Patents by Inventor Charles Spencer Whitman

Charles Spencer Whitman 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 producing desired tantalum phase
    Patent number: 6395148
    Abstract: The invention relates to a method for producing improved tantalum conductive and resistive materials for use in ink jet heater chips. Specifically, a method for producing thin film tantalum layers of a desired phase on a semiconductor substrate comprises depositing protective layers upon the semiconductor substrate; pre-sputter etching the semiconductor substrate; preheating the semiconductor substrate; maintaining the substrate at a predetermined temperature while depositing the thin film tantalum layer by sputtering for a predetermined period of time at a predetermined input power. Use of the method enables production of a desired tantalum phase for use on a semiconductor substrate thereby providing enhanced corrosion and/or cavitation resistance depending on the use of the semiconductor device.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: May 28, 2002
    Assignee: Lexmark International, Inc.
    Inventor: Charles Spencer Whitman
  • Controlled layer of tantalum for thermal ink jet printer
    Patent number: 6142612
    Abstract: A thermal ink jet printhead has a protective layer of Ta with an optimum thickness of about 9,000 A deposited on a protective layer of SiC under deposition conditions determined by a regression equation. The protective layer of SiC has an optimum thickness of about 5,000 A. The life of a thermal ink jet printhead having these two optimum thicknesses is at least twenty times the life of a thermal ink jet printhead not having these two optimum thicknesses in at least one embodiment. Etching of the layer of SiC prior to depositing the layer of Ta further increases the life of a thermal ink jet printhead.
    Type: Grant
    Filed: November 6, 1998
    Date of Patent: November 7, 2000
    Assignee: Lexmark International, Inc.
    Inventor: Charles Spencer Whitman
  • Fabrication of thermal ink-jet feed slots in a silicon substrate
    Patent number: 5658471
    Abstract: Improved methods for fabricating the ink feed slots in silicon substrate for use in thermal ink-jet print heads is disclosed. One method involves the partial anisotropic etching of an ink feed slot in a silicon substrate for use in aligning the electrical resistive elements on one surface of the substrate. Another embodiment involves laser drilling alignment holes and anisotropically etching the substrate. In both methods, at least one photoresist masking and development step is eliminated thereby reducing fabrication time and alignment difficulties for locating the feed slots relative to the electrical resistance elements and increasing product yield.
    Type: Grant
    Filed: September 22, 1995
    Date of Patent: August 19, 1997
    Assignee: Lexmark International, Inc.
    Inventors: Ashok Murthy, Lawrence Russell Steward, Charles Spencer Whitman