Patents by Inventor Li-Jiu Chen

Li-Jiu Chen 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 and apparatus for maintaining depth of focus
    Patent number: 8520189
    Abstract: A method includes directing a beam of radiation along an optical axis toward a workpiece support, measuring a spectrum of the beam at a first time to obtain a first profile, measuring the spectrum of the beam at a second time to obtain a second profile, determining a spectral difference between the two profiles, and adjusting a position of the workpiece support along the optical axis based on the difference. A different aspect involves an apparatus having a workpiece support, beam directing structure that directs a beam of radiation along an optical axis toward the workpiece support, spectrum measuring structure that measures a spectrum of the beam at first and second times to obtain respective first and second profiles, processing structure that determines a difference between the two profiles, and support adjusting structure that adjusts a position of the workpiece support along the optical axis based on the difference.
    Type: Grant
    Filed: May 3, 2010
    Date of Patent: August 27, 2013
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Chang-Tsun Hsieh, Fu-Jye Liang, Tzung-Chi Fu, Li-Jiu Chen, Chih-Ming Ke