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:
Jun. 08, 1993
Filed:
Nov. 27, 1991
Applicant:
Inventors:
Randal D King, Wilmington, DE (US);
Americus C Vitale, West Chester, PA (US);
Assignee:
McGean-Rohco, Inc., Cleveland, OH (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C23C / ;
U.S. Cl.
CPC ...
427 98 ; 427427 ; 427433 ; 427345 ;
Abstract
An efficient spray displacement tin plating process of copper printed circuit innerlayers is disclosed for the manufacture of multilayer printed circuit boards. The displacement tin plating solution is stabilized and replenished by incorporating free tin metal in the plating solution reservoir. Unwanted tin(IV) ions which are produced by aerial oxidation during the spray process, are reacted with tin metal in the reservoir to produce sufficient tin(II) ions to compensate for losses due to plating, oxidation and the like. Not only is the plating bath stabilized, but its useful life is extended dramatically.