Patents by Inventor Sadayuki Okuni

Sadayuki Okuni 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: 20070101926
    Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, comprising the steps of: providing a seed crystal having a tip end with a sharp-pointed shape or a truncation thereof in which an angle of the tip end is 28° or less; keeping the tip end of the seed crystal at just above a silicon melt to heat it before bringing the tip end of the seed crystal into contact with the silicon melt; bringing the tip end of the seed crystal into contact with the silicon melt and immersing the seed crystal into the silicon melt to a desired diameter; and shifting to pull the single crystal, wherein a temperature variation at a surface of the silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of the seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal.
    Type: Application
    Filed: January 4, 2007
    Publication date: May 10, 2007
    Applicant: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi FUSEGAWA, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
  • Patent number: 7179330
    Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, wherein a temperature variation at a surface of a silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of a seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal. Thereby, in a method of growing a silicon single crystal by Czochralski method without using Dash Necking method, a success ratio of growing a single crystal free from dislocation can be increased, at the same time a heavy silicon single crystal having a large diameter in which a diameter of a constant diameter portion is over 200 mm can be grown even in the case of growing a silicon single crystal having a crystal orientation of <110>.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: February 20, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
  • Publication number: 20050160966
    Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, wherein a temperature variation at a surface of a silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of a seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal.
    Type: Application
    Filed: April 23, 2003
    Publication date: July 28, 2005
    Applicant: SHIN-ETSU HANDOTAI CO., LTD
    Inventors: Izumi Fusegawa, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
  • Patent number: 6652358
    Abstract: In a double side simultaneous grinding machine, in which a plate-like workpiece is held and ground simultaneously on both a front surface and a back surface using a pair of grinding stones provided oppositely at both sides of the workpiece, a relative position between at least one of the center of thickness of the plate-like workpiece and the center of the holding means for holding the workpiece, and the center between stone surfaces of the pair of grinding stones is controlled during grinding. In a double side simultaneous grinding method, the generation of warpage of the plate-like workpiece is suppressed and degradation of warpage is prevented. Thereby, the plate-like workpiece can be processed to have high flatness on both sides. Further, the plate-like workpiece can be ground while a degree of warpage is controlled so that the workpiece is processed to have a warpage of a desired degree.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: November 25, 2003
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Shunichi Ikeda, Sadayuki Okuni, Tadahiro Kato
  • Patent number: 6491836
    Abstract: A method for producing a semiconductor wafer that yields a wafer having high flatness and back surface characteristics to address problems concerning the back surface of a wafer produced by the conventional surface grinding/double side polishing method and observed during the production process. The method comprises flattening both sides of the wafer by surface grinding means, eliminating a mechanically damaged layer by an etching treatment, and then subjecting a front surface of the wafer to a single side polishing treatment, wherein a back surface of the wafer has glossiness in a range of 20-80%.
    Type: Grant
    Filed: June 26, 2000
    Date of Patent: December 10, 2002
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Tadahiro Kato, Sadayuki Okuni, Shunichi Ikeda, Keiichi Okabe, Hisashi Oshima
  • Patent number: 6284658
    Abstract: The present invention has an object to provide a manufacturing process of a semiconductor wafer in which improvement on accuracy in a chamfering portion is realized. The manufacturing process of a semiconductor wafer comprises: a slicing step of obtaining a wafer in the shaped of a thin disk by slicing a single crystal ingot; a surface-grinding step of flattening a surface of the wafer; a chamfering step of chamfering the peripheral edge portions; and mirror-polishing step of mirror-polishing the surface of the wafer, wherein a simultaneous double-side surface-grinding step of grinding both sides of the wafer simultaneously by a double-side grinding machine is existent prior to the chamfering step in order to remove wafer waviness and a secondary grinding step is performed by grinding a single side or simultaneously both sides of the wafer after the chamfering step is carried out, so that improvement on accuracy in a chamfered portion is realized.
    Type: Grant
    Filed: July 7, 1999
    Date of Patent: September 4, 2001
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Tadahiro Kato, Sadayuki Okuni, Keiichi Okabe, Hisashi Oshima
  • Patent number: 6220928
    Abstract: The present invention provides a surface grinding method and apparatus for achieving a thin plate work such as a semiconductor wafer with high flatness, high accuracy and certainty and the apparatus comprises: a surface grinder in which a grinding wheel support member 3 by which a rotary shaft 5 of a grinding wheel 6 is supported is held by a pivotal shaft portion 4 and a grinding wheel shaft inclination control motor 9 which displaces the grinding wheel support member 3 by activating the pivotal shaft portion 4 is provided; a corrective angle storage device 15 which stores a corrective angle of an inclination angle of a rotary shaft 5 of the grinding wheel 6 to a rotary shaft 13 of a wafer 12; and a shaft inclination control apparatus 14 which sends out a signal to control the grinding wheel shaft inclination control motor 9 while reading a corrective angle of the corrective angle storage device 15, wherein a relative inclination angle of the grinding wheel to the thin plate work, in a more concrete manner a
    Type: Grant
    Filed: April 29, 1999
    Date of Patent: April 24, 2001
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Keiichi Okabe, Hisashi Oshima, Sadayuki Okuni, Tadahiro Kato
  • Patent number: 6050880
    Abstract: A surface grinding method for a thin-plate workpiece is provided including the steps of (a) roughly surface grinding a first surface of a thin-plate workpiece using a thin-plate workpiece surface grinding device to create a reference plane having no sori or waviness; (b) inverting the thin-plate workpiece, the first surface of which has been roughly surface ground and, with a surface grinding device having a hard chucking plate, chucking the first surface to the hard chucking plate to roughly surface grind a second surface of the thin-plate workpiece; (c) chucking to the hard chucking plate the first surface of the thin-plate workpiece, the second surface of which has been roughly surface ground with the surface grinding device having the hard chucking plate to further finely surface grind the second surface of the thin-plate workpiece; and (d) inverting the thin-plate workpiece, the second surface of which has been finely surface ground and, with the surface grinding device having the hard chucking plate, ch
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: April 18, 2000
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Tadahiro Kato, Sadayuki Okuni, Hideo Kudo, Hiroshi Tomioka
  • Patent number: 5942445
    Abstract: According to the invention, the flatness and quality can be improved while simplifying the process even when large size wafers of 200 to 300 mm or above are processed. Basic steps involved are a slicing step E for obtaining thin disc-shape wafers by slicing, a chamfering step F for chamfering the sliced wafers, a flattening step G for flattening the chamfered wafers, an alkali etching step H for removing process damage layers from the flattened wafers, and a double-side polishing step K of simultaneously polishing the two sides of the etched wafers. If necessary, a plasma etching step is used in lieu of the flattening and etching steps G and H respectively.
    Type: Grant
    Filed: March 25, 1997
    Date of Patent: August 24, 1999
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Tadahiro Kato, Hisashi Masumura, Sadayuki Okuni, Hideo Kudo