Effect of Wire Purity on Copper Wire Bonding

Abstract

Cu bonding has been making a wave in the IC packaging industry due to the combined efforts of wire, capillary and wirebonder manufacturers. The present challenge in copper bonding resides in minimizing the aluminium squeeze of the aluminium metallization of bond pads. This demands the copper ball to possess a lower yield stress for reduced energy to deform. In this article the methods that are adopted to understand and minimize the aluminium squeeze by the authors from the aspect of wire purity has been discussed in detail.