Shearing interferometry for at-wavelength wave front measurement of EUV projection optics

Author

Zhu, Y. ; Sugisaki, K. ; Murakami, K. ; Ota, K. ; Kondo, H. ; Ishii, M. ; Kawakami, J. ; Oshino, T. ; Saito, J. ; Suzuki, A. ; Hasegawa, M. ; Sekine, Y. ; Takeuchi, S. ; Ouchi, C. ; Kakuchi, O. ; Watanabe, Y. ; Hasegawa, T. ; Hara, S.

Author_Institution

EUV Metrol. Technol. Res. Dept., Assoc. of Super-Adv. Electron. Technol. (ASET), Kanagawa, Japan

fYear

2002

fDate

6-8 Nov. 2002

Firstpage

314

Abstract

Summary form only given. We propose a simple and compact lateral shearing interferometric optical system for at-wavelength wave front measurement of the extreme-ultraviolet lithography projection lens. The proposed lateral shearing interferometer has a common path configuration, which essentially can be operated over a spatially incoherent EUV light sources, therefore it is feasible to use EUV plasma sources. The outgoing wave front from the projection lens is detected by the grating lateral shearing interferometer based on algorithms for phase-shifting fringe analysis to suppress the effect of higher order interference patterns. A total of 1e12 photons from the light source must be collected for testing a 6-mirror projection system at present. The required grating pitches can be designed in excess of 90 nanometers for \n\n\t\t

Keywords

lenses; light interferometry; optical testing; ultraviolet lithography; 90 nm; EUV projection optics; at-wavelength wave front measurement; common path configuration; extreme-ultraviolet lithography projection lens; grating pitches; phase-shifting fringe analysis; shearing interferometry; spatially incoherent EUV light sources; Gratings; Interferometric lithography; Light sources; Optical interferometry; Phase shifting interferometry; Plasma measurements; Plasma sources; Ultraviolet sources;

fLanguage

English

Publisher

ieee

Conference_Titel

Microprocesses and Nanotechnology Conference, 2002. Digest of Papers. Microprocesses and Nanotechnology 2002. 2002 International

Conference_Location

Tokyo, Japan

Print_ISBN

4-89114-031-3

Type

conf

DOI

10.1109/IMNC.2002.1178669

Filename

1178669