Fast and accurate hybrid subgrid and subcell finite-difference time-domain methods for the simulation of mask electromagnetic effects in sub-45nm lithography

Subgrid and subcell FDTD (S-FDTD) methods are described. They can be used for the fast and accurate simulation of mask electromagnetic effects in sub-45nm lithography. The accuracies of the S-FDTD methods are verified by comparison with FDTD and with a very accurate pseudospectral reference solution. The S-FDTD methods are an order of magnitude or more faster than FDTD. Furthermore, the S-FDTD methods require much less memory than FDTD for time marching. Hence, much larger mask areas can be simulated with S-FDTD than with FDTD.