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Proceedings Paper

Control of Mo/Si multilayers for soft x-ray performance
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Paper Abstract

Molybdenum/Silicon soft x-ray optical coatings for extreme ultraviolet lithography are being developed for both projection optics and masks, and have only recently been produced on a production scale via magnetron sputtering. A number of critical factors must be met for successful development of these coatings for implementation into commercial EUV Lithography. We report on our results for several factors with a state-of-the-art in-line sputtering system. All coatings in a lithography system must match to obtain maximum energy transmission. Hence, process repeatability and characterization of the reflectivity and central wavelength is essential. Run-to-run performance and substrate uniformity is shown to have achieved less than 1% deviation in soft x-ray central wavelength between any two points on any two substrates coated in separate batches; coating uniformity on a given wafer is on the order of 0.3% total deviation. Hard x-ray measurements of d-spacing and reflectivity were correlated to soft x-ray measurements; these correlations were used to improve process control. Furthermore, the coatings must be as defect-free as possible; elimination of aerosol-based particulate generation has allowed improvements by nearly four orders of magnitude. Finally, efforts to understand and control coating stress as a function of processing parameters and post-coating annealing schedules will be reviewed. Results of the effects of deposition method, ion bombardment and interactions between sputter power, sputter pressure and deposition rate are reviewed.

Paper Details

Date Published: 23 November 1999
PDF: 9 pages
Proc. SPIE 3767, EUV, X-Ray, and Neutron Optics and Sources, (23 November 1999); doi: 10.1117/12.371123
Show Author Affiliations
Michael D. Kriese, Osmic, Inc. (United States)
Gary Fournier, Osmic, Inc. (United States)
James Rodriguez, Osmic, Inc. (United States)
Yuriy Ya. Platonov, Osmic, Inc. (United States)

Published in SPIE Proceedings Vol. 3767:
EUV, X-Ray, and Neutron Optics and Sources
Carolyn A. MacDonald; Kenneth A. Goldberg; Juan R. Maldonado; Huaiyu Heather Chen-Mayer; Stephen P. Vernon, Editor(s)

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