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. 11, 2017
Filed:
Jul. 24, 2015
Carl Zeiss Smt Gmbh, Oberkochen, DE;
Michael Gerhard, Aalen, DE;
Carl Zeiss SMT GmbH, Oberkochen, DE;
Abstract
A method and associated EUV lithography apparatus for determining the phase angle at a free interface () of an optical element () provided with a multilayer coating () that reflects EUV radiation and/or for determining the thickness (d) of a contamination layer () formed on the multilayer coating (). The multilayer coating () is irradiated with EUV radiation, a photocurrent (I) generated during the irradiation is measured, and the phase angle at the free interface () and/or the thickness (d) of the contamination layer () is determined on the basis of a predefined relationship between the phase angle and/or the thickness (d) and the measured photocurrent (I). The measured photocurrent (I) is generated from the entire wavelength and angle-of-incidence distribution of the EUV radiation impinging on the multilayer coating ().