Thermal reliability of Ag-8Au-3Pd alloy wire bonds

Ag-8Au-3Pd alloy wire has great potential of low-cost candidate for traditional gold wire interconnects. This study aims to light the behavior of degradation that took place in Ag-8Au-3Pd alloy wire bond interface. Two layers of intermetallic compound (IMC) at the Ag-8Au-3Pd/Al bond interface were observed by transmission electron microscopy (TEM). The specimens were annealed at 175°C in a closed oven for 24, 72, 168, 336 and 500 h in atmosphere respectively to reveal the evolution of IMC at interface. The high-temperature storage (HTS) test of Ag-8Au-3Pd/Al Ag-95Pd-5/Al and Ag-98Pd-2/Al interface was conducted for contrast. Interface evolution tracking by back scattered electron (BSE) imaging showed that after 336 h, the bonding interface began to fail. JEDEC standard of HTS test was successfully passed. Ag-8Au-3Pd wire showed great promise as an economical substitute for gold wire.