Efficient and rigorous three-dimensional model for optical lithography simulation

A new, rigorous model for solving three-dimensional light-scattering problems in the optical lithography process of semiconductor manufacturing is introduced. The new model employs a hybrid approach to solve Maxwell’s equations in the spatial frequency domain with the use of vector potentials. The model extends a successful two-dimensional lithography model and has been applied to the simulation of the patterning of light by three-dimensional (3-D) photomasks. The theory behind the new model is presented, and examples are given of the model’s results and computational efficiency on an engineering workstation. The efficiency is highest for fully symmetric structures where the paraxial partial-coherence approximation is valid. The model can easily be extended to the efficient simulation of light scattering in 3-D optical alignment and photosensitive polymer problems.