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:
Aug. 19, 1997
Filed:
Feb. 23, 1996
Mark Wagner, Rehovot, IL;
Noam Dotan, Givatayim, IL;
Opal Technologies Ltd., Nes Ziona, IL;
Abstract
A method for fast and reliable defect detection on semiconductor devices by comparing SEM images from a single perspective followed by a cross-check between at least two perspectives. An SEM equipped with at least two electron detectors each of which is capable of collecting electrons from different angular sectors. `Base` images of an area of the semiconductor wafer which is to be inspected are generated from both perspectives. For each perspective base image, a perspective `reference` image is generated, which is suitable for comparison with the base image. The reference image is registered with respect to the base image, for each perspective, the reference image is compared with the base image, and a comparison map of possible defect locations is produced, and, finally, a cross-check is carried out between the perspective comparison maps. The cross-check filters out events in the perspective comparison maps relating to variations other than defects such as pattern variations and noise.