Patents by Inventor Tohru Ohkuma

Tohru Ohkuma 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).

  • Forming method of resist pattern
    Patent number: 4933263
    Abstract: Disclosed is a method of forming a resist pattern by exposing a novolak type positive photoresist to ultraviolet light in a pattern, irradiating the entire surface with far ultraviolet light with wavelength of 200 to 320 nm in an atmosphere with inert gas partial pressure ratio of 90% or more, and developing it. According to this method, a specific gradient of solubility in developing solution becoming higher from the surface toward the depthwise direction is provided, and a contrast value of twice as high as in the conventional method can be obtained, and a resist pattern of high aspect ratio is formed.
    Type: Grant
    Filed: February 17, 1988
    Date of Patent: June 12, 1990
    Assignee: Matsushita Electronics Corporation
    Inventors: Yoshimitsu Okuda, Morio Inoue, Yukio Takashima, Tohru Ohkuma