High speed volumetric thickness profile measurement based on full-field wavelength scanning interferometer

Abstract

A novel high speed volumetric thickness profilometry based on a wavelength scanning full-field interferometer and its signal processing algorithm is described for a thin film deposited on pattern structures. A specially designed Michelson interferometer with a blocking plate in the reference path enables us to measure the volumetric thickness profile by decoupling two variables, thickness and profile, which affect the total phase function phi(k). We show experimentally that the proposed method provides a much faster solution in obtaining the volumetric thickness profile data while maintaining the similar level of accurate measurement capability as that of the least square fitting method. (C) 2008 Optical Society of America