JPS60164390A - Method of producing printed 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 The present invention relates to a method for manufacturing a printed wiring board on which a circuit can be formed on an insulating substrate having an adhesive layer on its surface.

The miniaturization of electrical equipment is progressing rapidly, and along with this, the printed wiring boards incorporated therein are increasingly required to be smaller and have higher density between printed circuits.

By the way, as in the CG-4 method, an adhesive layer and a plating resist layer are sequentially provided on a substrate in advance, and after the adhesive layer is roughened, plating is applied to areas other than the plating resist layer by electroless plating to form a circuit. In such printed wiring boards, a phenomenon occurs in which metal plating adheres to and grows on the plating resist layer during electroless plating. When the growth of such metal plating increases, insulation defects and short circuit defects occur, and such defects are particularly likely to occur in high-density printed wiring boards.

In order to improve these drawbacks, a borofluoric acid solution was conventionally used to roughen the adhesive, but this was replaced with a chromic anhydride sulfuric acid solution. This resulted in a reduction in insulation defects and short-circuit defects, but on the other hand, there was a drawback in that the solder heat resistance of circuits formed by electroless plating decreased.

It is an object of the present invention to provide a method for manufacturing a printed wiring board that improves the above-mentioned drawbacks, reduces insulation defects and short circuit defects, and improves solder heat resistance.

In order to achieve the above-mentioned object, the present invention assembles an adhesive layer provided on the surface of an insulating substrate with an anhydrous chromic acid l1III acid fluoride alkaline roughening solution, and after IC, forms a predetermined adhesive layer with an electroless plating solution. A method for producing a printed wiring board for forming a circuit, characterized in that the adhesive layer is roughened with an alkali anhydrous chromic acid sulfate fluoride roughening solution in which adhesive is melted at 10 g/l or more (printed wiring board). A method for manufacturing a board is provided.

The present invention will be explained below based on examples.

First, an adhesive containing a plating catalyst is applied to the surface of an insulating substrate such as paper containing a plating catalyst such as palladium, a phenol resin base material, or a paper-J poxy resin base material to form an adhesive layer. do. Next, on the surface of this adhesive layer, a plating resist I-ink is printed in a predetermined pattern by screen printing and dried to provide a plating resist +-m. The adhesive layer is then roughened by immersing the printed circuit board with the adhesive layer and the plating resist layer in an alkali anhydrous chromic acid sulfate fluoride assembling solution in which the adhesive is melted at 1011/1 or higher. do. Especially as a roughening liquid, 0rO3 is 20 to 60,
g/It, H, So, 150-500 ml/k and NaF 10-50' (1/l). After roughening the adhesive layer, electroless copper plating is applied to the insulating substrate. A circuit made of a copper plating layer is formed on the surface of the adhesive 1 by immersing it in a solution.

However, according to the above-mentioned embodiment of the present invention, since 10 g/1 or more of the adhesive is included in the roughening liquid in advance, appropriate unevenness is generated on the surface of the adhesive layer, and the adhesive layer and The peeling strength of the copper plating layer increases, and the heat resistance of the cliff 111 improves. In addition, since the roughening solution is an alkali-based roughening solution based on anhydrous chromic acid sulfate fluoride, it is difficult for copper plating to adhere to the plating resist layer during the slow plating process, which prevents poor insulation and short circuits.
Lr-Kill.

In addition, when the adhesive m contained in the roughening liquid is less than 1OL/2, the soldering heat resistance is almost the same as that of the conventional type without adhesive. Furthermore, when the insulating substrate is particularly a paper-phenolic resin substrate, it is more preferable that the amount of adhesive is 15 g/4 or more.

In Example R above, an adhesive layer containing a plating catalyst is provided on the surface of the insulating substrate, but an adhesive layer that does not contain a plating catalyst may also be used. In this case, after the adhesive layer is roughened, A plating catalyst may be applied to the surface.

Next, the solder heat resistance of printed wiring boards manufactured by the method of the present invention and the conventional method will be compared.

As the insulating substrate, a paper-phenolic resin base material containing a palladium-based plating catalyst is used, and an adhesive layer and a plating resist layer containing a nitrile rubber phenol resin and a plating catalyst are provided on the surface thereof. Next, this insulating substrate is immersed in a roughening solution at 40° C. for 12 minutes, taken out and dried. The roughening liquid is placed in C tube ゛0□ 30 Q/
1, II l-1z SOq, 300IIll
Add 0~50g of adhesive having the same composition as the adhesive layer provided on the insulating substrate to a liquid consisting of /L and NaF2OQ/1.
/I, use the one containing. After roughening the adhesive layer,
After electroless steel plating treatment, m+sr+ 71/l'
l Phasekk -No.■mW...Sesu 21.7;- A printed wiring board test piece (2!+, 4X25.
4 mm) in a solder melt at 21 degrees and 260 degrees Celsius to prevent the wire plating layer from peeling or blistering.
IIl-tl- was measured to determine the soldering heat resistance, and the results shown in the figure were obtained. From this diagram, the cheerful street,
According to the present invention, the soldering heat resistance is improved by more than 2.4 times, which is 6 seconds or more, compared to 2.5 seconds in the conventional example in which the adhesive is not dissolved.

As described above, according to the present invention, there is provided a method for manufacturing a printed wiring board that reduces insulation defects and short circuit defects, improves solder heat resistance, and improves solder heat resistance.

4, mM (DHJ1’JmlA The figure shows a graph of solder heat resistance versus the amount of adhesive melted.

Claims (1)

[Claims] (1) Manufacturing a printed wiring board by roughening the adhesive layer provided on the surface of an insulating substrate with an anhydrous chromic acid sulfate fluoride alkaline roughening solution, and then forming a predetermined circuit with an electroless plating solution. A method for producing a printed wiring board, characterized in that the adhesive layer is roughened using an alkali anhydrous chromic acid sulfate fluoride silting solution in which the adhesive is melted at a rate of 10 g/f/or more.