Patents by Inventor Takaharu Nagano

Takaharu Nagano 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).

  • Process for removing tin and tin-lead alloy from copper substrates
    Patent number: 5035749
    Abstract: Disclosed is a method for removing a layer of tin or tin-lead alloy from a copper substrate of a printed circuit board employing the two different reagents in a two-step procedure without damaging the substrate, and at the same time, preventing formation of whitish precipitates in the treating solution.In the first step, the layer of tin or tin-lead alloy is selectively removed with the first reagent having a comparatively mild oxidation capability, then in the second step the intermetallic layer consisting of tin and copper is removed with the second reagent having a comparatively strong oxidation capability.This process ensures a smooth and effective operation in the production of high quality printed circuit boards.
    Type: Grant
    Filed: August 6, 1990
    Date of Patent: July 30, 1991
    Assignee: MEC Co., Ltd.
    Inventors: Takashi Haruta, Takaharu Nagano, Takeyoshi Kishimoto, Yasushi Yamada, Tomoko Yuno