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Superfilling Damascene Trenches with Gold in Sulfite Electrolyte



Daniel Josell, Thomas P. Moffat


Superconformal Au deposition is demonstrated in a Na_(3)Au(SO_(3))_(2 -) Na_(2)SO-(3) based electrolyte using underpotential deposited (upd) Pb to catalyze the reduction of Au(SO_(3))_(2)^(3-). Micromolar additions of Pb^(2+) to the electrolyte give rise to acceleration of the Au deposition rate as evidenced by hysteretic voltammetry and rising chronoamperometric transients that convolve the diffusion, adsorption kinetics and coverage isotherm of the upd Pb catalyst. The catalytic activity on the Au deposition reaction may be quenched, or reset, by stepping the potential to more positive values to deactivate or strip the Pb catalyst. Void-free Damascene trench superfilling at various fixed potentials and Pb^(2+) concentration is demonstrated and shown to be congruent with the curvature enhanced accelerator model (CEAC) of superconformal growth. This includes enhanced deposition due to catalyst enrichment on concave surface segments at the bottom corners of the trenches, followed by rapid bottom-up growth and, for certain conditions, bump formation above the filled trenches.
Journal of the Electrochemical Society


Josell, D. and Moffat, T. (2013), Superfilling Damascene Trenches with Gold in Sulfite Electrolyte, Journal of the Electrochemical Society, [online], (Accessed April 19, 2024)
Created April 24, 2013, Updated February 26, 2020