Thickness measurement of transparent film by white-light interferometry

摘要

White-light scanning interferometry plays an important role in precise profile metrology of microstructure. However, applying this approach may also be limited because of the optical reflection behavior of the surface. While there is a thin film on the surface, the reflection behavior of top and bottom of the thin-film will cause severer phase errors. Recently, the method by combining both reflectometry and white-light scanning interferometry is proposed to measure the film thickness and surface profile. This article firstly explains the principle of the proposed method and then verifies the feasibility of the thickness-measurement method for transparent film on a Silicon surface. Both of the algorithm and the experiment system have been optimized to measure the film thickness with high precision.