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:
Jan. 17, 2012
Filed:
Jul. 22, 2008
Takashi Sukegawa, Utsunomiya, JP;
Takashi Sukegawa, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method for predicting imaging characteristics fluctuation of a projection optical system in an exposure apparatus which projects a pattern formed on a mask onto a photosensitive substrate through the projection optical system is provided. In a measurement step, the projection optical system is irradiated with exposure light under a first exposure condition to measure first imaging characteristics fluctuation of the projection optical system. Then, before an imaging characteristics value is restored to an initial value at the start of irradiation after irradiation is stopped, the projection optical system is irradiated with the exposure light under a second exposure condition to measure second imaging characteristics fluctuation of the projection optical system. Approximate expressions of the measured first and second imaging characteristics fluctuations are calculated based on an imaging characteristics model.
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