Abstract

Practical issues in the development of multilayer coatings for reflective imaging systems operating at λ ≈ 68 Å are discussed. The 1% bandpass of Ru/B₄C multilayers at this short wavelength imposes stringent tolerances with which the actual multilayer period variation across the curved surfaces must match the ideal period variation for a 20× demagnifying Schwarzschild objective. New deposition techniques that use masks to correct the period variation across the curved surfaces of each optic have been developed to ensure reflectance over the entire clear aperture. The narrow bandpass together with steep lateral period gradients and steeply curved surfaces requires improved metrology for an acceptable period variation to be obtained and the overlap of the reflectance peaks on the two mirrors to be verified.

© 1993 Optical Society of America

Multilayer mirror technology for soft-x-ray projection lithography

D. G. Stearns, R. S. Rosen, and S. P. Vernon
Appl. Opt. 32(34) 6952-6960 (1993)

Schwarzschild microscope for carbon Kα radiation

Katsuhiko Murakami, Tetsuya Oshino, Hiroshi Nakamura, Masayuki Ohtani, and Hiroshi Nagata
Appl. Opt. 32(34) 7057-7061 (1993)

Radiation hardness of molybdenum silicon multilayers designed for use in a soft-x-ray projection lithography system

David P. Gaines, Ronnie C. Spitzer, Natale M. Ceglio, Michael Krumrey, and Gerhard Ulm
Appl. Opt. 32(34) 6991-6998 (1993)

Soft-x-ray projection imaging with a 1:1 ring-field optic

A. A. MacDowell, J. E. Bjorkholm, K. Early, R. R. Freeman, M. D. Himel, P. P. Mulgrew, L. H. Szeto, D. W. Taylor, D. M. Tennant, O. R. Wood, J. Bokor, L. Eichner, T. E. Jewell, W. K. Waskiewicz, D. L. White, D. L. Windt, R. M. D’Souza, W. T. Silfvast, and F. Zernike
Appl. Opt. 32(34) 7072-7078 (1993)

Soft-x-ray projection lithography experiments using Schwarzschild imaging optics

D. A. Tichenor, G. D. Kubiak, M. E. Malinowski, R. H. Stulen, S. J. Haney, K. W. Berger, L. A. Brown, W. C. Sweatt, J. E. Bjorkholm, R. R. Freeman, M. D. Himel, A. A. MacDowell, D. M. Tennant, O. R. Wood, J. Bokor, T. E. Jewell, W. M. Mansfield, W. K. Waskiewicz, D. L. White, and D. L. Windt
Appl. Opt. 32(34) 7068-7071 (1993)