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:
Apr. 08, 2025
Filed:
Mar. 22, 2021
Asml Netherlands B.v., Veldhoven, NL;
Maarten Jozef Jansen, Casteren, NL;
Ping Liu, Eindhoven, NL;
ASML NETHERLANDS B.V., Veldhoven, NL;
Abstract
The invention provides a method for calibration of an optical measurement system, which may be a heterodyne interferometer system, wherein a first optical axis and a second optical axis have a different optical path length, the method comprises:measuring a first measurement value along the first optical axis using a first measurement beam,measuring a second measurement value along the second optical axis using a second measurement beam,changing a wavelength of the first measurement beam and the second measurement beam,measuring a further first measurement value along the first optical axis using the first measurement beam with changed wavelength, measuring a further second measurement value along the second optical axis using the second measurement beam with changed wavelength,determining a cyclic error of the optical measurement system on the basis of the measured values, andstoring a corrective value based on the cyclic error.