Optical scatterometer having improved sensitivity and bandwidth

摘要

An improved optical scatterometer includes a multiple detector array that enables the measurement of sample microstructure over an increased range of spatial frequency. One array of optical detectors is positioned in a plane perpendicular to the plane containing an incident laser beam and a specularly reflected beam to detect indications of back-scattered and forward-scattered light in that perpendicular plane. Two laser beams having different wavelengths may be employed to determine the optical characteristics of a film and an underlying substrate.