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. 22, 2017
Filed:
Oct. 08, 2015
Asahi Glass Company, Limited, Chiyoda-ku, JP;
Hiroshi Nakanishi, Chiyoda-ku, JP;
Junichi Kageyama, Chiyoda-ku, JP;
Yoshiaki Ikuta, Chiyoda-ku, JP;
Asahi Glass Company, Limited, Chiyoda-ku, JP;
Abstract
A process for inspecting an EUV mask blank capable of distinguishing phase defects and amplitude defects and capable of detecting small amplitude defects, a process for producing an EUV mask blank using the inspection process, and an EUV mask blank obtainable by such a process. A process for inspecting a reflective mask blank for EUV lithography having a multilayer reflective film and an absorber layer. The process includes a first step of detecting in-plane defects in the multilayer reflective film by applying EUV light to the surface of the multilayer reflective film, a second step of detecting in-plane defects from the absorber layer by applying light having a wavelength of from 150 to 600 nm to the surface of the absorber layer, and a step of distinguishing phase defects and amplitude defects in the reflective mask blank by comparison between the first and second in-plane defect data.