<title>Fabrication of an aspherical mirror for extreme-ultraviolet lithography (EUVL) optics</title>

Abstract

We report a progress in the aspherization of precision optical surface by deposition of graded-thickness films onto spherical substrate. As a deposition film, we examined single layer and multilayer film. Mo/Si multilayer had small stress and small surface roughness up to the total film thickness of 1 u m, and is suitable for the thin film to fabricate mirrors in the EUVL camera. We demonstrate an aspherical mirror fabrication using mask deposition technique. The result shows good agreement between the measured and desired thickness profiles.

Effect of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

“…[56][57][58] The sputtering gas pressure has also been shown to influence the interface roughness 49,59,60 and mechanical stress. 61,62 In this work, we demonstrate that a variation in the working gas pressure affects the width and the composition of the amorphous interlayers. The detailed information on the composition and the width of interlayers will allow for proper optimization of the optical characteristics of a particular Mo/Si MXM.…”

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

“…13,29,30 The gas pressure also influences mechanical stresses in multilayers. 31,32 In this work we show that a variation of working gas pressure affects the width and the composition of amorphous interlayers.…”