Patents by Inventor Shigemaru Maeda

Shigemaru Maeda 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: 6632411
    Abstract: The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0.1 &mgr;m or more is 1 count/cm2 or less when particles are counted by using a particle counter and a method for producing a silicon single crystal. Thus, there is provided a production technique that can improve productivity and reduce cost for high quality silicon wafers of excellent device characteristics by further reducing density and size of defects such as COP.
    Type: Grant
    Filed: November 23, 2001
    Date of Patent: October 14, 2003
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Ryoji Hoshi, Izumi Fusegawa, Tomohiko Ohta, Shigemaru Maeda
  • Publication number: 20020157598
    Abstract: The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0.1 &mgr;m or more is 1 count/cm2 or less when particles are counted by using a particle counter and a method for producing a silicon single crystal. Thus, there is provided a production technique that can improve productivity and reduce cost for high quality silicon wafers of excellent device characteristics by further reducing density and size of defects such as COP.
    Type: Application
    Filed: November 23, 2001
    Publication date: October 31, 2002
    Inventors: Ryoji Hoshi, Izumi Fusegawa, Tomohiko Ohta, Shigemaru Maeda
  • Patent number: 5833750
    Abstract: A crystal pulling apparatus is disclosed in which a single crystal ingot is pulled from a melt of a crystalline material by using a cable. A crimp portion and a spherical portion supported by the crimp portion are provided in the vicinity of the tip of the cable. Two divided couplings are screwed into a chuck body of a seed chuck. The couplings have an accommodation space therein so as to accommodate the cable and the spherical portion, and conical hole sections serving as the shoulder portion of the accommodation space contact and hold the spherical portion. This structure allows the cable to rotate during crystal pulling operation and facilitates attachment of the seed chuck to the cable and removal of the seed chuck from the cable.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: November 10, 1998
    Assignee: Shin-Etsu Handotai Co. Ltd.
    Inventors: Kouji Mizuishi, Shigemaru Maeda
  • Patent number: 5096677
    Abstract: A Czochralski-type single crystal pulling apparatus in which the heater device is adapted to shift vertically, and a control device is provided for controlling the vertical shifting of the heater and the crucible assembly in predetermined manners, of which a preferred manner is to control the vertical shifting of the heater and the crucible assembly such that the vertical velocities of the crucible assembly and the heater are in direct proportion to the vertical velocity of the pull means.
    Type: Grant
    Filed: May 30, 1990
    Date of Patent: March 17, 1992
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Nobuo Katsuoka, Koji Mizuishi, Shinichi Furuse, Shigemaru Maeda