John Langhout1,2,Debashish Sur1,3,G. Bahar Basim4
NSF Center for Particle and Surfactant Systems1,University of Florida2,University of Virginia3,NSF Center for Particle and Surfactant Syatems4
John Langhout1,2,Debashish Sur1,3,G. Bahar Basim4
NSF Center for Particle and Surfactant Systems1,University of Florida2,University of Virginia3,NSF Center for Particle and Surfactant Syatems4
Chemical mechanical planarization is an enabler for the packaging level integration schemes in addition to barrier level applications. The yield of chip packaging operations is a function of the surface finish that is solderable and wire-bondable. Palladium (Pd) is a material that is known for its ability to improve processing cost and reliability at the packaging level with lead frame in addition to its potential use as a sacrificial layer for copper (Cu) integration to protect the copper from oxidation. CMP selectivity becomes critical where a competitive removal rate is desired between the Cu, Cu-barrier (TaN) and Ni films against palladium. This paper focuses on removal rate selectivity of Pd in commercial silica-based slurries tuned for Cu CMP with detailed electrochemical analyses and incorporating the effect of temperature and its effects on surface energy as well as CMP selectivity. Pd being a novel metal shows strong passivation in the presence of an oxidizer, that can be tuned by slurry chemistries. Furthermore, lowering the slurry temperature promotes its CMP removal rate selectivity against Ni, Cu and TaN by enhancing slurry viscosity with no detrimental effect observed on surface defectivity.