Three-dimensional mesoscale model for the simulation of LER in photoresists

A three-dimensional kinetic Monte Carlo model has been developed to simulate design and processing effects on the line edge roughness and patterning of photoresists. The model is capable of simulating most all of the important parameters involved in resist processing from film formation and exposure to development. It can be used to examine the effect of photoacid generator loading, photoacid diffusion, deprotection reaction, quencher loading, base diffusion, and acid/base reactions, with the flexibility to add more physics as needed. The model is able to reproduce experimentally observed trends of the effect of base loading on LER through all levels of base loading and the effect of reduced aerial image contrast on the LER of resists. It also shows good agreement with experimental results on the effect of PAG loading through around 20% PAG loading. The scaling factors for LER were also examined. It was found that the gradient in polymer protection (dP/dx) provides a very good predictor for LER in some cases, but is insufficient for other conditions when the dominant cause of LER changes such as non-uniformity along the line edge from things like PAG or polymer aggregation.