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. 27, 2007
Filed:
Mar. 11, 2004
BO LI, Palo Alto, CA (US);
Bo Li, Palo Alto, CA (US);
KLA Tencor Technologies Corporation, Milpitas, CA (US);
Abstract
Spatial filtering is disclosed that improves the signal to noise ration of a sample inspection system of the type having a detector and collection optics that receive radiation scattered from a point on a sample surface and direct the scattered radiation toward the detector. The spatial filtering may screen the detector from substantially all of the forward-scattered radiation from back-scattered radiation that is scattered in a at an elevation angle less than about 45° with respect to a normal to the surface. Forward scattered noise is screened from the detector while backscattered signal reaches the detector. Programmable spatial filters may be used to selectively block scattered noise due to surface roughness while transmitting scattered signal due to surface defects.