Patents by Inventor David A. Joseph

David A. Joseph 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: 4926489
    Abstract: An automatic inspection system including an illuminator for illuminating a reticle or photomask to be inspected, while optically projecting a magnified image of the reticle or photomask onto a plurality of detector elements. A carriage assembly moves the object at a constant velocity to allow the detector elements to sequentially view the entire surface to be inspected. The detector elements are responsive to the intensity of light incident thereupon and are periodically scanned to obtain a two-dimensional measured representation of the object. A database adaptor formulates a two-dimensional representation from the design database description corresponding to the scanned object simultaneously and in synchronism with the scanning of the photomask or reticle. The measured and database adapted representation of the scanned object are input to a signal processor for alignment and defect detection.
    Type: Grant
    Filed: October 5, 1987
    Date of Patent: May 15, 1990
    Assignee: KLA Instruments Corporation
    Inventors: Donald L. Danielson, Mark J. Wihl, David A. Joseph
  • Patent number: 4448532
    Abstract: A method and apparatus for receiving two sets of digitized scan data from two optical detectors which simultaneously scan two supposedly identical portions of a photomask for comparing the two sets of scan data to detect defects, and for evaluating the defect data to determine whether or not it represents real defect information or false defect information. Scan lines containing defect data are scanned twice to produce two sets of defect data and the two sets are then compared to produce a real defect data set including only defects detected in both scans. False defects are thus eliminated from the final data set.
    Type: Grant
    Filed: March 31, 1981
    Date of Patent: May 15, 1984
    Assignee: KLA Instruments Corporation
    Inventors: David A. Joseph, Peter G. Eldredge