System Considerations for Large Copper Wire and Ribbon Bonding in Mass Production

Abstract:
Although copper has been demonstrated to be a more reliable interconnect material in high power applications, copper wire bonding poses several system challenges. Improvements in consumables, the ultrasonic system, the bond head, and the machine need to be made to achieve reliable high-volume production. High wear-resistant bond tools and cutters achieve >20 times longer lifetime (500,000 bonds for bond tool and 250,000 cuts for cutter) and a more consistent bonding process as compared to using standard consumables. A higher power ultrasonic system enables bonding larger copper wires and ribbons and is more reliable to work in challenging environments. A low-drag wire-feed tube improves loop consistency and reduces debris shedding that contaminates substrates. Heavy-duty dereelers hold larger size spools up to 2 kg. Special processes before and after main bonding segments improve copper bond quality and reliability. The system improvements result in higher production yield and lower cost of ownership.