Model-based optical proximity correction including effects of photoresist processes

Abstract

In this paper, a new automatic model-based Optical Proximity Correction (OPC) approach is reported. It combines a fast aerial image solver and a physically based empirical resist model. The fast aerial image calculation is achieved by using the algorithm of the coherent decomposition of the partially coherent optical systems. The first order resist model of Brunner is extended to accommodate intensity log- slope variations. The modified model can be calibrated by either experimental data or resist process simulations. In this paper, resist simulations using Depict are selected to fit the model parameters. Defocus effects in OPC are also discussed. A new scheme that combines edge biasing and the addition of sub-resolution features is shown to greatly improve the process latitude.