Reservoir effect in SiCN capped copper/SiO2 interconnects

By analyzing electromigration in large lines, the reservoir effect due to via connecting matrices has been studied evidencing the key role of the (via + via inter-space) area parameter to gain lifetime. This extra-lifetime can be converted into effective current density increase, useful for circuits very demanding in current, depending on metal level. The understanding of the reservoir effect finally allowed the comparison of electromigration performance of lines of different width. It pointed out that the lifetime decreases with increasing line width, which evidences the copper diffusion at grain boundaries as mechanism.