Technology benchmarking of copper electromigration using a grain-sensitive simulation framework

Abstract

A calibrated simulation framework for the analysis of electromigration (EM) in nano-interconnects, incorporating the intricate influence of microstructure, is presented. Different technology options were benchmarked for EM performance, taking copper texture and microstructural changes with scaling into account. Specifically, the impacts of metal cap and copper doping were simulated for a constant line height of 80nm and for linewidths between 20 and 100nm. An almost linear increase in normalized lifetime was observed for aspect ratios of 1 and above. An increase ranging from 10x to 100x was gained by using a metal cap for aspect ratios below 2. However, its effectiveness strongly weakened with decreasing CD with almost no EM lifetime gain for 20nm CD. Doping elements that lower grain boundary diffusivity were found to be more effective at these small dimensions.