Patents by Inventor Ryusuke YOKOYAMA

Ryusuke YOKOYAMA 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: 20210140066
    Abstract: A method of controlling a convection pattern of a silicon melt includes: acquiring a temperature at a first measurement point not overlapping a rotation center of a quartz crucible on a surface of the silicon melt, the quartz crucible rotating in a magnetic-field-free state; determining that the temperature at the first measurement point periodically changes; and fixing a direction of a convection flow to a single direction in a plane orthogonal with an application direction of a horizontal magnetic field in the silicon melt by starting a drive of a magnetic-field applying portion to apply the horizontal magnetic field to the silicon melt when a temperature change at the first measurement point reaches a predetermined state, and subsequently raising the intensity to 0.2 tesla or more.
    Type: Application
    Filed: February 27, 2019
    Publication date: May 13, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Ryusuke YOKOYAMA, Wataru SUGIMURA
  • Publication number: 20210108337
    Abstract: A method of manufacturing monocrystalline silicon by flowing inert gas in a chamber, applying horizontal magnetic field to a silicon melt in a quartz crucible, and pulling up monocrystalline silicon includes: forming a flow distribution of a flow of the inert gas flowing between a lower end of a heat shield and a surface of the silicon melt in the quartz crucible to be plane asymmetric with respect to a plane defined by a crystal pull-up axis of the pull-up device and an application direction of the horizontal magnetic field and rotationally asymmetric with respect to the crystal pull-up axis: maintaining the formed plane asymmetric and rotationally asymmetric flow distribution in a magnetic-field-free state until a silicon material in the quartz crucible is completely melted; and applying the horizontal magnetic field to the completely melted silicon material and starting pulling up the monocrystalline silicon.
    Type: Application
    Filed: February 27, 2019
    Publication date: April 15, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Ryusuke YOKOYAMA, Hideki SAKAMOTO, Wataru SUGIMURA
  • Publication number: 20200407870
    Abstract: A method of estimating an oxygen concentration in monocrystalline silicon, which is pulled up by a pull-up device having a hot zone with a plane-asymmetric arrangement with respect to a plane defined by a crystal pull-up shaft and an application direction of a horizontal magnetic field, includes, in at least one of a neck-formation step or a shoulder-formation step for the monocrystalline silicon: a step of measuring a surface temperature of a silicon melt at a point defining a plane-asymmetric arrangement of a hot zone, and a step of estimating the oxygen concentration in a straight body of the pulled-up monocrystalline silicon based on the measured surface temperature of the silicon melt and a predetermined relationship between the surface temperature of the silicon melt and the oxygen concentration in the monocrystalline silicon.
    Type: Application
    Filed: February 27, 2019
    Publication date: December 31, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Shin MATSUKUMA, Kazuyoshi TAKAHASHI, Toshinori SEKI, Tegi KIM, Ryusuke YOKOYAMA
  • Publication number: 20200407875
    Abstract: A method of controlling a convection pattern of a silicon melt includes applying a horizontal magnetic field having an intensity of 0.2 tesla or more to the silicon melt in a rotating quartz crucible to fix a direction of a convection flow in a plane orthogonal to an application direction of the horizontal magnetic field in the silicon melt, the horizontal magnetic field being applied so that a central magnetic field line passes through a point horizontally offset from a center axis of the quartz crucible by 10 mm or more.
    Type: Application
    Filed: February 27, 2019
    Publication date: December 31, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Naoki MATSUSHIMA, Ryusuke YOKOYAMA, Hideki SAKAMOTO, Wataru SUGIMURA
  • Publication number: 20200399780
    Abstract: A convection pattern estimation method of a silicon melt includes: applying a horizontal magnetic field of 0.2 tesla or more to a silicon melt in a rotating quartz crucible with use of a pair of magnetic bodies disposed across the quartz crucible; before a seed crystal is dipped into the silicon melt to which the horizontal magnetic field is applied; measuring temperatures at a first and second measurement points positioned on a first imaginary line that passes through a center of a surface of the silicon melt and is not in parallel with a central magnetic field line of the horizontal magnetic field as viewed vertically from above; and estimating a direction of a convection flow in a plane in the silicon melt orthogonal to the direction in which the horizontal magnetic field is applied on a basis of the measured temperatures of the first and second measurement points.
    Type: Application
    Filed: February 27, 2019
    Publication date: December 24, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Wataru SUGIMURA, Ryusuke YOKOYAMA, Toshiyuki FUJIWARA, Toshiaki ONO
  • Publication number: 20200399783
    Abstract: A convection pattern control method includes: heating a silicon melt in a quartz crucible using a heating portion; and applying a horizontal magnetic field to the silicon melt in the quartz crucible being rotated. In the heating of the silicon, the silicon melt is heated with the heating portion whose heating capacity differs on both sides across an imaginary line passing through a center axis of the quartz crucible and being in parallel to a central magnetic field line of the horizontal magnetic field when the quartz crucible is viewed from vertically above. In the applying of the horizontal magnetic field, the horizontal magnetic field of 0.2 tesla or more is applied to fix a direction of a convection flow in a single direction in a plane orthogonal to an application direction of the horizontal magnetic field in the silicon melt.
    Type: Application
    Filed: February 27, 2019
    Publication date: December 24, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Hideki SAKAMOTO, Wataru SUGIMURA, Ryusuke YOKOYAMA, Naoki MATSUSHIMA
  • Patent number: 10858753
    Abstract: A silicon single crystal manufacturing method by a Czochralski method pulls up a silicon single crystal from a silicon melt in a quartz crucible while applying a magnetic field to the silicon melt. During a pull-up process of the silicon single crystal, the surface temperature of the silicon melt is continuously measured, and crystal growth conditions are changed based on a result of frequency analysis of the surface temperature.
    Type: Grant
    Filed: May 9, 2017
    Date of Patent: December 8, 2020
    Assignee: SUMCO CORPORATION
    Inventors: Wataru Sugimura, Ryusuke Yokoyama, Mitsuaki Hayashi
  • Publication number: 20200165742
    Abstract: A silicon single crystal manufacturing method by a Czochralski method pulls up a silicon single crystal from a silicon melt in a quartz crucible while applying a magnetic field to the silicon melt. During a pull-up process of the silicon single crystal, the surface temperature of the silicon melt is continuously measured, and crystal growth conditions are changed based on a result of frequency analysis of the surface temperature.
    Type: Application
    Filed: May 9, 2017
    Publication date: May 28, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Wataru SUGIMURA, Ryusuke YOKOYAMA, Mitsuaki HAYASHI