Simulation and experimental results for copper deposition in a moving wafer tool to minimize terminal effects

Copper electrodepositon onto 200 mm silicon wafers containing a 30 nm ruthenium (Ru) barrier layer was studied using a novel horizontal research grade wafer processing tool. The wafer processing tool incorporates a virtual anode and a wafer holder that varies the wafer position vertically relative to the virtual anode opening during the plating process. The ability to change the distance between the wafer substrate and the virtual electrode opening during the plating process enables improved control of the dynamic current distribution across the wafer surface. The effect of the wafer position and wafer movement on the current distribution during the copper deposition process onto resistive Ru barrier layers is examined using numerical analysis. Experimental data for copper deposition onto the Ru barrier layer is compared with the simulation results. copyright The Electrochemical Society.