Post-Exposure Bake Kinetics in Epoxy Novolac-Based Chemically Amplified Resists

摘要

The chemical mechanism and the kinetics of photoacid initiated crosslinking reactions in epoxy novolac based chemically amplified resists are consistent with the strong cage effect observed during post exposure bake (PEB) in these resists. FTIR has confirmed that the acid initiating the crosslinking reaction is bound to the polymer and suggests that the bulky carbonium intermediate is the actually moving species. Single pixel e-beam exposures used to measure the influence of acid diffusion in lithographic feature dimensions show limited diffusion with increasing PEB time. Microlithographic results from deep UV and e-beam controlled at the PEB codnitiosn of lithographic interest: the conditions that favour reactant diffusion facilitate raction completion and increase resist contrast but can restrict resolution. Thermomechanical analysis and differential scannign calorimetry results are in agreement with the above observation.