Line-Width Variation with Absorber Thickness in Extreme Ultraviolet Lithography

Abstract

The types and thicknesses of the mask materials for extreme ultraviolet lithography significantly influence the pattern formation. Since the reflectance of the absorber changes periodically with the absorber thickness, we investigated the effect of the absorber thickness on the near-field and aerial image for 32 nm line/space and isolated pattern. We chose germanium and chromium as absorber materials. We also investigated the line-width variation by using absorber thicknesses with different duty ratios. The SOLID-EUV of sigma-C was used for this study.