THEORETICAL-STUDY OF LATENT IMAGE-FORMATION IN CHEMICALLY AMPLIFIED RESISTS

Theoretical analysis of chemically amplified resists indicates that a higher reaction order of acid-catalyzed reaction and lower diffusion length of acid enhance image quality. We identified the relation between diffusion length and the number of catalytic acids appropriate for inducing a given amount of acid-catalyzed reactions as a function of the difference between the activation energies of diffusion (E(ad)) and acid-catalyzed reaction (E(ar)), and the postexposure baking (FEB) temperature. When E(ad)=E(ar), the diffusion length required for a certain amount of acid-catalyzed reaction is inversely proportional to the square root of the amount of generated acids, regardless of FEB temperature. When E(ad) not equal E(ar), the required diffusion length depends on FEB temperature. When E(ad)<E(ar), the diffusion length is smaller at higher FEB temperatures, and this will be preferable for enhancing the resist resolution.