Investigation and modeling of stress effects on the formation of cobalt salicide

This letter studies resistance variations of the Co salicide interconnect accompanied by various surrounding in a sub-0.13-μm CMOS technology. Our analysis shows that, during the salicidation processes, the diffusion of Co atoms and thus salicide thickness and forms of Co salicide layer are greatly affected by the stresses from surrounding structures. Moreover, variations in resistance among the various structures could exceed 100%. Thus, these stress effects were analyzed in detail based on transmission electron microscopy micrographs of Co salicide layers accompanied by four different surrounding structures.