Numerical Simulation of Electrochemical Planarization of Copper Overburden

Numerical simulations are employed to demonstrate the daunting challenges involved in utilizing electrochemical polishing technologies as an alternative to lowdown-force chemical mechanical planarization. Results show that small-aspect ratio topographical features sitting on a relatively thin overburden are impossible to planarize by conventional electropolishing. Electrochemical-mechanical planarization (E-CMP), where an anodic dissolution process is coupled with a polishing pad, is a more viable approach. Numerical simulations are compared to results obtained by E-CMP, as a means of establishing an effective diffusion-layer thickness and as further demonstration of the infeasibility of electropolishing.