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:
Mar. 13, 1978
Fritz Stahl, Am Kehn, DE;
Kollmorgen Technologies Corporation, Dallas, TX (US);
Abstract
There is provided an improvement in the method of preparing printed circuit boards by chemically catalyzing the surface of an insulating material, electrolessly depositing a layer of copper thereon, masking selected areas of the copper layer not correspnding to the desired pattern of conductor lines, electrolytically depositing additional copper on the unmasked areas, removing the masking material and etching away the copper from the previously masked areas. The improvement comprises the steps of forming an etch-resistant protective layer of oxide on the surface of the electrolytically deposited copper layer before removing the masking material, then removing the masking material and etching away the electrolessly deposited copper from the previously masked areas.