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:
Feb. 28, 2012
Filed:
Oct. 09, 2008
Applicants:
Willem Kalf, Oosterhout, NL;
Ronald Franciscus Herman Hugers, Eindhoven, NL;
Inventors:
Willem Kalf, Oosterhout, NL;
Ronald Franciscus Herman Hugers, Eindhoven, NL;
Assignee:
ASML Netherlands B.V., Veldhoven, NL;
Primary Examiner:
Int. Cl.
CPC ...
G03B 27/52 (2006.01); G03B 27/72 (2006.01);
U.S. Cl.
CPC ...
Abstract
To detect whether a substrate is in a focal plane of an inspection apparatus, an optical focus sensor is arranged to receive a radiation beam via an objective lens. The optical focus sensor includes a splitter configured to split the radiation beam into a first sub-beam and a second sub-beam. With an aperture and a detector in the light path of each of the sub-beams it is possible to detect whether the substrate is in focus by comparing the amount of radiation received by each of the detectors.