Patents by Inventor T. H. P. Chang

T. H. P. Chang 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).

  • Precision alignment of microcolumn tip to a micron-size extractor aperture
    Patent number: 6297584
    Abstract: A method and an accompanied apparatus for aligning an electron emitter with an extractor hole of a microcolumn. Four V-grooves, defined together with the window for forming the membrane and having bottoms situated on two axis are microfabricated on a chip. The axis intersect at a right angle and defines a center point for the extractor hole. The V-grooves are then used as references to align the electron emitter with the extractor hole, one axis at a time. The emitter is precisely aligned to the extractor hole because the extractor hole was formed with reference to the V-grooves. The thickness of the chip is used as the spacing reference between the emitter and the extractor.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: October 2, 2001
    Assignee: Etec Systems, Inc.
    Inventors: Ho-Seob Kim, Kim Y. Lee, T. H. P. Chang
  • Precision alignment of microcolumn tip to a micron-size extractor aperture
    Patent number: 6171165
    Abstract: A method and an accompanied apparatus for aligning an electron emitter with an extractor hole of a microcolumn. Four V-grooves, defined together with the window for forming the membrane and having bottoms situated on two axis are microfabricated on a chip. The axis intersect at a right angle and defines a center point for the extractor hole. The V-grooves are then used as references to align the electron emitter with the extractor hole, one axis at a time. The emitter is precisely aligned to the extractor hole because the extractor hole was formed with reference to the V-grooves. The thickness of the chip is used as the spacing reference between the emitter and the extractor.
    Type: Grant
    Filed: November 19, 1998
    Date of Patent: January 9, 2001
    Assignee: Etec Systems, Inc.
    Inventors: Ho-Seob Kim, Kim Y. Lee, T. H. P. Chang