PEB sensitivity variation of 193-nm resist according to activation energy of protection groups

Post exposure bake temperature sensitivity (PEB sensitivity) is getting important for below 100nm device. There are several factors affecting the PEB sensitivity including acidity and diffusion of photogenerated acid, stiffness and free volume of base polymer, and so on. Among them, the activation energy for deprotection reaction is regarded as the most critical factor. We have investigated the influence of protection group with various activation energies as well as Tg of polymer. Several different protection groups were incorporated into the polymer chain to modify activation energy of the resist. Also, we have investigated the influence of acid diffusion and quencher diffusion ability on PEB sensitivity. Three photoresists were formulated with different concentration of acid diffusion controller to asses the influence of acid diffusion on CD variation. And to evaluate the effect of quencher diffusivity on CD change, photoresist was formulated by adding amines having various different molecular size. Detailed results and new resist with reduced the PEB sensitivity will be reported in this paper.