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:
Aug. 08, 2000
Filed:
May. 21, 1998
Robert J Falster, Milan, IT;
Fabrizio Leoni, Novara, IT;
Marco Bricchetti, Novara, IT;
Alessandro Corradi, Milan, IT;
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A process for removing copper from a boron doped, polished silicon wafer which contains copper on its polished surface and in its interior. In the process, the wafer is annealed at a temperature of at least about 75.degree. C. to increase the concentration of copper on the polished surface of the wafer and decrease the concentration of copper in the interior of the wafer. The polished surface of the annealed wafer is then cleaned to reduce the concentration of copper thereon. In addition, the annealing step is carried out at a temperature and a time such that the concentration of copper on the polished surface of the silicon will not increase by a factor of more than two upon storage of the annealed and cleaned wafer at room temperature for a period of 5 months.