Patents by Inventor Tohru Umezaki

Tohru Umezaki 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).

  • Amorphous silica powder, process for its production, and sealing material for semiconductors
    Patent number: 8048817
    Abstract: To provide an amorphous silica powder suitable for a sealing material for semiconductors having improved HTSL properties and HTOL properties, and a process for its production. An amorphous silica powder containing Al in an amount of from 0.03 to 20 mass % as calculated as Al2O3 measured by atomic absorption spectrophotometry, wherein the average particle size is at most 50 ?m, and when the amorphous silica powder is divided according to the average particle size into two powders, a powder having a particle size smaller than the average particle size has a higher content as calculated as Al2O3 than a powder having a particle size larger than the average particle size.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: November 1, 2011
    Assignee: Denki Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yasuhisa Nishi, Tohru Umezaki
  • AMORPHOUS SILICA POWDER, PROCESS FOR ITS PRODUCTION, AND SEALING MATERIAL FOR SEMICONDUCTORS
    Publication number: 20110021666
    Abstract: To provide an amorphous silica powder suitable for a sealing material for semiconductors having improved HTSL properties and HTOL properties, and a process for its production. An amorphous silica powder containing Al in an amount of from 0.03 to 20 mass % as calculated as Al2O3 measured by atomic absorption spectrophotometry, wherein the average particle size is at most 50 ?m, and when the amorphous silica powder is divided according to the average particle size into two powders, a powder having a particle size smaller than the average particle size has a higher content as calculated as Al2O3 than a powder having a particle size larger than the average particle size.
    Type: Application
    Filed: December 21, 2007
    Publication date: January 27, 2011
    Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Yasuhisa Nishi, Tohru Umezaki