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

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