The finite-difference time-domain (FDTD) method is widely used for rigorous lithography simulation. However, it is accurate only if the cell size is sufficiently small. As the feature size gets smaller and the accuracy requirement for rigorous simulation becomes correspondingly more stringent, the FDTD cell size must be reduced to obtain sufficient accuracy, which may result in significantly longer simulation time. This is particularly true for EUV lithography, where accurate simulation of multilayered structures containing intermixing layers would require the use of a very small FDTD cell size in the Z direction.

Fastlitho's rigorous simulator, on the other hand, is free from the limitations of FDTD: It can simulate arbitrarily complicated topography accurately without the need to use a very small cell size. Furthermore, it is at least two orders of magnitude faster than FDTD. Read more about our rigorous EM simulator on this website to find out how accurate it really is for DUV and EUV lithography simulation.