Broad band referencing reflectometer

A reflectometer, comprising:

• a light source that is utilized to create a sample channel light path, the sample channel light path configured to encounter a sample having at least one unknown property;
• and
• means for referencing the reflectometer to enable an adjustment of reflectance data obtained from the sample to account for reflectometer and environmental changes between a reflectometer calibration time and the time the sample reflectance data is obtained,
• wherein the means for referencing includes a reference channel light path and
• wherein the sample channel light path and the means for referencing form the balanced arms of an interferometer.

A reflectometer, comprising:

• a light source that is utilized to create a sample channel light path, the sample channel light path configured to encounter a sample having at least one unknown property;
• and
• means for referencing the reflectometer to enable an adjustment of reflectance data obtained from the sample to account for reflectometer and environmental changes between a reflectometer calibration time and the time the sample reflectance data is obtained,
• wherein the means for referencing includes a reference channel light path,
• wherein sample channel light path and the reference channel light path are established using one or more beam splitter devices to divide a source beam from the light source and to subsequently recombine said divided portions such that they are directed to common portions of a diffraction element and a detector, and
• wherein selection of individual channels is accomplished through use of controllable apertures.

A reflectometer, comprising:

• a light source that is utilized to create a sample channel light path, the sample channel light path configured to encounter a sample having at least one unknown property;
• and
• means for referencing the reflectometer to enable an adjustment of reflectance data obtained from the sample to account for reflectometer and environmental changes between a reflectometer calibration time and the time the sample reflectance data is obtained,
• wherein the means for referencing includes a reference channel light path and
• wherein the sample channel light path and the reference channel light path are established using two or more controllable beam stops in the form of motorized fully reflecting mirrors to direct the entirety of a source beam from the light source through either the sample channel light path or the reference channel light path and to direct the sample channel light path and the reference channel light path to a common diffraction clement and a common detector.

A reflectometer, comprising:

• a light source that is utilized to create a sample channel light path, the sample channel light path configured to encounter a sample having at least one unknown property;
• and
• means for referencing the reflectometer to enable an adjustment of reflectance data obtained from the sample to account for reflectometer and environmental changes between a reflectometer calibration time and the time the sample reflectance data is obtained,
• wherein the means for referencing includes a reference channel light path and
• wherein the reference channel light path and the sample channel light path are of near-equal optical path lengths in order to minimize environmental effects resulting from absorbing species in below deep ultra-violet (DUV) wavelengths.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel configured such that light of the sample optical channel and light of the reference optical channel share at least some common optical elements including at least some of the same portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample;
• and
• providing at least a first light source and a second light source which provide wavelengths of light in a first and second spectral regions respectively in the sample optical channel, the first and second spectral regions being different at least in part and at least one of the first and second spectral regions including below deep ultra-violet (DUV) wavelengths.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample,
• wherein the first sample is a calibration sample in the sample optical channel.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample,
• wherein the first sample is an unknown sample in the sample optical channel and wherein the referencing of the reflectance data accounts for system or environmental changes between a calibration time and the time the first sample reflectance data is obtained.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample,
• wherein the first sample is a calibration sample in the sample optical channel, the method further comprising performing a reflectance measurement for an unknown sample.

A method of obtaining reflectance data from a first sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the first sample,
• wherein the first sample is an unknown sample in the sample optical channel, the method further comprising performing a reflectance measurement for a calibration sample.

A method of obtaining reflectance data from an unknown sample, comprising:

• providing a sample optical channel;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements including common portions of at least a detector and a spatially separating optical element that spatially separates wavelengths;
• utilizing the detector to detect reflectance data from a calibration sample;
• utilizing the reference optical channel to obtain first referencing data with the detector proximate in time to the calibration, the first reference data indicative of system or environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• utilizing the detector to detect reflectance data from an unknown sample;
• utilizing the reference optical channel to obtain second referencing data with the detector proximate in time to the detecting of the unknown sample reflectance data, the second reference data indicative of system and environmental parameters independent of the use of any sample in the light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the unknown sample by utilizing the first referencing data and the second referencing data.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer;
• and
• at least one environmentally controlled chamber in which the sample channel light path and the reference channel light path are contained at least in part,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• and
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample and
• wherein the sample channel light path is configured to encounter the sample and the reference channel light path is configured so that it does not encounter the sample, and wherein the sample channel light path and the reference channel light path can be selected through manipulation of one or more controllable apertures.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• and
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample,
• wherein sample channel light path and the reference channel light path are established using one or more beam splitter devices to divide the source beam and to subsequently recombine said divided portions such that they are directed to common portions of a diffraction element and the detector, and
• wherein the selection of sample channel light path or the reference channel light path is accomplished through use of controllable apertures in the form of optical shutters.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• and
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample,
• wherein sample channel light path and the reference channel light path are established using one or more beam splitter devices to divide the source beam and to subsequently recombine said divided portions such that they are directed to common portions of a diffraction element and the detector, and
• wherein one or more of the beam splitter devices are partially transmissive beam splitters obscuring the entire beam diameter or fully reflecting mirrors obscuring some portion of the entire beam diameter.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• and
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample and
• wherein the reference channel light path and the sample channel light path are of near-equal optical path lengths in order to minimize environmental effects resulting from absorbing species that absorb wavelengths of below DUV.

A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising:

• at least one light source, the light source providing a source beam including wavelengths at or below DUV wavelengths;
• a sample channel light path;
• a reference channel light path;
• a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample;
• and
• a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer,
• wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample and
• wherein the detector is an array detector that receives the multiple spatially separated wavelengths of light to enable reflectance data to be simultaneously obtained for multiple sites within a two-dimensional area of the sample.

An optical reflectometer for obtaining reflectance data from a two-dimensional sample area, the reflectometer comprising:

• at least one light source providing a light beam;
• a plurality of optical elements configured to utilize a sample channel beam path to direct the light beam to and from a two-dimensional sample area;
• at least one reference channel beam path, the reference channel beam path configured to not encounter a sample;
• at least one optical element selectively enabling or disabling at least one of the reference channel beam path or the sample channel beam path;
• a spectrometer that is in both the reference channel beam path and the sample channel beam, the spectrometer providing multiple spatially separated wavelengths of light at an exit of the spectrometer;
• and
• an array detector that that is in both the reference channel beam path and the sample channel beam, the array detector receiving the multiple spatially separated wavelengths of light to enable reflectance data to be simultaneously obtained for multiple sites within the two-dimensional sample area,
• wherein the reference channel beam path is configured to collect data that may be utilized to account for system and environmental changes to adjust reflectance data obtained through the use of the reflectometer.

A method of analyzing the reflectance characteristics of a sample utilizing a reflectometer, the method comprising:

• providing at least one light beam;
• directing the light beam on a two-dimensional area of a sample by utilizing a sample optical channel;
• receiving at least a portion of the light beam within an imaging spectrometer after the light beam has been reflected from the sample;
• providing multiple spatially separated wavelengths of light at an exit plane of the spectrometer;
• receiving the multiple spatially separated wavelengths of light with a two-dimensional array detector in order to allow reflectance data to be simultaneously obtained for multiple sites within the two-dimensional area of the sample;
• providing a reference optical channel, the sample optical channel and the reference optical channel sharing at least some common optical elements;
• utilizing the reference optical channel to obtain referencing data with the detector, the reference data indicative of system and environmental parameters independent of the use of any sample in a light path of the sample optical channel;
• and
• referencing the reflectance data obtained from the light path of the sample optical channel by utilizing the referencing data associated with the collection of sample reflectance data from the sample.