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:
May. 11, 2004
Filed:
Apr. 02, 2002
David M. Lee, Hanover, PA (US);
Arthur S. Francomacaro, Eldersburg, MD (US);
Seppo J. Lehtonen, Columbia, MD (US);
Harry K. Charles, Jr., Laurel, MD (US);
The Johns Hopkins University, Baltimore, MD (US);
Abstract
A method of electrolessly gold plating copper on a printed circuit board (PCB). Starting with a copper patterned PCB, steps include: clean with ultrasonic agitation with the PCB initially oriented vertically and gradually moved to a 45° angle; rinse; sulfuric acid bath with ultrasonic and mechanical agitation; rinse; another sulfuric acid bath with ultrasonic and mechanical agitation; plate the copper with palladium with ultrasonic agitation with the PCB initially oriented at a 45° angle and flipped half way through to opposing 45° angle; rinse; post dip in sulfuric acid; rinse; electrolessly nickel plate with mechanical agitation; rinse; nitrogen blow dry; visual inspection for nickel coverage of the copper; hydrochloric acid bath with manual agitation; rinse; if full nickel coverage was not achieved, repeat preceding steps starting with second sulfuric acid bath; gold flash plate to establish a first layer of gold; rinse; autocatalytic gold plate; rinse; and nitrogen blow dry.