Application of Spectral Ellipsometry for Dielectric, Metal, and Semiconductor Films in Microelectronics Technology

This article discusses model and model-free approaches to solve problems of spectral ellipsometry as applied to microelectronic problems related to measuring the thicknesses and optical parameters of thin layers of dielectrics, metals, and semiconductors. Model approaches are based on the use of a priori information about the form of the Cauchy, Drude, Drude–Lorentz, and Tauc–Lorentz dispersion relation. Model-free approaches can use any smooth multiparameter functional relationship that can describe a smooth spectral curve. We can also use machine learning (ML) to implement a model-free approach, which is suited for determining the thickness of multilayer structures and their optical characteristics and can significantly increase the speed of data processing.