Gold Ball Shear Stress Analysis on Different Surface Morphology

As the trend of integrated circuit is lashing towards miniaturized facet, wire bonding interconnection is still vastly being utilized in the first level of electronic packaging. The bond strength of the bonded wires is scrutinized by wire bond shear test. Hence in this paper, the effects of bond pad surface on the stress response of gold ball bond during wire bond shear test were investigated through simulation. Three types of bond pad surface, flat surface, hemisphere surface and sharp groove surface are utilized for comparison purpose in this study. Ansys version 11 was used for the simulation. The simulation results showed that the gold ball bond on sharp groove surface bond pad obtained the highest stress response. The maximum stress responses for all three types of bond pad surface were obtained at the shear ram displacement distance of 35μm.