Ellipsometric and surface acoustic wave sensing of carbon contamination on EUV optics

Juequan Chen, Eric Louis, Frederik Bijkerk, Christopher James Lee, Herbert Wormeester, Reinhard Kunze, Hagen Schmidt, Dieter Schneider, Roel Moors, Willem van Schaik, Monika Lubomska

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Carbon contamination layers, deposited on extreme ultraviolet (EUV) multilayer mirrors during illumination were characterized ex situ using spectroscopic ellipsometry (SE), laser generated surface acoustic waves (LG-SAW), and by their EUV reflectance loss. We show SE is more sensitive to the deposition of carbon layers than the EUV reflectance loss, even in the presence of the highly heterogeneous structure of the multilayer. SE has better overall sensitivity, with a detection limit of 0.2 nm, while LG-SAW has an approximate detection limit < 5 nm
Original languageUndefined
Title of host publicationProceedings of SPIE, The International Society for Optical Engineering
EditorsFrank M. Schellenberg, Bruno M. La Fontaine
ISBN (Print)9780819475244
Publication statusPublished - 22 Feb 2009
EventAlternative Lithographic Technologies: Proceedings of SPIE, The International Society for Optical Engineering - San Jose, CA
Duration: 22 Feb 200927 Feb 2009

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


ConferenceAlternative Lithographic Technologies
Other24-26 February 2009


  • Spectroscopic ellipsometry
  • METIS-260100
  • Extreme ultraviolet lithography
  • EUV optics
  • multilayer mirrors
  • surface acoustic wave
  • carbon contamination
  • IR-77749

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