Reaction-diffusion mechanisms for the chemical shrink process of nanofabrication

The effectiveness of reaction-diffusion mechanisms on the formation of nanoscale polymer films in the chemical shrink process is investigated by a two-dimensional model. The model includes three mechanisms: the catalytic cross-linking reaction of water-soluble polymers and cross-linkers, the diffusion of photoacids, and the trapping of photoacids by the cross-linked polymers. It is found that, although the cross-linking reaction is the vital mechanism for the chemical shrink process, it is much less effective on the formation of nanoscale polymer films than the photoacids diffusion and trapping mechanisms.