We present our results of coating a first set of optical elements for an extreme-ultraviolet (EUV) lithography system. The optics were coated with Mo-Si multilayer mirrors by dc magnetron sputtering and characterized by synchrotron radiation. Near-normal incidence reflectances above 65% were achieved at 13.35 nm. The run-to-run reproducibility of the reflectance peak wavelength was maintained to within 0.4%, and the thickness uniformity (or gradient) was controlled to within ±0.05% peak to valley, exceeding the prescribed specification. The deposition technique used for this study is an enabling technology for EUV lithography, making it possible to fabricate multilayer-coated optics to accuracies commensurate with atomic dimensions.
© 2002 Optical Society of America
(110.3960) Imaging systems : Microlithography
(220.3740) Optical design and fabrication : Lithography
(260.7200) Physical optics : Ultraviolet, extreme
(310.1860) Thin films : Deposition and fabrication
(340.7470) X-ray optics : X-ray mirrors
Claude Montcalm, R. Frederick Grabner, Russell M. Hudyma, Mark A. Schmidt, Eberhard Spiller, Christopher C. Walton, Marco Wedowski, and James A. Folta, "Atomic-Precision Multilayer Coating of the First Set of Optics for an Extreme-Ultraviolet Lithography Prototype System," Appl. Opt. 41, 3262-3269 (2002)