Patents by Inventor Hieda Katsuhiko

Hieda Katsuhiko 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: 5917205
    Abstract: Photolithographic alignment marks (e.g., mask and measurement overlay marks) are formed of a pattern of very small marks using the design configuration and rule of a circuit pattern feature. A relatively large mark comprising a pattern of small marks modeled after the circuit pattern feature results in an etch rate within the mark area that is substantially the same as the etch rate in the circuit pattern (e.g., cell or peripheral circuit) area. This allows for simultaneous formation of circuit pattern features, and the alignment marks, in a common etching step, while avoiding underetching (shallow etch depth) due to a microloading effect. In this manner, proper formation of readily detectible marks is ensured.
    Type: Grant
    Filed: May 2, 1997
    Date of Patent: June 29, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Mitsui, Hieda Katsuhiko