We have demonstrated a hybrid extreme ultraviolet (EUV) multilayer mirror for 6.x nm radiation that provides selective suppression for infrared (IR) radiation. The mirror consists of an IR-transparent LaN∕B multilayer stack which is used as EUV-reflective coating and antireflective (AR) coating to suppress IR. The AR coating can be optimized to suppress CO2 laser radiation at the wavelength of 10.6 μm, which is of interest for application in next-generation EUV lithography systems.
Medvedev, V., van de Kruijs, R. W. E., Yakshin, A., Novikova, N. N., Krivtsun, V. M., Yakunin, A. M., & Bijkerk, F. (2013). Multilayer mirror with enhanced spectral selectivity for the next generation extreme ultraviolet lithography. Applied physics letters, 103(22), 221114-1-21114-4. . https://doi.org/10.1063/1.4837335