Further characterization of 2nd bond in bare Cu wire and Pd coated Cu wire on various leadframe plating scheme

Degradation of wire bonds in gold and copper ball bonding at high temperature storage normally associated with intermetallic growth defects and/or corrosion defects for the ball bonds (1st bond). Assessments during isothermal aging also mainly focus on intermetallic growth of Au-Al or Cu-Al. In general there is no reliability concern of 2nd bond for gold wire bonding thus far but for 2nd bond of Cu wire bonding there has not been studied sufficiently to date. New failure mechanism (i.e. lifted wedge) that is associated with second bond after high temperature storage had been reported in copper wire bonding. This paper discussed some characteristic of bare Cu and Pd coated Cu wire as bonded and also after high temperature storage. The effect of different wire type and leadframe plating scheme of 2nd bond failures during isothermal aging has been assessed and the mechanism of degradation is discussed.