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arXiv · 2403.17498

Surface figure correction using differential deposition of WSi$_2$

Ch. Morawe·P. Bras·S. Labouré·F. Perrin·A. Vivo
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Abstract

The surface figure of an x-ray mirror was improved by differential deposition of WSi$_2$ layers. DC magnetron sputtering through beam-defining apertures was applied on moving substrates to generate thin films with arbitrary longitudinal thickness variations. The required velocity profiles were calculated using a deconvolution algorithm. Height errors were evaluated after each correction iteration using offline visible light surface metrology. WSi$_2$ was selected as a promising material since it conserves the initial substrate surface roughness and limits the film stress to acceptable levels. On a 300 mm long flat Si mirror the shape error was reduced to less than 0.2 nm RMS.

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Ch. Morawe, P. Bras, S. Labouré, F. Perrin, A. Vivo. 2024-03-26. Surface figure correction using differential deposition of WSi$_2$. https://doi.org/10.1117/12.2676633

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