Patents by Inventor Hirotoshi Yamagishi

Hirotoshi Yamagishi 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: 5550354
    Abstract: A high-frequency induction heating coil is provided which enables a semiconductor single crystal in the process of growth to incorporate impurities uniformly therein, permits ready adjustment of the heat distributing property, and precludes the discharge of electricity across a slit. The high-frequency induction heating coil comprises a pair of annular conductors 21 and 22, a pair of power source terminals 23a and 23b for feeding a high-frequency electric current to the pair of annular conductors 21 and 22, and a plurality of small coils 24a through 24f and 25a through 25f having the pair of annular conductors as opposite electrodes and projecting toward the axis of the pair of annular conductors extending from a first annular conductor 21 to a second annular conductor 22.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: August 27, 1996
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masanori Kimura, Hirotoshi Yamagishi
  • Patent number: 5534112
    Abstract: The evaluation of the oxide film dielectric breakdown voltage of a silicon semiconductor single crystal is caried out by cutting a wafer out of the single crystal rod, etching the surface of the wafer with the mixed solution of hydrofluoric acid and nitric acid thereby relieving the wafer of strain, then etching the surface of the wafer with the mixed solution of K.sub.2 Cr.sub.2 O.sub.7, hydrofluoric acid, and water thereby inducing occurrence of pits and scale-like patterns on the surface, determining the density of the scale-like patterns, and computing the oxide film dielectric breakdown voltage by making use of the correlating between the density of scale-like patterns and the oxide film dielectric breakdown voltage. This fact established the method of this invention to be capable of effecting an evaluation equivalent to the evaluation of the oxide film dielectric breakdown voltage of a PW wafer prepared from the single crystal rod.
    Type: Grant
    Filed: May 5, 1994
    Date of Patent: July 9, 1996
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi, Nobuyoshi Fujimaki, Yukio Karasawa
  • Patent number: 5501172
    Abstract: The present invention provides a method of growing silicon single crystals by the Czochralski method, wherein the strength of a neck may be increased so as to delete the risk of severance thereof in a simple and easy way without the use of mechanically complex devices and thereby growing of a single crystal of a larger diameter and heavy weight is made practically possible.The method comprises the steps of: a single crystal being so grown from a seed crystal that the diameter of said single crystal gets gradually narrower until the length of a seed taper reaches 2.5 to 15 times the sectional size of the seed crystal; the diameter of a long near-cylindrical neck following the seed taper being so regulated that said diameter may be 0.09 to 0.9 times the sectional size of the seed crystal and 2.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: March 26, 1996
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Toshinari Murai, Eiichi Iino, Hideo Arai, Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5462010
    Abstract: An apparatus for continuously supplying granular polycrystal silicon to a crucible of a semiconductor single crystal pulling apparatus, comprising a funnel-shaped tank having a relatively large capacity, a main hopper having a relatively small capacity and weight, a subhopper having an intermediate capacity and weight and providing a passage from said tank to said main hopper, and a weight sensor for detecting the weight of the main hopper, wherein the overall weight of the main hopper is measured to obtain the flow rate (supply rate) of the granular polycrystal silicon.
    Type: Grant
    Filed: October 14, 1992
    Date of Patent: October 31, 1995
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Kiyotaka Takano, Izumi Fusegawa, Hirotoshi Yamagishi, Koji Mizuishi, Katsuhiko Ogino
  • Patent number: 5386796
    Abstract: Quick and inexpensive determination of an aggregate of point defects in a grown silicon semiconductor single crystal bar is accomplished by a method which comprises cutting a wafer from a freshly grown silicon single crystal bar, etching the surface of this wafer with the mixture of hydrofluoric acid and nitric acid thereby relieving the wafer of strain, treating the wafer with the mixture of K.sub.2 Cr.sub.2 O.sub.7, hydrofluoric acid, and water thereby giving rise to pits 2 and ripple patterns 1 therein, determining the density of the pits 2 and that of the ripple patterns 1, and rating the aggregate of point defects by virtue of the correlation between the densities of the pits 1 and the ripple patterns 1 and the aggregate of point defects.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: February 7, 1995
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi, Nobuyoshi Fujimaki, Yukio Karasawa
  • Patent number: 5373805
    Abstract: A single crystal pulling apparatus based on Czochralski technique having a conduit for continuously supplying granular polycrystal material to the crucible and a vertical purge tube suspended centrally into the heating chamber, wherein the purge tube is vertically shiftable; a heat shield ring is connected to the lower end of the purge tube, and a cylindrical quartz partition ring made of a quartz glass containing no bubbles is held vertically by the heat shield ring in a manner such that the lower end of the quartz partition ring comes substantially lower than the lower end of the purge tube so that, by being dipped in the polycrystal melt, the partition ring isolates the interior surface of the melt from the exterior surface of the melt, over which latter the granular polycrystal material is poured.
