Patents by Inventor Hiromi Kawamata

Hiromi Kawamata 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).

  • Lead-free solder ball
    Patent number: 7750475
    Abstract: A Sn—Ag—Cu based lead-free solder ball which does not undergo yellowing of its surface when formed into a solder bump on an electrode of an electronic part such as a BGA package. The solder ball has excellent wettability and does not form voids at the time of soldering, even when it has a minute diameter such as 0.04-0.5 mm. It has a composition comprising 1.0-4.0 mass % of Ag, 0.05-2.0 mass % of Cu, 0.0005-0.005 mass % of P, and a remainder of Sn.
    Type: Grant
    Filed: October 6, 2004
    Date of Patent: July 6, 2010
    Assignee: Senju Metal Industry Co., Ltd.
    Inventors: Daisuke Souma, Takahiro Roppongi, Hiroshi Okada, Hiromi Kawamata
  • Lead-free solder ball
    Publication number: 20070069379
    Abstract: A Sn—Ag—Cu based lead-free solder ball which does not undergo yellowing of its surface when formed into a solder bump on an electrode of an electronic part such as a BGA package. The solder ball has excellent wettability and does not form voids at the time of soldering, even when it has a minute diameter such as 0.04-0.5 mm. It has a composition comprising 1.0-4.0 mass % of Ag, 0.05-2.0 mass % of Cu, 0.0005-0.005 mass % of P, and a remainder of Sn.
    Type: Application
    Filed: October 6, 2004
    Publication date: March 29, 2007
    Inventors: Daisuke Souma, Takahiro Roppongi, Hiroshi Okada, Hiromi Kawamata