Super secondary grain growth initiation in electroplated copper

Abstract

Super secondary grain growth is initiated in electroplated copper films deposited on thin seed layers on a alpha-Ta barrier layer. Both growth dynamics and self annealing time strongly depend on the copper seed layer bias conditions, barrier bias conditions, barrier composition and the ECD/PVD thickness ratio. This is consistent with an orientation dependent driving force for super grains in an ECD/PVD bi-layer system. The barrier layer seems to play a critical role in the initiation of abnormal SSGG, while strain energy minimization seems to be an important driving force.