Non-delta-chrome optical proximity correction methodology for process models with three-dimensional mask effects

Abstract

As integrated circuit design dimensions continue to shrink, previously ignored three-dimensional (3-D) mask effects have become significant for the accurate prediction and correction of proximity effects. Optical proximity correction (OPC) process models must consequently take into account 3-D mask effects. The state-of-the-art model-based OPC methodology, which is called delta-chrome OPC (DCOPC), needs the repeated computation of the mask perturbation to facilitate its convergence. The increasing complexity of OPC process models challenges this DCOPC methodology because each computation of the mask perturbation becomes prohibitively expensive. In this study, a new model-based OPC methodology, which is called non-delta-chrome OPC (non-DCOPC), is proposed without introducing any mask perturbations. It only requires image intensity information to achieve convergence using classical control techniques, and its effectiveness is demonstrated, showing that the run time with and without considering 3-D mask effects can be significantly improved. In addition, the correction accuracy of the DCOPC and non-DCOPC methodologies without considering 3-D mask effects is quite comparable. However, the correction accuracy considering 3-D mask effects can be slightly improved by the non-DCOPC methodology.