Patents by Inventor Edward T. Smith

Edward T. Smith 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 of making a rim-type phase-shift mask
    Patent number: 5484672
    Abstract: A method of forming rim type phase-shift lithography mask (140) involving backside overexposure of a positive resist layer (130) overlying a patterned light-blocking layer (120). By subjecting the resist layer to electromagnetic radiation (132) (e.g., broad band UV) transmitted via the backside (115) of the mask substrate (112), portions (134) of the resist layer extending from peripheral edges of the light blocking layer inwardly a selected distance are activated. After developing activated portions of the resist layer, the "pull back" of the resist layer is transferred to the underlying light blocking layer by anisotropically etching portions of the light blocking layer not covered by the resist layer, thereby forming the desired rim structure.
    Type: Grant
    Filed: January 25, 1995
    Date of Patent: January 16, 1996
    Assignee: International Business Machines Corporation
    Inventors: Stanislav P. Bajuk, David S. O'Grady, Edward T. Smith