Patent ID: 6297880
Filing Date: 2001-10-02
Classification: G01B

Abstract:
An apparatus for analyzing a sample having a multiple layer thin film stack thereon comprising:a first ellipsometer having a laser for generating a first probe beam of a known wavelength which is stable to within one percent, said first probe beam being directed to reflect off a spot on the sample at a non-normal angle of incidence, said first ellipsometer having a detector for monitoring the change in polarization state of the first probe beam after reflection from the sample and generating first output signals corresponding thereto;a second spectroscopic ellipsometer having a broad band light source for generating a second probe beam, said second probe beam being directed to reflect off the spot on the sample at a non-normal angle of incidence, said second ellipsometer including a detector for monitoring the change in polarization state of the second probe beam after reflection from the sample and simultaneously generating a plurality of second output signals corresponding to a plurality of different wavelengths; anda processor for analyzing the characteristics of the thin film layers on the sample based on a combination of the first and second output signals.