Patents by Inventor Mitsugu Murata

Mitsugu Murata 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).

  • Regeneration process of etching solution, etching process, and etching system
    Patent number: 7238295
    Abstract: A regeneration process is disclosed for an etching solution composed of a phosphoric acid solution and used in etching silicon nitride films in an etch bath. As a result of the etching, the etching solution contains a silicon compound. According to the regeneration process, the etching solution with a silicon compound contained therein is taken out of the etch bath. Water is then added to the taken-out etching solution to lower a concentration of phosphoric acid in the etching solution to 80 to 50 wt. %. By the lowing of the concentration of phosphoric acid, the silicon compound is caused to precipitate. The thus-precipitated silicon compound is removed from the etching solution. An etching process making use of the regeneration process and an etching system suitable for use in practicing the regeneration process and etching process are also disclosed.
    Type: Grant
    Filed: September 15, 2003
    Date of Patent: July 3, 2007
    Assignee: m·FSI Ltd.
    Inventors: Nobuhiko Izuta, Mitsugu Murata
  • Regeneration process of etching solution, etching process, and etching system
    Publication number: 20040200806
    Abstract: A regeneration process is disclosed for an etching solution composed of a phosphoric acid solution and used in etching silicon nitride films in an etch bath. As a result of the etching, the etching solution contains a silicon compound. According to the regeneration process, the etching solution with a silicon compound contained therein is taken out of the etch bath. Water is then added to the taken-out etching solution to lower a concentration of phosphoric acid in the etching solution to 80 to 50 wt. %. By the lowing of the concentration of phosphoric acid, the silicon compound is caused to precipitate. The thus-precipitated silicon compound is removed from the etching solution. An etching process making use of the regeneration process and an etching system suitable for use in practicing the regeneration process and etching process are also disclosed.
    Type: Application
    Filed: September 15, 2003
    Publication date: October 14, 2004
    Applicant: m FSI LTD.
    Inventors: Nobuhiko Izuta, Mitsugu Murata