Effect of Ag-11Au-4.5Pd alloy bonding wire properties and structure on bond strengths and reliability

The different of Ag-11Au-4.5Pd and Ag-11Au-4.5Pd-0.1Y alloy bonding wire mechanical properties, fusing current and structure were analyzed by strength tester, electronic conductivity tester, and scanning electron microscope. The effects of Y on Ag-11Au-4.5Pd and Ag-11Au-4.5Pd-0.1Y alloy bonding wire ball size, bonded micro phonology and bonded strength were investigated. The results show that the elongation and tensile strengths of Ag-11Au-4.5Pd-0.1Y alloy bonding wire increases from 14.55%, 9.4g to 16.35%, 10.2g because of doping Y, and the fusing current of Ag-11Au-4.5Pd-0.1Y alloy bonding is smaller than Ag-11Au-4.5Pd alloy bonding wire, the Ag-11Au-4.5Pd-0.1Y alloy bonding wire bonded strength is higher than Ag-11Au-4.5Pd alloy bonding wire. The heat affect zone length decreases from 60μm to 45μm because of doping Y. For Ag-11Au-4.5Pd-0.1Y alloy bonding wire, Y can refine the grain, then the grain size decreases, and the grain quantity increases, then the inhomogeneous deformation of different grain decrease, and the ball bonded shape is uniform. After HTS test, cracks phenomenon happens at the bonding interface because of Ag atoms rapidly migrate, Y can decrease the Ag migrate rate and avoid the crack in bonded interface.