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. 15, 1998
Filed:
Jul. 31, 1997
Joseph P Kirk, Chelsea, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The preferred embodiments of the present invention provide a method and apparatus for visually inspecting features on a wafer that are smaller than can be optically resolved using normally using visible light. By providing a method for visually inspecting the features, the overall performance of the fabrication system can be determined. The preferred method patterns resist with two patterns having different spatial frequencies. The patterns combine to form a pattern in the resist that exhibits Moire beats. The Moire beat spatial frequency of the resulting pattern is significantly lower than the two spatial frequencies used, and thus can be visually inspected using light in the visible regions.