Super heavy 6.0 mils Cu wire ball bonding

Abstract

The quest to replace wire material from gold (Au) to Copper (Cu) in wire bonding interconnect has been in the industry since few decades. As the Cu wire bonding manufacturing process matures, the idea of substituting Al wedge bond with Cu ball bond is mooted. Such substitution could potentially reap benefits of lower machine cost of ownership and better utilization of silicon real estate. It also comes with better conductivity, slower intermetallic growth and possibly cheaper material price. However, the associated challenges such as hardness and oxidation could be overwhelming and requires a careful assessment. The objective of this study is to provide insight of the 6.0 mils Cu wire bonding process. 6.0 mils Cu wire is the key candidate in this Al - Cu wire substitution idea. Bonding interaction of Cu wire, chip & lead are studied experimentally.