Patent ID: 6774997
Filing Date: 2004-08-10
Classification: G01B

Abstract:
An apparatus for analyzing the characteristics of a semiconductor wafer comprising:a narrowband ellipsometer, said narrowband ellipsometer including a gas discharge laser for generating a narrowband output defining a first probe beam directed to reflect off the sample at a non-normal angle of incidence, said narrowband ellipsometer further including a detector for monitoring the first probe beam after reflection from the wafer and generating first output signals corresponding thereto, said narrowband ellipsometer further including one or more elements selected from the group consisting of polarizers and compensators and wherein a motor is provided for varying the azimuthal angle of at one least of said elements; a broadband spectroscopic ellipsometer, said broadband spectroscopic ellipsometer including a broad band light source for generating a second probe beam, said broadband spectroscopic ellipsometer further including a spectrometer for simultaneously monitoring the intensity of the reflected second probe beam at a plurality of wavelengths after reflection from the wafer, said broadband spectroscopic ellipsometer further including one or more elements selected from the group consisting of polarizers and compensators and wherein a motor is provided for varying the azimuthal angle of at least one of said elements; and a processor for analyzing the characteristics of the wafer based on a combination of the first and second output signals and information regarding the azimuthal positions of the elements in the narrowband and broadband spectroscopic ellipsometers.