Microscopic\nMechanisms of Reaction-Coupled Acid Diffusion\nin Chemically Amplified Photoresists

Diffusion in photoresists is a fundamental\nprocess that significantly\nimpacts micro-nano manufacturing. However, it often intertwines with\nchemical reactions, leading to intricate kinetics that compounds our\ncomprehension. Here, we successfully applied all-atom molecular dynamics\nsimulations to simultaneously describe the diffusion of acids and\nthe deprotection reactions they catalyze in extreme ultraviolet photoresists,\nwhich are critical materials for high-resolution patterning. The results\nshow that acids hop between binding sites with the aid of the other\nspecies present in photoresists, akin to observations of ion transport\nin organic electrolytes. The deprotection reactions enable acids to\novercome spatially prohibitive barriers. These chemical reactions\nalso create local free volume, facilitating the motion of the organic\nmatrix and consequently promoting acid movement. We show that by simultaneously\ndescribing diffusion and chemical reactions, atomic-level simulations\ncan reproduce the features of experimental reaction dynamics, highlighting\nthe potential of molecular modeling in advancing photoresist design.\nThese insights broaden our understanding of diffusion in organic solids\nand serve as a theoretical reference in the development of photoresists\nfor higher performances.