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. 25, 2003
Filed:
Aug. 20, 2001
Bryan Kevin Clark, Mountain View, CA (US);
Beyond 3, Fremont, CA (US);
Abstract
An optical measurement and inspection method and apparatus having enhanced path length detection uses a Fabry-Perot cavity to increase the phase detection sensitivity for light reflected from optical structures within a device under inspection. A partially reflective surface is inserted between an illumination subsystem and the device under inspection and the position of the partially reflective surface may be adjusted by a positioner to create the Fabry-Perot cavity between one or more surfaces within the device under inspection. The detection of phase changes is improved, providing improved sensitivity to optical path differences produced by structures within the device under inspection.