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:
May. 01, 2018
Filed:
Jul. 24, 2015
Nanometrics Incorporated, Milpitas, CA (US);
Jason Robert Shields, Pleasanton, CA (US);
Nir Ben Moshe, Cupertino, CA (US);
Andrew J. Hazelton, San Carlos, CA (US);
Nanometrics Incorporated, Milpitas, CA (US);
Abstract
A cover plate or lens for an optical metrology device that is positioned under a wafer during measurement is protected with a purge device. The purge device may include a ring that extends around a periphery of the cover plate or lens. The ring includes a plurality of apertures through which a purge gas or air is expelled over the surface of the cover plate or lens. Additionally or alternatively, one or more heating elements may be provided that extend around the periphery of the cover plate or lens. The heating elements heat the cover plate above a dewpoint temperature of contaminant vapor. A heat sensor may be used to monitor the temperature of the cover plate to control the heating elements and/or to compensate for optical changes of the cover plate caused by heating during measurement of a wafer.