Rigorous three-dimensional time-domain finite-difference electromagnetic simulation for photolithographic applications

The parallel electromagnetic simulation program TEMPEST has been generalized to analyze three-dimensional problems in photolithography. TEMPEST, which has been made available on the National Center for Supercomputing Applications, combines together techniques for rigorous simulation of electromagnetic scattering and diffraction, a novel and efficient absorbing boundary condition, and synthesis of partially coherent images including the effects of optical system aberrations. The electromagnetic solution is based on the time-domain finite difference method, but exploits the power of parallel computer architectures. Equations suitable for parallel implementation are given. Simulation time is fifteen to twenty minutes with 64 M simulation nodes on a CM-5 with 512 nodes and 16 GBytes of memory. The usefulness and effectiveness of the program for photolithographic applications are demonstrated by considering problems in projection printing of polarization and transmission effects in contact holes, and reflective notching which causes undesired exposure in photoresists