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. 10, 2002
Filed:
Jan. 24, 2000
Masahiro Nei, Yokohama, JP;
Taro Ogata, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Transmittances of the optical system are calculated and a predicitive line of time-varying transmittance is calculated. When the exposure is started, the transmittance of the optical system is calculated at the elapsed time of exposure based on the predictive line of time-varying transmittance, and the intensity of exposure light is controlled The illuminance on the wafer can be compensated for depending on the actual variation of the transmittance. The accumulated quantity of exposure light incident to the wafer is regulated to ensure a target exposure dose of the wafer regardless of the variation in the transmittance of an illumination optical system or a projection optical system during exposure.