Inhibitor Alkyne-PEG4-amine Contributes to Cobalt Superfilling

In the field of electronic plating, the addition of additives is the key to achieve cobalt superfilling, while finding and researching suitable additives is a major challenge. In this work, alkyne-PEG4-amine (AP4A) was used as an inhibitor to achieve nanometer scale superfilling of cobalt electrodeposition. The inhibition of AP4A was analyzed by electrochemical methods, including cyclic voltammetry and chronopotentiometry tests. AP4A effectively inhibits the cobalt electrodeposition, adsorbing onto the surface of the electrode and showing an outstanding ability for polarization. Quantum chemical calculations show that the amino group within AP4A may be the main active site for reaction, which possesses capacity for donating electrons. Furthermore, surface morphology and crystalline structure characterizations indicate that, under the effect of AP4A, the cobalt film maintains excellent electrical properties while obtaining better flatness and preferential orientation of the (101) crystal plane. In superfilling of nanometer scale structures with high aspect ratios, AP4A was used and the bottom-up electrodeposition of cobalt was successfully achieved, which demonstrates that AP4A is an effective inhibitor for cobalt superfilling and offers an excellent solution strategy in electrodeposition area.