EUV testing of multilayer mirrors: Critical issues

S. B. Hill, Ivan Ermanoski, S. Grantham, C. Tarrio, T. B. Lucatorto, T. E. Madey, S. Bajt, M. Chandhok, P. Yan, O. Wood, S. Wurm, N. V. Edwards

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

    15 Scopus citations


    Recently, while performing extensive EUV irradiation endurance testing on Ru-capped multilayer mirrors in the presence of elevated partial pressures of water and hydrocarbons, NIST has observed that the amount of EUV-induced damage actually decreases with increasing levels of water vapor above -5×10 -7 Torr. It is thought that the admitted water vapor may interact with otherwise stable, condensed carbonaceous species in an UHV vacuum system to increase the background levels of simple gaseous carbon-containing molecules. Some support for this hypothesis was demonstrated by observing the mitigating effect of very small levels of simple hydrocarbons with the intentional introduction of methyl alcohol in addition to the water vapor. It was found that the damage rate decreased by at least an order of magnitude when the partial pressure of methyl alcohol was just one percent of the water partial pressure. These observations indicate that the hydrocarbon components of the vacuum environment under actual testing conditions must be characterized and controlled to 10 -11Torr or better in order to quantify the damage caused by high levels of water vapor. The possible effects of exposure beam size and out-of-band radiation on mirror lifetime testing will also be discussed.

    Original languageEnglish (US)
    Title of host publicationEmerging Lithographic Technologies X
    StatePublished - 2006
    EventEmerging Lithographic Technologies X - San Jose, CA, United States
    Duration: Jan 21 2006Jan 23 2006

    Publication series

    NameProceedings of SPIE - The International Society for Optical Engineering
    Volume6151 I
    ISSN (Print)0277-786X


    OtherEmerging Lithographic Technologies X
    Country/TerritoryUnited States
    CitySan Jose, CA


    • EUV optics
    • Extreme ultraviolet
    • Lifetime testing
    • Lithography
    • Reflectometry
    • Ruthenium films

    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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