Challenges and developments of copper wire bonding technology

Copper wire bonding has been studied for more than two decades. While copper wire bonding has many advantages over gold wire bonding, many challenges have to be solved to meet its application requirements. This paper presents the measures to overcome Cu oxidation, the optimization of bonding parameters and the improvement in capillary design. The reliability mechanism of copper wire bonding is described from the standpoints of IMC growth, pad Al squeeze and the ability of wire looping. The challenges of copper wire bonding on low-k wafers and some solutions are also briefly introduced.