Patents by Inventor Akihisa Oishi

Akihisa Oishi 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).

  • Semiconductor device having an alignment mark
    Patent number: 5475268
    Abstract: A semiconductor device having an alignment mark which is improved to enable accurate recognition of the alignment mark is provided. A first interconnection layer is provided on a semiconductor substrate. A second interconnection layer is provided on an interlayer insulating film so that first and second interconnection layers cross each other with interlayer insulating film therebetween. A surface of second interconnection layer includes, in a region where first and second interconnection layers cross each other, a flat portion which reflects laser beam vertically and upwardly and a portion including concaves and convexes which reflects laser beam irregularly, which together form an alignment mark.
    Type: Grant
    Filed: December 13, 1994
    Date of Patent: December 12, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tomoya Kawagoe, Akihisa Oishi, Mitsutaka Niiro, Katsumi Dosaka