Therma-wave, Inc.

Bell Telephone Laboratories

Bell Communications Research, Inc.

At&t Bell Laboratories

Kla Tencor Corporation

North Carolina State University

David E Aspnes

Jon Opsal

Jeffrey Thomas Fanton

Brian G Bagley

Rajaram Bhat

Martin Ebert

William E Quinn

Arthur C Adams

Etienne G Colas

James P Harbison

Amabrose A Studna

Joanne Yu Man Law

Ambrose A Studna

Leigh T Florez

A normal incidence rotating compensator ellipsometer includes an illumination source that produces a broadband probe beam. The probe beam is redirected by a beam splitter to be normally incident on a sample under test. Before reaching the sample, the probe beam is passed through a rotating compensator. The probe beam is reflected by the sample and passes through the rotating compensator a second time before reaching a detector. The detector converts the reflected probe beam into equivalent signals for analysis.

Normal incidence rotating compensator ellipsometer

An ellipsometer, and a method of ellipsometry, for analyzing a sample using a broad range of wavelengths, includes a light source for generating a beam of polychromatic light having a range of wavelengths of light for interacting with the sample. A polarizer polarizes the light beam before the light beam interacts with the sample. A rotating compensator induces phase retardations of a polarization state of the light beam wherein the range of wavelengths and the compensator are selected such that at least a first phase retardation value is induced that is within a primary range of effective retardations of substantially 135&deg; to 225&deg;, and at least a second phase retardation value is induced that is outside of the primary range. An analyzer interacts with the light beam after the light beam interacts with the sample. A detector measures the intensity of light after interacting with the analyzer as a function of compensator angle and of wavelength, preferably at all wavelengths simultaneously. A processor determines the polarization state of the beam as it impinges the analyzer from the light intensities measured by the detector.

Broadband spectroscopic rotating compensator ellipsometer

A spectroscopy system having enhanced noise reduction that comprises (i) an arc lamp light source of emitted light, which emitted light is projected as an image of the light source; (ii) a slit aperture through which the emitted light is projected; and (iii) a detector operably associated with the slit aperture for detecting the emitted light. The slit aperture, the arc lamp, and the image of the arc lamp each have a major axis. The major axis of the slit aperture is oriented essentially orthogonally to the major axis of the image of the arc lamp, so that the signal-to-noise ratio of the spectroscopy system is improved as compared to the signal-to-noise ratio of the spectroscopy system when the major axis of the slit aperture is oriented essentially parallel to the major axis of the image of the arc lamp.

Method of reducing noise generated by arc lamps in optical systems employing slits

An optical measurement system for evaluating a reference sample that has at least a partially known composition. The optical measurement system includes a reference ellipsometer and at least one non-contact optical measurement device. The reference ellipsometer includes a light generator, an analyzer and a detector. The light generator generates a beam of quasi-monochromatic light having a known wavelength and a known polarization for interacting with the reference sample. The beam is directed at a non-normal angle of incidence relative to the reference sample to interact with the reference sample. The analyzer creates interference between the S and P polarized components in the light beam after the light beam has interacted with reference sample. The detector measures the intensity of the light beam after it has passed through the analyzer. A processor determines the polarization state of the light beam entering the analyzer from the intensity measured by the detector, and determines an optical property of the reference sample based upon the determined polarization state, the known wavelength of light from the light generator and the composition of the reference sample. The processor also operates the optical measurement device to measure an optical parameter of the reference sample. The processor calibrates the optical measurement device by comparing the measured optical parameter from the optical measurement device to the determined optical property from the reference ellipsometer.

Thin film optical measurement system and method with calibrating ellipsometer

An ellipsometer for evaluating a sample includes a light generator that generates a beam of light having a known polarization for interacting with the sample. A polarimeter of the ellipsometer includes a compensator, an analyzer and a detector. The compensator is formed of an optically uniaxial material. The compensator has a planar front face, and a planar rear face that is substantially parallel to the front face. The compensator is configured such that one ordinary axis of the crystal, but not the second ordinary axis of the crystal, lies in the plane of the front face. The compensator is positioned in the path of the light beam such that the light beam is normally incident to the front face of the compensator. As such, the ordinary ray is not displaced as it passes through the compensator. The ellipsometer further includes means for rotating the compensator about an axis that is perpendicular to both the front face and to the rear face. The analyzer interacts with the light beam after the light beam interacts with the sample and with the compensator. The detector measures the intensity of the light after the interaction with the analyzer as a function of an angle of the rotation of the compensator about the axis. The measurements can be used to determine the change in polarization state that occurs as light is reflected from the sample.

Ellipsometer and polarimeter with zero-order plate compensator

An ellipsometer, and a method of ellipsometry, for analyzing a sample using a broad range of wavelengths, includes a light source for generating a beam of polychromatic light having a range of wavelengths of light for interacting with the sample. A polarizer polarizes the light beam before the light beam interacts with the sample. A rotating compensator induces phase retardations of a polarization state of the light beam wherein the range of wavelengths and the compensator are selected such that at least a first phase retardation value is induced that is within a primary range of effective retardations of substantially 135.degree. to 225.degree., and at least a second phase retardation value is induced that is outside of the primary range. An analyzer interacts with the light beam after the light beam interacts with the sample. A detector measures the intensity of light after interacting with the analyzer as a function of compensator angle and of wavelength, preferably at all wavelengths simultaneously. A processor determines the polarization state of the beam as it impinges the analyzer from the light intensities measured by the detector.

An optical measurement system for evaluating a reference sample that has at least a partially known composition. The optical measurement system includes a reference ellipsometer and at least one non-contact optical measurement device. The reference ellipsometer includes a light generator, an analyzer and a detector. The light generator generates a beam of quasimonochromatic light having a known wavelength and a known polarization for interacting with the reference sample. The beam is directed at a non-normal angle of incidence relative to the reference sample to interact with the reference sample. The analyzer creates interference between the S and P polarized components in the light beam after the light beam has interacted with reference sample. The detector measures the intensity of the light beam after it has passed through the analyzer. A processor determines the polarization state of the light beam entering the analyzer from the intensity measured by the detector, and determines an optical property of the reference sample based upon the determined polarization state, the known wavelength of light from the light generator and the composition of the reference sample. The processor also operates the optical measurement device to measure an optical parameter of the reference sample. The processor calibrates the optical measurement device by comparing the measured optical parameter from the optical measurement device to the determined optical property from the reference ellipsometer.

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Apex, NC, United States of America

David E Aspnes