Patents by Inventor Masayuki Uto

Masayuki Uto 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).

  • Publication number: 20230243066
    Abstract: A semiconductor wafer including a single crystal doped with a dopant, wherein a resistivity of the wafer is 0.7 m?-cm or less, and wherein a striation height of the wafer is 6 mm or more. The resistivity of the wafer may be 0.8 m?-cm or less, and the striation height may be 13 mm or more. The resistivity of the wafer may be 0.7 m?-cm or less, and the striation may be 22 mm or more. Example features relate to a method of making a semiconductor wafer that includes adding a dopant to a silicon melt, rotationally pulling a crystal from the silicon melt, and applying a magnetic field of 3000 G or more such that the semiconductor wafer has a resistivity that is equal to or less than 0.8 m?-cm and a striation height that is equal to or more than 13 mm.
    Type: Application
    Filed: January 25, 2023
    Publication date: August 3, 2023
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Masayuki UTO
  • Patent number: 11598023
    Abstract: A semiconductor wafer including a single crystal doped with a dopant, wherein a resistivity of the wafer is 0.7 m?-cm or less, and wherein a striation height of the wafer is 6 mm or more. The resistivity of the wafer may be 0.8 m?-cm or less, and the striation height may be 13 mm or more. The resistivity of the wafer may be 0.7 m?-cm or less, and the striation may be 22 mm or more. Example features relate to a method of making a semiconductor wafer that includes adding a dopant to a silicon melt, rotationally pulling a crystal from the silicon melt, and applying a magnetic field of 3000 G or more such that the semiconductor wafer has a resistivity that is equal to or less than 0.8 m?-cm and a striation height that is equal to or more than 13 mm.
    Type: Grant
    Filed: June 29, 2020
    Date of Patent: March 7, 2023
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Masayuki Uto
  • Publication number: 20210404087
    Abstract: A semiconductor wafer including a single crystal doped with a dopant, wherein a resistivity of the wafer is 0.7 m?-cm or less, and wherein a striation height of the wafer is 6 mm or more. The resistivity of the wafer may be 0.8 m?-cm or less, and the striation height may be 13 mm or more. The resistivity of the wafer may be 0.7 m?-cm or less, and the striation may be 22 mm or more. Example features relate to a method of making a semiconductor wafer that includes adding a dopant to a silicon melt, rotationally pulling a crystal from the silicon melt, and applying a magnetic field of 3000 G or more such that the semiconductor wafer has a resistivity that is equal to or less than 0.8 m?-cm and a striation height that is equal to or more than 13 mm.
    Type: Application
    Filed: June 29, 2020
    Publication date: December 30, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Masayuki UTO
  • Patent number: 11047065
    Abstract: A method of producing a monocrystalline silicon uses a monocrystal pull-up apparatus including a crucible, a crucible driver, a pull-up portion, a heat shield having a circular hollow cylindrical lower end portion, and a chamber. The heat shield satisfies a formula (1) below in growing the monocrystalline silicon, R?1.27×C??(1) where C represents a radius (mm) of a straight body of the monocrystalline silicon, and R represents an inner radius (mm) at the lower end portion of the heat shield.
    Type: Grant
    Filed: October 12, 2017
    Date of Patent: June 29, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Masayuki Uto
  • Publication number: 20200115821
    Abstract: A method of producing a monocrystalline silicon uses a monocrystal pull-up apparatus including a crucible, a crucible driver, a pull-up portion, a heat shield having a circular hollow cylindrical lower end portion, and a chamber. The heat shield satisfies a formula (1) below in growing the monocrystalline silicon, R?1.27×C??(1) where C represents a radius (mm) of a straight body of the monocrystalline silicon, and R represents an inner radius (mm) at the lower end portion of the heat shield.
    Type: Application
    Filed: October 12, 2017
    Publication date: April 16, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Masayuki UTO
  • Patent number: 10329686
    Abstract: A manufacturing method of a monocrystal includes: a shoulder-formation step to form a shoulder of the monocrystal; and a straight-body-formation step to form a straight body of the monocrystal, in which, in the shoulder-formation step, providing that a distance from a lowermost portion inside the crucible to a top surface of the dopant-added melt is defined as H (mm) and a radius of the top surface of the dopant-added melt is defined as R (mm), the shoulder starts to be formed in a condition that a relationship of 0.4<H/R<0.78 is satisfied.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: June 25, 2019
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Toshimichi Kubota, Masayuki Uto
  • Patent number: 10233562
    Abstract: A manufacturing method of a single crystal uses a single-crystal pull-up apparatus includes: adding the red phosphorus to the silicon melt so that a resistivity of the single crystal falls in a range from 0.7 m?·cm to 0.9 m?·cm; subjecting an evaluation silicon wafer obtained from the single crystal to a heat treatment in which the evaluation silicon wafer is heated at 1200 degrees C. for 30 seconds in a hydrogen atmosphere; and pull-up the single crystal while appropriately controlling a period for a temperature of the single crystal to be in a range of 570±70 degrees C. so that the number of pits generated on the evaluation silicon wafer becomes 0.1/cm2 or less.
