Patents by Inventor Cynthia F. Hall

Cynthia F. Hall 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 for rotating a crucible of a crystal pulling machine
    Patent number: 5766341
    Abstract: Apparatus and methods for pulling a semiconductor crystal according to a Czochralski method are disclosed. The apparatus includes a crucible containing a melt, a crystal pulling mechanism which pulls the semiconductor crystal from the melt, a motor coupled to the crucible, and a control circuit for energizing the motor to rotate the crucible at a variable speed. The control circuit may energize the motor to rotate the crucible at a continuously varying acceleration and continuously varying rotational speed while the crystal pulling mechanism is pulling at least a portion of the semiconductor crystal from the melt in the crucible. The control circuit may also energize the motor to rotate the crucible at a rotational speed which monotonically increases and decreases.
    Type: Grant
    Filed: October 4, 1996
    Date of Patent: June 16, 1998
    Assignee: MEMC Electric Materials, Inc.
    Inventors: Steven L. Kimbel, Harold W. Korb, Cynthia F. Hall
  • Apparatus for rotating a crucible of a crystal pulling machine
    Patent number: 5593498
    Abstract: Apparatus and methods for pulling a semiconductor crystal according to a Czochralski method are disclosed. The apparatus includes a crucible containing a melt, a crystal pulling mechanism which pulls the semiconductor crystal from the melt, a motor coupled to the crucible, and a control circuit for energizing the motor to rotate the crucible at a variable speed. The control circuit may energize the motor to rotate the crucible at a continuously varying acceleration and continuously varying rotational speed while the crystal pulling mechanism is pulling at least a portion of the semiconductor crystal from the melt in the crucible. The control circuit may also energize the motor to rotate the crucible at a rotational speed which monotonically increases and decreases.
    Type: Grant
    Filed: June 9, 1995
    Date of Patent: January 14, 1997
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Steven L. Kimbel, Harold W. Korb, Cynthia F. Hall