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:
Dec. 16, 1997
Filed:
Dec. 11, 1996
Arun A Aiyer, Fremont, CA (US);
Kyoichi Suwa, San Mateo, CA (US);
Nikon Precision Inc., Belmont, CA (US);
Abstract
A method of detecting particles on a wafer support surface comprising positioning a wafer in a first position on the surface with the wafer in the first position, generating a first pattern on the wafer, and moving the wafer. Then, after moving the wafer, generating a second pattern on the wafer to generate a moire pattern by the interaction of the second pattern with the first pattern. The moire pattern is inspected to identify any visual distortion in the moire pattern due to physical distortion of the wafer caused by a particle on the support surface during the generation of the first pattern. The patterns may be ruled parallel lines, and the second pattern may be moved during inspection to shift the moire pattern to reveal distortions over a wide area.