Interferometric coherent Fourier scatterometry: A method for obtaining high sensitivity in the optical inverse-grating problem

Abstract

In recent times, coherent Fourier scatterometry has been considered as an emerging optical grating scatterometry technique for semiconductor metrology since it shows large sensitivity owing to its scanning ability. However, further utilization of coherence is possible by making additional measurements using the principle of temporal phase-shifting interferometry. In this paper, through numerical simulation, we show how scanning and interferometry can be coupled together to improve the sensitivity of coherent Fourier scatterometry, to extend its range of applicability and to obtain sufficient information to calculate the complex scattering matrix for all angles of incidences inside the numerical aperture of a microscope objective. © 2013 IOP Publishing Ltd.