Mitsubishi Gas Chemical Company, Inc.

Naohito Yoshimura

Yasuo Tanaka

Morio Gaku

Tetsuo Aoyama

Toshihiko Kobayashi

Takeshi Nagasaka

Youichi Takizawa

Koichi Nakano

Takashi Nakata

Touru Nohtomi

A developing solution comprising a specific amount of a quaternary ammonium hydroxide represented by the general formula [(R.sup.1).sub.3 N--R].sup.+ .multidot.OH.sup.- (R indicates an alkyl group having 1 to 3 carbon atoms or a hydroxy-substituted alkyl group having 1 to 3 carbon atoms, and R.sup.1 indicates an alkyl group having 1 to 3 carbon atoms) and, if necessary, a quaternary ammonium hydrogen carbonate represented by the general formula [(R.sup.1).sub.3 N--R].sup.+ .multidot.HCO.sub.3.sup.- (R and R.sup.1 are the same as the above) and having a pH in the range of 9 to 13, and a process for producing printed circuit boards using an organic alkali solution, are provided. The developing solution needs no defoaming agent because it causes little foaming. Printed circuit boards produced by using the developing solution have excellent finished accuracy. Therefore, fine circuits of printed circuit networks can be produced with stability.

Developing solution for producing printed circuit boards and a process

A process for producing a multilayer printed wiring board, characterized in that copper surface of internal layer(s) is chemically oxidized, thereby forming a brown or black, oxidized copper surface on the internal layer board; and said oxidized copper surface of said internal layer board is treated with an acidic aqueous solution of a reducing agent containing at least one material selected from the group consisting of zinc formaldehyde sulfoxylate and sodium hypophosphite.

Process for producing multilayer printed wiring board

Growing community of inventors

Tokyo, Japan

Naohito Yoshimura