Wavelength separation from extreme ultraviolet mirrors using phaseshift reflection

A generic design and fabrication scheme of Mo/Si multilayer-grating phaseshift reflector systems is reported. Close to optimized extreme ultraviolet (EUV, lambda = 13.5 nm) reflectance values up to 64% are demonstrated, while the diffractive properties can be exploited in spectral filtering applications. The results can contribute to a wavelength-unspecific solution for the suppression of lambda > 100 nm out-of-band radiation in EUV lithography. (C) 2012 Optical Society of America