Patents by Inventor Takehiko Gunji

Takehiko Gunji 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).

  • Process of producing exposure mask
    Patent number: 5202204
    Abstract: A process of producing an exposure mask by which the accuracy of a pattern of a mask film to be formed on a surface of a transparent substrate is improved and also the accuracy in registration between layers is improved. The process comprises the step of correcting, upon exposure for the formation of a mask pattern, the position of a mask pattern by a different correction amount in accordance with a ratio at which the area of the mask film which remains after etching occupies in the entire area of a transparent substrate on which the mask film is formed.
    Type: Grant
    Filed: June 11, 1990
    Date of Patent: April 13, 1993
    Assignee: Sony Corporation
    Inventors: Hiroichi Kawahira, Takehiko Gunji, Satoru Nozawa