Prediction of E-Beam-Lithography Performance of PAGs Using Quantum Chemistry Calculations

Photoacid generators (PAGs) are critical components in electron-beam lithography (EBL), initiating acid-catalyzed reactions through ionization and dissociation within the resist. Yet, identifying structural motifs that enhance PAG performance remains challenging. Here, using density functional theory calculations and the Binary-Encounter-Bethe model, we systematically evaluate the ionization cross sections and vertical electron affinities of a widely employed PAG─triphenyl sulfonium 4-(methacryloxy)-2,3,5,6-tetrafluorobenzenesulfonate─and its isomers across incident electron energies of 30-100 keV, and 10-50 eV. We further examine how distinct functional groups and their substitution patterns govern these electronic properties. Key results demonstrate that carbon-carbon double bonds promote ionization more effectively than carbonyl groups; hydroxyl substitution position and number exert negligible influence on ionization cross sections; while fluorine substitution markedly modulates electron affinity without significantly altering ionization. This work establishes structure-property guidelines that can inform the rational design of next-generation PAGs for high-resolution EBL.