Redundant C4 power pin placement to ensure robust power grid delivery

Power supply C4 (flip-chip) bonds are susceptible to failures due to electro-migration caused by high on-chip temperatures, large currents and manufacturing variability. A single C4 bond failure can result in catastrophic failures in the power supply network and thus redundant bonds are naively added to the circuit to mitigate the impact of bond failures. We propose a method for improved redundant bond placement using an Integer Linear Program (ILP) that reduces the required number of redundant bonds by 33% while ensuring power supply integrity in the presence of a single-bond failure.