    Type: Grant
    Filed: October 15, 1992
    Date of Patent: December 20, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Kiyotaka Takano, Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5361721
    Abstract: A single crystal pulling apparatus of Czochralski technique type including (i) a cylindrical partition adapted to divide the surface portion of the melt into an inner part and an outer part, the former being where the single crystal is grown and the latter being where granular polycrystal material is supplied, (ii) a flat ring having heat reflecting and insulating property held horizontally above the melt, and (iii) a vertically shiftable purge tube suspended centrally into the heating chamber adapted to enter into the inner hole of the flat ring.
    Type: Grant
    Filed: February 2, 1993
    Date of Patent: November 8, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Kiyotaka Takano, Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5359959
    Abstract: A semiconductor single crystal rod having a controlled oxygen concentration distribution in the direction of length is produced by method of pulling up a semiconductor melt held in a quartz glass crucible under application of a magnetic field, which method is characterized by fixing the speed of revolution of the quartz glass crucible and varying the intensity of the magnetic field applied to the melt according to the length of pull-up of the single crystal rod.
    Type: Grant
    Filed: September 30, 1992
    Date of Patent: November 1, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5348893
    Abstract: A method for the impartation of a mechanical distortion to a semiconductor wafer by the collision of particles against the surface of the semiconductor wafer is disclosed which represses the pollution of the semiconductor wafer with impurities from the particles, permits effective removal of the impurities adhering to the surface of the semiconductor wafer, and allows the density of lattice defects imparted into the semiconductor wafer to be freely varied and controlled as desired. The method which effects the intentional impartation of lattice distortion to the surface of the semiconductor wafer by the collision of particles against the semiconductor wafer comprises molding a substance possessing a melting point of not higher than 30.degree. C. and exhibiting solubility in water into particles of a diameter in the range of from 0.001 to 1 mm and causing the particles to collide against the surface of the semiconductor wafer.
    Type: Grant
    Filed: March 12, 1993
    Date of Patent: September 20, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Hirotoshi Yamagishi
  • Patent number: 5340434
    Abstract: A process for producing a silicon single crystal is disclosed which comprises the steps of providing a silicon melt in a crucible, feeding grains of silicon polycrystal to the silicon melt and pulling up a silicon single crystal from the silicon melt. The concentration of residual hydrogen in the grains of silicon polycrystal is more than 10 ppmwt and less than 100 ppmwt. The process prevents the silicon single crystal from being polycrystalline.
    Type: Grant
    Filed: February 1, 1993
    Date of Patent: August 23, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Kiyotaka Takano, Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5306387
    Abstract: A semiconductor single crystal rod having a controlled oxygen concentration distribution in the direction of length is produced by method of pulling up a semiconductor melt held in a quartz glass crucible under application of a magnetic field, which method is characterized by fixing the rotational speed of said quartz crucible at a level exceeding 5 rpm and varying the intensity of said magnetic field applied to said molten semiconductor according to the length of pull of said single crystal rod.
    Type: Grant
    Filed: June 12, 1991
    Date of Patent: April 26, 1994
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi
  • Patent number: 5262338
    Abstract: A semiconductor device of the MOS construction such that a gate oxide film of the device has a gate area in the range of from 5 to 15 mm.sup.2 and a thickness in the range of from 15 to 40 nm and the oxide film dielectric breakdown voltage is not less than 8 MV/cm when a gate current caused to flow in response to application of a direct-current voltage between a phosphorus-doped polysilicon electrode formed on the oxide film and a silicon single crystal substrate increases past 1 .mu.A/mm.sup.2 as current density is obtained by using a silicon wafer substrate having an oxygen concentration of not more than 1.times.10.sup.18 atoms/cm.sup.3.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: November 16, 1993
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi, Nobuyoshi Fujimaki, Yukio Karasawa
  • Patent number: 5258092
    Abstract: The present invention is intended to provide a method of growing a silicon monocrystalline rod by an FZ process, wherein the dopant distribution of the silicon monocrystalline rod in the diametrical direction is made microscopically uniform, characterized in that a magnetic field forming means is arranged above and/or below a melting zone of said silicon monocrystalline rod to surround said silicon monocrystalline rod and a magnetic field is applied to the melting zone of the silicon monocrystalline rod through said magnetic forming means, and preferably the magnetic field forming means is constituted by supplying a direct electric current through a solenoid coil surrounding said silicon monocrystalline rod.
