Super-resolution spectral interference fitting method for the simultaneous measurement of the thin film thickness and surface profile

Abstract

Conventional spectral interferometry cannot measure film thicknesses less than optical resolution. However, none of the existing super-resolution methods can obtain the film thickness distribution and surface profile in a single measurement, which will seriously reduce the measurement efficiency and accuracy. We propose a fitting method for Linnik-type spectral interferometry to solve these problems. Compared to the traditional reflectance spectral model for thin films, a new spectral interferometric model is developed for measurements. The results obtained from this method were compared with those from ellipsometry and stylus profilometry, respectively. We confirmed the results matched each other well and proved the validity of the solution.