Patents by Inventor Masao Yoshimuta

Masao Yoshimuta 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).

  • Method for manufacturing silicon wafer
    Patent number: 7902039
    Abstract: A method for manufacturing a silicon wafer is characterized by performing one or both of grinding and polishing to a thin discoid silicon wafer to give bowl-shaped warpage that is concave at a central part to a wafer surface. One main surface of the thin discoid silicon wafer is adsorbed and held, and one or both of grinding and polishing are performed to the other main surface to fabricate a convex wafer whose thickness is increased from a wafer outer periphery toward a wafer center or fabricate a concave wafer whose thickness is reduced from the wafer outer periphery toward the wafer center. Then, the other main surface is adsorbed and held to protrude the center or the periphery of the one main surface side based on elastic deformation. One or both of grinding and polishing are carried out with respect to the one main surface to flatten the main surface, and adsorption and holding are released to give bowl-shaped warpage that is concave at the central part to the other main surface or the one main surface.
    Type: Grant
    Filed: November 28, 2007
    Date of Patent: March 8, 2011
    Assignee: Sumco Corporation
    Inventors: Shinichi Tomita, Masao Yoshimuta, Yasuyuki Hashimoto, Akira Nakashima
  • Method for manufacturing silicon wafer
    Patent number: 7781313
    Abstract: A method for manufacturing a silicon wafer is characterized by performing one or both of grinding and polishing to a thin discoid silicon wafer to give bowl-shaped warpage that is concave at a central part to a wafer surface. One main surface of the thin discoid silicon wafer is adsorbed and held, and one or both of grinding and polishing are performed to the other main surface to fabricate a convex wafer whose thickness is increased from a wafer outer periphery toward a wafer center or fabricate a concave wafer whose thickness is reduced from the wafer outer periphery toward the wafer center. Then, the other main surface is adsorbed and held to protrude the center or the periphery of the one main surface side based on elastic deformation. One or both of grinding and polishing are carried out with respect to the one main surface to flatten the main surface, and adsorption and holding are released to give bowl-shaped warpage that is concave at the central part to the other main surface or the one main surface.
    Type: Grant
    Filed: September 1, 2009
    Date of Patent: August 24, 2010
    Assignee: Sumco Corporation
    Inventors: Shinichi Tomita, Masao Yoshimuta, Yasuyuki Hashimoto, Akira Nakashima
  • Method for manufacturing silicon wafer
    Publication number: 20090325385
    Abstract: A method for manufacturing a silicon wafer is characterized by performing one or both of grinding and polishing to a thin discoid silicon wafer to give bowl-shaped warpage that is concave at a central part to a wafer surface. One main surface of the thin discoid silicon wafer is adsorbed and held, and one or both of grinding and polishing are performed to the other main surface to fabricate a convex wafer whose thickness is increased from a wafer outer periphery toward a wafer center or fabricate a concave wafer whose thickness is reduced from the wafer outer periphery toward the wafer center. Then, the other main surface is adsorbed and held to protrude the center or the periphery of the one main surface side based on elastic deformation. One or both of grinding and polishing are carried out with respect to the one main surface to flatten the main surface, and adsorption and holding are released to give bowl-shaped warpage that is concave at the central part to the other main surface or the one main surface.
    Type: Application
    Filed: September 1, 2009
    Publication date: December 31, 2009
    Inventors: Shinichi Tomita, Masao Yoshimuta, Yasuyuki Hashimoto, Akira Nakashima
  • METHOD FOR MANUFACTURING SILICON WAFER
    Publication number: 20080132032
    Abstract: A method for manufacturing a silicon wafer is characterized by performing one or both of grinding and polishing to a thin discoid silicon wafer to give bowl-shaped warpage that is concave at a central part to a wafer surface. One main surface of the thin discoid silicon wafer is adsorbed and held, and one or both of grinding and polishing are performed to the other main surface to fabricate a convex wafer whose thickness is increased from a wafer outer periphery toward a wafer center or fabricate a concave wafer whose thickness is reduced from the wafer outer periphery toward the wafer center. Then, the other main surface is adsorbed and held to protrude the center or the periphery of the one main surface side based on elastic deformation. One or both of grinding and polishing are carried out with respect to the one main surface to flatten the main surface, and adsorption and holding are released to give bowl-shaped warpage that is concave at the central part to the other main surface or the one main surface.
    Type: Application
    Filed: November 28, 2007
    Publication date: June 5, 2008
    Inventors: Shinichi Tomita, Masao Yoshimuta, Yasuyuki Hashimoto, Akira Nakashima