Shearing Speed Induced Stress Comparison on Gold and Copper Ball Interconnection

As the trend for semiconductor packaging is heading towards BGA and flip chip interconnection methods, the conventional wire bonding process still dominates the industry primarily due the flexibility of wire bonds. The reliability of the bonded wires is assessed through wire bond shear test. In this study, the effects of shear ram speed on the stress response of bonded wires during wire bond shear test were investigated. The stress response of two wire materials, gold(Au) and copper(Cu) at varied shear ram speed were evaluated.A 3D non-linear finite element model was developed for the simulation. The shear ram speed of 100 µm/sand 1mm/s were used in this study. The results showed that the shear ram speed has significant effects on the stress response of the bonded wire. The simulation was done using Ansys version 11.