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. 26, 2016
Filed:
Sep. 08, 2011
Pai-hsueh Yang, Palo Alto, CA (US);
Pai-Hsueh Yang, Palo Alto, CA (US);
Nikon Corporation, Tokyo, JP;
Abstract
Methods are disclosed for calibrating a force constant of a movable stage. In an exemplary method, in first and second preliminary pre-stepping motions of the stage, a baseline force and a calibration force, respectively, as exerted by the stage are measured. From a force-variation ratio of the baseline force and calibration force an inverse closed loop factor is estimated. In at least one subsequent pre-stepping motion of the stage before a respective use of the stage for holding an object, a residual force-variation ratio is estimated, a force-compensation factor is updated from the residual force-variation ratio, and a respective force-variation coefficient is determined from the force-compensation factor.