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:
Nov. 17, 1998
Filed:
Dec. 12, 1997
Jing Chai, St. Charles, MO (US);
Henry F Erk, St. Louis, MO (US);
Judith Ann Schmidt, St. John, MO (US);
Thomas Eugene Doane, St. Charles, MO (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A process for cleaning contaminants from the surface of a semiconductor wafer after the wafer has been lapped. The process comprises contacting the wafer with an oxidizing agent to oxidize organic contaminants which may be present on the surface of the wafer. The wafer is then immersed in an aqueous bath comprising citric acid into which sonic energy is being directed to remove metallic contaminants which may be present on the surface of the wafer. After being immersed in the citric acid bath, the wafer is contacted with hydrofluoric acid to remove a layer of silicon dioxide which may be present on the surface of the wafer. The wafer is then immersed in an aqueous bath comprising an alkaline component and a surfactant, and into which sonic energy is being directed.