Patents Assigned to Smithley Instruments, Inc.
  • Method and apparatus for measurement of mobile charges with a corona screen gun
    Patent number: 5767693
    Abstract: The surface of a wafer is charged with corona passing through a screen. The screen is part of a feedback loop that forces a constant corona current. This results in the potential of the wafer surface following the potential of the screen. This allows contemporaneous measurement of the surface charge and potential that are used to measure mobile charge in an oxide layer on the wafer.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: June 16, 1998
    Assignee: Smithley Instruments, Inc.
    Inventor: Roger L. Verkuil