Kinetic and morphological investigation of copper electrodeposition from sulfate electrolytes in the presence of an additive based on ethoxyacetic alcohol and triethyl-benzyl-ammonium chloride

A comparative study of the influence of a new additive (IT-85), based on et hoxyacetic alcohol and triethyl-benzyl-ammonium chloride, and thiourea on c opper electrodeposition from acidic sulfate solutions has been performed in order to obtain information about the kinetics of the cathodic process. In spite of their different chemical nature, both additives were found to be efficient as leveling agents, leading to fine-grained cathodic deposits. Th e study was based on scanning electron microscopy and X-ray dispersive anal ysis of the Cu deposits, coupled with an electrochemical investigation usin g cyclic voltammetry (CV) and steady-state polarization measurements at a r otating disc electrode. CV results and kinetic parameters obtained from Taf el plots led to the conclusion that both additives have a pronounced inhibi ting effect on Cu2+ discharge, the strongest inhibition being observed for thiourea. An induction period related to a slow nucleation, increasing with additive concentration, was clearly put on evidence on the polarization cu rves, for both additives. (C) 2001 Elsevier Science B.V. All rights reserve d.