The copper ball bonding wire of coating Pd

The invention provides the copper cash of a kind of ball bonding with coating palladium, it can improve the joint reliability to aluminium electrode.In the copper cash of ball bonding of the present invention with coating palladium, formed in palladium interlayer surfaces and comprise the layer gold that thickness is the thin layer of below 5nm, heat-treat in hydrogeneous torpescence atmosphere, the palladium in intermediate layer invades golden thin layer, carried out the layer island mixed mode growth of three dimensional growth by fine metallographic and palladium mutually, form gold-palladium intermixed layer.In heat treatment process, palladium absorbs hydrogen, carry out quenching after heat treatment, make the palladium stabilisation of above-mentioned intermixed layer thus, melt as early as possible when fusion weld ball is formed, gold along with covered wire end face arrives the palladium fusing of end face, is distributed to fine uniform structure melting soldered ball superficial layer, suppresses the oxidation with the aluminium in the joint interface of aluminium.