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:
Mar. 28, 2000
Filed:
Nov. 12, 1997
Masatoshi Ikeda, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A holder improving the optical performance of a reflecting optical member in a projection optical system which projects an image of a pattern formed on a mask onto a photosensitive substrate, and an exposure apparatus having the holder. A support mechanism supports a back surface of the reflecting optical member, which is reverse to a reflecting surface thereof, at at least three points. The support points are positioned on a circumference away from the center of the reflecting surface by a distance at least 0.6 times the distance from the center of the reflecting surface to the outer periphery of the reflecting optical member such that the support points are circumferentially spaced along the circumference at equal intervals. Alternatively, a holding member supports the reflecting optical member and forms a closed chamber in combination with the reflecting optical member. The pressure in the closed chamber at the back of the reflecting surface of the reflecting optical member is regulated to a predetermined level. The reflecting optical member is integrally formed with a mounting portion which is secured to the projection optical system.