"Mechanism of copper electrodeposition in the presence of different additives"

A.L. PORTELA; G.I. LACCONI; M. LÓPEZ TEIJELO

Thessaloniki, Grecia

Conferencia; 55th Annual Meeting of the International Society of Electrochemistry.; 2004

International Society of Electrochemistry (ISE)

Mechanism of copper electrodeposition in the presence of different additives A.L. Portela; G.I. Lacconi*; M. López Teijelo INFIQC, Depto. Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre y Medina Allende, Ciudad Universitaria, 5000 Córdoba, Argentina. E-mail: glacconi@fisquim.fcq.unc.edu.ar *; M. López Teijelo INFIQC, Depto. Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre y Medina Allende, Ciudad Universitaria, 5000 Córdoba, Argentina. E-mail: glacconi@fisquim.fcq.unc.edu.ar glacconi@fisquim.fcq.unc.edu.ar The addition of organic molecules to plating baths is usually the effective way to control the electrodeposition process and the final quality of the deposits. The presence of the additives determines the physical and mechanical properties of the electrodeposit, such as the grain size, hardness, brightness, adherence, etc. In this communication we present detailed information about the mechanism of copper electrodeposition in the presence of nicotinic acid (NA), picolonic acid (PA) and polyethilenglycol (PEG). The electrochemical behaviour is correlated with the chemical nature of the additives and the properties of the deposits. Copper deposition was made on Pt substrates from a slightly acidic bath consisting of 0.01M CuSO4 + 0.1M Na2SO4 + xM additive solutions under different experimental conditions (concentration, pH, etc.). The voltammetric results evidence that in the presence of these additives, complex reaction pathways are involved in copper deposition. Depending on the chemical structure, concentration of the additive and pH, the competitive electroreduction of different complex copper species takes place. The effect of the adsorption of the additives molecule is also detected. They have an important influence through the partial blocking of the surface, mainly when PEG is used. In addition, complex reaction mechanisms including acidic dissociation equilibria of the pyridine-carboxylic acids (NA, PA), Cu2+ complex species formation and H+ ions electroreduction occurring simultaneously with copper deposition, are evidenced. The morphology of the copper deposits under different experimental conditions was obtained by SEM and AFM. The additives produce uniform, bright and adherent copper deposits. Both, the nature of the additive and the experimental conditions have a marked influence on the deposition mechanism as well as on the morphology of the copper layers. Acknowledgements: We thank CONICET, SECYT-UNC, Agencia Córdoba Ciencia S.E. and ANPCyT for their financial support. The morphology of the copper deposits under different experimental conditions was obtained by SEM and AFM. The additives produce uniform, bright and adherent copper deposits. Both, the nature of the additive and the experimental conditions have a marked influence on the deposition mechanism as well as on the morphology of the copper layers. Acknowledgements: We thank CONICET, SECYT-UNC, Agencia Córdoba Ciencia S.E. and ANPCyT for their financial support. The voltammetric results evidence that in the presence of these additives, complex reaction pathways are involved in copper deposition. Depending on the chemical structure, concentration of the additive and pH, the competitive electroreduction of different complex copper species takes place. The effect of the adsorption of the additives molecule is also detected. They have an important influence through the partial blocking of the surface, mainly when PEG is used. In addition, complex reaction mechanisms including acidic dissociation equilibria of the pyridine-carboxylic acids (NA, PA), Cu2+ complex species formation and H+ ions electroreduction occurring simultaneously with copper deposition, are evidenced. The morphology of the copper deposits under different experimental conditions was obtained by SEM and AFM. The additives produce uniform, bright and adherent copper deposits. Both, the nature of the additive and the experimental conditions have a marked influence on the deposition mechanism as well as on the morphology of the copper layers. Acknowledgements: We thank CONICET, SECYT-UNC, Agencia Córdoba Ciencia S.E. and ANPCyT for their financial support. The morphology of the copper deposits under different experimental conditions was obtained by SEM and AFM. The additives produce uniform, bright and adherent copper deposits. Both, the nature of the additive and the experimental conditions have a marked influence on the deposition mechanism as well as on the morphology of the copper layers. Acknowledgements: We thank CONICET, SECYT-UNC, Agencia Córdoba Ciencia S.E. and ANPCyT for their financial support.