Patents by Inventor Takayuki Togawa

Takayuki Togawa 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: 20120304762
    Abstract: A method for producing a pyrolytic boron nitride (PBN) article comprises introducing a nitrogen containing gas and a boron containing gas into a heated reactor furnace under temperature and pressure conditions sufficient to form a PBN deposit and pulsing the flow of the reactant gases between an on and an off state. The method provides a multi-layered PBN article that exhibits a relatively weak bonding interface between adjacent PBN layers to allow for the layers to be peeled away from one another in a controlled manner.
    Type: Application
    Filed: June 3, 2011
    Publication date: December 6, 2012
    Inventors: Caixuan XU, Subbanna MANJUNATH, Takayuki TOGAWA
  • Patent number: 7686887
    Abstract: An object of the invention is to provide a quartz glass crucible reduced in the generation of vibration occurring on the surface of a silicon melt and free from the generation of rough surface and cristobalite spots, yet capable of pulling up single crystal silicon stably and at high yield even in long-term operations; it is also an object to provide a method for producing the same. In a quartz glass crucible for pulling up single crystal silicon comprising a crucible base body having a bottom part and a straight shell part with an inner layer provided to the inner surface thereof, the quartz glass crucible is characterized by that said inner layer comprises a synthetic quartz glass layer from the lowest end to at least a height of 0.25 H; a naturally occurring quartz glass layer or a mixed layer of naturally occurring quartz glass and synthetic quartz glass extended in a range of from at least 0.5 H to 0.
    Type: Grant
    Filed: July 30, 2003
    Date of Patent: March 30, 2010
    Assignees: Heraeus Quarzglas GmbH & Co. KG, Shin-Etsu Quartz Products Co., Ltd.
    Inventors: Yasuo Ohama, Takayuki Togawa
  • Patent number: 7299658
    Abstract: A quartz glass crucible for use in pulling up a silicon single crystal, wherein it has, at least in the curved portion thereof, a three-layer structure comprising a transparent inner layer being composed of a synthetic quartz glass and having a low Al concentration, a transparent or nontransparent intermediate layer being composed of a natural quartz glass or a mixture of natural and synthetic quartz glasses and having a high Al concentration, and a nontransparent outer layer being composed of a natural quartz glass and having an Al concentration higher than that of the intermediate layer. The quartz glass crucible is reduced in the deformation of the transparent inner layer, and allows the suppression of the change in the amount of dissolution of the quartz glass crucible associated with the pull-up of a single crystal and the achievement of the uniform oxygen concentration in the longitudinal direction of a single crystal.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: November 27, 2007
    Assignees: Heraeus Quarzglas GmbH & Co. K.G., Shin-Etsu Quartz Products Co. Ltd.
    Inventors: Yasuo Ohama, Takayuki Togawa, Shigeo Mizuno
  • Patent number: 7074731
    Abstract: It is an object of the present invention to provide a hydrogen-doped silica powder that is useful in the formation of a quartz glass crucible that is capable of pulling a silicon single crystal without causing a state having dislocations in the silicon single crystal due to peeling of quartz glass segment. It is a further object of the invention to provide a quartz glass crucible for use in pulling a silicon single crystal whose inner surface is formed by use of the hydrogen-doped silica powder and a producing method of the silica powder.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: July 11, 2006
    Assignees: Heraeus Quarzglas GmbH & Co. KG, Shin-Etsu Quartz Products Co., Ltd.
    Inventors: Yasuo Ohama, Takayuki Togawa
  • Publication number: 20060144327
    Abstract: A quartz glass crucible for use in pulling up a silicon single crystal, wherein it has, at least in the curved portion thereof, a three-layer structure comprising a transparent inner layer being composed of a synthetic quartz glass and having a low Al concentration, a transparent or nontransparent intermediate layer being composed of a natural quartz glass or a mixture of natural and synthetic quartz glasses and having a high Al concentration, and a nontransparent outer layer being composed of a natural quartz glass and having an Al concentration higher than that of the intermediate layer. The quartz glass crucible is reduced in the deformation of the transparent inner layer, and allows the suppression of the change in the amount of dissolution of the quartz glass crucible associated with the pull-up of a single crystal and the achievement of the uniform oxygen concentration in the longitudinal direction of a single crystal.
