Patents by Inventor Masaaki Itou

Masaaki Itou 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: 5305364
    Abstract: Reduction projection type X-ray lithography with an exposing beam wavelength of 40-150A, longer than in conventional 1:1 proximity exposure, has a high-vacuum space. This would reduce wafer replacement work efficiency and contaminate optical mirrors with substances released by a resist decomposed during exposure except for separating an optical system chamber and a wafer exposing chamber by a differential pumping section and a thin-film window. Wafer exposure is under atmospheric pressure, improving productivity, accuracy of exposure and longevity of the optical devices.
    Type: Grant
    Filed: September 15, 1992
    Date of Patent: April 19, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Kozo Mochiji, Hiroaki Oizumi, Shigeo Moriyama, Shinji Okazaki, Tsuneo Terasawa, Masaaki Itou
  • Patent number: 5272744
    Abstract: In a reflection mask, there is formed at least one laminate structure comprising a high reflectivity portion, a middle portion and a high reflectivity portion. When there is a defect in the high reflectivity portion as the top layer, this high reflectivity portion and the underlying middle portion are removed in that defective position, thereby allowing the high reflectivity portion as the bottom layer to be exposed to repair the defect.
    Type: Grant
    Filed: August 21, 1992
    Date of Patent: December 21, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Itou, Hiroaki Oizumi, Shigeo Moriyama
  • Patent number: 5222112
    Abstract: In printing patterns on a mask onto a wafer with high accuracy via a reflective reduction projection optical system by using an X-ray or vacuum ultraviolet beam there is an elliptical mirror having a source position defined in an X-ray source and a position of reflection image of entrance pupil of an imaging optical system with respect to the mask as foci and introducing means for synchronously scanning the mask and wafer. Due to inserting a plane mirror for bending an X-ray by approximately 90.degree. at at least one point in the imaging optical system so that the plane of incidence may be perpendicular to the polarization plane the reflectivity does not lower even when the angle of incidence is 45.degree..
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: June 22, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Tsuneo Terasawa, Masaaki Itou, Shigeo Moriyama, Soichi Katagiri, Hiroshi Fukuda
  • Patent number: 5200798
    Abstract: A method for detecting position detection marks on the bottom surface of a sample substrate and for determining the pattern forming positions on the top surface of the sample on the basis of the detected mark positions makes it possible to virtually eliminate the measurement errors caused by sample tilt in the position measurements regarding the sample top surface. When the sample tilts, a positional difference occurs between the top and bottom surfaces of the sample, and errors are accordingly generated in the position measurements from the sample top surface. According to the invention, the mark position measurements from the sample bottom surface are made to contain a deviation that varies with the tilt angle of the sample. The deviation is used to cancel the errors in the measured positions.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: April 6, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Soichi Katagiri, Shigeo Moriyama, Tsuneo Terasawa, Masaaki Itou
  • Patent number: 4984259
    Abstract: An X-ray exposure apparatus comprises an X-ray source, a reflecting mirror for deflecting an X-ray beam radiated from the X-ray source to an object, and mechanisms for rotating the reflecting mirror about an axis of rotation apart from a reflecting surface of the reflecting mirror. The reflecting mirror has such a shape that the angle of incidence remains constant relative to the X-ray beam at given angles of rotation.
    Type: Grant
    Filed: February 20, 1990
    Date of Patent: January 8, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Itou, Shigeo Moriyama