Coupled Stress Evolution in Polygranular Clusters and Bamboo Segments in Near-Bamboo Interconnects

Abstract

AbstractElectromigration-induced failure of near-bamboo interconnects depends strongly on the number and lengths of both polygranular clusters and bamboo segments in a line. We have used numerical techniques to calculate the stress profile as a function of position and time for near-bamboo lines with a variety of microstructures. Our results show that coupling of stress profiles between nearby clusters can affect the time to reach a pre-defined critical, or failure, stress. The degree of coupling depends both on the spacing between clusters and the ratio of the diffusivities between polygranular and single crystal regions. Electromigration failure is therefore sensitive to the distribution and lengths of bamboo segments, and the likelihood of long polygranular clusters coinciding with adjacent short bamboo segments.