JPS6148987A - Method of producing circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a method for manufacturing a wiring board, and more particularly to a method for manufacturing a wiring board in which a circuit pattern of insulating coated wires is wired and fixed on an insulating substrate having adhesive properties. .

(Background) In recent years, conductive circuits have been formed on an insulated substrate as necessary, and a circuit pattern of insulated wires has been fixed via an insulating adhesive layer, and then through-holes have been formed at desired positions. By forming a metal conductor layer on the inner wall surface of the through hole and connecting it to the core wire of the insulated wire, a so-called multi-wire wiring board, which electrically connects each padan, is used. It has become.

(Prior Art) An example of a typical manufacturing method of this type of conventional wiring board will be explained with reference to FIG.

As shown in FIG. 1(a), a patterned copper layer 2 is formed on one or both sides of an insulating substrate 1 containing a catalyst for electroless plating so that it can be used, for example, as a power supply layer or an earth layer. Next, as shown in FIG. 1(b), after forming an adhesive layer 3 containing an electroless plating catalyst in contact with the insulating substrate 1 and the copper layer 2,
Insulated wire 4 as a signal circuit as shown in Fig. 1(C)
The wiring pattern is fixed on the adhesive layer 3. Next, as shown in FIG. 1(d), prepreg containing a catalyst for electroless plating is laminated and bonded in order to protect the circuit pattern formed by the insulated wire 4 that has been fixed and to ensure the fixation. Then, an insulating layer 5 having catalytic properties for electroless plating is formed. Next, after forming a non-conforming mask 6 that does not have catalytic properties against electroless plating on the outer surface, as shown in FIG.
As shown in e), a through hole 7 is formed at a desired position so as to cross either or both of the insulated wire 4 and the copper layer 2, and at least a portion of the insulated wire 4 and the copper layer 2 are formed through the through hole. After exposing the inner surface of the through hole 7, a metal conductor layer 8 is deposited on the inner wall surface of the through hole 7 by immersing it in an electroless plating solution to form a through hole, and as shown in FIG. is removed to obtain the desired wiring board.

(Conventional disadvantages) However, in the wiring board manufactured by the above-mentioned conventional technique, the insulating substrate 1, the adhesive layer 3, and the insulating layer 5 all contain a catalyst for electroless plating, for example, 0.5 to 10% by weight of palladium chloride. (a) The material cost of the substrate is high, (b) the electrical insulation properties are poor, and (c) it is a special material that is difficult to obtain. ) Furthermore, such a wiring board is
It is difficult to form the land portion during the manufacturing process. For this reason, protrusions called beats were provided in place of lands to improve solder climbing properties during soldering, but this caused problems as the beads were frequently damaged when handling the wiring board.

(Object of the present invention) An object of the present invention is to provide a method for manufacturing a wiring board that eliminates such conventional drawbacks.

That is, the method for manufacturing the wiring board of the present invention includes the steps of forming an adhesive layer on an insulating substrate provided with a conductor pattern, and after wiring an insulated coated wire on the adhesive layer, forming an insulating resin layer thereon. and a step of forming an electroless plating resist film on the insulating resin layer, drilling through holes at desired positions, and applying an electroless plating catalyst by immersing it in an electroless plating catalyst aqueous solution of a base metal colloid aqueous solution. and a step of removing the electroless plating catalyst on the electroless resist film on the electroless plating resist film by mechanical means, and removing the electroless plating catalyst on the electroless plating resist film on the inner wall surface of the through hole and the insulating resin layer. The method is characterized in that it includes a step of immersing the portion in an electroless plating solution to form a metal conductor layer.

(Example) An example of the manufacturing method of the present invention will be described below with reference to FIG. 2. As shown in FIG. 2(a), a patterned copper layer 2 is formed on one or both sides of an insulating substrate 1 so that it can be used as a power supply layer or an earth layer, if necessary. Next, as shown in FIG. 2(b), after forming an adhesive layer 3 in contact with the insulating substrate 1 and the copper layer 2, a circuit pattern of the insulating coated wire 4 as a signal circuit is formed as shown in FIG. 2(e). Adhesive layer 3
Attach the wire to the top. Next, as shown in FIG. 2(d), prepregs are laminated and bonded to form an insulating layer 5 in order to protect the circuit pattern formed by the insulated wire 4 which has been fixed and to ensure the fixing. Next, after forming an electroless plating resist film 10 at a desired position on the outer surface,
As shown in FIG. 2(e), a through hole 7 is bored at a desired position so as to cross either or both of the insulated wire 4 and the copper layer 2, and at least one of the insulated wire 4 and the copper layer 2 is After exposing the part to the inner surface of the through hole 7, the temperature is 40 to 70°C.
Clean the inner wall surface of the hole by immersing it in an alkaline solution.

Next, as shown in Figure 2 (f), base gold! After applying an electroless plating catalyst 9 by immersing it in an electroless plating melting medium aqueous solution containing a colloidal solution of 10% (for example, copper), the electroless plating resist film 10 is coated by mechanical means such as a sponge roller soaked with water. The electroless plating catalyst 9 on the electroless plating resist film 10 is removed by rubbing. Next, after washing with water, the metal conductor layer 8 is deposited on the inner wall surface of the through hole 7 by immersing it in an electroless plating solution to form a through hole, thereby obtaining the desired wiring board (FIG. 2 (X)).

(Effects) The wiring board obtained by the manufacturing method of the present invention has the following effects by using the electroless plating catalyst of the base metal colloid aqueous solution. (1) There is no need to include a catalyst in the substrate material, reducing material costs. (11) Since the substrate material does not contain a catalyst, the electrical insulation properties do not deteriorate. Since GiD can use normal substrate materials, it is easy to obtain materials. (
Since the ψ land portion can be formed, the solder climbability is good and it can be handled in the same way as a normal wiring board.

[Brief explanation of drawings]

1(a) to (f) are cross-sectional views showing the manufacturing process of a wiring board by the conventional manufacturing method, and FIGS. 2(a) to (g) are sectional views showing the manufacturing process of the wiring board by the manufacturing method of the present invention. It is. 1...Insulating substrate, 2...Copper layer, 3...
... Adhesive layer, 4 ... Insulation coated wire, 5
...Insulating resin layer, 6 ... Mismatched mask, 7 ... Through hole, 8 ... Metal conductor layer,
9... Electroless plating catalyst, 10... Electroless plating resist film. )/Figure 5 Figure 2 1 Strain Z diagram

Claims (1)

[Claims] a step of forming an adhesive layer on an insulating substrate provided with a conductor pattern; a step of laying an insulating coated wire on the adhesive layer and then forming an insulating resin layer thereon; and a step of forming an insulating resin layer on the insulating resin layer. After forming an electroless plating resist film on the electroless plating resist film, forming a through hole at a desired position and applying an electroless plating catalyst by immersing it in an electroless plating catalyst aqueous solution; a step of removing the plating catalyst; and a step of immersing the inner wall surface of the through hole and the portion of the insulating resin layer not covered with the electroless plating resist film in an electroless plating solution to form a metal conductor layer. A method of manufacturing a wiring board, comprising: