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:
Mar. 25, 2008
Filed:
Oct. 08, 2004
Marcel Hendrikus Maria Beems, Veldhoven, NL;
Engelbertus Antonius Fransiscus Van Der Pasch, Oirschot, NL;
Marcel Hendrikus Maria Beems, Veldhoven, NL;
Engelbertus Antonius Fransiscus Van Der Pasch, Oirschot, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
Embodiments of the invention include an interferometer measurement system in which at least one reflective surface is arranged such that, in use, the beam path of interferometer radiation of the interferometer measurement system incident on the at least one reflective surface has an offset angle in the range of from 0.1 to 10 milliradians with respect to the normal to the at least one reflective surface. In that way, the effect of spurious radiation on the interferometer measurement system produced within the interferometer measurement system may be suppressed. In another embodiment, a parallel-sided plate is used in an interferometer measurement system to obtain a signal dependent on the angle of a beam of radiation reflected from a mirror. In that way, the flatness of the mirror can be mapped. One surface of the plate is a beam-splitter and the opposite surface of the plate is a reflector.