Nanomechanical properties of intermetallic compounds formed in electrodeposited Cu/Sn and Cu/Ni/Sn multilayer interconnects

Abstract

Nanomechanical properties of intermetallic compounds (IMCs) formed in electrodeposited Cu/Sn and Cu/Ni/Sn multilayer interconnects were investigated in this study. The layers of Cu, Sn and Ni were formed by electrodeposition technique using copper pyrophosphate, tin methanesulfonic and nickel Watts bath, respectively. Deposition current density was set at 10 mA/cm2 for the copper bath and 20 mA/cm2 for tin and nickel baths. The interconnects were subjected to high temperature aging at 150˚C for 168 h. A Hysitron Triboindenter 750 Ubi system was used for the nanoindentation experiments at ambient temperature. Elastic modulus and hardness of the IMCs were measured with good accuracy. Average Creep displacement under constant load was obtained for all the IMCs formed in Cu/Sn and Cu/Ni/Sn multilayer ultra small interconnects.