| Extensions to an existing two dimensional (2D) rigorous optical lithography model for metrology and alignment are presented. New applications are shown for the existing model's numerical engine, the efficient waveguide method which solves Maxwell's equations in the spatial frequency domain. Using these extensions we have created a vector 2D photolithography simulator which incorporates non-planar photomasks, nonvertically travelling light, high numerical (NA) aperture projection lenses, extended light sources, time dependent bleaching of positive photoresists and non-planar substrate structures. The simulator, Metropole, runs on common engineering workstation platforms and is shown in multiple studies to be flexible, accurate and faster than other models.; Also presented is a new model for three dimensional (3D) photolithography simulation based upon a unique vector potential waveguide method formulation. This is a rigorous 3D spatial frequency solution electromagnetic model. We have completed the 3D formulation, and implemented it into a computer simulation program, Metropole-3D, for the modeling of photomasks in VLSI semiconductor manufacturing. Examples are given in which the model is shown to be flexible and accurate. Run time and memory usage are given to highlight the program's usability on desktop workstations. |
