Patents by Inventor Tetsuo Takezawa

Tetsuo Takezawa 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: 5543256
    Abstract: The present invention relates to a method for exposing a pattern plate having an alignment pattern, controlling the positional relationship between the alignment pattern and the device pattern with high accuracy. When exposing a device pattern B such as reticle pattern, shadow mask pattern, etc. and alignment patterns A1, A2 and A3, the alignment patterns A1, A2 and A3 are exposed at least once before exposing the device pattern B, and the alignment patterns A1, A2 and A3 are overlap-exposed again after the device pattern has been exposed. Thus, it is possible to almost perfectly correct relative positional deviation between the alignment patterns, which change depending upon the exposure time during exposure of the device pattern, and the device pattern, and to reduce the degradation of the positional accuracy of exposure, which changes according to pattern size.
    Type: Grant
    Filed: July 17, 1992
    Date of Patent: August 6, 1996
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Toshiki Shinoda, Tetsuo Takezawa, Shigeru Noguchi