Twelve nanometer half-pitch W–Cr–HSQ trilayer process for soft x-ray tungsten zone plates
2011 (English)In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 29, no 6, 06FG02-1-06FG02-4 p.Article in journal (Refereed) Published
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 Cl2/O2, and subsequently to the W layer by cryogenic RIE with SF6/O2. The anisotropy of the W etch as a function of substrate temperature was investigated, and the best etch profile was achieved at −50 °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 λ = 2.48 nm), twice as high as has been reported previously.
Place, publisher, year, edition, pages
2011. Vol. 29, no 6, 06FG02-1-06FG02-4 p.
zone plates; x-ray optics; tungsten; electron beam lithography; HSQ; reactive ion etching; nanofabrication
IdentifiersURN: urn:nbn:se:kth:diva-47400DOI: 10.1116/1.3643760ISI: 000298538800085ScopusID: 2-s2.0-84255172356OAI: oai:DiVA.org:kth-47400DiVA: diva2:454914
QC 201111142011-11-082011-11-082012-02-20Bibliographically approved