A statistical analysis of ultraviolet, x-ray, and charged-particle lithographies

Abstract

We analyze photo, x-ray, e-beam, and ion-beam lithographies from a statistical point of view in order to relate linewidth control to the contrast provided by the exposure technique, the resist contrast, and the resist sensitivity. Assuming a linewidth control of 20% at a minimum linewidth of 0.5 μm, we compare UV and x-ray lithographies and find that the former is practical only with very high contrast resists (δN/N̄<0.16). We derive a simple expression for the minimum number of photons or charged particles required per pixel, and compare the pixel-transfer rates of various lithographies. We find that beyond UV photolithography, synchrotron and pulsed-plasma x-ray sources offer the highest pixel-transfer rates and appear most attractive for submicron lithography.