Stochastic Effect on Contact Hole Imaging of Chemically Amplified Extreme Ultraviolet Resists

Abstract

With the near realization of extreme ultraviolet (EUV) lithography, the critical dimension uniformity and edge roughness of contact holes have attracted much attention. In this study, the stochastic effect on contact hole patterns was investigated using a Monte Carlo method on the basis of the reaction mechanisms of chemically amplified EUV resists. The standard deviation of the number of protected units did not depend on exposure dose or acid generator concentration under the process conditions optimized in terms of the chemical gradient. However, the standard deviation of the number of protected units depended on the effective reaction radius for deprotection.