Patents by Inventor Akifumi Yao

Akifumi Yao 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: 20180211844
    Abstract: A technique capable of removing a natural oxide film formed on a surface of a semiconductor layer which contains a compound of indium and an element other than indium as a main ingredient, without making a temperature of the semiconductor layer relatively high. The technique includes supplying a first etching gas which is ?-diketone to the semiconductor layer and heating the semiconductor layer to remove an oxide of the indium constituting the natural oxide film; and supplying a second etching gas to the semiconductor layer and heating the semiconductor layer to remove an oxide of the element constituting the natural oxide film. By using the first etching gas, it is possible to remove the indium oxide even if the temperature of the semiconductor layer is relatively low. This eliminates the need to increase the temperature to a relatively high level when removing the natural oxide film.
    Type: Application
    Filed: June 7, 2016
    Publication date: July 26, 2018
    Inventors: Jun LIN, Koji TAKEYA, Shinichi KAWAGUCHI, Mitsuhiro TACHIBANA, Akifumi YAO, Kunihiro YAMAUCHI
  • Publication number: 20180212131
    Abstract: A thermoelectric conversion material is used in which columnar or spherical nanodots 1 having a diameter of 20 nm or less are embedded in an embedding layer 3 at an area density of 5×1010/cm2 or more and an interval between the nanodots of 0.5 nm or more and 30.0 nm or less, and the first material constituting the nanodot 1 is a material containing silicon in an amount of 30 atom % or more, and, either one or both of a difference in energy between the valence band of the first material and the valence band of the second material constituting the embedding layer 3 and a difference in energy between the conduction band of the first material and the conduction band of the second material constituting the embedding layer are in the range of 0.1 eV or more and 0.3 eV or less.
    Type: Application
    Filed: March 23, 2018
    Publication date: July 26, 2018
    Inventors: Akiou KIKUCHI, Akifumi YAO, Seiji SAMUKAWA, Takahito ONO
  • Publication number: 20180204728
    Abstract: Disclosed is a dry etching method for etching a laminated film of silicon oxide layers and silicon nitride layers on a substrate. The dry etching method includes providing a mask on the laminated film, generating a plasma from a dry etching agent and etching the laminated film by the plasma through the mask under a bias voltage of 500 V or higher to form a through hole in the laminated film vertically to the layers, wherein the dry etching agent contains at least C3H2F4, an unsaturated perfluorocarbon represented by CxFy and an oxidizing gas, and wherein a volume of the unsaturated perfluorocarbon contained in the dry etching agent is 0.1 to 10 times a volume of the C3H2F4 contained in the dry etching agent.
    Type: Application
    Filed: July 1, 2016
    Publication date: July 19, 2018
    Inventors: Hiroyuki OOMORI, Akifumi YAO
  • Patent number: 9991138
    Abstract: An etching method includes a step of etching a cobalt film formed on a surface of a target object by supplying an etching gas containing ?-diketone and an oxidizing gas for oxidizing the cobalt film to the target object. The supply of the etching gas and the oxidizing gas is carried out such that a flow rate ratio of the oxidizing gas to the etching gas is ranging from 0.5% to 50% while heating the target object to a temperature lower than or equal to 250° C.
    Type: Grant
    Filed: July 25, 2016
    Date of Patent: June 5, 2018
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Jun Lin, Koji Takeya, Mitsuhiro Tachibana, Akifumi Yao, Kunihiro Yamauchi, Tatsuo Miyazaki
  • Publication number: 20180138053
    Abstract: Disclosed is a wet etching method for etching a metal-containing film on a substrate with the use of an etching solution, wherein the etching solution contains an organic solvent and a ?-diketone having a trifluoromethyl group and a carbonyl group bonded to each other, and wherein the metal-containing film contains a metal element capable of forming a complex with the ?-diketone.
    Type: Application
    Filed: June 22, 2016
    Publication date: May 17, 2018
    Inventors: Akifumi YAO, Kunihiro YAMAUCHI, Masaki FUJIWARA, Tatsuo MIYAZAKI
  • Patent number: 9929021
    Abstract: A dry etching method provided to involve the steps of: (a) disposing a substrate within a chamber, the substrate having an amorphous carbon film; (b) preparing a plasma gas by converting a dry etching agent into a plasma, the dry etching agent containing at least oxygen and alkylsilane; and (c) conducting plasma etching on the amorphous carbon film by using the plasma gas and an inorganic film as a mask.
