Patents by Inventor Michihiro Ohwa

Michihiro Ohwa 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).

  • Single crystal pulling-up apparatus of pulling-up silicon single crystal and single crystal pulling-up method of pulling-up silicon single crystal
    Patent number: 8936679
    Abstract: According to one exemplary embodiment, a single crystal pulling-up apparatus of pulling-up silicon single crystals by a Czochralski method, is provided with: a neck diameter measuring portion which measures a diameter of a grown neck portion; a first compensation portion which outputs a first compensated pulling-up speed for the seed crystals based on a difference between a measured value of the diameter of the neck portion and a target value of the neck portion diameter previously stored; a second compensation portion which outputs a second pulling-up speed while limiting an upper limit of the first pulling-up speed to a first limit value; and a crucible rotation number compensation portion which lowers the number of a rotation of a crucible at least in a period where the upper limit of the first pulling-up speed is limited to the first limit value.
    Type: Grant
    Filed: September 14, 2011
    Date of Patent: January 20, 2015
    Assignee: Globalwafers Japan Co., Ltd
    Inventors: Hironori Banba, Hiromichi Isogai, Yoshiaki Abe, Takashi Ishikawa, Shingo Narimatsu, Jun Nakao, Hiroyuki Abiko, Michihiro Ohwa
  • Single crystal pulling-up apparatus and single crystal pulling-up method
    Publication number: 20120067272
    Abstract: According to one exemplary embodiment, a single crystal pulling-up apparatus of pulling-up silicon single crystals by a Czochralski method, is provided with: a neck diameter measuring portion which measures a diameter of a grown neck portion; a first compensation portion which outputs a first compensated pulling-up speed for the seed crystals based on a difference between a measured value of the diameter of the neck portion and a target value of the neck portion diameter previously stored; a second compensation portion which outputs a second pulling-up speed while limiting an upper limit of the first pulling-up speed to a first limit value; and a crucible rotation number compensation portion which lowers the number of a rotation of a crucible at least in a period where the upper limit of the first pulling-up speed is limited to the first limit value.
    Type: Application
    Filed: September 14, 2011
    Publication date: March 22, 2012
    Applicant: Covalent Materials Corporation
    Inventors: Hironori Banba, Hiromichi Isogai, Yoshiaki Abe, Takashi Ishikawa, Shingo Narimatsu, Jun Nakao, Hiroyuki Abiko, Michihiro Ohwa
  • Neutron transmutation doping of a silicon wafer
    Patent number: 4910156
    Abstract: A silicon wafer and a method of producing a silicon wafer comprising a phosphor-doping method of doping phosphor into a single silicon crystals by transmuting isotope Si.sup.30 contained in said single silicon crystals made by the CZ method or the MCZ method into p.sup.31 under neutron irradiation to said single silicon crystals.
    Type: Grant
    Filed: December 22, 1987
    Date of Patent: March 20, 1990
    Assignee: Toshiba Ceramics Co., Ltd.
    Inventors: Shin'ichiro Takasu, Michihiro Ohwa, Kazuhiko Kashima, Eiichi Toji, Kazumoto Homma
  • Method of and device for growing single crystals
    Patent number: 4849188
    Abstract: A device for growing single cristals comprising a pair of electromagnetic coils disposed opposed to each other in a symmetry with respect to a central axis of a crucible at an outer side of a heater, an effective average radius of said coil being from 1.5 to 5 times of a radius of said crucible.
    Type: Grant
    Filed: March 26, 1987
    Date of Patent: July 18, 1989
    Assignee: Toshiba Ceramics Co., Ltd.
    Inventors: Shin'ichiro Takasu, Eiichi Toji, Kazumoto Homma, Michihiro Ohwa
  • Device for growing single crystals
    Patent number: 4847052
    Abstract: A device for growing single crystals comprising a pair of electromagnetic coils disposed opposed to each other in a symmetry with respect to a central axis of a crucible at an outer side of a heater, a diameter for said coils being greater than 0.8 times of a diameter for said heater and a distance between said coils being greater than 1.5 times of said diameter for said heater.
    Type: Grant
    Filed: March 26, 1987
    Date of Patent: July 11, 1989
    Assignee: Toshiba Ceramics Co., Ltd.
    Inventors: Shin'ichiro Takasu, Eiichi Toji, Kazumoto Homma, Michihiro Ohwa