Copper-metallized integrated circuits having electroless thick copper bond pads

A metal structure ( 100 ) for a contact pad of a semiconductor device, which has interconnecting traces of a first copper layer ( 102 ). The substrate is protected by an insulating overcoat ( 104 ). In the structure, the first copper layer of first thickness and first crystallite size is selectively exposed by a window ( 110 ) in the insulating overcoat. A layer of second copper ( 105 ) of second thickness covers conformally the exposed first copper layer. The second layer is deposited by an electroless process and consists of a transition zone, adjoining the first layer and having copper crystallites of a second size, and a main zone having crystallites of the first size. The second thickness is selected so that the distance a void from the second layer can migrate during the life expectancy of the structure is smaller than the combined thicknesses of the first and second layers. A layer of nickel ( 106 ) is on the second copper layer, and a layer of noble metal ( 107 ) is on the nickel ...