Patents by Inventor Blaine D. Johs

Blaine D. Johs has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5805285
    Abstract: Disclosed is a dispersive optics system, in the context of sample substrate system investigating spectroscopic reflectometer and the like systems, which, in use, produce a plurality of "Orders" of essentially single wavelength beams of light from a polychromatic beam of light. In use the availability of more than one "Order" of essentially single wavelength beams of light allows simultaneous measurement of more essentially single wavelength beams of light, over a larger range, than would be possible were only one "Order" of essentially single wavelength beams of light present. Filters are present to reduce the effects of stray light on detector elements and to allow separating the wavelengths in overlapping regions of adjacent Orders. Also disclosed is a quadrant detector means of dispersive optics alignment, and a compensator means for reducing the effect of detector element polarization state dependence.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: September 8, 1998
    Assignee: J.A. Woollam Co. Inc.
    Inventors: Blaine D. Johs, Ping He, Steven E. Green, Shakil A. Pittal, John A. Woollam
  • Patent number: 5796983
    Abstract: Novel dielectric function parametric model oscillator structures comprised of finite order polynomials and/or essentially zero-width finite magnitude discontinuities in appropriate sequences, which novel oscillator structures are suitable for application in a Kronig-Kramer consistent dielectric function oscillator structure based mathematical model, are disclosed. The present invention method of application enables production of one-dimensional normalized dependent variable vs. independent variable evaluating look-up tables by application of convolution integration effected oscillator structure Gaussian broadening, as applied to finite order polynomials, without the requirement that numerical derivatives or integrations be performed. In use, addition of contributions from one or more said present invention oscillator structures allows determination of dependent variable values given independent variable values, without requiring subtraction of relatively large numbers.
    Type: Grant
    Filed: August 14, 1995
    Date of Patent: August 18, 1998
    Assignee: J. A. Woollam Co. Inc.
    Inventors: Craig M. Herzinger, Blaine D. Johs
  • Patent number: 5757494
    Abstract: The present invention is applicable generally to Spectroscopic Rotatable and Rotating Element Ellipsometers which utilize a relatively large range of wavelengths. Disclosed is a system and method for controlling the polarization state of a polarized beam of light so that it is in a range where the sensitivity of a Polarization State Detector used to measure changes in said polarized beam of light resulting from interaction with a Sample System, to noise and measurement errors etc., is reduced. Exemplified is a system, and method of use, for simultaneously setting both measured ellipsometric ALPHA, and ellipsometric BETA parameter values, (or equivalents), within ranges, in which ranges the sensitivity of transfer functions, and mathematical regressions which utilize said ellipsometric ALPHA and ellipsometric BETA values in the calculation of sample system characterizing PSI and DELTA constant values, to noise and errors in measurement etc., is found to be negligible.
    Type: Grant
    Filed: April 14, 1995
    Date of Patent: May 26, 1998
    Assignee: J.A. Woollam Co. Inc.
    Inventors: Steven E. Green, Craig M. Herzinger, Blaine D. Johs, John A. Woollam
  • Patent number: 5706212
    Abstract: A sample system investigation system, such as an ellipsometer or polarimeter system, for use in investigating sample systems with electromagnetic wavelengths in the infrared range, and a calibration method for compensating nonidealities in multi-dimensional system rotated and non-rotated component representing matricies, are disclosed. An essentially achromatic compensator of dual-rhomb construction, which introduces a (3*LAMBDA/4) phase shift, but essentially no deviation in the direction of propagation of a polarized beam of electromagnetic wavelengths caused to pass therethrough, even when said compensator is caused to continuously rotate, is also disclosed.
    Type: Grant
    Filed: March 20, 1996
    Date of Patent: January 6, 1998
    Assignees: Board of Regents of University of Nebraska, J.A. Woollam Co. Inc.
    Inventors: Daniel W. Thompson, Blaine D. Johs
  • Patent number: 5666201
    Abstract: Disclosed is a dispersive optics system, in the context of ellipsometer or polarimeter and the like systems, which, in use, produces a plurality of "Orders" of essentially single wavelength beams of light from a polychromatic beam of light. In use the availability of more than one "Order" of essentially single wavelength beams of light allows simultaneous measurement of more essentially single wavelength beams of light than would be possible were only one "Order" of essentially single wavelength beams of light present. Filters are present to reduce the effects of stray light on detector elements and to allow separating the wavelengths in overlapping regions of adjacent Orders.
    Type: Grant
    Filed: September 20, 1995
    Date of Patent: September 9, 1997
    Assignee: J.A. Woollam Co. Inc.
    Inventors: Blaine D. Johs, Ping He, Steven E. Green, Shakil A. Pittal, John A. Woollam
  • Patent number: 5657126
    Abstract: In an ellipsometer, a phase-modulated, polarized light beam is applied to a sample, electrical signals are obtained representing the orthogonal planes of polarization of the light after it has interacted with the sample and the constants of the sample are calculated from the two resulting electrical signals. The phase modulation is sufficiently small so that the calibration errors are negligible. For this purpose, the phase modulator, phase modulates the light within a range of no more than ten degrees peak to peak. The two electrical signals are expanded by Fourier analysis and the coefficients thereof utilized to calculate psi and delta.
