Patents by Inventor Maxwell M. Chi

Maxwell M. Chi 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: 5981949
    Abstract: The invention provides method and apparatus for fast, accurate, and nondestructive imaging of defects and determining defect densities in solid materials including a semiconductor wafer. A wafer is illuminated on one side by an infrared (IR) source and a camera is placed on the other side of the wafer, to detect IR radiation that is transmitted through such wafer. The inventive method employs an imaging camera, e.g. a focal plane array camera, to image the so illuminated wafer. The wafer material must be substantially transparent in the camera bandwidth but can contain defects that absorb or scatter radiation in such bandwidth. Camera filters are used, for example, to select specific wavelengths or bands of wavelengths, to detect and image precipitates, subsurface defects, residual damage from polishing and other defects.
    Type: Grant
    Filed: November 3, 1997
    Date of Patent: November 9, 1999
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventors: Darin J. Leahy, Maxwell M. Chi, Jonathan M. Mooney, Michael N. Alexander