ELECTROLESS NICKEL AND GOLD PLATING IN SEMICONDUCTOR DEVICE

摘要

A described example semiconductor device includes a passivation layer (230) formed over a semiconductor substrate (210) and a portion of a metal contact pad (220). Nickel is deposited over the passivation layer and metal contact pad and gold is deposited over the nickel using an ENIG electroless plating process. The nickel includes a first non-porous nickel region (layer 250A) free of porous nickel at an interface (180) of the nickel with the passivation layer and at a junction (290) of the nickel with the passivation layer and metal contact pad. The nickel also includes a porous nickel region (layer 270) over the first nickel layer (250A). A gold region (layer 260) is over the porous nickel layer (270). A second non-porous nickel region (layer 250B) may be between the porous nickel region and the gold region. A gold-rich nickel region (275) may be between the porous nickel region and the gold region. Relative thicknesses of the deposited nickel and the deposited gold are chosen to prevent corrosion of the nickel layer from reaching the device layer during the electroless gold plating process.