Patents by Inventor David Sturdevant

David Sturdevant 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: 7492049
    Abstract: A layered test pattern for measuring registration and critical dimension (CD) for multi-layer semiconductor integrated circuits is disclosed. A first layer includes a first pattern having vertical and horizontal portions. A second layer is formed over the first layer and includes a second pattern having vertical and horizontal portions having nominal vertical and horizontal phase shifts with respect to the vertical and horizontal portions, respectively, of the first pattern. The vertical and horizontal portions include periodically repeating vertical lines and horizontal lines, respectively. The nominal phase shifts may be half of the period of the vertical and horizontal lines. A scatterometry tool measures the width of the lines and the phase shift of the first pattern relative to the second pattern. The width of the lines corresponds to CD, whereas the difference between the measured phase shift and the nominal phase shift indicates variation in registration.
    Type: Grant
    Filed: June 26, 2007
    Date of Patent: February 17, 2009
    Assignee: LSI Corporation
    Inventors: Phong Thanh Do, Kirk Rolofson, David Sturdevant
  • Patent number: 7258953
    Abstract: A layered test pattern for measuring registration and critical dimension (CD) for multi-layer semiconductor integrated circuits is disclosed. A first layer includes a first pattern having vertical and horizontal portions. A second layer is formed over the first layer and includes a second pattern having vertical and horizontal portions having nominal vertical and horizontal phase shifts with respect to the vertical and horizontal portions, respectively, of the first pattern. The vertical and horizontal portions include periodically repeating vertical lines and horizontal lines, respectively. The nominal phase shifts may be half of the period of the vertical and horizontal lines. A scatterometry tool measures the width of the lines and the phase shift of the first pattern relative to the second pattern. The width of the lines corresponds to CD, whereas the difference between the measured phase shift and the nominal phase shift indicates variation in registration.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: August 21, 2007
    Assignee: LSI Corporation
    Inventors: Phong Thanh Do, Kirk Rolofson, David Sturdevant