| 摘要 |
A metal structure for a contact pad of a wafer or substrate (101), which have copper interconnecting traces (102) surrounded by a barrier metal layer (103). The wafer or substrate is protected by an insulating overcoat (104). In the structure, the barrier metal layer is selectively exposed by a window (110) in the insulating overcoat. A layer of copper (105), adherent to the barrier metal, conformally covers the exposed barrier metal. Preferably, the copper layer is deposited by sputtering using a shadow mask. A layer of nickel (106) is adherent to the copper layer and a layer of noble metal (106) is adherent to the nickel layer. The noble metal may be palladium, or gold, or a palladium layer with an outermost gold layer. Preferably, the nickel and noble metal layers are deposited by electroless plating.
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