Computational study of pattern formation for chemically amplified resists in extreme ultraviolet lithography

Abstract

A computational study of the pattern formation process for chemically amplified resists in extreme ultraviolet (EUV) lithography has been performed using the stochastic approach. The initial structures of the resist molecules are formed by sequential bonding of randomly arranged monomers. The effect of EUV light exposure is introduced by activation of acid generators according to the deposited energy distribution in the resist, which is calculated by Monte Carlo simulation of photoelectron scattering. Acid diffusion and the polymer deprotection reactions during the post-exposure bake (PEB) are then simulated. Development of the resist is modeled by removal of the polymers with relatively large conversion ratio from the resist. The dependence of the resist molecular weight, EUV exposure, and PEB conditions on the pattern shapes are demonstrated by the simulation.