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[摘要]：The authors describe a new W-Cr-HSQ trilayer nanofabrication process for high-resolution and high-diffraction-efficiency soft x-ray W zone-plate lenses. High-resolution HSQ gratings were first fabricated by electron-beam lithography and high-contrast development in a NaCl/NaOH solution. The HSQ pattern was then transferred to the Cr layer by RIE with Cl-2/O-2, and subsequently to the W layer by cryogenic RIE with SF6/O-2. The anisotropy of the W etch as a function of substrate temperature was investigated, and the best etch profile was achieved at -50 degrees C. Using this optimized process, W gratings with half-pitches down to 12 nm and a height of 90 nm were fabricated. For a zone plate with corresponding parameters, this would result in a theoretical diffraction efficiency of 9.6% (at lambda = 2.48 nm), twice as high as has been reported previously. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3643760] |
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