Patents by Inventor Graham S. Plows

Graham S. Plows 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: 6941006
    Abstract: A method for calibrating the scan amplitude of an electron beam lithography instrument by determining the position of a feature within the scan. The method is effective at the operating frequency of the scan and using a limited bandwidth video signal including the steps of determining the reference feature to be an edge over which the video signal rises abruptly from a background level to a white level. The method turns the beam on only over a short region of the scan and represents the degree of overlap between the beam on portion of the scan and the white part of the feature as the total video signal accumulated in that scan.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: September 6, 2005
    Assignee: DuPont Photomasks, Inc.
    Inventors: Michael J. Penberth, Graham S. Plows, Adam Woolfe
  • Patent number: 6288406
    Abstract: The approach taken to provide variable writing speeds consists of the following: (1) Software in the Job Control subsystem that Identifies the minimum and maximum valid writing speeds, given the resist sensitivity, maximum beam current density, and requested write address size. if the variable writing speed option is enabled, Job Control selects the maximum valid speed. (2) Software in the Pattern Data Conversion subsystem that determines the number of stripes of pattern figure data to combine into each output bitmap for the selected writing speed. (3) Hardware in the Timing Logic Board to clock bitmap data to the serializer at the desired frequency.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: September 11, 2001
    Assignee: DuPont Photomasks, Inc.
    Inventors: Michael J. Penberth, Graham S. Plows, Adam Woolfe
  • Patent number: 6278124
    Abstract: An electron beam blanking method and system for selectively interrupting the flow of electrons during an electron beam lithographic process minimizes electron beam movement during blanking as the electron beam reaches a target lithographic mask. A first deflection plate pair deflects electrons flowing in the electron beam in the direction of the target lithographic mask. The first deflection plate pair includes a first tapered gap that is formed so that electrons which enter the first tapered gap before the initialization of a blanking voltage experience progressively greater electric field as they pass through the plates for controlling the cumulative deflection as the electrons travel through the first deflection plate pair.
    Type: Grant
    Filed: March 3, 1999
    Date of Patent: August 21, 2001
    Assignee: DuPont Photomasks, Inc
    Inventors: Michael J. Penberth, Graham S. Plows, Adam Woolfe
  • Patent number: 4587425
    Abstract: Electron beam apparatus includes a voltage measuring electron collector including solid electrodes with central apertures. The electrodes comprise a corrector electrode (63) maintained at zero volts, an extractor electrode (15) at about 5 kilovolts positive, a filter electrode (16) which has an internally tapered tubular central part (67), a mirror electrode (64) and a scintillator (17) in the annular space between the mirror electrode and the filter electrode.
    Type: Grant
    Filed: March 6, 1984
    Date of Patent: May 6, 1986
    Inventor: Graham S. Plows
  • Patent number: 4242671
    Abstract: A tag transponder which is capable of receiving a signal from a transmitter and re-transmitting the signal after a delay. The incident electromagnetic wave from the transmitter is converted into an acoustic wave in a piezoelectric member of the tag, the acoustic wave traversing the piezoelectric member before re-transmission as an electromagnetic wave; the lower velocity of the acoustic wave compared with the electromagnetic wave provides the delay between the signal received and transmitted by the tag. During the signal pulse from the transmitter the tag continuously re-transmits the signal, and the re-transmitted signal from the tag is sustained after cessation of the signal from the transmitter for a sufficient duration to be distinguished from other transient reflected signals.
    Type: Grant
    Filed: December 8, 1978
    Date of Patent: December 30, 1980
    Inventor: Graham S. Plows
  • Patent number: 4169244
    Abstract: A method of testing electronic networks in which an electron probe is moved from point to point in the network and a current of secondary electrons emitted in response to the impingement of the probe is converted to a signal denoting voltage or field strength at the various points. A scanning apparatus in which an electronic collector including grids in the path of the beam and an annular scintillator is described.
    Type: Grant
    Filed: February 3, 1978
    Date of Patent: September 25, 1979
    Inventor: Graham S. Plows