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:
Apr. 20, 2021
Filed:
Jul. 10, 2017
Hoya Corporation, Tokyo, JP;
Masaru Tanabe, Tokyo, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
A mask blank substrate and a method for selecting a mask blank substrate wherein a square calculation region is set on the main surface of the substrate. Specific points are set at the corner portions of the calculation region. The heights of the specific points from a reference plane are acquired, an imaginary plane passing through three of the specific points is set, an intersection between the imaginary plane and a perpendicular line that passes through the remaining of the specific points and that is perpendicular to the reference plane is set, and the distance between the remaining of the specific points and the intersection is calculated. A substrate in which the distance satisfies a predetermined reference value is selected as a mask blank substrate.