Patents by Inventor Gerald A. Keller

Gerald A. Keller 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 forming a retrograde photoresist profile
    Patent number: 5221596
    Abstract: A retrograde profile is formed in a photoresist layer (11, 20) by modifying the rate at which a photoresist developer solution dissolves a portion (12) of a photoresist layer (11, 20). The photoresist layer (11, 20) is exposed to a chemical such as hexamethyldisilizane or dimethylsulfoxane to allow a portion (12) of the photoresist (11, 20) to absorb the chemical. The photoresist (11, 20) is then heated in order to enhance a reaction between the photoresist (11, 20) and the chemical. The reaction modifies a portion (12) of the photoresist (11, 20) to reduce the rate at which the portion (12) of the photoresist (11, 20) is dissolved by a developer solution.
    Type: Grant
    Filed: September 3, 1991
    Date of Patent: June 22, 1993
    Assignee: Motorola, Inc.
    Inventor: Gerald A. Keller