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:
May. 21, 2019
Filed:
Jan. 25, 2018
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Tsuneo Terasawa, Echizen, JP;
Hiroshi Fukuda, Echizen, JP;
Atsushi Yokohata, Echizen, JP;
Takahiro Kishita, Joetsu, JP;
Daisuke Iwai, Joetsu, JP;
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Abstract
A photomask blank having a thin film on a transparent substrate is inspected for defects by irradiating inspection light to a surface region of the blank, collecting the reflected light from the irradiated region via an inspection optical system to form a magnified image of the region, extracting a feature parameter of light intensity distribution from the magnified image, and identifying the bump/pit shape of the defect based on the feature parameter combined with the structure of the thin film. The defect inspection method is effective for discriminating defects of bump or pit shape in a highly reliable manner. On application of the defect inspection method, photomask blanks having no pinhole defects are available at lower costs and higher yields.