Halogen and Halomethyl Substitution Effects in Anthracene-Based Extreme Ultraviolet Resist Models: A Theoretical...

Extreme ultraviolet (EUV) photoresist design involves a careful trade-off between maximizing absorption of highly energetic EUV photons (92 eV) and controlling electron-hole-induced chemical pathways driven by low-energy electrons (<20 eV). Using first-principles calculations, including density functional theory (DFT) and time-dependent DFT for optical properties, we systematically investigated the effects of halogen and halomethyl substitution on the electronic structure and electron-hole-induced chemistry for potential application in EUV photoresists. Iodine substitution promotes radical generation via an exothermic process along a dissociative electron attachment pathway and increases the intensity of the electron energy loss function and EUV absorption relative to fluorine, chlorine, and bromine. These results establish iodine as the most effective substituent for improving cross-linking efficiency and photon absorption and provide a first-principles framework for guiding the rational design of halogenated EUV photoresist materials.