Comparison of simulation approaches for chemically amplified resists
Lithography simulators have become a standard tool in industrial and governmental research and development departments. In contrast to the modeling approaches for the optical system and for the lithographic performance of i-line resists, there is still no consensus on the modeling of chemically amplified resists (CAR). Existing models differ in the description of the kinetics and the diffusion phenomena during post exposure bake (PEB) and in the specification of the development rate. A modeling approach was established, that combines the light induced generation of photoacid, in- and outdiffusion of acid or base components, a generalized deprotection kinetics, Fickian and non-Fickian diffusion of resist components and an arbitrary development rate model. Existing models such as the effective acid model and a standard deprotection model for CAR can be considered as special cases of the implemented model. To evaluate the importance of certain options of the model and of the model par ameters we have evaluated the performance of the model by comparing simulated CD data and resist profiles with experimental data.