JP2742124B2 - Manufacturing method of printed circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention eliminates distortion generated during heating and press molding by performing after-baking of a laminate formed by heating and press molding, and provides a printed circuit having excellent dimensional stability. The present invention relates to a method for producing a laminated board for use.

<Prior art> A laminated board (hereinafter, referred to as a composite laminate) obtained by impregnating an epoxy resin into a glass woven fabric as a surface layer substrate, and applying heat and pressure to these substrates as a printed circuit laminate. Board) has been used in large quantities.

Laminates made of glass woven fabric only and impregnated with epoxy resin have excellent mechanical strength, dimensional stability, heat resistance, etc., and high reliability of through-hole plating. Is widely used in industrial electronic devices. However, since only a glass woven fabric is used as a base material, a punching process cannot be performed in a hole forming process, which is one of the processing steps of a printed circuit board, and the fact is that drilling is performed.

On the other hand, composite laminates are economically less expensive than glass woven substrate laminates and are superior in that they can be punched. And the reliability of the through-hole plating was evaluated to be lower than that of the glass woven fabric base laminate. The reason for this is that the weight ratio of the epoxy resin, which is an organic substance, and the glass woven cloth, which is an inorganic substance, is about 40:60. In this case, it is considered that the epoxy resin mainly improves various electrical performances, and the glass woven fabric improves mechanical performances such as dimensional stability of bending strength.

By the way, in general composite laminates, glass nonwoven fabric is used as a base material for the intermediate layer, and distortion during heating and pressing is more likely to occur than a laminate using a woven base material, so dimensional stability is low. There is a problem of inferiority.

<Problems to be Solved by the Invention> The present invention provides an after-baking after heat-press molding to reduce the dimensional shrinkage during the processing of a laminated board without losing the excellent features of the conventional composite laminated board. The purpose is to make it equivalent to a laminate using a cloth substrate.

<Means for Solving the Problems> According to the present invention, the surface layer is made of a thermosetting resin-impregnated glass woven prepreg, and the intermediate layer is made of a thermosetting resin-impregnated glass nonwoven fabric or prepreg. Is subjected to after-baking treatment after heat-press molding, and is a process for producing a printed circuit board laminate.

<Effect> Since the conventional composite laminate uses a glass nonwoven fabric as the base material of the intermediate layer, there is a problem that the dimensional stability is inferior in the laminate processing step as compared with the glass woven base material laminate. .

The present invention solves this drawback. By performing an alter baking process, the distortion of the material generated at the time of hot press molding is corrected, and the dimensional stability at the time of processing is improved. Can be improved to the same level as.

The after-baking condition in the present invention is a temperature of 130.
A treatment time of 10 to 120 minutes at ~ 200 ° C is desirable. At a temperature of 130 ° C. or less, distortion cannot be eliminated, and at a temperature of 200 ° C. or more, other characteristics such as electrical characteristics are adversely affected. If the processing time is less than 10 minutes, the distortion cannot be eliminated, and if the processing time is more than 120 minutes, the time is too long and adversely affects other characteristics such as electric characteristics. Particularly desirable after-baking conditions are as follows.

Temperature (° C.) Treatment time (min) 131 to 14040 to 80 141 to 15030 to 60 151 to 16020 to 40 161 to 18015 to 30 181 to 20010 to 20 <Example> The composition of the epoxy resin varnish is as follows.

The above materials were mixed to produce a uniform varnish. Next, the varnish blended for the surface layer was coated on a glass woven fabric (Nitto Boseki).
WE-18K-RB84) was impregnated and dried so that the resin content became 42 to 45%, to obtain a glass woven fabric prepreg.

Subsequently, an inorganic filler having the following composition was added to the varnish similarly formulated for the intermediate layer with respect to 100 parts of the resin component, followed by stirring and mixing to prepare an inorganic filler-containing varnish.

Silica (Crystalite VX-3 manufactured by Tatsumori) 25 parts Aluminum hydroxide (Al ₂ O ₃ · 3H ₂ O) 70 parts Ultra fine powdered silica (Carplex manufactured by Shionogi Pharmaceutical Co., Ltd.) 5 parts A prepreg was obtained by impregnating and drying the base material (manufactured by Nippon Vileen Co., Ltd.) so that the contents of the resin and the inorganic filler became 90%.

The glass non-woven base prepreg as an intermediate layer, wherein the glass fabric prepreg was placed, further overlapping metal foils thereon, molding temperature 165 ° C., and laminate molding at a pressure of 70 kg / cm ² 90 minutes up and down the surface layer, A copper-clad laminate having a thickness of 1.6 mm was obtained.

<Comparative Example> A copper-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Examples 1 and 2 except that the after-baking treatment was not performed. With respect to the obtained copper-clad laminate, a dimensional change rate (shrinkage rate) in a processing step of a circuit board was measured.

 Table 2 shows the results.

As is clear from Table 2, the after-baked copper-clad laminate is excellent in dimensional stability.

<Effect of the Invention> Since the laminate according to the present invention is obtained by performing after-baking treatment after hot-press molding, the dimensional shrinkage is significantly reduced as compared with the conventional composite laminate, and the glass woven substrate laminate This is a level equivalent to that of the present invention, and is suitable as an industrial method for manufacturing a printed circuit board.

In addition, the obtained laminate has improved deformation such as warpage and twist.

Claims (1)

(57) [Claims] The surface layer is made of a glass woven fabric impregnated with a thermosetting resin, and the intermediate layer has a filler to the thermosetting resin.
A method for manufacturing a printed circuit board laminate, comprising performing after-baking on a laminate made of a glass woven fabric impregnated with a resin containing 10 to 200% by weight after heating and pressing.