    Type: Application
    Filed: May 21, 2004
    Publication date: July 6, 2006
    Inventors: Yasuo Ohama, Takayuki Togawa, Shigeo Mizuno
  • Publication number: 20060096946
    Abstract: A wafer processing device for use in semiconductor wafer processing applications as an Electro-Static Chuck (ESC) comprising a graphite substrate and at least one electrode pattern, wherein the grooves in the electrode pattern are filled with insulating or semiconducting material selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and rare earth metals, or complexes and/or combinations thereof, forming a substantially planar surface. The substantially planar surface is then coated with at least a semiconducting layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and rare earth metals, or complexes and/or combinations thereof.
    Type: Application
    Filed: October 28, 2005
    Publication date: May 11, 2006
    Inventors: Marc Schaepkens, Takayuki Togawa
  • Publication number: 20050235907
    Abstract: An object of the invention is to provide a quartz glass crucible reduced in the generation of vibration occurring on the surface of a silicon melt and free from the generation of rough surface and cristobalite spots, yet capable of pulling up single crystal silicon stably and at high yield even in long-term operations; it is also an object to provide a method for producing the same. In a quartz glass crucible for pulling up single crystal silicon comprising a crucible base body having a bottom part and a straight shell part with an inner layer provided to the inner surface thereof, the quartz glass crucible is characterized by that said inner layer comprises a synthetic quartz glass layer from the lowest end to at least a height of 0.25 H; a naturally occurring quartz glass layer or a mixed layer of naturally occurring quartz glass and synthetic quartz glass extended in a range of from at least 0.5 H to 0.
    Type: Application
    Filed: July 30, 2003
    Publication date: October 27, 2005
    Inventors: Yasuo Ohama, Takayuki Togawa
  • Publication number: 20040025783
    Abstract: It is an object of the present invention to provide a hydrogen-doped silica powder that is useful in the formation of a quartz glass crucible that is capable of pulling a silicon single crystal without causing a state having dislocations in the silicon single crystal due to peeling of quartz glass segment. It is a further object of the invention to provide a quartz glass crucible for use in pulling a silicon single crystal whose inner surface is formed by use of the hydrogen-doped silica powder and a producing method of the silica powder.
    Type: Application
    Filed: May 16, 2003
    Publication date: February 12, 2004
    Inventors: Yasuo Ohama, Takayuki Togawa
  • Patent number: 6510707
    Abstract: Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then converted to a continuous layer, thereby minimizing or eliminating bubble formation. The inner layer is also formed using a gettering agent which getters alkaline and alkaline-earth elements while the inner layer is formed. The alkaline and alkaline-earth elements are gettered on an innermost portion of the inner layer which is later removed, leaving an inner layer with relatively few impurities. When used in a CZ-crystal growing process, the inner surface of the crucible remains smooth and substantially no bubbles grow in the inner layer.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: January 28, 2003
    Assignee: Heraeus Shin-Etsu America, Inc.
    Inventors: Katsuhiko Kemmochi, Takayuki Togawa, Robert Mosier, Paul Spencer
  • Publication number: 20020166340
    Abstract: Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then converted to a continuous layer, thereby minimizing or eliminating bubble formation. The inner layer is also formed using a gettering agent which getters alkaline and alkaline-earth elements while the inner layer is formed. The alkaline and alkaline-earth elements are gettered on an innermost portion of the inner layer which is later removed, leaving an inner layer with relatively few impurities. When used in a CZ-crystal growing process, the inner surface of the crucible remains smooth and substantially no bubbles grow in the inner layer.
    Type: Application
    Filed: March 15, 2001
    Publication date: November 14, 2002
    Inventors: Katsuhiko Kemmochi, Takayuki Togawa, Robert Mosier, Paul Spencer