The Adsorption and Removal of Corrosion Inhibitors During Metal CMP

Corrosion inhibitor plays a key role during Chemical mechanical planarization (CMP) of metal surfaces during semiconductor processing. Strong metal-inhibitor passivation formation during the CMP process and its easy removal during post-CMP cleaning are highly required. However, there are no studies available explaining this phenomenon. In this work, passivation changes of copper (Cu) and cobalt (Co) surfaces during CMP and post CMP cleaning by adsorption and removal of benzotriazole (BTA), was characterized using a new sequential electrochemical impedance spectroscopy (EIS) technique. It was found that stable Cu/Co-BTA complex (metal-inhibitor passivation) was formed when each metal surface was exposed to BTA solution. However, it was found that adsorbed BTA on Co surface could be removed just by de-ionized (DI) water rinsing while BTA on Cu surface was not removed.