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:
Jun. 05, 2001
Filed:
Feb. 09, 1999
Venkat R. Nagaswami, Nijmegen, NL;
Johannes G. Van Gessel, Nijmegen, NL;
Dries A. Van Wezep, Nijmegen, NL;
U.S. Phillips Corporation, New York, NY (US);
Abstract
Visible defects are detected on a process semiconductor wafer. Defects are classified according to appearance and an association is kept between classes and apparatuses. When the density of defects in a given class exceeds a control limit the associated apparatus is switched off-line. In an embodiment, the same wafer is inspected repeatedly, each time after a different processing steps and information about the location of detected defects is kept. Defects which occur at a location where defects have already been detected in a previous inspection after an earlier processing step are eliminated from the density which is compared to the control limit.