Stochastic simulation of the UV curing process in nanoimprint lithography: Pattern size and shape effects in sub-50 nm lithography

Abstract

The authors have performed stochastic simulations of the ultraviolet (UV) curing process of the resist in nanoimprint lithography. Chain formation between an activated monomer and a randomly selected monomer within the critical reaction radius occurred until there was no unreacted monomer within the reaction radius. A deactivation mechanism was introduced to prevent the chain reaction at the resist surface by setting a smaller maximum reaction radius at the resist surface than in the middle of the resist. By introducing the deactivation effect, the conversion ratio of the UV-cured resist decreased with decreasing resist pattern size and depended on the pattern shape. Resist pattern shrinkage after UV curing was also simulated by relaxing the structures with the molecular mechanics method.