Reliability of circuits under pads for Au and Cu wire bonding

The reliability of circuits (wiring and vias) under bond pads has been studied for both Au wire bonding and Cu wire bonding, for bond pads and wiring levels typical of those used in RF technology. Electrical test structures under bond pads were used to characterize wire and via integrity after wire bonding and reliability stresses. In addition, SEM analysis was used to inspect for possible damage to the structures under bond pads after wire bonding. No damage was observed with either electrical testing or with SEM analysis, indicating that it is possible to allow a large variety of layouts under bond pads for both Au wire bonding and Cu wire bonding.