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:
Jul. 28, 1998
Filed:
Jun. 17, 1996
Yoshihiko Okamoto, Kodaira, JP;
Yasuhiro Koizumi, Sayama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In order to improve the inspection efficiency of a photomask having a phase shifter pattern, the inspection of the photomask having the phase shifter pattern is divided into three steps, an anomaly extraction step, a first anomaly discrimination step and a second anomaly discrimination step. These inspection steps are performed at different inspection regions. An anomaly extraction station 7 for the anomaly extraction inspects the presence or absence of an anomaly for all the regions of the photomask 1. An anomaly discrimination station 8 for the anomaly discrimination classifies the content of the anomaly. A phase difference measurement station 9 for the anomaly discrimination measures the phase difference error.