Theoretical study on effects of electron thermal energy on sensitization process of chemically amplified electron beam resists—contribution to resist heating effect in electron beam mask writing

Abstract

The elevation of resist temperature during exposure to electron beam (EB) deforms the patterns of chemically amplified resists. The resist heating effect is a significant problem in mask production using a high-current EB mask writer. However, its mechanism is still unknown. In this study, the effects of electron thermal energy on the sensitization process of chemically amplified EB resists were investigated using simulation on the basis of their sensitization mechanism. The decomposition yield of sensitizers increased with resist temperature. The effect of the increase of decomposition yield on the critical dimension (CD) was calculated on the basis of the reaction mechanism. When the exposure pattern width was set to the same as the half-pitch (16 nm), the values of dCD/dT were 0.019, 0.013 and 0.010 nm K−1 for the sensitizer concentrations of 0.2, 0.3 and 0.4 (molecules) nm−3, respectively. dCD/dT was decreased by decreasing the exposure pattern width.