Patent ID: 7413974

Claim:
A metal structure for a contact pad of a semiconductor device having interconnecting traces of a first copper layer, the device protected by an insulating overcoat, comprising: the first copper layer of first thickness and first crystallite size selectively exposed by a window in the insulating overcoat; a second copper layer of second thickness conformally covering the exposed first copper layer, the second layer consisting of a transition zone, adjoining the first layer and having crystallites of a second size, and a main zone having crystallites of the first size; the second thickness selected so that the distance a void from the second layer can migrate during the life expectancy of the metal structure is smaller than the combined thicknesses of the first and second layers; a layer of nickel on the second copper layer; and a layer of noble metal, wherein said noble metal is selected from the group consisting of palladium, platinum, silver, gold, or a combination thereof, on the nickel layer.