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AssigneeHughes Aircraft Company
InventorsPhilip A. Trask, Vincent A. Pillai, Thomas J. Gierhart
Estimating the term…
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.
A method of preparing an electrical interconnection substrate to receive electrical circuit elements by both wire bonded and soldered connections, the substrate having a plurality of wire bond contact pads formed with a layer of conductive wire bonding material, comprising:
A method of converting a wire bondable contact pad on a substrate to a solderable contact pad, said wire bondable contact pad having a layer of conductive wire bondable material, comprising:
Dependencies are inferred from the claim text.