Patents by Inventor Shafer David R.

Shafer David R. 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).

  • Illumination system for Half-Field Dyson stepper
    Patent number: 5303001
    Abstract: An illumination system for use in a unit magnification optical projection system (such as a Half-Field Dyson system) is provided. In a Half-Field Dyson system, a reticle and a wafer are parallel to each other with a window being provided on the reticle to allow for projection of the reticle pattern onto the wafer. The present invention provides uniform bright illumination over the reticle pattern with little or no spill over through the reticle window.
    Type: Grant
    Filed: December 21, 1992
    Date of Patent: April 12, 1994
    Assignee: Ultratech Stepper, Inc.
    Inventors: Hwan J. Jeong, Shafer David R.