0012] A glass cloth epoxy resin laminated plate containing the above-mentioned plating catalyst, an acrylonitrile butadiene rubber as a main component with an adhesive containing the same electroless plating catalyst as the main component, an alkylphenol resin, an epoxy resin, an inorganic filling An insulating substrate whose surface was covered with an adhesive prepared by coating silica, zirconium silicate in a solvent as a material, drying, and heat curing was prepared. Then, holes were formed by a high speed drill machine, a photosensitive resist film was attached, and the resist was selectively exposed and developed to form a plating resist.

The substrate after this resist formation was exposed to a sodium fluoride-based roughening liquid (25 g of CrO ₃ , 200 ml of concentrated sulfuric acid, 30 g of sodium fluoride diluted with water to make 1 l in total) at 40 ° C. for 15 minutes. The surface of the adhesive of the circuit portion was selectively roughened by immersion, washed with water and neutralized. This substrate was immersed in a CC-41 plating solution (Hitachi Chemical Co., Ltd., trade name) as an electroless plating solution at 70 ° C. to deposit a copper plating of 20 μm, and then on a substrate surface other than the through hole. A solder resist was printed and applied by a screen printing method and heat-cured to obtain a test printed wiring board.

Example 2 As the electroless plating catalyst, first, E-glass (trade name, manufactured by Toshiba Ballotini) which can be melted in a fluorine compound is used.
0 g and platinum chloride were kneaded and ground. Subsequent steps were performed in the same manner as in Example 1 to prepare a catalyst for electroless plating. Using the plating catalyst thus obtained, a test printed wiring board was prepared in the same manner as in Example 1.

[0015]

[Table 1]

[0016]

As described above, as an effect of the present invention, the glass is melted by the chemical roughening which is the pretreatment step of the electroless copper plating, and the metal catalyst which is the active point of the electroless copper plating is It is characterized by being exposed on the surface. From these facts, it is presumed that the depositability of copper plating on the inner wall of the through hole could be improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Fukai, 1500 Ogawa, Shimodate, Ibaraki Prefecture Shimodate, Hitachi Chemical Co., Ltd. Shimodate factory (72) Inventor Shigeru Nonaka 4133, Hisashida, Ninomiya Town, Haga-gun, Tochigi Prefecture Company Ninomiya factory

Claims (1)

[Claims] 1. A method for manufacturing a wiring board, which comprises the following steps. a. On the surface of an insulating substrate containing an electroless plating catalyst in which one or more metals such as palladium, gold, platinum or silver are contained in a total amount of 0.05 to 1% in glass particles which can be dissolved by a fluorine compound, An adhesive layer containing a catalyst for electrolytic plating is formed. b. Drill a hole that will serve as a sur-wheel. c. A resist for electroless plating is formed on the portion other than the through hole and the circuit board. c. The surface of the portion where the resist is not formed is selectively roughened by immersion in a chemical roughening solution containing a chromic acid compound, sulfuric acid and sodium fluoride or a chemical roughening solution containing a chromic acid compound and borofluoric acid. e. It is dipped in an electroless copper plating solution and copper plating is applied to the through hole and the circuit part.