Mechanism exploration on Cu interconnect negative resistance shift during stress migration

Negative shift of resistance during stress migration was observed in Cu-based, dual-damascene technologies. One significant reason is caused by via copper crushing through the barrier layer into copper trench underneath, which means that via location acts main role in large shrinking of via resistance. Besides, negative shift of via resistance is found to be increasing with baking time, which indicates that anneal effect can also play an important role in decreasing via resistance.