Proton Dynamics in Chemically Amplified Electron Beam Resists

The proton dynamics of poly(4-hydroxystyrene) (PHS) films were investigated using Coumarin 6 (C6). The acid density was 0.022 nm -3 at the exposure dose of 10 µC cm -2 (75 keV electron beam). The absorption intensity of C6 proton adducts was saturated at a certain concentration of C6, indicating an almost complete addition of protons at this C6 concentration. Protons can move in PHS films near C6 molecules even at room temperature. Also, the absorbed dose was estimated using 60 Co γ-rays. The acid yield can be well explained by an acid generation model involving the ionization of a base polymer.