Effect of Guanidinium Ions on Ruthenium CMP in H2O2-Based Slurry

With the development of integrated circuits (IC), ruthenium (Ru) has been selected as one of the most promising barrier metals for copper interconnects to replace traditional Ta/TaN bilayer. The present work investigates certain chemical aspects of this strategy of Ru-CMP by using guanidinium ions (Gnd(+)). And the experiments are designed to study Ru CMP in pH 9 using colloidal silicaabrasive based slurry with an oxidizer (H2O2), Gnd(+). Zeta potential, electrochemical and atomic force microscopy are employed to probe the surface effects that facilitate material removal in chemically prevailing CMP of Ru. The results of CMP show that Gnd(+) are better than that of potassium ions (K+) on the removal rate (RR) of Ru under the same conditions; and the improvement of Ru RR has a guiding significance for the development of next generation IC in the addition of Gnd(+), which is proven by zeta potential increasing, open circuit potentials decreasing, corrosion current density increasing and corrosion potential decreasing. (C) 2017 The Electrochemical Society. All rights reserved.