Collector optic in-situ Sn removal using hydrogen plasma

John R. Sporre, Dan Elg, David N Ruzic, Shailendra N. Srivastava, Igor V. Fomenkov, David C. Brandt

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The presence of Sn on the collector optic of an extreme ultraviolet (EUV) light lithography tool continues to be a concern for source manufacturers. A mere nanometers deposition results in reduction of EUV light reflectivity to unacceptable levels. It has been shown previously that hydrogen radical etching of Sn provides a promising technique for in-situ cleaning of the collector optic. One concern in this technique is the redeposition by radicalized SnH4 breaking apart after making contact with a surface. To address this concern, large scale etching measurements were made using a metallic antenna as the substrate. Optimized etch rates approaching 7.5±1 nm/min have been achieved with a flow rate of 500 sccm at a pressure of 80 mTorr. The effect of variations in the Sn cleaning environment will be investigated with respect to temperature increases as well as air, oxygen, and methane contamination gasses. Furthermore, the effect of Sn located away from the cleaning location will also be presented.

Original languageEnglish (US)
Title of host publicationExtreme Ultraviolet (EUV) Lithography IV
StatePublished - Jun 5 2013
EventExtreme Ultraviolet (EUV) Lithography IV - San Jose, CA, United States
Duration: Feb 25 2013Feb 28 2013

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherExtreme Ultraviolet (EUV) Lithography IV
CountryUnited States
CitySan Jose, CA


  • Collector
  • Contamination
  • EUV
  • Hydrogen
  • Plasma
  • Sn cleaning

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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