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:
Mar. 13, 1979
Filed:
Sep. 30, 1977
Oleh B Dutkewych, Maplewood, NJ (US);
Charles A Gaputis, Kansas City, MO (US);
Michael Gulla, Sherborn, MA (US);
Leonard R Levy, Framingham, MA (US);
Other;
Abstract
This invention is directed to an etchant and to a process for its use. The etchant comprises sulfuric acid activated with hydrogen peroxide or the synergistic combination of hydrogen peroxide and molybdenum. The etchant is characterized by a source of phosphate ions as an inhibitor against attack on tin, especially immersion tin, as well as several other metals such as nickel and alloys of nickel such as gold alloys. The etchant is especially useful for etching copper and its alloys in the presence of a tin etch resist, and therefore, provides a new procedure for the fabrication of printed circuit boards using immersion tin as an etch resist.