27 December 2002 Pattern Inspection of EUV Masks Using DUV Light
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Abstract
Inspection of extreme ultraviolet (EUV) lithography masks requires reflected light and this poses special challenges for inspection tool suppliers as well as for mask makers. Inspection must detect all the printable defects in the absorber pattern as well as printable process-related defects. Progress has been made under the NIST ATP project on "Intelligent Mask Inspection Systems for Next Generation Lithography" in assessing the factors that impact the inspection tool sensitivity. We report in this paper the inspection of EUV masks with programmed absorber defects using 257nm light. All the materials of interests for masks are highly absorptive to EUV light as compared to deep ultraviolet (DUV) light. Residues and contamination from mask fabrication process and handling are prone to be printable. Therefore, it is critical to understand their EUV printability and optical inspectability. Process related defects may include residual buffer layer such as oxide, organic contaminants and possible over-etch to the multilayer surface. Both simulation and experimental results will be presented in this paper.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ted Liang, Edita Tejnil, Alan R. Stivers, "Pattern Inspection of EUV Masks Using DUV Light", Proc. SPIE 4889, 22nd Annual BACUS Symposium on Photomask Technology, (27 December 2002); doi: 10.1117/12.467298; https://doi.org/10.1117/12.467298
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