Electromigration for microarchitects

Abstract

Degradation of devices has become a major issue for processor design due to continuous device shrinkage and current density increase. Transistors and wires suffer high stress, and failures may appear in the field. In particular, wires degrade mainly due to electromigration when driving current. Techniques to mitigate electromigration to some extent have been proposed from the circuit point of view, but much effort is still required from the microarchitecture side to enable wire scaling in future technologies. This survey brings to the microarchitecture community a comprehensive study of the causes and implications of electromigration in digital circuits and describes the challenges that must be faced to mitigate electromigration by means of microarchitectural solutions.