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:
Sep. 17, 1996
Filed:
May. 23, 1995
Gerald A Krulik, San Clemente, CA (US);
Nenad V Mandich, Homewood, IL (US);
Rajwant Singh, Fullerton, CA (US);
Applied Electroless Concepts, Inc., San Clemente, CA (US);
Abstract
A process for control of recycle of ammoniacal copper etchant which uses metallic aluminum to remove copper without substantially adding undesirable byproducts, by controlling the temperature and mixture rate of the removal process. The very rapid reaction can be controlled by using a diluent of copper-free etchant, heating to process temperature, then adding spent, copper containing etchant at a controlled rate while actively cooling the system to control the temperature. The copper concentration can be monitored by colorimetry while maintaining the pH above pH 8. The separated metallic copper and aluminum hydroxide sludge are easily filtered from the etchant. The purified etchant is now suitable for chemical adjustment and reuse.