Nanowire Reliability: Atomistic Simulation of Electromigration in Nanoscale Metallic Interconnects

Kristi Harris, University of Maryland, Baltimore County

The primary cause of integrated circuit failure is the effect of electromigration on the copper interconnects that connect circuit components. As interconnect dimensions shrink towards the nanoscale, it is increasingly important to develop a physical understanding of electromigration failure mechanisms on an atomistic scale. In our research, we are investigating the electromigration effect on nanoscale metallic structures through atomistic modeling and simulation.

Since nanostructures have a high surface-to-volume ratio, surface diffusion is the primary method of mass transport. Thus, one approach to understanding nanowire failure is through changes in surface structure, which can be modeled as a series of step fluctuations. Step fluctuations of a material undergoing current stressing have been simulated and analyzed in terms of the persistence probability as a parameter to characterize the effect of electromigration.

Copper interconnects in integrated circuits have specific size, structural, and microstructural characteristics which help determine the dominant electromigration failure mechanism. We are working on the development of a kinetic Monte Carlo simulation of realistic nanowires under an electromigration driving force, taking into account the factors that must be considered in order to ensure an accurate model of the interconnects in current and future integrated circuits.

Abstract Author(s): Kristi Harris, Tim Bole, and Philip Rous