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:
Jun. 16, 1998
Filed:
Jan. 17, 1996
Hisayoshi Higashiguchi, Itami, JP;
Kunihiro Hosono, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Ryoden Semiconductor System Engineering Corporation, Hyogo, JP;
Abstract
An apparatus and method for inspecting photomask pattern defects, discriminating true defects from false ones, efficiently detects only the true defects. The apparatus includes a light source; an irradiation section for transmitting light from the light source to a photomask; a light detecting section for detecting the light passing through transparent parts of the photomask; an image processing section for acquiring image data of the pattern according to signals from the light detecting section; a first condition setting section for setting a coordinate threshold that defines a misregistration defect in the pattern; a second condition setting section for setting an area threshold that defines an area defect of the pattern; a testing section that determines whether the coordinates of a pattern feature and the area of the pattern satisfy the thresholds upon comparison to a second pattern; and an output section for outputting a signal indicating a defect only when at least one of the thresholds is exceeded.