Volume -I , Issue -III, February 2014

A KINETIC STUDY OF CURRENT DISTRIBUTION BY ELECTRODEPOSITION IN COPPER COATINGS

S R RAJKUMAR AND M ALAGAR

This model addresses the precise an analytically derived model for the current distribution on a resistive electrode subject to Butler-Volmer kinetics, with parameters typical to copper plating. The deposit thickness uniformity in copper metalized semiconductor wafers is adversely affected by the limited conductivity of the thin copper seed layer. It is noted that, as expected, the current distribution is more uniform when a less conductive electrolyte is used and when the electrode kinetics are slow down. The resistive substrate tends to cause the copper to plate primarily near the terminal contact at the wafer edge. Models for this terminal-effect have been presented for simpler electrode configurations using unrealistically simplified, linear electrode polarization. The predicted current distributions are compared to numerical simulations using electrochemical computer aided design (CAD) software program, is a freeware program written in MATLAB.

Deposition kinetics; Numerical modeling, electrode kinetics, electrode polarization, Galvanic electrode position

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