Impact of photoresist composition and polymer chain length on line edge roughness probed with a stochastic simulator

Abstract

The impact of various parameters such as photoacid generator (PAG) concentration, acid diffusion length, and polymer size on the finally obtained line edge roughness (LER) in chemically amplified photoresists are investigated with a stochastic simulator. A new aspect of the simulations is to start with a polymer matrix modeled by molecular dynamics simulation and subsequently simplify the description of the resist composition for mesoscopically simulating the post-exposure bake (PEB) and development steps. The results show that decreasing the molecular weight (MW) of chain-like polymers does not necessarily lead to lower roughness values. Acid-breakable polymers are simulated as well showing that they can lead to improved LER characteristics.