The impact of resist model on mask 3D simulation accuracy beyond 40nm node memory patterns

Beyond 40nm lithography node, mask topograpy is important in litho process. The rigorous EMF simulation should be applied but cost huge time. In this work, we compared experiment data with aerial images of thin and thick mask models to find patterns which are sensitive to mask topological effects and need rigorous EMF simulations. Furthur more, full physical and simplified lumped (LPM) resist models were calibrated for both 2D and 3D mask models. The accuracy of CD prediction and run-time are listed to gauge the most efficient simulation. Although a full physical resist model mimics the behavior of a resist material with rigor, the required iterative calculations can result in an excessive execution time penalty, even when simulating a simple pattern. Simplified resist models provide a compromise between computational speed and accuracy. The most efficient simulation approach (i.e. accurate prediction of wafer results with minimum execution time) will have an important position in mask 3D simulation.