Patents Assigned to Frontier Semiconductor Measurements, Inc.
  • System for measuring the curvature of a semiconductor wafer
    Patent number: 5227641
    Abstract: A system for measuring the curvature of a surface includes a laser for emitting a beam of light to be incident upon the surface; a photodetector for detecting light reflected by the surface; a first stage for selectively moving the surface in a direction normal to the direction of the incident beam; a second stage for selectively moving the photodetector in a direction normal to the reflected beam; a sensor connected to the photodetector for detecting the displacement of the reflected beam relative to the photodetector.
    Type: Grant
    Filed: November 18, 1991
    Date of Patent: July 13, 1993
    Assignee: Frontier Semiconductor Measurements, Inc.
    Inventor: David Cheng