Patents by Inventor Fumio Kawahigashi

Fumio Kawahigashi 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).

  • Patent number: 6767400
    Abstract: In the CZ process using a cooling member surrounding a single crystal, the cooling member is permitted to effectively serve to increase a pulling speed. Cracks of the single crystal due to excessive cooling are prevented to occur. A high crystal quality is acquired. In order to realize these objects, the temperature of the inner peripheral surface of the cooling member 6 opposing to the outer peripheral surface of the single crystal 4 is restricted to 500° C. or below, even in the lower end, the temperature of which becomes the highest. To achieve this restriction, the thickness T of the cooling member 5 is 10 to 50 mm. The height H of the cooling member 6 is 0.1 to 1.5 times the diameter D of the single crystal 4.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: July 27, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano, Shinichiro Miki, Manabu Nishimoto
  • Patent number: 6764547
    Abstract: An apparatus for growing a crystal, using the cooler 10 surrounding the single crystal 8 for high speed pulling. The cooler 10 is prepared using a copper-based metal and is water cooled. The supporting arm 12 that supports the cooler 10 is prepared using stainless steel or the like, which is higher in mechanical strength than copper-based metals and is inferior in thermal conductivity, and is detachably connected to the cooler 10. Excessive cooling of the supporting arm 12 and disposition due to precipitation of silicon oxide are prevented, leading to improvement in disposition free pulling rate without the prevention of speed-up. The cost of manufacture of the cooler 10 is saved. The support strength of the cooler is improved.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: July 20, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano, Naohiro Takaoka
  • Patent number: 6740160
    Abstract: In a high rate pulling with a cooler 10 surrounding a single crystal 8, steam explosion by leakage from the cooler 10 is prevented. Flow rates La, Lb of cooling water are measured by flowmeters 14a, 14b on a cooling water inflow side and cooling water outflow side of the cooler 10. When flow rate difference &Dgr;L (La−Lb) determined from the flow rates La, Lb exceeds 20 cc/minute, open/close valves 15a, 15b, 15c are operated to stop water supply to the cooler 10 and drain outward the cooing water in the cooler 10.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: May 25, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takayuki Kubo, Hiroshi Asano, Fumio Kawahigashi, Akira Tsujino
  • Patent number: 6702892
    Abstract: An apparatus is provided which is to be used in producing single crystals for silicon wafers useful as semiconductor materials and which can stably produce large-diameter, long-length and high-quality single crystals from which wafers limited in the number of grown-in defects can be taken. This silicon single crystal production apparatus comprises a cooling member surrounding the single crystal to be pulled up and having an internal surface coaxial with the pulling axis and thermal insulating members disposed outside the outer surface and below the bottom surface of the cooling member, the cooling member having an internal surface diameter of 1.20D to 2.50D (D being the diameter of the single crystal to be pulled up) and a length of not less than 0.25D, the distance from the melt surface to the bottom surface of the cooling member being 0.30D to 0.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: March 9, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Masahiko Okui, Manabu Nishimoto, Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano
  • Publication number: 20030183163
    Abstract: In a high rate pulling with a cooler 10 surrounding a single crystal 8, steam explosion by leakage from the cooler 10 is prevented. Flow rates La, Lb of cooling water are measured by flowmeters 14a, 14b on a cooling water inflow side and cooling water outflow side of the cooler 10. When flow rate difference &Dgr;L (La−Lb) determined from the flow rates La, Lb exceeds 20 cc/minute, open/close valves 15a, 15b, 15c are operated to stop water supply to the cooler 10 and drain outward the cooing water in the cooler 10.
    Type: Application
    Filed: March 26, 2002
    Publication date: October 2, 2003
    Inventors: Takayuki Kubo, Hiroshi Asano, Fumio Kawahigashi, Akira Tsujino
  • Publication number: 20030150373
    Abstract: In the CZ process using a cooling member surrounding a single crystal, the cooling member is permitted to effectively serve to increase a pulling speed. Cracks of the single crystal due to excessive cooling are prevented to occur. A high crystal quality is acquired. In order to realize these objects, the temperature of the inner peripheral surface of the cooling member 6 opposing to the outer peripheral surface of the single crystal 4 is restricted to 500° C. or below, even in the lower end, the temperature of which becomes the highest. To achieve this restriction, the thickness T of the cooling member 5 is 10 to 50 mm. The height H of the cooling member 6 is 0.1 to 1.5 times the diameter D of the single crystal 4.
    Type: Application
    Filed: September 24, 2002
    Publication date: August 14, 2003
    Inventors: Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano, Shinichiro Miki, Manabu Nishimoto
  • Publication number: 20030051661
    Abstract: An apparatus for growing a crystal, using the cooler 10 surrounding the single crystal 8 for high speed pulling. The cooler 10 is prepared using a copper-based metal and is water cooled. The supporting arm 12 that supports the cooler 10 is prepared using stainless steel or the like, which is higher in mechanical strength than copper-based metals and is inferior in thermal conductivity, and is detachably connected to the cooler 10. Excessive cooling of the supporting arm 12 and disposition due to precipitation of silicon oxide are prevented, leading to improvement in disposition free pulling rate without the prevention of speed-up. The cost of manufacture of the cooler 10 is saved. The support strength of the cooler is improved.
    Type: Application
    Filed: October 15, 2002
    Publication date: March 20, 2003
    Inventors: Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano, Naohiro Takaoka
  • Publication number: 20020139298
    Abstract: An apparatus is provided which is to be used in producing single crystals for silicon wafers useful as semiconductor materials and which can stably produce large-diameter, long-length and high-quality single crystals from which wafers limited in the number of grown-in defects can be taken. This silicon single crystal production apparatus comprises a cooling member surrounding the single crystal to be pulled up and having an internal surface coaxial with the pulling axis and thermal insulating members disposed outside the outer surface and below the bottom surface of the cooling member, the cooling member having an internal surface diameter of 1.20D to 2.50D (D being the diameter of the single crystal to be pulled up) and a length of not less than 0.25D, the distance from the melt surface to the bottom surface of the cooling member being 0.30D to 0.
    Type: Application
    Filed: November 20, 2001
    Publication date: October 3, 2002
    Inventors: Masahiko Okui, Manabu Nishimoto, Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano