High-performance chemical mechanical polishing slurry for aluminum alloy using hybrid abrasives of zirconium phosphate and alumina

Chemical mechanical polishing (CMP) is the most effective technology for the global and local planarization of metal surfaces. In this study, an environment-friendly and highly efficient CMP slurry for aluminum alloy is prepared by using 2D layered zirconium phosphate (ZrP) platelets and alumina (Al2O3) particles as hybrid abrasives, polyethylene glycol (PEG) as dispersant, hydrogen peroxide (H2O2) as oxidant and sodium dodecyl sulfate (SDS) as corrosion inhibitor. Using the optimized CMP slurry, surface roughness (Ra) of aluminum alloy is decreased from ~200 nm to ~13 nm and material removal rate (MRR) can be increased from 150 nm/min to 300 nm/min. The addition of ZrP platelets can improve the stability and dispersion of the Al2O3 abrasives due to the PEG-induced hydrogen bonding interactions between the used hybrid abrasives. Moreover, the X-ray photoelectron spectroscopy (XPS) and electrochemical analysis reveal that adjusting the concentrations of H2O2 and SDS in the CMP slurry would help to achieve an excellent balance between the chemical corrosion and mechanical removal. The use of binary hybrid abrasives in CMP slurries provides a novel route for the efficient planarization of aluminum alloy and also sheds light on precise polishing for metallic and non-metallic materials with desired surface requirements.