Wirebonding on various multichip module substrates and metallurgies

Wirebonding is still the mainstay, first-level interconnect for worldwide electronic products. As high-density circuit technology such as multichip modules enter production, wirebonding is faced with new challenges. Characteristic of these challenges is the requirement to bond to a wide range of pad metallurgies placed on top of a variety of substrates or layers including semiconductors, oxides, ceramics, and organics. Our work presents a systematic study of thermosonic gold ball bonding on aluminum, gold, and composite (e.g., chromium/copper/gold) metallization layers on several rigid and soft substrate systems. Bondability is evaluated using the ball shear and other test methods.