Multiple angle spectroscopic analyzer utilizing interferometric and ellipsometric devices
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.
Claims34
A detection system for simultaneously measuring the intensity of rays within a polychromatic beam as function of the position within the beam and at a plurality of wavelengths, said detection system comprising:
- filter means located in the path of the beam and including an elongated aperture for transmitting a portion of the beam;
- dispersion means for creating an angular spreading of the transmitted portion of the beam as a function of the wavelength of the light with the angular spreading being in a direction orthogonal to the orientation of the aperture in the filter means;
- and
- detector means for receiving the transmitted portion of the beam after passing through the dispersion means, said detector means including a two dimensional array of individual elements and having at least one row of elements oriented to measure the intensity of individual rays as a function of the position within the beam and at least one column of elements for measuring the intensity of the individual rays of the beam as a function of wavelength.
A detection system for simultaneously measuring the intensity of rays within a polychromatic beam as function of the position within the beam and at a plurality of wavelengths, wherein the polarization of the beam is predominantly S-polarized along one axis and predominantly P-polarized along an orthogonal axis, said detection system comprising:
- filter means located in the path of the beam and including an elongated slit oriented along one of said axes in a manner so that only S or P-polarized light is transmitted;
- dispersion means for creating an angular spreading of the transmitted portion of the beam as a function of the wavelength of the light, with the angular spreading being in a direction orthogonal to the orientation of the aperture in the filter means;
- and
- detector means for receiving the transmitted portion of the beam after passing through the dispersion means, said detector means including a two dimensional array of individual elements and having at least one row of elements oriented to measure the intensity of individual rays as a function of the position within the beam and at least one column of elements for measuring the intensity of the individual rays of the beam as a function of wavelength.
An apparatus for evaluating a thin film formed on a sample comprising:
- a polychromatic light source for generating a probe beam;
- color filter means for selectively transmitting a plurality of different wavelengths of said probe beam;
- means for focusing said probe beam on the surface of the sample such that the rays within the focused probe beam create a spread of angles of incidence with respect to said surface;
- detector means for receiving the probe beam after it has interacted with the sample, said detector means for measuring the intensity of the various rays at each of a plurality of angles of incidence;
- and
- processor means for evaluating the characteristics of the sample based on the angular dependent intensity measurements made by the detector means at a plurality of different wavelengths, with said intensity measurements being a function of the interference effects created by the interaction of the probe beam with the surface of the thin film and the interface between the thin film and the sample.
An apparatus for evaluating a sample comprising:
- a polychromatic light source for generating a probe beam;
- lens means for focusing said probe beam on the surface of the sample such that the rays within the focused probe beam create a spread of angles of incidence with respect to said surface;
- filter means located in the path of the probe beam after it has interacted with the sample and including an elongated slit for transmitting a portion of the probe beam, said filter means being located in an image plane of the lens means;
- dispersion means for creating an angular spreading of the transmitted portion of the probe beam as a function of the wavelength of the light with the angular spreading being in a direction orthogonal to the orientation of the slit in the filter means;
- detector means for receiving the transmitted portion of the probe beam after passing through the dispersion means, said detector means including a two dimensional array of individual elements and having at least one row of elements oriented to measure the intensity of individual rays as a function of the position within the probe beam and at least one column of elements for measuring the intensity of the probe beam as a function of wavelength;
- and
- processor means for evaluating the characteristics of the sample based on the angular dependent intensity measurements made by the detector means at a plurality of different wavelengths.
Dependencies are inferred from the claim text.