Diffusional Creep in Damascene Cu Lines

Damascene Cu lines are increasingly being used as electrical interconnects in microelectronic integrated circuits. During the manufacturing process, Cu interconnects are subjected to thermal cycling that leads to complex stress states, which affect their reliability. While a realistic assessment of the impact of thermal stresses on the reliability should take into account the inelastic behavior of the damascene Cu lines, unfortunately, little is known about their mechanical behavior. The goal of this work was to identify the physical mechanisms responsible for the inelastic behavior of damascene Cu lines, and to assess the effects of the varied dimensions and passivation layers.