Stochastic modeling and simulation of photoresist surface and line-edge roughness evolution

Polymeric photosensitive materials due to their vital role as imaging films in lithography should have low line-edge roughness (LER) in order to assist in continuous device shrinking. Through stochastic 2 dimensional simulations, it is indicated that a dissolving polymer film exhibits self-affine characteristics. Its surface roughness (SR) evolution is investigated using a dynamic dissolution algorithm based on critical ionization model. LER is studied with a fast quasi-static dissolution algorithm. Investigation of self-affine properties of both SR and LER has been performed in terms of degree of polymerization, chain architecture, and critical ionization fraction. No base diffusion and acid–base neutralization was considered in the study.