The development of EUV scatterometry, as a potentially interesting option for the characterization of photomasks, has made significant progress in the last decade. The at-wavelength performance is directly assessed, and the measurements are potentially fast, a relevant precondition for the development of production-worthy instruments. However, an accurate prediction of the imaging properties requires a high effort in simulation and the precise determination of fundamental parameters such as the optical constants to correctly model the interaction of the EUV radiation with the nano-structured EUV mask. Another possibility to further increase the sensitivity and minimize the uncertainties in the reconstruction could be a polarization-resolved analysis of the scattered EUV radiation. The high degree of linear polarization of the beamline is ideal for investigating this question. However, it remains to be proven whether the additional measurement effort leads to a reduction of the uncertainties in the geometric reconstruction of the nanostructures. Besides theoretical modeling addressing this question, we also present benchmark measurements performed by PTB at the soft X-ray beamline of BESSY II.
Themenbereich der Metrologie
Photometrie und Radiometrie
Zitierung
Soltwisch, V., Biskup, T., Kolbe, M., & Scholze, F. (2023). Opportunities of polarization-resolved EUV scatterometry on photomasks. 38th European Mask and Lithography Conference (EMLC), Dresden, 19-21, May 2023, Germany. https://doi.org/10.1117/12.2675921
