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:
Feb. 05, 2002
Filed:
Apr. 26, 2000
Hirofumi Saito, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a distortion measuring method, a mask having at least a first diffraction grating pattern having an array of a plurality of large patterns and a second diffraction grating pattern having arrays of a plurality of micropatterns spaced apart from the first diffraction grating pattern by a predetermined interval is formed. The plurality of micropatterns are arrayed in a direction perpendicular to an array direction of the second diffraction grating pattern at a predetermined pitch. At least the first and second diffraction grating patterns formed on the mask are projected on a photosensitive substrate through a lens. Distortion including a positional shift component of an image point by aberration of the lens is measured by scanning the photosensitive substrate using coherent light having a diffractable wavelength and by measuring an interval between at least the first and second diffraction grating patterns. A distortion measuring apparatus and reticle are also disclosed.