Fabrication of high-resolution Fresnel zone plates by a single layer resist process

Hiroshi Hiroshima*, Masanori Komuro, Massimo Gentili, Luca Grella, Enzo Di Fabrizio, Romano Maggiora

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

In this work, fabrication of a high-resolution Fresnel zone plate (ZP) by a single layer electron beam (EB) resist process combined with a gold electroplating process is described. The ZP designed has a diameter of 80 μm and is composed of 250 rings (499 zones) of which the width of the outermost ring is nominally 40 nm. In order to fabricate a 150-nm-thick gold layer which acts as a phase-shifter for X-rays, a 200-nm-thick polymethylmethacrylate (PMMA) is used as a single layer resist. A 50 kV EB lithography system with a probe diameter of 3 nm is employed for high-resolution patterning. To prevent resist patterns with an aspect ratio of 5 from collapsing, we reinforce the ZP patterns by combining neighboring rings with ribs. It is demonstrated that a modified ZP pattern with a 40-nm-wide outermost ring which will not collapse can be fabricated whereas the original ZP pattern collapses at a high aspect ratio. Although control of the width of the gold phase shifter should be improved, the outermost ring with the nominal width of 40 nm can be electroplated.

Original languageEnglish (US)
Pages (from-to)6447-6451
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume35
Issue number12 SUPPL. B
DOIs
StatePublished - Dec 1996

Keywords

  • Cobweb
  • Electron beam lithography
  • Fresnel zone plate
  • High aspect ratio
  • High-resolution
  • Polymethylmethacrylate (PMMA)
  • Single resist process
  • X-ray

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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