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:
Oct. 25, 2022
Filed:
Apr. 12, 2021
Hoya Corporation, Tokyo, JP;
Yohei Ikebe, Tokyo, JP;
Tsutomu Shoki, Tokyo, JP;
Takahiro Onoue, Tokyo, JP;
Hirofumi Kozakai, Tokyo, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
Provided are a reflective mask blank, having a phase shift film having little dependence of phase difference and reflectance on film thickness, and a reflective mask. The reflective mask blank is characterized in that the phase shift film is composed of a material comprised of an alloy having two or more types of metal so that reflectance of the surface of the phase shift film is more than 3% to not more than 20% and so as to have a phase difference of 170 degrees to 190 degrees, and when a group of metal elements that satisfies the refractive index n and the extinction coefficient k of k>α*n+β is defined as Group A and a group of metal elements that satisfies the refractive index n and the extinction coefficient k of k<α*n+β is defined as Group B, the alloy is such that the composition ratio is adjusted so that the amount of change in the phase difference is within the range of ±2 degrees and the amount of change in reflectance is within the range of ±0.2% when one or more types of metal element each is selected from the Group A and the Group B and the film thickness of the phase shift film has fluctuated by ±0.5% with respect to a set film thickness (provided that α: proportional constant, β: constant).