Enhancing the electromigration resistance of copper interconnects

Various factors such as grain boundary/surface diffusion as well as structural properties of materials are known to affect the final electro-migration (EM) behavior of copper interconnections. Results presented in this paper show that the barrier layer has a strong influence in controlling the width of EM failure distributions. EM tests of samples with alternate barrier, fill and capping layers show that atomic layer chemical vapor deposited (ALCVD) barrier and/or metallic cap layers are key to realize structures with superior EM lifetimes.