Adsorption Mechanism of Potassium Oleate on Cobalt Surface Based on Cobalt Interconnection CMP: A Combined Experimental and DFT Investigation

Abstract

Potassium oleate (PO) is a promising corrosion inhibitor to replace benzotriazole (BTA) for cobalt (Co) wiring in the integrated circuit (IC). The adsorption characteristics of different cobalt surfaces were characterized by the contact angle measurement. The formation of passive Co–PO film and the corrosion inhibitor efficiency of PO to cobalt was analyzed by electrochemistry and electrochemical impedance spectroscopy (EIS), and the change of chemical elements on the cobalt surface was analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, quantum chemical calculation and molecular dynamics simulation based on density functional theory (DFT) further revealed the adsorption mechanism of PO and cobalt at the molecular level. The results showed that Co–PO passivation film formed on the cobalt surface, besides, 2 mM PO has achieved the best inhibition efficiency on cobalt surface.