Accelerated optical topography inspection using parameterized model order reduction

This paper describes an efficient method for solving an inverse optical scattering problem associated with the optical semiconductor process inspection. The method determines the geometric features of a fabricated structure, from spectroscopic ellipsometry measurements, by combining a parameterized low-order model with an optimization algorithm. We make improvements on the polynomial fitting-based parameterized moment matching technique to extract such model automatically. Since the resulting model is inexpensive to evaluate, the method shows large speedup without losing much accuracy: the examples show more than 1000 times speedup with less than 1% error in the final geometric parameter estimation.