Plastic encapsulation for integrated circuits having plated copper top

Abstract

A plastic packaged integrated circuit (20) having a thick copper plated top surface level interconnection structure. A semiconductor integrated circuit (20) is formed having devices at the surface of a semiconductor substrate (23). First and second metallization layers (27, 31) are formed over the substrate and contacting selected ones of said devices. The first and second levels of metallization may be in contact with one another through vias. A thick top surface level metal interconnect layer (35) is then formed over the second metal layer (31), either physically contacting it or selectively electrically contacting it. The surface level metal (35) is fabricated of a highly conductive copper layer. The thick surface level metal layer (35) substantially lowers the resistance of the interconnect metallization of the device (20) and further eliminates current debiasing and early failure location problems experienced with integrated circuits of the prior art. In one embodiment, the copper surface level interconnect layer (35) is coated with a thin barrier layer of material (37) which may receive a bond wire. The entire structure is then encapsulated in a plastic package (22) such that the plastic is in physical contact with the copper interconnect metal (35). The use of the plastic packaging (22) in physical contact with the copper interconnect metal (35) eliminates the need for the passivation layers of the prior art. Other devices and methods are described.