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:
Jun. 03, 2008
Filed:
Apr. 12, 2006
Noriaki Kandaka, Sagamihara, JP;
Katsuhiko Murakami, Sagamihara, JP;
Takaharu Komiya, Yokohama, JP;
Masayuki Shiraishi, Kumagaya, JP;
Noriaki Kandaka, Sagamihara, JP;
Katsuhiko Murakami, Sagamihara, JP;
Takaharu Komiya, Yokohama, JP;
Masayuki Shiraishi, Kumagaya, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A multilayer mirror aims to reduce incidence angle dependence of reflectivity. A substrate is made of low thermal polished expansion glass with 0.2 nm RMS or less roughness of the surface. On the surface thereof formed is a Ru/Si multilayer having a wide full-width half maximum of peak reflectivity, and on the Ru/Si multilayer formed is a Mo/Si multilayer having a high peak reflectivity value. This enables higher reflectivity than when Ru/Si alone provided and a reflectivity peak having a wider full-width half maximum than when the Mo/Si multilayer alone provided. Since Ru absorbs EUV ray more than Mo does, higher reflectivity is obtainable than that of a structure having the Ru/Si multilayer formed on the Mo/Si multilayer. The multilayer with a wide full-width half maximum has small incidence angle dependence of reflectivity in spectral reflectivity, thereby achieving high imaging performance in projection optical system.