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:
Dec. 28, 2004
Filed:
Dec. 17, 2002
Norio Komine, Sagamihara, JP;
Akiko Yoshida, Yamato, JP;
Hiroki Jinbo, Yokohama, JP;
Seishi Fujiwara, Sagamihara, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A silica glass member of the present invention is one wherein when a composition thereof is expressed by SiO , x is not less than 1.85 nor more than 1.95, wherein a concentration of hydrogen molecules included therein is not less than 1×10 molecules/cm nor more than 5×10 molecules/cm , and wherein a difference A−B between an absorption coefficient A immediately before an end of irradiation with 1×10 pulses of ArF excimer laser light in an average one-pulse energy density of 2 mJ/cm and a second absorption coefficient B at 600 seconds after a stop of the irradiation with the ArF excimer laser light is not more than 0.002 cm . When this silica glass member is applied to an illumination optical system and/or a projection optical system in projection exposure apparatus, it becomes feasible to implement uniform exposure while reducing variation in illuminance on a reticle surface and in an exposure area on a wafer.