Effect of plating condition on the mechanical properties and residual stress of electroplated copper film

Abstract

This paper discusses the effect of plating condition on the mechanical properties and residual stress of electroplated Cu film. The inlaid copper structure was fabricated on silicon wafer where silicon oxide was thermally grown. Seed layer was deposited by sputtering method followed by copper electro-deposition. Copper was electrodeposited with IBM paddle type electroplating machine Residual stress, hardness, elastic modulus, and surface roughness of electroplated copper film were investigated at various organic additives in plating solution and current types with a nanoindenter and a surface profilometer. The dishing amounts in chemical mechanical polishing (CMP) was also investigated at various additives. The results show that, in the case of residual stress, the copper film deposited at higher additive or PC current result in lower residual stress. The additives do not significantly affect the mechanical properties of Cu deposit.