Patents Assigned to Kyushu Electronic Metal Co., Ltd.
  • Patent number: 5392729
    Abstract: A method of producing a silicon single crystal, in which a cylindrical partition is immersed in a molten pure silicon liquid or molten silicon liquid containing a Sb dopant within a crucible and the molten liquid inside the partition is pulled up from the crucible to produce the silicon single crystal, wherein an interval between a lower end of the partition and a crucible bottom is changed to control an oxygen concentration in the pulling-up silicon single crystal. The interval is reduced in the case where the oxygen concentration in the pulling-up silicon single crystal is to be increased while the interval is increased in the case where the oxygen concentration is to be reduced.
    Type: Grant
    Filed: September 26, 1990
    Date of Patent: February 28, 1995
    Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.
    Inventors: Kaoru Kuramochi, Makoto Ito, Kiichiro Kitaura
  • Patent number: 5260037
    Abstract: An apparatus and a method for producing a silicon single crystal by Czochralski method, whereby the silicon single crystal is pulled up from a crucible while the crucible is heated by a side heater in the lateral periphery of the crucible and a bottom heater facing the bottom of the crucible. The outputs of the side heater and bottom heater are controlled independently each other so that an oxygen concentration in the pull-up direction of the pulled-up silicon single crystal is rendered uniform. In addition to the output control of the heaters, a magnetic field is applied to a molten liquid in the crucible, so that, a dopant concentration in a radial direction of the pulled-up silicon single crystal is rendered uniform.
    Type: Grant
    Filed: June 26, 1992
    Date of Patent: November 9, 1993
    Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.
    Inventors: Kiichiro Kitaura, Makoto Ito, Kaoru Kuramochi
  • Patent number: 5225235
    Abstract: A semiconductor wafer on which silicon or the like is epitaxially grown and p-type or n-type impurities are doped and which has at the rear surface except for the peripheral edge portion thereof a blocking film for preventing jumping out of impurities therefrom which causes auto-doping, thereby preventing silicon particles from being produced at the peripheral surface and preventing the semiconductor wafer from being contaminated by the silicon particles during the manufacturing a semiconductor device.
    Type: Grant
    Filed: August 5, 1991
    Date of Patent: July 6, 1993
    Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.
    Inventors: Tetsujiro Yoshiharu, Haruo Kamise
  • Patent number: 5152867
    Abstract: An apparatus and a method for producing a silicon single crystal by the Czochralski method, whereby the silicon single crystal is pulled up from a crucible while the crucible is heated by a side heater in the lateral periphery of the crucible and a bottom heater facing the bottom of the crucible. The outputs of the side heater and bottom heater are controlled independently of each other so that an oxygen concentration in the pull-up direction of the pulled-up silicon single crystal is rendered uniform. In addition to the output control of the heaters, a magnetic field is applied to a molten liquid in the crucible, so that, a dopant concentration in a radial direction of the pulled-up silicon single crystal is rendered uniform.
    Type: Grant
    Filed: July 19, 1990
    Date of Patent: October 6, 1992
    Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.
    Inventors: Kiichiro Kitaura, Makoto Ito, Kaoru Kuramochi
  • Patent number: 5051375
    Abstract: Disclosed is a method of producing a semiconductor wafer through gettering by means of sand blasting in a semiconductor wafer fabrication process. The method includes blasting abrasives each having a configuration at least similar to a sphere against a back surface of the semiconductor wafer, causing shear stress having a maximum point in the interior of the wafer to be generated, whereby damage is produced mainly in the interior of the wafer.
    Type: Grant
    Filed: July 10, 1989
    Date of Patent: September 24, 1991
    Assignees: Kyushu Electronic Metal Co., Ltd., Osaka Titanium Co., Ltd.
    Inventors: Sueo Sakata, Yasunori Oka, Toshio Naritomi
  • Patent number: 4986215
    Abstract: A susceptor for use in a vertical vapor-phase growth system designed to heat substrates by means of heat transferred and radiated from a susceptor heated to cause vapor-phase growth on the substrates. The susceptor has a large number of spot-faced portions for receiving substrates, respectively. Each spot-faced portion has a concentrical circular ridge to define a pair of inner and outer spaces at the inner and outer sides, respectively, of the ridge, each of the inner and outer spaces having a concave bottom having a circular radial section, so that a substrate is supported by the circular ridge. Thus, the substrate is uniformly heated by means of the RF induction heat from the susceptor, so that generation of a thermal stress exceeding the critical strength of the substrate is suppressed and substantially no slip occurs.
    Type: Grant
    Filed: September 1, 1989
    Date of Patent: January 22, 1991
    Assignees: Kyushu Electronic Metal Co., Ltd., Osaka Titanium Co., Ltd.
    Inventors: Takayuki Yamada, Takeshi Kii
  • Patent number: 4925809
    Abstract: A semiconductor wafer on which silicon or the like is epitaxially grown and p-type or n-type impurities are doped and which has at the rear surface except for the peripheral edge portion thereof a blocking film for preventing jumping out of impurities therefrom which causes auto-doping, thereby preventing silicon particles from being produced at the peripheral surface and preventing the semiconductor wafer from being contaminated by the silicon particles during the manufacturing of a semiconductor device.
    Type: Grant
    Filed: July 1, 1988
    Date of Patent: May 15, 1990
    Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.
    Inventors: Tetsujiro Yoshiharu, Haruo Kamise