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:
May. 01, 2001
Filed:
Feb. 08, 2000
Nikon Corporation, Tokyo, JP;
Abstract
A method for positioning a wafer with respect to a reticle in a projection exposure apparatus for a photolithographic process capable of high speed search alignment of a wafer without any limitation imposed on the arrangement of the search marks on the wafer. For the first wafer in one lot, a first alignment sensor system is used to detect the positions of first and second search marks, and define a coordinate system with reference to the positions of the search marks based on the detection results. Then, while the first search mark is detected by the first alignment sensor system, the position of a street-line is detected by a second alignment sensor system and stored. For any of the second and later wafers in the lot, while the first search mark is detected by the first alignment sensor system, the position of a street-line is detected by the second alignment sensor system, and the offsets between the detected position and the stored position are used to define a coordinate system which refers to the search marks.