Study on deprotonation from radiation-induced ionized acrylate polymers including acid-generation promoters for improving chemically amplified resists

The demand for improved performance of chemically amplified resists (CARs) is continually increasing with the development of extreme ultraviolet lithography. Acid-generation promoters (AGPs) increase the sensitivity of CARs by increasing the initial acid yield immediately after the exposure process. However, the detailed mechanism of acid-yield enhancement has not been clarified yet. Deprotonation from the ionized polymer (i.e. radical cations) is an important reaction to assess acid generation. In this study, we investigated the dynamics of the radical cations of methacrylate polymers and the effect of an AGP on deprotonation from the radical cations formed by ionizing radiation. We clarified that the promotion of deprotonation by the AGP is more effective for the polymer with lower deprotonation efficiency. In addition, a molecular-level approach using density functional theory and molecular dynamics calculations were carried out.