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. 26, 1998
Filed:
Aug. 23, 1996
Applicant:
Inventor:
Jun Kawakami, Yamato, JP;
Assignee:
Nikon Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356349 ; 356358 ;
Abstract
The displacement of the stage of an exposure apparatus can be measured by obtaining the phase difference between a light beam reflected by a stationary mirror and a light beam reflected by a movable mirror placed on the stage. This apparatus calculates the position data of the stage at second time by using the position data of the stage at first time which is measured by using first and second frequencies, the position data of the stage at the first time which is measured by using a third frequency, and the position data of the stage at the second time which is measured by using the third frequency.