    Type: Grant
    Filed: April 15, 2014
    Date of Patent: March 19, 2019
    Assignee: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito Narushima, Toshimichi Kubota, Fukuo Ogawa, Masayuki Uto
  • Patent number: 10227710
    Abstract: A manufacturing method of a silicon monocrystal uses a monocrystal pulling-up apparatus including: a chamber; a crucible disposed in the chamber and configured to receive dopant-added melt; a pulling-up portion that pulls up a seed crystal after the seed crystal is in contact with the dopant-added melt; a cooler disposed above the crucible to cool a monocrystal that is being grown; and a magnetic field applying unit disposed outside the chamber to apply a horizontal magnetic field to the dopant-added melt. The method includes: during a formation of a shoulder of the silicon monocrystal, starting the formation while moving the cooler downward; stopping the cooler from moving downward at a stop position before a top of the shoulder reaches a level of a lower end of the cooler; and continuing the formation of the shoulder while the cooler is kept at the stop position.
    Type: Grant
    Filed: June 28, 2016
    Date of Patent: March 12, 2019
    Assignee: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito Narushima, Toshimichi Kubota, Masayuki Uto
  • Patent number: 10100429
    Abstract: A method for producing a single crystal includes: bringing a seed crystal into contact with a dopant-added melt, in which a red phosphorus is added to a silicon melt, such that a resistivity of the single crystal is 0.9 m?·cm or less and subsequently pulling up the seed crystal, to form a straight body of the single crystal; and withdrawing the single crystal from the dopant-added melt in a state that a temperature of an upper end of the straight body is 590 degrees C. or more.
    Type: Grant
    Filed: April 8, 2015
    Date of Patent: October 16, 2018
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Masayuki Uto, Toshimichi Kubota
  • Publication number: 20170327966
    Abstract: A manufacturing method of a monocrystal includes: a shoulder-formation step to form a shoulder of the monocrystal; and a straight-body-formation step to form a straight body of the monocrystal, in which, in the shoulder-formation step, providing that a distance from a lowermost portion inside the crucible to a top surface of the dopant-added melt is defined as H (mm) and a radius of the top surface of the dopant-added melt is defined as R (mm), the shoulder starts to be formed in a condition that a relationship of 0.4<H/R<0.78 is satisfied.
    Type: Application
    Filed: November 17, 2015
    Publication date: November 16, 2017
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Masayuki UTO
  • Publication number: 20170283980
    Abstract: A method for producing a single crystal includes: bringing a seed crystal into contact with a dopant-added melt, in which a red phosphorus is added to a silicon melt, such that a resistivity of the single crystal is 0.9 m?·cm or less and subsequently pulling up the seed crystal, to form a straight body of the single crystal; and withdrawing the single crystal from the dopant-added melt in a state that a temperature of an upper end of the straight body is 590 degrees C. or more.
    Type: Application
    Filed: April 8, 2015
    Publication date: October 5, 2017
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Masayuki UTO, Toshimichi KUBOTA
  • Publication number: 20170029975
    Abstract: A manufacturing method of a silicon monocrystal uses a monocrystal pulling-up apparatus including: a chamber; a crucible disposed in the chamber and configured to receive dopant-added melt; a pulling-up portion that pulls up a seed crystal after the seed crystal is in contact with the dopant-added melt; a cooler disposed above the crucible to cool a monocrystal that is being grown; and a magnetic field applying unit disposed outside the chamber to apply a horizontal magnetic field to the dopant-added melt.
    Type: Application
    Filed: June 28, 2016
    Publication date: February 2, 2017
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Masayuki UTO
  • Publication number: 20160102418
    Abstract: A manufacturing method of a single crystal uses a single-crystal pull-up apparatus includes: adding the red phosphorus to the silicon melt so that a resistivity of the single crystal falls in a range from 0.7 m?·cm to 0.9 m?·cm; subjecting an evaluation silicon wafer obtained from the single crystal to a heat treatment in which the evaluation silicon wafer is heated at 1200 degrees C. for 30 seconds in a hydrogen atmosphere; and pull-up the single crystal while appropriately controlling a period for a temperature of the single crystal to be in a range of 570±70 degrees C. so that the number of pits generated on the evaluation silicon wafer becomes 0.1/cm2 or less.
    Type: Application
    Filed: April 15, 2014
    Publication date: April 14, 2016
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Fukuo OGAWA, Masayuki UTO
  • Patent number: 8888911
    Abstract: The present invention provides a technique which enables production of single crystal silicon having relatively low resistivity by preventing cell growth during crystal growth from occurring, especially in a case where a relatively large amount of dopant is added to a molten silicon raw material. Specifically, the present invention provides a method of producing single crystal silicon by the Czochralski process, comprising producing single crystal silicon having relatively low resistivity by controlling a height of a solid-liquid interface when the single crystal silicon is pulled up.
    Type: Grant
    Filed: September 3, 2010
    Date of Patent: November 18, 2014
    Assignee: Sumco Techxiv Corporation
    Inventors: Masayuki Uto, Tuneaki Tomonaga, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima
  • Publication number: 20110056428
    Abstract: The present invention provides a technique which enables production of single crystal silicon having relatively low resistivity by preventing cell growth during crystal growth from occurring, especially in a case where a relatively large amount of dopant is added to a molten silicon raw material. Specifically, the present invention provides a method of producing single crystal silicon by the Czochralski process, comprising producing single crystal silicon having relatively low resistivity by controlling a height of a solid-liquid interface when the single crystal silicon is pulled up.
    Type: Application
    Filed: September 3, 2010
    Publication date: March 10, 2011
    Applicant: SUMCO CORPORATION
    Inventors: Masayuki Uto, Tuneaki Tomonaga, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima