Electromigration

Abstract

The power current requirements of integrated circuits are rapidly rising, as discussed in Chapter 1. The current density in on-chip power and ground lines can reach several hundred thousands of amperes per square centimeter. At these current densities, electromigration becomes significant. Electromigration is the transport of metal atoms under the force of an electron flux. The depletion and accumulation of the metal material resulting from the atomic flow can lead to the formation of extrusions (or hillocks) and voids in the metal structures. The hillocks and voids can lead to short circuit and open circuit faults [51], respectively, as shown in Figure 4.1, degrading the reliability of an integrated circuit.