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:
Jul. 28, 2009
Filed:
Jun. 21, 2005
Naota Konda, Tokyo, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Naota Konda, Tokyo, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An aerial image of a measurement mark arranged on a measurement mask is conformed to a center in an X-axis direction of a slit arranged on a Z tilt stage. While illuminating the measurement mark with an illumination light, a slit plate on which the slit is formed is continuously moved in a Z-axis direction, and based on position information of the slit obtained during the movement and a photoelectric conversion signal outputted from an optical sensor that receives the illumination light from the measurement mark via a projection optical system and the slit, a best focus position is detected. Thus, the best focus position of the projection optical system can be measured in a short period of time.