Patents Assigned to Sumco Corporation
  • 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: 20210123159
    Abstract: The amount of gas evacuation from a reaction chamber of an apparatus for manufacturing epitaxial wafers is controlled to any one of: a first amount of gas evacuation when an epitaxial film formation process is performed in the reaction chamber; a second amount of gas evacuation smaller than the first amount of gas evacuation when a gate valve is opened to load or unload a wafer between the reaction chamber and a wafer transfer chamber; and a third amount of gas evacuation larger than the first amount of gas evacuation until a purge process for a gas in the reaction chamber is completed after the epitaxial film formation process is completed in the reaction chamber.
    Type: Application
    Filed: November 5, 2018
    Publication date: April 29, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Yu MINAMIDE, Naoyuki WADA, Yasutaka TAKEMURA
  • Patent number: 10982350
    Abstract: A production method of a monocrystalline silicon includes: forming a shoulder of the monocrystalline silicon; and forming a straight body of the monocrystalline silicon. In forming the shoulder, the shoulder is formed such that a part of growth striations, which extend radially across the shoulder, has an outer end interrupted by another part of the growth striations not to reach a peripheral portion of the shoulder and that no remelt growth area with a height of 200 ?m or more in a growth direction is generated.
    Type: Grant
    Filed: April 26, 2017
    Date of Patent: April 20, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Toshimichi Kubota
  • 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
  • Patent number: 10975495
    Abstract: An epitaxial growth apparatus that can provide an improved thickness uniformity of an epitaxial film is provided. An epitaxial growth apparatus in accordance with the present disclosure includes a susceptor and a preheat ring surrounding a side of the susceptor having a gap interposed therebetween. A width of the gap at least in part between the susceptor and the preheat ring is set to be longer than a width w1 of the gap between the susceptor and the preheat ring in the vicinity of the reactant gas inlet.
    Type: Grant
    Filed: March 1, 2018
    Date of Patent: April 13, 2021
    Assignee: SUMCO CORPORATION
    Inventor: Haku Komori
  • Patent number: 10971351
    Abstract: Example features relate to a method of polishing a chamfered wafer surface, the method including beveling a wafer to generate the chamfered wafer surface, the chamfered wafer surface being inclined with respect to a main wafer surface by an angle ?; and polishing the chamfered wafer surface with a polishing pad, a polishing surface of the polishing pad being inclined with respect to the chamfered wafer surface by an angle ?; wherein the angle ? is equal to or smaller than the angle ?. Example features relate to a system for polishing the chamfered surface, the system including a polishing pad mounting jig configured to polish the chamfered surface, an angle ? being defined between the chamfered surface and the main surface; and a polishing pad in contact with the chamfered surface at an angle ? during polishing; wherein the angle ? is smaller than the angle ?.
    Type: Grant
    Filed: September 13, 2019
    Date of Patent: April 6, 2021
    Assignee: SUMCO CORPORATION
    Inventor: Kenji Yamashita
  • Publication number: 20210098259
    Abstract: A method for manufacturing an ingot block in which an ingot of a silicon single crystal pulled up by a Czochralski process is cut and subjected to outer periphery grinding to manufacture an ingot block of the silicon single crystal, the method including: a step of measuring a radial center position of the ingot at one or more locations along a longitudinal direction of the ingot, a step of setting a reference position at which an offset amount of the measured radial center position of the ingot is equal to or less than a predetermined eccentricity amount, a step of cutting the ingot into the ingot blocks based on the set reference position, and a step of performing outer periphery grinding on each of the cut ingot blocks.
    Type: Application
    Filed: October 22, 2018
    Publication date: April 1, 2021
    Applicant: SUMCO CORPORATION
    Inventor: Yasuhiro SAITO
  • Publication number: 20210083058
    Abstract: Provided is a method of producing an epitaxial silicon wafer having high gettering capability resulting in even more reduced white spot defects in a back-illuminated solid-state imaging device. The method includes: a first step of irradiating a surface of a silicon wafer with cluster ions of CnHm (n=1 or 2, m=1, 2, 3, 4, or 5) generated using a Bernas ion source or an IHC ion source, thereby forming, in the silicon wafer, a modifying layer containing, as a solid solution, carbon and hydrogen that are constituent elements of the cluster ions; and a subsequent second step of forming a silicon epitaxial layer on the surface. In the first step, peaks of concentration profiles of carbon and hydrogen in the depth direction of the modifying layer are made to lie in a range of more than 150 nm and 2000 nm or less from the surface.
