# US 2020/0399783 A1 · Method for controlling convection pattern of silicon melt, method for producing silicon single crystals, and device for pulling silicon single crystals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0399783 A1 - Document ID: US20200399783A1 - Status: Published application - Kind: A1 - Application number: 16/971,441 - Filed: 2019-02-27 - Published: 2020-12-24 - Earliest claimed: 2018-02-28 - Assignees: Sumco Corporation - Applicants: Sumco Corporation - Inventors: Hideki SAKAMOTO; Wataru SUGIMURA; Ryusuke YOKOYAMA; Naoki MATSUSHIMA - Web page: https://patentgrep.com/patent/US20200399783A1 ## CPC - C30B 15/305: {Stirring of the melt} - C30B 29/06: Silicon - C30B 15/14: Heating of the melt or the crystallised materials - C30B 15/20: Controlling or regulating (controlling or regulating in general G05) - C30B 15/206: {the thermal history of growing the ingot} - C30B 30/04: using magnetic fields - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR ## 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. ## Claims ### Claim 1 A convection pattern control method of a silicon melt used for manufacturing monocrystalline silicon, the method comprising: heating the silicon melt in a quartz crucible in a magnetic-field-free state with a heating portion; and applying a horizontal magnetic field to the silicon melt in the quartz crucible being rotated, wherein in the heating of the silicon melt, 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, and 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 the silicon melt in a plane orthogonal to a direction in which the horizontal magnetic field is applied. ### Claim 2 (depends on 1) The convection pattern control method according to claim 1, wherein the heating capacity of the heating portion is set in a first state where the heating capacity of the heating portion is lower in a positive direction than in a negative direction of an X axis or in a second state where the heating capacity of the heater is higher in the positive direction than in the negative direction of the X axis with respect to the imaginary line as viewed from a positive direction of a Z axis in a right-handed XYZ Cartesian coordinate system defining a center of a surface of the silicon melt as an origin, a vertically upward direction as the positive direction of the Z axis, and a direction in which the horizontal magnetic field is applied as a positive direction of a Y axis, and in the applying of the horizontal magnetic field, the direction of the convection flow as viewed in a negative direction of the Y axis is fixed clockwise when the heating capacity is in the first state, and the direction of the convection flow is fixed anticlockwise when the heating capacity is in the second state. ### Claim 3 (depends on 1) The convection pattern control method according to claim 1, wherein in the heating of the silicon melt, the silicon melt is heated such that a difference between a maximum temperature and a minimum temperature on the surface of the silicon melt is 6 degrees C. or more. ### Claim 4 (depends on 3) The convection pattern control method according to claim 3, wherein in the heating of the silicon melt, the silicon melt is heated such that the difference between the maximum temperature and the minimum temperature is 12 degrees C. or less. ### Claim 5 (depends on 1) A manufacturing method of monocrystalline silicon, comprising: conducting the convection pattern control method of the silicon melt according to claim 1; and pulling up the monocrystalline silicon while an intensity of the horizontal magnetic field is kept at 0.2 tesla or more. ### Claim 6 A pull-up device of monocrystalline silicon, comprising: a quartz crucible; a heating portion configured to heat a silicon melt in the quartz crucible; and magnetic-field applying portions located across the quartz crucible and configured to apply a horizontal magnetic field of 0.2 tesla or more to the silicon melt, wherein a heating capacity of the heating portion 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. ### Claim 7 (depends on 6) The pull-up device of the monocrystalline silicon according to claim 6, wherein the heating portion comprises a heater surrounding the quartz crucible, and the heater has a resistance value differing in regions on the respective sides. ### Claim 8 (depends on 6) The pull-up device of the monocrystalline silicon according to claim 6, wherein the heating portion comprises a heater surrounding the quartz crucible, and a voltage-applying portion configured to apply voltage to the heater, the heater comprises a first section heater on one side and a second section heater on the other side with respect to the imaginary line, and the voltage-applying portion applies voltage such that power outputted by the first section heater is different from power outputted by the second section heater. ### Claim 9 (depends on 6) The pull-up device of the monocrystalline silicon according to claim 6, wherein the heating portion comprises a heater surrounding the quartz crucible, and a heat insulation material surrounding the heater, and the heat insulation material has a heat insulation performance differing in regions on the respective sides.