Study on diffraction efficiency of Cr nanograting prepared by laser-focused atomic deposition

Abstract

One dimensional (1D) Cr nanograting fabricated by laser-focused atomic deposition (LFAD) is suitable for reference materials in nanometrology, owing to its self-traceable to SI meter definition and high accuracy with good uniformity. For further preparing small-scale and traceable reference materials, extremely ultraviolet (EUV) interference lithography with 13.4nm wavelength is utilized to accurately shorten the grating pitch of Cr nanograting (212.8nm). Diffraction efficiency is a key attribute in EUV interference lithography. In this paper, based on rigorous coupled wave analysis (RCWA), diffraction efficiency with EUV light of Cr nanograting was studied. Impacts such as EUV light wavelength, background layer and grating height were mainly taken into consideration. The result shows that Cr background layer has significant influence on diffraction efficiency of Cr nanograting, and an optimized diffraction efficiency of the first diffraction order about 1.4% has been achieved under the practical experimental condition.