    Type: Application
    Filed: August 24, 2018
    Publication date: March 18, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Takeshi KADONO, Kazunari KURITA
  • Patent number: 10935510
    Abstract: Provided is a method of measuring a carbon concentration of a silicon sample, the method including introducing hydrogen atoms into a measurement-target silicon sample; subjecting the measurement-target silicon sample into which hydrogen atoms have been introduced to evaluation by an evaluation method of evaluating a trap level in a silicon band gap, without an electron beam irradiation treatment; and determining the carbon concentration of the measurement-target silicon sample on the basis of an evaluation result at least one trap level selected from the group consisting of Ec-0.10 eV, Ec-0.13 eV and Ec-0.15 eV, among the evaluation results obtained by the evaluation, wherein the determined carbon concentration is lower than 1.0E+16 atoms/cm3.
    Type: Grant
    Filed: January 18, 2017
    Date of Patent: March 2, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Kazutaka Eriguchi, Shuichi Samata, Noritomo Mitsugi, Ayumi Masada
  • Publication number: 20210055213
    Abstract: A method for measuring carbon concentration in silicon single crystal according to the present invention includes a step of measuring a carbon concentration of a sample of silicon single crystal using FT-IR, a step of measuring a temperature of the sample during, prior to, or after the measurement of the carbon concentration of the sample, and steps of correcting a measured value Ycs of the carbon concentration of the sample based on the measuring temperature of the sample when the measured Ycs value of the carbon concentration of the sample is at or below 0.5×1016 atoms/cm3.
    Type: Application
    Filed: May 23, 2019
    Publication date: February 25, 2021
    Applicant: SUMCO CORPORATION
    Inventor: Shogo KOBAYASHI
  • Patent number: 10920339
    Abstract: A pulling condition calculation program enables a computer to perform the steps of: setting a plurality of sets of pulling conditions based on solid-liquid interface height and distance between a surface of a silicon melt and a heat shield plate; performing, for each set of the pulling conditions, the steps of: calculating a heat flux (q) (W/m2) and a crystal surface temperature (T); defining a reference temperature (Tref) given by an equation (1) below and a geometry of the solid-liquid interface as boundary conditions, recalculating an in-crystal temperature distribution; calculating a mean stress in the monocrystalline silicon; calculating a defect distribution in a pulling direction based on the mean stress and the in-crystal temperature distribution; determining a defect-free region in the pulling direction; and drawing a contour line showing a dimension of the defect-free region on a two-dimensional map defined by the distance and the solid-liquid interface height.
    Type: Grant
    Filed: December 7, 2017
    Date of Patent: February 16, 2021
    Assignee: SUMCO CORPORATION
    Inventor: Ryota Suewaka
  • Publication number: 20210040642
    Abstract: A production method of monocrystalline silicon includes: growing the monocrystalline silicon having a straight-body diameter in a range from 301 mm to 330 mm that is pulled up through a Czochralski process from a silicon melt including a dopant in a form of red phosphorus; controlling a resistivity of the monocrystalline silicon at a straight-body start point to fall within a range from 1.20 m?cm to 1.35 m?cm; and subsequently sequentially decreasing the resistivity of the monocrystalline silicon to fall within a range from 0.7 m?cm to 1.0 m?cm at a part of the monocrystalline silicon.
    Type: Application
    Filed: June 15, 2018
    Publication date: February 11, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Yasufumi KAWAKAMI, Koichi MAEGAWA
  • Patent number: 10916425
    Abstract: A manufacturing method of monocrystalline silicon includes: disposing a flow regulator including a body in a form of an annular plate, provided under a heat shield, surrounding monocrystalline silicon; controlling an internal pressure of a chamber to 20 kPa or more during growth of monocrystalline silicon; keeping the flow regulator spaced from a dopant-added melt; and introducing inert gas into between the monocrystalline silicon and the heat shield to divide the inert gas into a first flow gas and a second flow gas.
    Type: Grant
    Filed: November 14, 2017
    Date of Patent: February 9, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Fukuo Ogawa, Yasuhito Narushima, Koichi Maegawa, Yasufumi Kawakami
  • Patent number: 10910328
    Abstract: Provided is a silicon wafer manufacturing method capable of reducing the warpage of the wafer occurring during a device process and allowing the subsequent processes, which have been suffered from problems due to severe warping of the wafer, to be carried out without problems and its manufacturing method. A silicon wafer manufacturing method according to the present invention is provided with calculating a target thickness of the silicon wafer required for ensuring a warpage reduction amount of a silicon wafer warped during a device process from a relationship between an amount of warpage of a silicon wafer and a thickness thereof occurring due to application of the same film stress to a plurality of silicon wafers having mutually different thicknesses; and processing a silicon single crystal ingot to thereby manufacture silicon wafers having the target thickness.
    Type: Grant
    Filed: June 6, 2018
    Date of Patent: February 2, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Bong-Gyun Ko, Toshiaki Ono
  • Publication number: 20210028023
    Abstract: The method of etching a boron-doped p-type silicon wafer includes preparing an etching gas by introducing an ozone-containing gas and hydrofluoric acid mist into a chamber and mixing them; and performing gas phase decomposition of a surface layer area of a boron-doped p-type silicon wafer with a resistivity of 0.016 ?cm or less by bringing the etching gas into contact with a surface of the boron-doped p-type silicon wafer; and further includes introducing the ozone-containing gas into the chamber at a flow rate of 3,000 sccm or more; and preparing the hydrofluoric acid mist by atomizing hydrofluoric acid with a hydrofluoric acid concentration of 41 mass % or more.
    Type: Application
    Filed: December 12, 2018
    Publication date: January 28, 2021
    Applicant: SUMCO CORPORATION
    Inventors: Hirokazu KATO, Takafumi YAMASHITA
  • Patent number: 10903099
    Abstract: Provided is a semiconductor wafer placement position determination method making it possible to measure a position deviation at a placement position of a semiconductor wafer when using a susceptor that is N-fold symmetric with respect to the center of the susceptor as a rotation axis. In this method, an opening edge of a counterbore portion of the susceptor is N-fold symmetric with respect to the center of the susceptor as a rotation axis (N?2). This method includes: a measurement step of measuring, while rotating the susceptor on which the semiconductor wafer is placed, a gap distance between a periphery of the semiconductor wafer and the opening edge; a first calculation step of performing, based on variation of the gap distance, period regression analysis; and a second calculation step of determining the position deviation based on an amplitude of a trigonometric function obtained by the first calculation step.
    Type: Grant
    Filed: November 29, 2018
    Date of Patent: January 26, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Ikuhiro Nakamura, Keiichi Takanashi
  • Patent number: 10895018
    Abstract: A production method of a monocrystalline silicon includes: forming a shoulder of the monocrystalline silicon; and forming a straight body of the monocrystalline silicon. To form the shoulder, a crucible is heated such that a heating ratio, which is calculated by dividing a volume of heat from a lower heater by a volume of heat from an upper heater, increases from a predetermined value of 1 or more.
    Type: Grant
    Filed: April 18, 2017
    Date of Patent: January 19, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Yasuhito Narushima, Toshimichi Kubota
  • Patent number: 10895538
    Abstract: Provided is a method of preparing a sample surface on which a marking is formed, wherein the marking is a local oxide film locally formed on the sample surface, the local oxide film is formed by applying voltage between a probe and the sample surface while a tip of the probe is in contact with the sample surface, and the probe is brought into contact with the sample surface after moisture supply.
    Type: Grant
    Filed: March 6, 2017
    Date of Patent: January 19, 2021
    Assignee: SUMCO CORPORATION
    Inventors: Keiichiro Mori, Kaori Hashimoto, Chie Hide
  • Publication number: 20210010156
    Abstract: A seed crystal holder for pulling up a single crystal is made of a carbon fiber-reinforced carbon composite material, and has a substantially cylindrical shape with a hollow space having a shape matching an outer shape of a substantially rod-shaped seed crystal. A direction of carbon fibers at a part in contact with at least an outer peripheral surface of the seed crystal has isotropy as viewed from a central axis of the hollow space.
    Type: Application
    Filed: September 30, 2020
    Publication date: January 14, 2021
    Applicant: SUMCO CORPORATION
    Inventor: Eiichi KAWASAKI
  • Publication number: 20200411392
    Abstract: Provided is a method capable of predicting the warpage caused when a silicon wafer is subjected to heat treatment taking into account the effect of oxygen and a method of producing a silicon wafer. The method includes: determining the mobile dislocation density, the stress, and the time evolution of the strain of the silicon wafer being subjected to heat treatment from the rate of change in the strain and the rate of change in the mobile dislocation density; and determining the magnitude of plastic deformation of the silicon wafer as a warpage. The mobile dislocation density Ni at the start of the heat treatment is given as: Ni=A×(?Oi×L?L0)2.5??(1), where A and L0: constants, ?Oi: the concentration of oxygen used by oxygen precipitates in the silicon wafer at the start of the heat treatment, L: the mean size of the oxygen precipitates at the start of the heat treatment.
    Type: Application
    Filed: May 21, 2018
    Publication date: December 31, 2020
    Applicant: SUMCO CORPORATION
    Inventors: Bong-Gyun KO, Kousuke TAKATA