Modeling influence of structural changes in photoacid generators an 193 nm single layer resist imaging

We present recent modeling work aimed at understanding the influence of structural changes in photoacid generators (PAGs) on acid generation efficiency, deprotection efficiency, and photoacid diffusion in 193 nm chemically amplified resists. An analytical model for the postexposure bake process is used to study the reaction and diffusion properties of the various acids generated by the PAGs. Fourier transfer infrared spectroscopy is used to monitor the generation of photoacid during exposure. Resist thickness loss after FEB as a function of exposure dose is related to the deprotection extent to extract the reaction rate parameters. The effects of the acid size and boiling point on process latitude, line end shortening, and line edge roughness are presented. analytical model predictions of process latitude and line end shortening are also presented and compared to experimental data. In this study, the photogenerated acid with the smallest molar volume and highest boiling point temperature gave the best overall lithographic performance. (C) 2000 American Vacuum Society. [S0734-211X(00)16606-5].