Patents by Inventor Takahiro Kohashi

Takahiro Kohashi 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: 4614706
    Abstract: A film of a photoresist having phenolic hydroxyl groups is irradiated with far-ultraviolet radiation, and is thereafter developed with an alkaline aqueous solution. Using as a mask a resist pattern thus obtained, dry etching is carried out to form a microscopic pattern. Since the photoresist is highly immune against the dry etching, the microscopic pattern can be formed at a high precision. By adding an azide of a specified structure, the photoresist has its sensitivity to the far-ultraviolet radiation enhanced more.
    Type: Grant
    Filed: May 2, 1984
    Date of Patent: September 30, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Toshiharu Matsuzawa, Takao Iwayanagi, Kikuo Douta, Hiroshi Yanazawa, Takahiro Kohashi, Saburo Nonogaki
  • Patent number: 4561169
    Abstract: In manufacturing a field effect transistor, a pattern which has a wider upper layer and a narrower lower layer is formed at a gate electrode position. Using the pattern as a mask, first and second impurity regions are formed on both the sides of a gate region by ion implantation. Subsequently, at least the lower layer is buried in a material, such as an organic high polymer material, having a selectivity in etching characteristics with respect to the pattern material. After removing the lower layer, an electrode material is embedded in the resulting hole so as to form a gate electrode.
    Type: Grant
    Filed: July 26, 1983
    Date of Patent: December 31, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Masaru Miyazaki, Susumu Takahashi, Takahiro Kohashi, Kiichi Ueyanagi
  • Patent number: 4520094
    Abstract: A photosensitive composition turning shicky by light exposure, which comprises a salt or p-aminobenzenediazonium compound and at least one of salts of o- and m-aminobenzenediazonium compounds, has a distinguished effect in forming a phosphor screen of a color picture tube.
    Type: Grant
    Filed: October 19, 1982
    Date of Patent: May 28, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Hajime Morishita, Motoo Akagi, Nobuaki Hayashi, Saburo Nonogaki, Shoichi Uchino, Takahiro Kohashi
  • Patent number: 4469778
    Abstract: Disclosed is a pattern formation method comprising exposing a photosensitive composition comprising a bisazide compound represented by the following general formula: ##STR1## wherein A stands for an atom or atomic group selected from O, S, CH.sub.2, CH.sub.2 CH.sub.2, SO.sub.2 and S.sub.2, X stands for an atom or atomic group selected from H and N.sub.3, and when X is H, Z is a group of N.sub.3 and when X is N.sub.3, Z is an atom of H or Cl, and a polymeric compound to deep UV rays, to form fine patterns.
    Type: Grant
    Filed: April 14, 1983
    Date of Patent: September 4, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Takao Iwayanagi, Takahiro Kohashi, Saburo Nonogaki, Yoshio Hatano
  • Patent number: 4465768
    Abstract: A radiation-sensitive composition comprising an iodine-containing azide compound at least a part of which can be fixed substantially in a polymer by exposure to a radiation and a polymer, or a radiation-sensitive composition comprising an azide compound, an iodine compound at least a part of which can be fixed substantially in a polymer by exposure to a radiation and a polymer. This composition can be subjected to the dry development with oxygen plasma after the exposure followed by heating.
    Type: Grant
    Filed: July 13, 1982
    Date of Patent: August 14, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Takumi Ueno, Hiroshi Shiraishi, Takao Iwayanagi, Takahiro Kohashi, Saburo Nonogaki
  • Patent number: 4409313
    Abstract: A photosensitive composition improved in sensitivity by adding a salt of a compound represented by the general formula: ##STR1## (wherein R.sub.1 and R.sub.2 each represents a straight chain alkyl group, and X, Y and Z each represents H, a straight chain alkyl group or an alkoxy group, but two or more of X, Y and Z can not be H at the same time) to an aromatic diazonium salt which gets sticky upon exposure to light.
    Type: Grant
    Filed: September 29, 1982
    Date of Patent: October 11, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Hajime Morishita, Takahiro Kohashi, Saburo Nonogaki, Motoo Akagi, Nobuaki Hayashi, Shoichi Uchino
  • Patent number: 4377630
    Abstract: A photosensitive composition improved in sensitivity by adding a salt of a compound represented by the general formula: ##STR1## (wherein R.sub.1 and R.sub.2 each represents a straight chain alkyl group, and X, Y and Z each represents H, a straight chain alkyl group or an alkoxy group, but two or more of X, Y and Z can not be H at the same time) to an aromatic diazonium salt which gets sticky upon exposure to light.
    Type: Grant
    Filed: July 2, 1981
    Date of Patent: March 22, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Hajime Morishita, Takahiro Kohashi, Saburo Nonogaki, Motoo Akagi, Nobuaki Hayashi, Shoichi Uchino
  • Patent number: 4241162
    Abstract: This invention relates to light sensitive photoresist materials which are used in the photo-engraving process or in the production of the phosphor screens of color picture tubes. The light sensitive photoresist materials of this invention are novel, water-soluble azide materials.
    Type: Grant
    Filed: December 2, 1976
    Date of Patent: December 23, 1980
    Assignee: Hitachi, Ltd.
    Inventors: Yoshio Hatano, Takahiro Kohashi, Michiaki Hashimoto, Saburo Nonogaki
  • Patent number: 4191571
    Abstract: The present invention relates to a novel light sensitive photoresist composition which is used for the photo-engraving process or for production of phosphor screen of color picture tubes. The light sensitive photoresist composition of the present invention comprises a novel water-soluble aromatic azide compound and a photo-crosslinkable water-soluble polymer.
    Type: Grant
    Filed: February 7, 1977
    Date of Patent: March 4, 1980
    Assignee: Hitachi, Ltd.
    Inventors: Saburo Nonogaki, Takahiro Kohashi, Yoshio Hatano
  • Patent number: 4086090
    Abstract: The present invention affords a process for forming a pattern having a surface area substantially equal to or smaller than area of apertures of shadow-mask through which beams pass on a photoresist film, which contains an acrylamidediacetoneacrylamide copolymer and a water-soluble aromatic bisazide compound, by exposing said photoresist film to light through a mask having the pattern and then developing the film.The use of said photoresist film for the preparation of a phosphor screen of a color picture tube of a black matrix or black stripe type does not require a special technique such as post-etching of a shadow mask and makes it possible to form a three primary color phosphor pattern having a surface area substantially equal to or smaller than the area of apertures of the shadow mask through which lightbeams pass, without mutual "bridging" between phosphor dots. Thus, an excellent phosphor screen of a color picture tube of a black matrix or black stripe type can be prepared.
    Type: Grant
    Filed: September 22, 1975
    Date of Patent: April 25, 1978
    Assignee: Hitachi, Ltd.
    Inventors: Takahiro Kohashi, Motoo Akagi, Yoichi Oba, Saburo Nonogaki, Makoto Tanaka, Tadao Kaneko, Yoshifumi Tomita