J.a. Woollam Co.

Board of Regents of the University of Nebraska

David W Doerr

Blaine D Johs

John A Woollam

Reed A Christenson

Steven E Green

Shakil A Pittal

Dennis R Alexander

Brian W Milulka

Disclosed are systems and methods for reducing the adverse effects of particles which become dislodged by scribing and laser machining of materials, which dislodged particles otherwise accumulate on laser machined material surfaces and cause adverse effects.

Laser machining of materials

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.

System and method for compensating polarization-dependent sensitivity of

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.

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. A second diffraction grating and a second sensing means may receive the specularly reflected white light from a first diffraction grating and reflect it to another diffraction grating to investigate another spectrum of light. A spectroscopic ellipsometer uses a stacked photodiode in which the first photodiode and second photodiode have overlapping spectral ranges.

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Lincoln, NE, United States of America

David W Doerr