    Type: Grant
    Filed: March 23, 1992
    Date of Patent: November 2, 1993
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hirotoshi Yamagishi, Masanori Kimura, Hideo Arai
  • Patent number: 5248378
    Abstract: A method of producing a Czochralski-grown silicon single crystal stably and efficiently with high production yield comprises the steps of setting pulling conditions such that at least a portion of a growing silicon single crystal having a temperature in excess of 1150.degree. C. is spaced upwardly from a surface of silicon melt by a distance greater than 280 mm; and pulling the growing silicon single crystal upward while maintaining the pulling conditions. The silicon single crystal produced by this method has an excellent oxide film dielectric breakdown strength. An apparatus for carrying out the method is also disclosed.
    Type: Grant
    Filed: March 17, 1992
    Date of Patent: September 28, 1993
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Tetsuhiro Oda, Izumi Fusegawa, Hirotoshi Yamagishi, Atsushi Iwasaki, Akiho Maeda, Shinobu Takeyasu, Nobuyoshi Fujimaki, Yukio Karasawa
  • Patent number: 5126113
    Abstract: An apparatus for producing a single crystal ingot grown by the Czochralski method includes a plurality of grip arms each having a grip finger engageable with a downwardly facing engagement step formed on an upper part of the single crystal, and a ring slidably fitted around a plurality of grip arms to hold the grip arms in a closed position in which the engagement step of the single crystal is firmly gripped by the grip fingers against detachment. The apparatus having such a ring is particularly advantageous when used for the production of a heavy single crystal ingot in which the grip arms are forced to spread apart by the weight of the single crystal ingot.
    Type: Grant
    Filed: March 29, 1991
    Date of Patent: June 30, 1992
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hirotoshi Yamagishi, Kouji Mizuishi, Fumihiko Hasegawa
  • Patent number: 5110404
    Abstract: In a method for heat process of silicon, a single crystal silicon produced by the Czochralski process is thermally processed at a low temperature ranging from 400.degree. C. to 550.degree. C. Outside this temperature range, the oxygen precipitate is not adequate. The result is that a predetermined oxygen precipitate can be obtained uniformly in the crystal growth direction without any reduction especially at the crystal bottom part. The resulting silicon is particularly suitable for manufacture of LSI.
    Type: Grant
    Filed: March 21, 1990
    Date of Patent: May 5, 1992
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Hirotoshi Yamagishi, Takao Abe
  • Patent number: 5067989
    Abstract: Single crystal silicon for a substrate of semiconductor integrated circuits is disclosed. Cu, Fe, Ni and Cr are contained as impurities in a concentration smaller than 0.1 ppta, respectively, and the total content of the impurities is less than 0.4 ppta. Oxygen-induced stacking faults are reduced to an absolute minimum.
    Type: Grant
    Filed: August 22, 1990
    Date of Patent: November 26, 1991
    Assignee: Shin Etsu Handotai Co., Ltd.
    Inventors: Shuji Yokota, Hirotoshi Yamagishi
  • Patent number: 4956153
    Abstract: An improved apparatus for growing a single crystal of semiconductor silicon by the Czochralski method which apparatus has a heat-resistant and heat-insulating covering board in direct contact with the upper ends of heat-insulating members surrounding a quartz glass silicon melting crucible and having a circular center opening, and a heat-resistant and heat-insulating tube having an outer diameter approximately equal to the diameter of the center opening in the covering board gas-tightly joined to an upwardly extending argon gas supplying conduit and extending downwardly from the joint of the top wall of a metal housing and the upwardly extending conduit and extending through the center opening in the covering board in such a manner that the single crystal during growing is coaxially surrounded thereby, the lower end thereof being at a height above and in the proximity of the surface of the melt in the crucible.
    Type: Grant
    Filed: September 9, 1988
    Date of Patent: September 11, 1990
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hirotoshi Yamagishi, Izumi Fusegawa, Shuuji Yokota, Takao Abe