    Type: Grant
    Filed: September 13, 2016
    Date of Patent: March 27, 2018
    Assignee: Central Glass Company, Limited
    Inventors: Hiroyuki Oomori, Akifumi Yao
  • Publication number: 20180066187
    Abstract: What is disclosed is a dry etching gas containing 1,3,3,3-tetrafluoropropene, wherein 1,3,3,3-tetrafluoropropene has purity of 99.5 mass % or more, and a total of concentration of each mixed metal component of Fe, Ni, Cr, Al, and Mo is 500 mass ppb or less. Furthermore, regarding to the dry etching gas, it is preferable that a content of nitrogen is 0.5 volume % or less, and that a content of water is 0.05 mass % or less. In a dry etching with a plasma gas obtained by making a dry etching gas into plasma, the dry etching gas of the present invention can improve etching selectivity of silicon-based material with respect to a mask.
    Type: Application
    Filed: March 4, 2016
    Publication date: March 8, 2018
    Inventors: Yosuke NAKAMURA, Masaki FUJIWARA, Hiroyuki OOMORI, Akifumi YAO
  • Patent number: 9708720
    Abstract: Disclosed is a gas generation device 100 that has a mist trap 50a equipped with a tubular housing 51, a gas inlet port 52 for allowing the gas generated from an electrolytic cell, a gas outlet port 53 for allowing the gas to flow out of the housing, a filler receiving section 58 that is positioned between the gas inlet port 52 and the gas outlet port 53 and receives a filler 56 for adsorbing mist and microparticles, and a gas diffusion section 57 that is positioned between the gas inlet port 52 and the filler receiving section 58 and is for diffusing the gas generated from the electrolytic cell 1 through the housing 51, that the gas outlet port 53 has a gas inlet tube 55 connecting to the interior of the housing 51, and that a gas entry portion 59 of the gas inlet tube 55 is arranged so as to be embedded in the filler 56 received in the filler receiving section 58.
    Type: Grant
    Filed: October 23, 2012
    Date of Patent: July 18, 2017
    Assignee: Central Glass Company, Limited
    Inventors: Akifumi Yao, Akiou Kikuchi
  • Publication number: 20170084467
    Abstract: A dry etching method provided to involve the steps of: (a) disposing a substrate within a chamber, the substrate having an amorphous carbon film; (b) preparing a plasma gas by converting a dry etching agent into a plasma, the dry etching agent containing at least oxygen and alkylsilane; and (c) conducting plasma etching on the amorphous carbon film by using the plasma gas and an inorganic film as a mask.
    Type: Application
    Filed: September 13, 2016
    Publication date: March 23, 2017
    Inventors: Hiroyuki OOMORI, Akifumi YAO
  • Publication number: 20170032990
    Abstract: An etching method includes a step of etching a cobalt film formed on a surface of a target object by supplying an etching gas containing ?-diketone and an oxidizing gas for oxidizing the cobalt film to the target object. The supply of the etching gas and the oxidizing gas is carried out such that a flow rate ratio of the oxidizing gas to the etching gas is ranging from 0.5% to 50% while heating the target object to a temperature lower than or equal to 250° C.
    Type: Application
    Filed: July 25, 2016
    Publication date: February 2, 2017
    Inventors: Jun LIN, Koji TAKEYA, Mitsuhiro TACHIBANA, Akifumi YAO, Kunihiro YAMAUCHI, Tatsuo MIYAZAKI
  • Patent number: 9238872
    Abstract: Disclosed is an electrode for electrolytic synthesis of a fluorine compound, including: an electrode substrate having at least a surface thereof formed of a conductive carbon material; a conducting diamond layer formed on a part of the surface of the electrode substrate; and a metal fluoride-containing coating layer formed on an exposed part of the electrode substrate that is uncovered by the conducting diamond layer. It is possible for the electrolytic synthesis electrode to limit the growth of a graphite fluoride layer on the electrode surface, prevent decrease in effective electrolysis area and allow stable electrolysis in an electrolytic bath of a hydrogen fluoride-containing molten salt.
