Patents by Inventor Masafumi Ura

Masafumi Ura 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).

  • Method for manufacturing single crystal semiconductor
    Patent number: 7374614
    Abstract: The method for manufacturing a single crystal semiconductor achieves an object to reduce the impurity concentration nonuniformity within a semiconductor wafer plane and thus to improve the wafer planarity by introducing an impurity into the single crystal semiconductor more uniformly during the pulling of the single crystal semiconductor from a melt. In the course of pulling the single crystal semiconductor (6), the rotating velocity (?2) of the single crystal semiconductor (6) being pulled is adjusted to a predetermined value or higher, and a magnetic field having a strength in a predetermined range is applied to the melt (5). Particularly, the crystal peripheral velocity is adjusted to 0.126 m/sec or higher, and M/V1/3 is adjusted to 35.5?M/V1/3?61.3. More desirably, the crystal peripheral velocity is adjusted to 0.141 m/sec or higher, and M/V1/3 is adjusted to 40.3?M/V1/3?56.4.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: May 20, 2008
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Masafumi Ura, Hidetoshi Kurogi, Toshiharu Yubitani, Noboru Furuichi
  • Method for manufacturing single crystal semiconductor
    Publication number: 20070131158
    Abstract: The method for manufacturing a single crystal semiconductor achieves an object to reduce the impurity concentration nonuniformity within a semiconductor wafer plane and thus to improve the wafer planarity by introducing an impurity into the single crystal semiconductor more uniformly during the pulling of the single crystal semiconductor from a melt. In the course of pulling the single crystal semiconductor (6), the rotating velocity (?2) of the single crystal semiconductor (6) being pulled is adjusted to a predetermined value or higher, and a magnetic field having a strength in a predetermined range is applied to the melt (5). Particularly, the crystal peripheral velocity is adjusted to 0.126 m/sec or higher, and M/V1/3 is adjusted to 35.5?M/V1/3?61.3. More desirably, the crystal peripheral velocity is adjusted to 0.141 m/sec or higher, and M/V1/3 is adjusted to 40.3?M/V1/3?56.4.
    Type: Application
    Filed: February 18, 2005
    Publication date: June 14, 2007
    Applicant: KOMATSU DENSHI KINZOKU KABUSHIKI KAISHA
    Inventors: Masafumi Ura, Hidetoshi Kurogi, Toshiharu Yubitani, Noboru Furuichi
  • Method for pulling crystal
    Patent number: 5911826
    Abstract: An electrode is disposed at the lower end of a radiation screen. The electrode is made of single-crystal silicon. A circuit including a power source is established by contacting the electrode and the seed crystal to a silicon melt.
    Type: Grant
    Filed: June 19, 1998
    Date of Patent: June 15, 1999
    Assignee: Komatsu Electronic Metals Co., Ltd.
    Inventors: Yoshinobu Hiraishi, Masafumi Ura