Resist line edge roughness and aerial image contrast

Abstract

We report the results of an experimental study of the correlations between line edge roughness (LER) and aerial image contrast for different lithographies in identical processing conditions. The characterization has been performed using atomic force microscopy carbon nanotube tips to image the top and bottom of trenches with very high resolution. Experimental results generally support that higher aerial image contrast leads to lower line edge roughness, but differences exist among the lithographies and resists. Top surface roughness results show similar trends with LER. Higher aerial image modulation also yields higher resist sidewall angle.