    Type: Grant
    Filed: January 27, 2012
    Date of Patent: January 19, 2016
    Assignee: Central Glass Company, Limited
    Inventors: Isamu Mori, Akifumi Yao, Akiou Kikuchi, Masaaki Yonekura, Hiroshi Horiuchi
  • Patent number: 9194050
    Abstract: A fluorine gas generating device 100 which is characterized by having a cylindrical member 31a for circulating therein the main-product gas, a gas feed port 51a for introducing the main-product gas into the cylindrical member 31a, a gas discharge port 52a for discharging the main-product gas from the cylindrical member 31a, an adsorbent holding member 201 arranged in the cylindrical member 31a to form a space to provide a channel for the main-product gas circulated in the cylindrical member 31a, a stirring blade 202 for stirring the main-product gas that is introduced through the gas feed port 51a, and a gas flow guiding cylinder 203 for circulating or diffusing the main-product gas in the space within the cylindrical member 31a.
    Type: Grant
    Filed: May 17, 2012
    Date of Patent: November 24, 2015
    Assignee: Central Glass Company, Limited
    Inventors: Takuya Kita, Tatsuo Miyazaki, Akifumi Yao
  • Publication number: 20150292092
    Abstract: Disclosed is a gas generation device 100 that has a mist trap 50a equipped with a tubular housing 51, a gas inlet port 52 for allowing the gas generated from an electrolytic cell, a gas outlet port 53 for allowing the gas to flow out of the housing, a filler receiving section 58 that is positioned between the gas inlet port 52 and the gas outlet port 53 and receives a filler 56 for adsorbing mist and microparticles, and a gas diffusion section 57 that is positioned between the gas inlet port 52 and the filler receiving section 58 and is for diffusing the gas generated from the electrolytic cell 1 through the housing 51, that the gas outlet port 53 has a gas inlet tube 55 connecting to the interior of the housing 51, and that a gas entry portion 59 of the gas inlet tube 55 is arranged so as to be embedded in the filler 56 received in the filler receiving section 58.
    Type: Application
    Filed: October 23, 2012
    Publication date: October 15, 2015
    Inventors: Akifumi Yao, Akiou Kikuchi
  • Patent number: 9139918
    Abstract: A fluorine gas generating apparatus includes: a first main passage connected to a first gas chamber and supplying a fluorine gas to an external device; a first conveying device leading out and conveying the fluorine gas from the first gas chamber; a first pressure detector detecting the pressure on the upstream side of the first conveying device; a first pressure regulating valve returning the fluorine gas from the first conveying device to the suction side of the first conveying device; a controller controlling the opening degree of the first pressure regulating valve so that the pressure detected by the first pressure detector becomes a first set value; a start valve provided on the upstream side of the pressure detector; and a differential pressure detector for detecting the pressure difference before and after the start valve in the closed valve state.
    Type: Grant
    Filed: April 4, 2011
    Date of Patent: September 22, 2015
    Assignee: CENTRAL GLASS COMPANY, LIMITED
    Inventors: Akifumi Yao, Keita Nakahara
  • Patent number: 8961631
    Abstract: There is provided a process for producing a fluorinated nanodiamond dispersion liquid, including a purification step of mixing a fluorinated nanodiamond with an alcohol having a carbon number of 4 or fewer, then conducting an ultrasonic treatment to produce a suspension, and subjecting the obtained suspension to a classification treatment by centrifugation to produce a dispersion liquid of fluorinated nanodiamond; a drying step to prepare a dry fluorinated nanodiamond by removing the alcohol from the dispersion liquid of fluorinated nanodiamond that is obtained by the purification step; and a redispersion step to prepare the fluorinated nanodiamond dispersion liquid by mixing the dry fluorinated nanodiamond that is obtained by the drying step, with an aprotic polar solvent and then conducting an ultrasonic treatment.
    Type: Grant
    Filed: October 10, 2008
    Date of Patent: February 24, 2015
    Assignee: Central Glass Company, Limited
    Inventor: Akifumi Yao
  • Patent number: 8951393
    Abstract: A provided emergency stop facility includes an alternative gas supply facility capable of supplying a cooling medium in a refining device as an alternative gas instead of an entrained gas shut-off by closure of an entrained gas shut-off valve with loss of a driving source caused by the emergency stop; an alternative entrained gas shut-off valve switching between supply and shut-off of an alternative gas to a hydrogen fluoride supply passage; and an instrumentation gas supply facility for emergency stop having an instrumentation gas shut-off valve enabling supply of an instrumentation gas by opening with loss of the driving source caused by the emergency stop, wherein at the emergency stop of the fluorine gas generating apparatus, the alternative entrained gas shut-off valve is opened upon receipt of the supply of the instrumentation gas, and the alternative gas is supplied to the hydrogen fluoride supply passage.
