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. 16, 1999
Filed:
Mar. 25, 1997
Masahiko Okumura, Tokyo, JP;
Shinji Wakamoto, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Methods and apparatus are disclosed for exposing a reticle pattern onto a sensitive substrate (such as a sensitized semiconductor wafer) by projection-exposure at high focusing precision. According to the method, multiple evaluation marks are projected onto an area of the surface to form images of the evaluation marks. An image of a measurement mark is projected on or near at least some of the evaluation marks. Respective Z-direction displacements of each evaluation mark relative to a reference plane are detected by detecting a characteristic of the respective measurement mark that varies with a change in position of the measurement mark relative to the respective evaluation mark. Based on such measurements, an axial relationship of the projection-optical system relative to the substrate can be changed to place the substrate at a best-focus position before exposing the substrate with a reticle pattern. Associated apparatus are also disclosed.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile