Patents by Inventor Hisashi Furuya

Hisashi Furuya 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: 5871581
    Abstract: A single crystal pulling apparatus comprising: a gas tight container, a double crucible for storing a semiconductor melt inside the gas tight container comprising an outer crucible and an inner crucible which are connected at a lower edge, and source material supply means for adding source material to the semiconductor melt at a position between the outer crucible and the inner crucible, characterized in that a flow restriction member is provided inside the semiconductor melt region between the outer crucible and the inner crucible for restricting the flow of the semiconductor melt.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: February 16, 1999
    Assignees: Mitsubishi Materials Silicon Corporation, Mitsubishi Materials Corporation
    Inventors: Takashi Atami, Hiroaki Taguchi, Hisashi Furuya, Michio Kida
  • Patent number: 5858087
    Abstract: The principal construction of a single crystal pulling apparatus involves a chamber (gas tight chamber) inside of which is a double crucible 3 for storing a semiconductor melt 21, comprising an outer crucible 11 and an inner crucible 12 communicated with each other, and a source material supply tube 5 suspended from an upper portion of the chamber, and positioned so that granular source material 8 can be introduced from a lower end opening 5a thereof into the semiconductor melt 21 between the outer crucible 11 and the inner crucible 12. An incline portion 13 is provided at a lower end of the source material supply tube 5 on the inner crucible 12 side, for introducing source material 8 discharging from the lower end opening 5a to the semiconductor melt 21 in the vicinity of the side wall of the outer crucible 11.
    Type: Grant
    Filed: December 26, 1996
    Date of Patent: January 12, 1999
    Assignees: Mitsubishi Materials Silicon Corp., Mitsubishi Materials Corp.
    Inventors: Hiroaki Taguchi, Takashi Atami, Hisashi Furuya, Michio Kida
  • Patent number: 5843228
    Abstract: The invention is directed to preventing meltdown of conductive metal electrodes 5, 5 used to supply current to a heater 104 of a crucible 103. A single crystal pulling apparatus comprises: the heater 104 which encircles the crucible 103, and the pair of electrodes 5, 5, respectively threaded to a pair of graphite intermediate electrodes 6 of the heater 104, and a voltage source 9 for supplying power to the pair of electrodes 5, 5. A switch 11 switches the power on and off. A watthour meter 10a, continuously measures the current flowing through the heater 104. Investigation by the present inventors showed that in the case of a crack 8 in a lower portion of the intermediate electrode 6, minute fluctuations occurred in the measured value of the current, arising from an electric discharge phenomena in the crack 8 prior to meltdown of the electrodes 5, 5.
    Type: Grant
    Filed: April 1, 1997
    Date of Patent: December 1, 1998
    Assignees: Mitsubishi Materials Silicon Corporation, Mitsubishi Materials Corporation
    Inventors: Masao Saitoh, Daisuke Wakabayashi, Takashi Atami, Hisashi Furuya
  • Patent number: 5840115
    Abstract: A method of growing a single crystal of semiconductor using a CZ growth technique, having a step (0<t<t1) wherein a single crystal of semiconductor is pulled while a source material is supplied continuously to maintain a constant amount of semiconductor melt, and a step (t2<t<t3) wherein the supply of source material is halted, and the single crystal of semiconductor is pulled using residual melt from the first step.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: November 24, 1998
    Assignee: Zag Ltd.
    Inventors: Hiroaki Taguchi, Takashi Atami, Hisashi Furuya, Michio Kida
  • Patent number: 5797638
    Abstract: An annular member hoist apparatus which lifts an annular member and carries and positions the annular member at a predetermined location by a carrier apparatus fitted with an elevator mechanism, including a suspension member suspended from the elevator mechanism, and a plurality of support arms which extend out radially in a horizontal plane from the suspension member. Each of the support arms has an engagement tip portion for supporting the annular member from inside the annular member.
    Type: Grant
    Filed: March 24, 1997
    Date of Patent: August 25, 1998
    Assignees: Mitsubishi Materials Silicon, Mitsubishi Materials Corporation
    Inventors: Masakazu Yamazaki, Michio Yanaba, Hiroaki Taguchi, Takashi Atami, Hisashi Furuya
  • Patent number: 5779792
    Abstract: The present invention provides an improved single crystal pulling apparatus for pulling a single crystal semiconductor such as silicon or gallium arsenide. The apparatus of the present invention comprises a gas tight container, a crucible which is disposed inside the container, a heater, and a pair of coils to apply a cusp magnetic field in the semiconductor melt. The crucible is separated into two regions by a cylindrical partition body, and an outside region is used to supply source material and to melt the source material and an inside region is used for pulling up the single crystal. The inside and outside regions are communicated with the communication passage provided at the bottom of the partition body. Electrical currents in opposing directions are applied to a pair of coils for generating in the melt a cusp magnetic field which includes a vertical portion and a horizontal portion relative to the crucible.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: July 14, 1998
    Assignees: Mitsubishi Materials Silicon Corporation, Mitsubishi Materials Corporation
    Inventors: Takashi Atami, Hisashi Furuya, Michio Kida
  • Patent number: 5714267
    Abstract: Thermal stress at a point portion of a seed crystal generated when the seed crystal is brought into contact with molten silicon liquid is relieved, thereby to prevent generation of dislocation, to curtail the time of a seed contraction process and to surely support a heavy weight single crystal. A seed crystal of a silicon single crystal used when the single crystal is grown from molten silicon liquid by a Czochralski method is formed to show the heat emissivity of 0.5 or higher and lower than 1.0 at the point portion of the seed crystal. The point portion of the seed crystal is either a part or the whole of the portion that makes contact with the molten silicon liquid or a portion that makes contact with the molten silicon liquid and a portion that makes no contact with the molten silicon liquid in the vicinity of that portion. It is desirable to form at least 16 lines per 1 cm.sup.2 of fine grooves each having a width of 0.3 to 1.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: February 3, 1998
    Assignees: Mistsubishi Material Corporation, Mitsubishi Materials Silicon Corporation
    Inventors: Norihisa Machida, Hisashi Furuya
  • Patent number: 5674756
    Abstract: To provide a silicon-wafer intrinsic-gettering method making it possible to obtain a desired intrinsic-gettering effect through a heat treatment of 1,000.degree. C. or lower and optionally change the thickness of a DZ layer. To obtain a silicon wafer with large intrinsic-gettering effectiveness, a silicon wafer containing oxygen precipitate nuclei is quickly heated from room temperature up to 800.degree. to 1,000.degree. C. and holding the state for 0.5 to 20 min is used. In addition to the above heat treatment step, it is preferable to further use the step of naturally cooling the silicon wafer up to room temperature and the step of heating the naturally-cooled silicon wafer from 500.degree. to 700.degree. C. up to 800.degree. to 1,100.degree. C. at a rate of 2.degree. to 10.degree. C./min and holding the silicon wafer at the temperature for 2 to 48 hr.
    Type: Grant
    Filed: July 14, 1995
    Date of Patent: October 7, 1997
    Assignees: Mitsubishi Materialc Corporation, Mitsubishi Materials Silicon Corporation
    Inventors: Yuhki Satoh, Hisashi Furuya
  • Patent number: 5474022
    Abstract: There is provided a double crucible for growing a silicon single crystal in which the partition wall 17 in the shape of ring is concentric with the main crucible 6 in the shape of bottomed cylinder and the lower end of the partition wall 17 is fixed on the inner bottom of the main crucible, and thus the outer crucible 18 and the inner crucible 19 are formed inside the main crucible. The partition wall 17 is uniform in thickness and has introducing holes 20 in its lower part which link the outer crucible with the inner crucible. The partition wall is made so that the inner diameter of its lower part may be smaller than the inner diameter of its upper part. Supposing that A is the diameter of the partition wall at a level of molten silicon, h is a depth from the surface of the molten silicon to the introducing holes, V(out) is an amount of molten silicon stored in the outer crucible, and V(in) is an amount of molten stored in the inner crucible, the relation of D/A=1.5 to 3, 2h/A>1, and V(out)/V(in)=0.
    Type: Grant
    Filed: April 11, 1995
    Date of Patent: December 12, 1995
    Assignees: Mitsubishi Materials Corporation, Mitsubishi Materials Silicon Corporation
    Inventors: Keisei Abe, Hisashi Furuya, Norihisa Machida, Yoshiaki Arai
  • Patent number: 4981549
    Abstract: A silicon single-crystal growing method is disclosed which immerses a seed crystal in a silicon melt and pulls the seed crystal from the melt to thereby grow a silicon single-crystal, and in which the dwelling time of the silicon single-crystal, which is being pulled in a temperature range of between 1,050.degree. to 850.degree. C., is set to be no longer than 140 min. The apparatus suitable for practicing the above method has a crucible, a pulling mechanism, and a temperature control shell. The temperature control shell is located above the crucible for cooling said silicon single-crystal at a cooling rate such that the dwelling time of said silicon single-crystal, which is being pulled in a temperature range of between 1,050.degree. to 850.degree. C., is not longer than 140 min.
    Type: Grant
    Filed: February 22, 1989
    Date of Patent: January 1, 1991
    Assignees: Mitsubishi Kinzoku Kabushiki Kaisha, Japan Silicon Co., Ltd.
    Inventors: Ichiro Yamashita, Koutaro Shimizu, Yoshiaki Banba, Yasushi Shimanuki, Akira Higuchi, Hisashi Furuya