Toppan Printing Co., Ltd.

Risaburo Yoshida

Kiyotomo Nakamura

Yasuhiro Sakuma

Masahiro Itoh

Mitsuaki Taguchi

Akira Muraki

Akitsu Ota

A process for producing a printed wiring board, comprising the steps of forming a photosensitive resist layer on a copper layer provided on an insulating substrate, patterning the photosensitive resist layer, and etching the copper layer made bare from the photosensitive resist layer to form a copper wiring layer, wherein the surface of the copper layer is subjected to pretreatment comprising the steps of black-oxide treating the surface by the use of an alkaline oxidizing solution and subsequently finely surface-roughening the black-oxide treated surface by the use of an acidic treating solution comprised of phosphoric acid or an organic acid, followed by drying in the presence of oxygen, and thereafter the photosensitive resist layer is formed thereon. Such pretreatment enables formation of fine and uniform roughness on the copper layer surface to bring about an improvement in its adhesion to the resist layer, so that ethcing solutions can be prevented from penetrating the interface between these layers. The drying step causes the copper layer surface to undergo oxidation to decrease reflectance on its surface, so that it is possible to prevent pattern disorder of photosensitive regions during patternwise exposure.

Process for producing printed wiring board

A method of manufacturing a multi-layered wiring board, which is characterized in that the oxidation of a wiring layer for roughening the surface of the layer is performed by two steps (a) oxidizing a wiring layer of inner circuit plate with a first alkaline oxidizing solution thereby forming a first oxidized film comprising CuO and Cu.sub.2 O, then etching said first oxidized film to obtain a thinned first oxidized film, and (b) oxidizing said thinned first oxidized film with a second alkaline oxidizing solution thereby forming a second oxidized film enriched with Cu.sub.2 O.

Method of manufacturing a multi-layered wiring board

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Higashimurayama, Japan

Risaburo Yoshida