Patents by Inventor Tatsuo Okamoto

Tatsuo Okamoto 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: 4997360
    Abstract: An apparatus for manufacturing a heat-shrinkable tube has a die formed with a center bore through which a resin tube passes and a plurality of radial holes extending from the bore to the outer periphery of the die. The die is contained in a tank filled with a cooling fluid so that the die will be immersed in the cooling fluid. The interior of the tank is kept under reduced pressure. At the inlet side of the die, a pre-cooling unit is provided which supplies a cooling fluid to the outer periphery of a resin tube which have been heated to a temperature above its softening point beforehand. The tube is expanded at least by the suction force applied thereto while passing through the die kept under reduced pressure. The cooling fluid in the tank and that supplied from the pre-cooling unit serve to reduce the friction between the tube and the inner periphery of the die, thus preventing the tube from expanding lengthwise. A jacket may be provided around the die to supply the cooling fluid.
    Type: Grant
    Filed: April 20, 1989
    Date of Patent: March 5, 1991
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tatsuo Okamoto, Tatsuya Horioka
  • Patent number: 4985319
    Abstract: A photomask manufacturing process including a step of forming metal silicide film on a transparent silica glass substrate. A resist is applied onto the metal silicide film and then a patterning mask is provided by light or electron beam, followed by developing step. Exposed portions of the metal silicide film is etched away using a dry etching process.
    Type: Grant
    Filed: October 23, 1989
    Date of Patent: January 15, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yaichiro Watakabe, Tatsuo Okamoto, Shuichi Matsuda
  • Patent number: 4977105
    Abstract: Conductive layers (5a, 8a) included in a multi-layer structure (30a) are electrically interconnected through an conductive connection wall (13a) provided in a contact hole (12) and contacting the side surface (22) of the multi-layer structure (30a). The upper conductive layer (11a) existing on the multi-layer structure (30a) and the lower conductive layer (3) existing under the multi-layer structure (30a) are electrically interconnected through a conductive film (11b) provided in the contact hole (12). These two interconnections are insulated from each other by an insulating film (18) provided on the connection wall (13a).
    Type: Grant
    Filed: August 9, 1989
    Date of Patent: December 11, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Hideo Kotani, Takio Oono, Kiyoto Watabe, Yasushi Kinoshita, Yoshikazu Nishikawa
  • Patent number: 4959329
    Abstract: The present invention relates to a semiconductor device having a contact electrode structure and a method of manufacturing the same. An insulating layer is provided in a second semiconductor layer or in a junction part between the second semiconductor layer and a first semiconductor layer correspondence to a contact hole. Therefore, even if a pit generated at a junction part between the second semiconductor layer and a conductive layer in the contact hole grows, the growth of the pit is inhibited by the insulating layer, whereby leakage current caused between the first and second semiconductor layers can be reduced, a reliability of the device being thus enhanced.
    Type: Grant
    Filed: October 24, 1989
    Date of Patent: September 25, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Akihiko Ohsaki
  • Patent number: 4916508
    Abstract: A MOS type integrated circuit transistor includes: a channel region comprising a monocrystalline epitaxial layer; and a source/drain region of said transistor and a wiring region of a diffusion layer formed of a polycrystalline silicon layer grown on an embedded insulating film.
    Type: Grant
    Filed: January 7, 1987
    Date of Patent: April 10, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsuhiro Tsukamoto, Tatsuhiko Ikeda, Tatsuo Okamoto
  • Patent number: 4910578
    Abstract: A semiconductor device comprises a silicon substrate (1) formed with impurity diffusion layers (5, 9) in a region defined by insulating films (2a, 2b) for separating elements and an aluminum alloy film (11) for electrode interconnection having a contact hole portion 7 whose bottom is electrically in contact with the impurity diffusion layers (5, 9). A titanium silicide (TiSi.sub.2) film (4) is deposited on the surfaces of the impurity diffusion layers (5, 9) to reduce sheet resistivity thereof as well as reduce contact resistance between the same and the aluminum alloy film (11). A molybdenum silicide (MoSi.sub.2) film (8) is further formed thereon to prevent the TiSi.sub.2 film (4) from corrosion in removal of an oxide film through etching, while a titanium nitride (TiN) film (10) is formed thereon to prevent thermal reaction of the aluminum alloy film (11) and the MoSi.sub.2 film (8).
    Type: Grant
    Filed: February 11, 1988
    Date of Patent: March 20, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Tatsuo Okamoto
  • Patent number: 4903117
    Abstract: A silicon oxide film and a BPSG film are formed on a silicon substrate to serve as insulating films, and a contact hole is selectively formed in the insulating films. An impurity diffusion layer is formed on the surface layer of the semiconductor substrate at the bottom portion of the contact hole. A second metal film serving as a metal electrode is formed to cover the BPSG film and the impurity diffusion layer, and a first metal film serving as a barrier layer is formed between the second metal film and the BPSG film and impurity diffusion layer. The first metal film prevents boron contained in the BPSG film from being diffused in the second metal film, thereby to prevent precipitation of silicon in the contact hole.
