Investigation the plating and wetting ability of reactive sputtered Molybdenum-Tungsten multi-layers for advanced Cu metallization

Molybdenum-Tungsten (MoxW) alloy films were deposited on SiO2 substrates by reactive sputtering. Direct electroplating Cu on Molybdenum-Tungsten alloy films and annealing in N2 were carried out. In this study, the effect of electroplating time and annealing temperature on the structural, plating and wetting ability of Molybdenum-Tungsten alloy films was investigated. The films were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The results show that Cu can be directly electroplated on Molybdenum-Tungsten alloy films with uniform nucleation. After annealing, de-wetting behavior of Molybdenum-Tungsten alloy films are shown to be better than Ta even up to 500°C.