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:
Nov. 08, 2011
Filed:
Aug. 21, 2008
Dieter Kraus, Oberkochen, DE;
Dirk Heinrich Ehm, Lauchheim, DE;
Stefan-wolfgang Schmidt, Aalen, DE;
Carl Zeiss SMT GmbH, Oberkochen, DE;
Abstract
The invention relates to an EUV lithography apparatus with at least one EUV-reflective optical surface and a cavity ringdown reflectometer adapted to determine the contamination status of the EUV-reflective optical surface for at least one contaminating substance by determining the reflectivity of the EUV-reflective optical surface for radiation at a measuring wavelength (λ). The invention further relates to a method for determining the contamination status of at least one EUV-reflective optical surface arranged in an EUV lithography apparatus for at least one contaminating substance comprising determining the reflectivity of the EUV-reflective optical surface for radiation at a measuring wavelength (λ) using a cavity ringdown reflectometer.