    Type: Grant
    Filed: May 15, 1995
    Date of Patent: August 12, 1997
    Assignee: The Board of Regents of the University of Nebraska
    Inventors: Stephen Paul Ducharme, Hassanayn Machlab El Hajj, Blaine D. Johs, John A. Woollam
  • Patent number: 5582646
    Abstract: A method of, and system for, applying light beam producing systems such as ellipsometers, polarimeters, polarized light reflectance and functionally similar systems, such that a beam of light produced thereby is caused to be incident upon a process element at an angle in excess of an associated Brewster angle while enabling the production of a signal sufficiently sensitive to changes in process element parameters, for use in "real-time" process element process monitoring and control, is disclosed. In addition a process element processing system and electron beam producing system and light beam producing system combination system is taught, wherein the electron beam producing and light beam producing systems are mounted to the process element processing system, (typically a (MBE) system), by input and output interface systems present at a location appropriate for conventional Reflection High Energy Electron Diffraction (RHEED) systems.
    Type: Grant
    Filed: October 21, 1994
    Date of Patent: December 10, 1996
    Assignee: J.A. Woollam Co. Inc.
    Inventors: John A. Woollam, Blaine D. Johs, Peter P. Chow
  • Patent number: 5521706
    Abstract: An ellipsometer system which includes a pivotal dispersive optics positioned to receive polychromatic light from an analyzer thereof, without further focusing after reflection from a substrate system, is presented. In addition, a rotating compensator, positioned between the analyzer and the dispersive optics, which serves to reduce detector element polarization dependent sensitivity to light entering thereto after it interacts with the dispersive optics, is disclosed. The method of the present invention can include application of mathematical correction factors to, for instance, substrate system characterizing PSI and DELTA values, or Fourier ALPHA and BETA coefficients.
    Type: Grant
    Filed: June 24, 1994
    Date of Patent: May 28, 1996
    Assignee: J. A. Woollam Co. Inc.
    Inventors: Steven E. Green, Shakil A. Pittal, Blaine D. Johs, John A. Woollam, David W. Doerr, Reed A. Christenson
  • Patent number: 5504582
    Abstract: An ellipsometer system which includes a pivotal dispersive optics positioned to receive polychromatic light from an analyzer thereof, without further focusing after reflection from a substrate system, is presented. In addition, a stationary compensator, positioned between an analyzer and the dispersive optics, which serves to reduce detector element polarization dependent sensitivity to light entering thereto after it interacts with the dispersive optics, is disclosed. The use of a light fiber to carry light from a source thereof, to a polarization state generator, is also disclosed. The method of the present invention can include application of mathematical correction factors to, for instance, substrate system characterizing PSI and DELTA values, or Fourier ALPHA and BETA coefficients.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: April 2, 1996
    Assignee: J. A. Woollam Co. Inc.
    Inventors: Blaine D. Johs, Shakil A. Pittal, Steven E. Green, John A. Woollam, David W. Doerr, Reed A. Christenson
  • Patent number: 5416588
    Abstract: In an ellipsometer, a phase-modulated, polarized light beam is applied to a sample, electrical signals are obtained representing the orthogonal planes of polarization of the light after it has interacted with the sample and the constants of the sample are calculated from the two resulting electrical signals. The phase modulation is sufficiently small so that the calibration errors are negligible. For this purpose, the phase modulator phase modulates the light within a range of no more than ten degrees modulations peak to peak. The two electrical signals are expanded by Fourier analysis and the coefficients thereof utilized to calculate psi and delta.
    Type: Grant
    Filed: August 2, 1994
    Date of Patent: May 16, 1995
    Assignee: The Board of Regents of the University of Nebraska
    Inventors: Stephen P. Ducharme, Hassanayn M. El Hajj, Blaine D. Johs, John A. Woollam
  • Patent number: 5373359
    Abstract: To sense characteristics of a sample, an ellipsometer includes a pivotal diffraction grating positioned to receive white light from the analyzer without further focusing of the light after the light leaves the sample. The diffraction grating is focused on the sensor at a predetermined angle with a precision of at least plus or minus one-half degree using an alignment-sensing means positioned between the analyzer and diffraction grating. The sensor includes an aperture through which the incident beam of light is transmitted, light-sensitive areas on opposite sides of said sensor and a comparator for comparing the signal from said light-sensitive areas. Equality of the light from the light-sensitive areas indicates that the incident beam of light is perpendicular to the diffraction grating.
    Type: Grant
    Filed: September 18, 1992
    Date of Patent: December 13, 1994
    Assignee: J. A. Woollam Co.
    Inventors: John A. Woollam, Blaine D. Johs, David W. Doerr, Reed A. Christenson