Bond tool life improvement for large copper wire bonding

The aluminum (Al) wire interconnect cannot fulfill the increased demand in power electronics. The Copper (Cu) wire interconnect is being introduced in high power, high temperature applications. The Cu wire is much harder material and wears the bond tool much faster than the Al wire. Improving the bond tool life and maintaining the process stability are challenges that must be met before the Cu wire interconnect will go to mass production. The bond tool wear mechanism is investigated and potential solutions are proposed and validated. By reducing bond tool groove depth, the tip of bond tool is further away from substrates and the bond tool can make more bonds before the tool is worn out and discarded. By optimizing the bond process, a standard bond tool interacts differently with Cu wire and the bond tool life is doubled. A high coupling bond tool is developed to reduce the relative motion between the bond tool and Cu wire and decrease the bond tool wear, making a longer tool life and fewer Cu flakes. By combining bond tool tip geometry design and bond process optimization, the bond tool life can be significantly extended.