Atomistic insights into EUV photoresist photolysis via full temporal dynamics

One of the challenges in the development of photoresist materials is the trade-off between resolution, line roughness and sensitivity, however, the underlying dynamics remain underexplored. Here, we develop an integrated full temporal framework-combining Fermi's Golden Rule for photoionization calculation, natural orbital branching real-time TDDFT for excited-state dynamics simulation, and ab initio molecular dynamics for fragment evolution-to resolve atomistic mechanisms of EUV-induced photolysis in phenyl triflate. Simulations reproduce experimental photoelectron spectra and fragmentation products, although the computational resource limitation prevents statistically quantitative comparison with the experimental branching ratios. We find: (1) Dual bond-breaking pathways: Hole occupation weakens bonds in shallow eigenenergy-level ionizations, while energy transfer during wavefunction collapse drives direct breakage in deep ionizations; (2) Post- evolution reorganization: Electrostatic attraction mediates fragment recombination (e.g., PhO+CF₃⁺ → PhO-CF₃⁺), and residual kinetic energy induces phenyl ring rotation. Our method provides a new way to simulate the photolysis processes based on density functional theory accuracy.