Sample characteristic analysis utilizing multi wavelength and multi angle polarization and magnitude change detection
AssigneeTherma-Wave, Inc.
InventorsAllan Rosencwaig, David L. Willenborg
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Abstract
An optical measurement device is disclosed for evaluating the parameters of a sample. The device includes a polychromatic source for generating a probe beam. The probe beam is focused on the sample surface. Individual rays within the reflected probe beam are simultaneously analyzed as a function of the position within the beam to provide information at multiple wavelengths. A filter, dispersion element and a two-dimensional photodetector array may be used so that the beam may be simultaneously analyzed at multiple angles of incidence and at multiple wavelengths. A variable image filter is also disclosed which allows a selection to be made as to the size of the area of the sample to be evaluated.
Claims9
An apparatus for evaluating a characteristic of a sample comprising:
- a polychromatic light source means for generating at least one probe beam directed to reflect off and interact with the sample surface;
- a first detector for measuring changes in a magnitude of the reflected probe beam resulting from the interaction with the sample and generating first output signals corresponding to a plurality of different wavelengths;
- second detector for analyzing a change in polarization state of the reflected probe beam resulting from the interaction with the sample and generating second output signals corresponding to a plurality of different wavelengths, with said second output signals being separate and independent from the first output signals;
- and
- processor for deriving information about a characteristic of the sample based on a combination of the first output signals representing the change in magnitude measurement as a function of wavelength and the second, independent output signals representing the polarization state analysis as a function of wavelength such that ambiguities in the result are minimized.
Dependencies are inferred from the claim text.