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 l ength of acid enhance image quality. We identified the relation betwee n diffusion length and the number of catalytic acids appropriate for i nducing a given amount of acid-catalyzed reactions as a function of th e difference between the activation energies of diffusion (E(ad)) and acid-catalyzed reaction (E(ar)), and the postexposure baking (FEB) tem perature. When E(ad)=E(ar), the diffusion length required for a certai n amount of acid-catalyzed reaction is inversely proportional to the s quare root of the amount of generated acids, regardless of FEB tempera ture. When E(ad) not equal E(ar), the required diffusion length depend s on FEB temperature. When E(ad)<E(ar), the diffusion length is smalle r at higher FEB temperatures, and this will be preferable for enhancin g the resist resolution.