    Type: Grant
    Filed: June 7, 1988
    Date of Patent: February 20, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Ikuo Ogoh
  • Patent number: 4887143
    Abstract: The present invention relates to a semiconductor device having a contact electrode structure and a method of manufacturing the same. An insulating layer is provided in a second semiconductor layer or in a junction part between the second semiconductor layer and a first semiconductor layer correspondence to a contact hole. Therefore, even if a pit generated at a junction part between the second semiconductor layer and a conductive layer in the contact hole grows, the growth of the pit is inhibited by the insulating layer, whereby leakage current caused between the first and second semiconductor layers can be reduced, a reliability of the device being thus enhanced.
    Type: Grant
    Filed: March 28, 1988
    Date of Patent: December 12, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Akihiko Ohsaki
  • Patent number: 4876164
    Abstract: A photomask manufacturing process including a step of forming metal silicide film on a transparent silica glass substrate. A resist is applied onto the metal silicide film and then a patterning mask is provided by light or electron beam, followed by developing step. Exposed portions of the metal silicide film is etched away using a dry etching process.
    Type: Grant
    Filed: July 17, 1987
    Date of Patent: October 24, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yaichiro Watakabe, Tatsuo Okamoto, Shuichi Matsuda
  • Patent number: 4873163
    Abstract: A photomask material according to the present invention comprises a transparent substrate and a silicide film of a transition metal formed on the transparent substrate.
    Type: Grant
    Filed: August 8, 1988
    Date of Patent: October 10, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yaichiro Watakabe, Hiroaki Morimoto, Tatsuo Okamoto
  • Patent number: 4872050
    Abstract: Conductive layers (5a, 9a) included in a multi-layer structure (30a) are electrically interconnected through a conductive connection wall (13a) provided in a contact hole (12) and contacting the side surface (22) of the multi-layer structure (30a). The upper conductive layer (11a) existing on the multi-layer structure (30a) and the lower conductive layer (3) exisitng under the multi-layer structure (30a) are electrically interconnected through a conductive film (11b) provided in the contact hole (12). These two interconnections are insulated from each other by an insulating film (18) provided on the connection wall (13a).
    Type: Grant
    Filed: March 15, 1988
    Date of Patent: October 3, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Hideo Kotani, Takio Oono, Kiyoto Watabe, Yasushi Kinoshita, Yoshikazu Nishikawa
  • Patent number: 4710790
    Abstract: A gate electrode (4') of a MOS transistor is formed in a depression (16) provided in a substrate (1). Source and drain regions (6 and 7) of the MOS transistor are formed in the substrate (1) to be opposed to each other with the gate electrode (4') being located therebetween.
    Type: Grant
    Filed: July 3, 1984
    Date of Patent: December 1, 1987
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Kouji Eguchi, Saburou Oosaki
  • Patent number: 4708904
    Abstract: A semiconductor device and a method of manufacturing the same which comprises a semiconductor substrate and a conductive region formed thereon in multilayer structure of a film of refractory metal or refractory metal silicide inferior in corrosion resistance against a solution containing hydrofluoric acid and a film of refractory metal silicide excellent in corrosion resistance against the solution containing hydrofluorine acid and low electric resistance formed on the same.
    Type: Grant
    Filed: November 15, 1985
    Date of Patent: November 24, 1987
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masahiro Shimizu, Tatsuo Okamoto, Katsuhiro Tsukamoto
  • Patent number: 4707723
    Abstract: A semiconductor device in which a multilayer film comprising a low resistance refractory metal silicide film and a low resistance ternary alloy film formed thereon and having corrosion resistance to hydrofluoric acid is used as an electrode and interconnection. The above stated low resistance refractory metal silicide is titanium silicide or tantalum silicide. The above stated ternary alloy is titanium-M-silicon or tantalum-M-silicon, M being any of molybdenum, tungsten, niobium, vanadium and tantalum.
    Type: Grant
    Filed: February 18, 1986
    Date of Patent: November 17, 1987
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Masahiro Shimizu, Katsuhiro Tsukamoto
  • Patent number: 4665608
    Abstract: A method of manufacturing a semiconductor device comprises a step of preparing a semiconductor substrate (12) having a surface layer of silicon, a step of forming a conductive thin film (14) of a silicide composed of a metal having a high melting point and silicon on the semiconductor substrate (12), a step of forming an oxidation-resistant mask (18) on a first portion (14a) of the conductive thin film (14) and a step of converting a second, exposed, portion (19) of the conductive thin film (14) into an insulating film (19a) of a composite oxide composed of silicon oxide and an oxide of the subject metal by oxidizing the exposed portion (19) while maintaining the first portion (14a) of the conductive thin film (14) covered by the mask (18).
    Type: Grant
    Filed: December 14, 1984
    Date of Patent: May 19, 1987
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuo Okamoto, Hiroshi Harada
  • Patent number: 4043037
    Abstract: A cord-type mowing tool having a cutter body formed with at least one radially extending bore for receiving a cord serving as a grass cutting blade, and a clamping member fitted in the central bottom opening of the cutter body for forcing against the central portion of the cutter body an end portion of the cord inserted in the radially extending bore to hold the cord in place. The clamping member is threadably connected to the cutter body, so that by loosening and tightening the threadable connection it is possible to readily replace the old cord by a new cord of a predetermined length. The grass cutting tool is simple in construction, light in weight and reliable in performance.
    Type: Grant
    Filed: October 14, 1976
    Date of Patent: August 23, 1977
    Assignee: Kioritz Corporation
    Inventors: Tatsuo Okamoto, Masat Nogawa, Nobuyoshi Okabe