Patents by Inventor Charles E. Van Wagoner

Charles E. Van Wagoner 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).

  • Method and apparatus for eliminating displacement current from current measurements in a plasma processing system
    Patent number: 6433553
    Abstract: In a plasma processing system, displacement current is removed from a current measurement by providing a secondary capacitor connected in parallel with a primary capacitor defined by an anode and a cathode spaced from one another within the plasma doping chamber. The secondary capacitor is chosen or adjusted to have a same or nearly the same capacitance as the primary capacitor. When a voltage pulse is applied to both the primary and secondary capacitors, the respective currents through the capacitors are measured. In order to remove the effects of the displacement current that is present at the leading and falling edges of the voltage pulse, and in order to measure the ion current within the doping chamber, the secondary current through the secondary capacitor is subtracted from the primary current through the primary capacitor.
    Type: Grant
    Filed: October 27, 1999
    Date of Patent: August 13, 2002
    Assignee: Varian Semiconductor Equipment Associates, Inc.
    Inventors: Matthew J. Goeckner, Charles E. Van Wagoner
  • Charge monitor for high potential pulse current dose measurement apparatus and method
    Patent number: 5572038
    Abstract: A charge measuring system for determining implantation dose in a PI.sup.3 system with means to compensate for current in the charge sensor which does not arise from positive ions arriving on the wafer.
    Type: Grant
    Filed: May 7, 1993
    Date of Patent: November 5, 1996
    Assignee: Varian Associates, Inc.
    Inventors: Terry T. Sheng, Charles B. Cooper, III, Susan B. Felch, Charles E. Van Wagoner