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).
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Publication number: 20230243066Abstract: 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: ApplicationFiled: January 25, 2023Publication date: August 3, 2023Applicant: SUMCO CORPORATIONInventors: Yasuhito NARUSHIMA, Masayuki UTO
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Patent number: 11598023Abstract: 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: GrantFiled: June 29, 2020Date of Patent: March 7, 2023Assignee: SUMCO CORPORATIONInventors: Yasuhito Narushima, Masayuki Uto
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Publication number: 20210404087Abstract: 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: ApplicationFiled: June 29, 2020Publication date: December 30, 2021Applicant: SUMCO CORPORATIONInventors: Yasuhito NARUSHIMA, Masayuki UTO
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Patent number: 11047065Abstract: 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: GrantFiled: October 12, 2017Date of Patent: June 29, 2021Assignee: SUMCO CORPORATIONInventors: Yasuhito Narushima, Masayuki Uto
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Publication number: 20200115821Abstract: 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: ApplicationFiled: October 12, 2017Publication date: April 16, 2020Applicant: SUMCO CORPORATIONInventors: Yasuhito NARUSHIMA, Masayuki UTO
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Patent number: 10329686Abstract: 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: GrantFiled: November 17, 2015Date of Patent: June 25, 2019Assignee: SUMCO CORPORATIONInventors: Yasuhito Narushima, Toshimichi Kubota, Masayuki Uto
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Patent number: 10233562Abstract: 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: GrantFiled: April 15, 2014Date of Patent: March 19, 2019Assignee: SUMCO TECHXIV CORPORATIONInventors: Yasuhito Narushima, Toshimichi Kubota, Fukuo Ogawa, Masayuki Uto
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Patent number: 10227710Abstract: 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: GrantFiled: June 28, 2016Date of Patent: March 12, 2019Assignee: SUMCO TECHXIV CORPORATIONInventors: Yasuhito Narushima, Toshimichi Kubota, Masayuki Uto
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Patent number: 10100429Abstract: 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: GrantFiled: April 8, 2015Date of Patent: October 16, 2018Assignee: SUMCO CORPORATIONInventors: Yasuhito Narushima, Masayuki Uto, Toshimichi Kubota
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Publication number: 20170327966Abstract: 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: ApplicationFiled: November 17, 2015Publication date: November 16, 2017Applicant: SUMCO CORPORATIONInventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Masayuki UTO
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Publication number: 20170283980Abstract: 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: ApplicationFiled: April 8, 2015Publication date: October 5, 2017Applicant: SUMCO CORPORATIONInventors: Yasuhito NARUSHIMA, Masayuki UTO, Toshimichi KUBOTA
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Publication number: 20170029975Abstract: 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: ApplicationFiled: June 28, 2016Publication date: February 2, 2017Applicant: SUMCO TECHXIV CORPORATIONInventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Masayuki UTO
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Publication number: 20160102418Abstract: 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: ApplicationFiled: April 15, 2014Publication date: April 14, 2016Applicant: SUMCO TECHXIV CORPORATIONInventors: Yasuhito NARUSHIMA, Toshimichi KUBOTA, Fukuo OGAWA, Masayuki UTO
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Patent number: 8888911Abstract: 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: GrantFiled: September 3, 2010Date of Patent: November 18, 2014Assignee: Sumco Techxiv CorporationInventors: Masayuki Uto, Tuneaki Tomonaga, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima
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Publication number: 20110056428Abstract: 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: ApplicationFiled: September 3, 2010Publication date: March 10, 2011Applicant: SUMCO CORPORATIONInventors: Masayuki Uto, Tuneaki Tomonaga, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima