Rapid Galvanostatic Determination on Levelers for Superfilling in Cu Electroplating

Abstract

4-Amino-2,1,3-benzothiadiazole and 6-aminobenzo-thiazole were studied as potential levelers for Cu plating in submicrometer trenches. We conducted galvanostatic measurements on rotating disk electrodes at various concentrations and recorded their respective voltages at 200 and 430 rpm. A profile of voltage difference between them at various concentrations revealed a volcano curve in which superfilling was expected to occur for 4-amino-2,1,3-benzothiadiazole but not for 6-aminobenzo-thiazole. Direct scanning electron microscopy observations on the plated Cu confirmed predictions from the volcano curves. A diffusion-adsorption mechanism was proposed for these two compounds to explain their leveling abilities on Cu superfilling. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3265971] All rights reserved.