Patents by Inventor Si-Tuan Lam

Si-Tuan Lam 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).

  • Etching process to selectively remove copper plating seed layer
    Patent number: 6767477
    Abstract: Write head coils for magnetic disk systems are commonly formed through electroplating onto a seed layer in the presence of a photoresist mask. It is then necessary to remove the seed layer everywhere except under the coil itself. The present invention achieves this through etching in a solution of ammonium persulfate to which has been added the complexing agent 1,4,8,11 tetraazundecane. This suppresses the reduction of Cu++ to Cu, thereby increasing the dissolution rate of copper while decreasing that of nickel-iron. Two ways of implementing this are described—adding the complexing agent directly to the ammonium persulfate and introducing the 1,4,8,11 tetraazundecane through a dipping process that precedes conventional etching in the ammonium persulfate.
    Type: Grant
    Filed: June 12, 2002
    Date of Patent: July 27, 2004
    Assignee: Headway Technologies, Inc.
    Inventors: Xue Hua Wu, Wensen Li, Si-Tuan Lam, Henry C. Chang, Kochan Ju, Jei-Wei Chang
  • Etching process to selectively remove copper plating seed layer
    Publication number: 20020168223
    Abstract: Write head coils for magnetic disk systems are commonly formed through electroplating onto a seed layer in the presence of a photoresist mask. It is then necessary to remove the seed layer everywhere except under the coil itself. The present invention achieves this through etching in a solution of ammonium persulfate to which has been added the complexing agent 1,4,8,11 tetraazundecane. This suppresses the reduction of Cu++ to Cu, thereby increasing the dissolution rate of copper while decreasing that of nickel-iron. Two ways of implementing this are described—adding the complexing agent directly to the ammonium persulfate and introducing the 1,4,8,11 tetraazundecane through a dipping process that precedes conventional etching in the ammonium persulfate.
    Type: Application
    Filed: June 12, 2002
    Publication date: November 14, 2002
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Xue Hua Wu, Wensen Li, Si-Tuan Lam, Henry C. Chang, Kochan Ju, Jei-Wei Chang
  • Etching process to selectively remove copper plating seed layer
    Patent number: 6428719
    Abstract: Write head coils for magnetic disk systems are commonly formed through electroplating onto a seed layer in the presence of a photoresist mask. It is then necessary to remove the seed layer everywhere except under the coil itself. The present invention achieves this through etching in a solution of ammonium persulfate to which has been added the complexing agent 1,4,8,11 tetraazundecane. This suppresses the reduction of Cu++ to Cu, thereby increasing the dissolution rate of copper while decreasing that of nickel-iron. Two ways of implementing this are described—adding the complexing agent directly to the ammonium persulfate and introducing the 1,4,8,11 tetraazundecane through a dipping process that precedes conventional etching in the ammonium persulfate.
    Type: Grant
    Filed: January 19, 2000
    Date of Patent: August 6, 2002
    Assignee: Headway Technologies, Inc.
    Inventors: Xuehua Wu, Wensen Li, Si-Tuan Lam, Henry C. Chang, Kochan Ju, Jei-Wei Chang