    Type: Grant
    Filed: January 18, 2011
    Date of Patent: February 10, 2015
    Assignee: Central Glass Company, Limited
    Inventors: Akifumi Yao, Nobuyuki Tokunaga
  • Publication number: 20140360884
    Abstract: A fluorine gas generating device 100 is provided which facilitates the maintenance operation of recovery and replacement of an adsorbing material that adsorbs hydrogen fluoride and supplies fluorine gas in a stable manner. The device comprises a refining line 20 that includes refining devices that, with the aid of adsorbing material, remove hydrogen fluoride gas that has been evaporated from a molten salt of an electrolytic tank 1 and mixed to fluorine gas generated at a positive pole 103a of the electrolytic tank. The refining line 20 comprises a first refining section 21 that includes at least two refining devices arranged in parallel and a second refining section 22 that includes at least two refining devices arranged in parallel and is positioned downstream of the first refining section 21. Fluorine gas that has passed through either one of the refining devices of the first refining section 21 is selectively led to either one of the refining devices of the second refining section.
    Type: Application
    Filed: August 25, 2014
    Publication date: December 11, 2014
    Inventors: Isamu MORI, Tatsuo MIYAZAKI, Akifumi YAO, Takuya KITA
  • Publication number: 20140326596
    Abstract: A fluorine gas generating device comprises an electrolytic tank that generates at an anode side a main-product containing as a main component fluorine gas and at a cathode side a by-product gas containing as a main component hydrogen gas by subjecting, in an electrolytic bath, hydrogen fluoride in a molten salt containing therein hydrogen fluoride to an electrolysis; a hydrogen fluoride supply source that stores therein hydrogen fluoride that is to be fed to the electrolytic tank to fill up hydrogen fluoride; a hydrogen fluoride supply passage through which hydrogen fluoride flows from the hydrogen fluoride supply source to the electrolytic tank; and a vaporizer that is connected to the hydrogen fluoride supply passage to vaporize hydrogen fluoride supplied from the hydrogen fluoride supply source.
    Type: Application
    Filed: October 31, 2012
    Publication date: November 6, 2014
    Applicant: Central Glass Company, Limited
    Inventors: Tatsuya Irie, Akifumi Yao
  • Patent number: 8864961
    Abstract: A fluorine gas generating apparatus includes an electrolytic cell where the molten salt is retained and which is separated and divided above the liquid level of the molten salt into a first gas chamber where a product gas mainly containing a fluorine gas generated at an anode immersed in the molten salt is led and a second gas chamber where a byproduct gas mainly containing a hydrogen gas generated at a cathode immersed in the molten salt is led, and a refining device refining the fluorine gas by coagulating with a cooling medium and trapping a hydrogen fluoride gas evaporated from the molten salt in the electrolytic cell and mixed in the product gas generated from the anode. The cooling medium for coagulation of the hydrogen fluoride gas in the refining device and discharged is re-used as a utility gas used at spots in the fluorine gas generating apparatus.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: October 21, 2014
    Assignee: Central Glass Company, Limited
    Inventors: Akiou Kikuchi, Akifumi Yao, Tatsuo Miyazaki, Nobuyuki Tokunaga
  • Patent number: 8864960
    Abstract: A fluorine gas generating apparatus generating a fluorine gas by electrolyzing hydrogen fluoride in molten salt, includes: an electrolytic cell including, above a liquid level of molten salt, a first gas chamber into which a product gas mainly containing the fluorine gas generated at an anode immersed in the molten salt and a second gas chamber separated from the first gas chamber into which a byproduct gas mainly containing a hydrogen gas generated at a cathode immersed in the molten salt; a hydrogen fluoride supply source retaining hydrogen fluoride to be replenished in the electrolytic cell; a refining device trapping a hydrogen fluoride gas evaporated from the molten salt in the electrolytic cell and mixed in the product gas generated from the anode to refine the fluorine gas; and a recovery facility conveying and recovering the hydrogen fluoride trapped in the refining device in the electrolytic cell or the hydrogen fluoride supply source.
    Type: Grant
    Filed: November 25, 2010
    Date of Patent: October 21, 2014
    Assignee: Central Glass Company, Limited
    Inventors: Akifumi Yao, Tatsuo Miyazaki, Yosuke Nakamura, Keita Nakahara, Nobuyuki Tokunaga