A semiconductor device contact structure practically eliminating the copper diffusion into the solder as well as the current crowding at the contact with the subsequent electromigration in the solder. A column-like electroplated copper stud (108) is on each contact pad. The stud is sized to provide low, uniform electrical resistance in order to spread the current from the contact to an approximately uniform, low density. Preferably, the stud height (108a) is at least ten times the thickness of the copper interconnect layer (104). Stud (108) is capped by an electroplated nickel layer (109) thick enough (preferably about 2 μm) to suppress copper diffusion from stud (108) into solder body (120), thus practically inhibiting intermetallic compound formation and Kirkendall voiding.
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