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. 14, 2013
Filed:
Sep. 23, 2011
Applicant:
Masaru Tanabe, Tokyo, JP;
Inventor:
Masaru Tanabe, Tokyo, JP;
Assignee:
Hoya Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03F 1/22 (2012.01);
U.S. Cl.
CPC ...
Abstract
A mask blank substrate for a photomask is chucked on a mask stage of an exposure apparatus. A main surface, on the side where a thin film for a transfer pattern is to be formed, of the mask blank substrate has a flatness of 0.3 μm or less in a 142 mm square area including its central portion and has a convex shape being relatively high at its central portion and relatively low at its peripheral portion. The difference upon fitting, to the main surface of the mask blank substrate, a virtual reference main surface, having a spherical shape in a 132 mm square area, of a virtual reference substrate is 40 nm or less.