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. 21, 2007
Filed:
Oct. 25, 2004
Robert W. Du, Danville, CA (US);
Ronald J. Lesnick, Jr., Hollister, CA (US);
John T. Nogatch, Boulder Creek, CA (US);
Robert W. Du, Danville, CA (US);
Ronald J. Lesnick, Jr., Hollister, CA (US);
John T. Nogatch, Boulder Creek, CA (US);
Synopsys, Inc., Mountain View, CA (US);
Abstract
One embodiment of the present invention provides a system that computes translational differentials between a database-image and a scanned-image of a photomask. During operation, the system receives a noise-free database-image and a scanned-image that is generated by an imaging process. Next, the system determines whether the database-image has complex geometry and whether the database-image is a line-and-space pattern. If the database-image is a line-and-space pattern, the system first converts the scanned-image into a polarity-enhanced-image. The system then computes translational differentials by performing a correlation using the database-image and the polarity-enhanced-image. On the other hand, if the database-image is not a line-and-space pattern, the system computes translational differentials by performing a correlation using the database-image and the scanned-image. Note that the accuracy of the computed translational differentials is significantly increased because the system chooses a technique for computing the translational differentials which is suitable for the type of pattern present in the database-image.