Polarization and other complex electromagnetic effects that arise because of mask topography are becoming increasingly more important to model. Commercial lithography simulation tools that operate on small layout areas of order 1-10μm2 have advanced models requiring solution of Maxwell’s three-dimensional boundary problem. However, this technique is not viable for full-chip modeling. Here, we show results that demonstrate the accuracy of domain decomposition method adapted for full-chip modeling of mask topography effects. The intensity error relative to the complete 3D solution is shown to be < 3%.