Synergistic Control on Co/Cu Galvanic Corrosion and Its Application for Co Barrier Chemical Mechanical Planarization in Alkaline Slurry

Selective chelation and protective film formation were synergistically combined to achieve Co/Cu galvanic corrosion control. Chelating agent imionodisuccinic acid and protective film formation agent benzotriazole are strategically chosen for fulfilling the above proposed task in alkaline solution for Co barrier chemical mechanical planarization (CMP). Chronopotentiometry and linear dynamic potential polarization methods are used to investigate the thermodynamics and kinetics of Co and Cu corrosion. A synergistic control of Co/Cu corrosion was accomplished by judiciously balancing the power of selective chelation and protective film formation. This systematic approach can be expanded to systematically design other metal CMP slurries to fulfil the desired polishing performance.