Study on line edge roughness for electron beam acceleration voltages from 50to5kV

Abstract

Electrical characteristics of devices depend on the line edge roughness (LER). LER contributes to the off-state leakage budget and short-channel effect. Therefore, it has to be controlled during the lithography step since it strongly impacts the final component’s roughness. This work aims at the characterization of LER dependence on the beam acceleration voltage. Usually publications consider many lithography parameters that can influence LER. Different resists were exposed to beam acceleration voltage from 5to50kV. Thus, only two parameters that influence LER varied during experiments for a given resist: the exposure dose (i.e., shot noise) and the spot size. Then, simulations were carried out with those parameter variations. The impact of other LER contributors was considered as constant. Comparison between model and experimental results allows one to link resist sensitivity, exposure time, and LER.