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:
Sep. 26, 2017
Filed:
Sep. 04, 2015
Toshiba Memory Corporation, Minato-ku, JP;
Nobuhiro Komine, Nagoya, JP;
Kazuo Tawarayama, Yokkaichi, JP;
TOSHIBA MEMORY CORPORATION, Minato-ku, JP;
Abstract
According to one embodiment, there is provided a mask alignment mark disposed on a photomask irradiated by an illumination optical system with illumination light from a direction inclined with respect to an optical axis and used to form a latent image on a substrate through a projection optical system. The mask alignment mark including a plurality of patterns arranged in a predetermined direction at a pitch of substantially P=λ/{2×(1−σ)×(LNA)}, where σ is a ratio of a numerical aperture INA of illumination light incident on the photomask from the illumination optical system to a numerical aperture LNA of an object side of the projection optical system (INA)/(LNA), and λ is a wavelength of light.