Effects of Dielectric Constant on Acid Generation in Chemically Amplified Resists for Post-Optical Lithography

Abstract

Acid generation in chemically amplified resists for post-optical lithographies such as electron beam and EUV lithographies is different from that in chemically amplified photoresists. In chemically amplified resists for post-optical lithographies, the role of acid generators is to produce not protons but counter anions of acids through reactions with low-energy electrons generated at ionization events. As the distribution of counter anions determines latent acid image, the dynamics of low energy electrons are important in post-optical lithographies. As the dynamics of low energy electrons are affected by the dielectric constant, the resist performance may be affected as well. In this study, we investigated the effect of dielectric constants of base polymers on the sensitivity and resolution of chemically amplified resists. The electron dynamics were simulated using the Smoluchowski equation. The efficiency of acid generation and the distribution of acids (resolution blur) are discussed in terms of the dielectric constant. The simulation results predict that the acid yield increases and the resolution blur decreases slightly with an increase in the dielectric constants.