The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 13, 1982
Filed:
Jun. 17, 1980
Hitoshi Oka, Yokohoma, JP;
Hiroshi Kikuchi, Zushi, JP;
Hitoshi Yokono, Yokohama, JP;
Haruo Suzuki, Katsuta, JP;
Toyofusa Yoshimura, Katsuta, JP;
Akira Matsuo, Yokohama, JP;
Osamu Miyazawa, Yokosuka, JP;
Isamu Tanaka, Yokosuka, JP;
Tokio Isogai, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
During recyclic use of a chemical copper plating solution, counter anions to copper ions, anions formed by oxidation of a reducing agent, and carbon dioxide by absorption of carbon dioxide from air, which all have an inhibiting effect upon the plating, and also sodium ions having no inhibiting effect are accumulated in the plating solution. These accumulated ions can be removed by electrodialysis. Particularly, regeneration can be satisfactorily regenerated by adjusting the pH of used chemical plating solution to 2-11 before the electrodialysis, and using a selectively monovalent anion permeable membrane as an anion exchange membrane at the electrodialysis.