Patents by Inventor Thomas J. Gierhart

Thomas J. Gierhart 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).

  • Electrical interconnection substrate with both wire bond and solder contacts, and fabrication method
    Patent number: 5445311
    Abstract: An electrical interconnection substrate (20) is prepared to receive both wire bonded and soldered connections (60,64,66) by forming a dielectric solder mask (30) over the substrate (20), with openings (36) in the mask (30) to expose the contact pads (22) for which soldered connections are desired. The substrate (20) is exposed to a molten solder alloy (44) in a wave soldering process that dissolves the wire bonding material (28) (preferably gold) from the exposed pads (22) and deposits solder bonding pads (52) in its place. Excess solder is then removed from the substrate, and openings (54) are formed through the solder mask (30) to expose the wire bond contact pads (22'). The selective dissolving of gold bonding layers (28) and their replacement by solder pads (52) prevents the establishment of brittle gold-solder intermetallics, and the deposited solder (52) requires no further heat treatment for correct alloy formation.
    Type: Grant
    Filed: October 13, 1994
    Date of Patent: August 29, 1995
    Assignee: Hughes Aircraft Company
    Inventors: Philip A. Trask, Vincent A. Pillai, Thomas J. Gierhart
  • Electrical interconnection substrate with both wire bond and solder contacts
    Patent number: 5311404
    Abstract: An electrical interconnection substrate (20) is prepared to receive both wire bonded and soldered connections (60,64,66) by forming a dielectric solder mask (30) over the substrate (20), with openings (36) in the mask (30) to expose the contact pads (22) for which soldered connections are desired. The substrate (20) is exposed to a molten solder alloy (44) in a wave soldering process that dissolves the wire bonding material (28) (preferably gold) from the exposed pads (22) and deposits solder bonding pads (52) in its place. Excess solder is then removed from the substrate, and openings (54) are formed through the solder mask (30) to expose the wire bond contact pads (22'). The selective dissolving of gold bonding layers (28) and their replacement by solder pads (52) prevents the establishment of brittle gold-solder intermetallics, and the deposited solder (52) requires no further heat treatment for correct alloy formation.
    Type: Grant
    Filed: June 30, 1992
    Date of Patent: May 10, 1994
    Assignee: Hughes Aircraft Company
    Inventors: Philip A. Trask, Vincent A. Pillai, Thomas J. Gierhart