The Influence of the Anion on Copper Electrocrystallization

Abstract
Structural studies of copper electrodepositions from pyrophosphate, chloride, cyanide, and citrate solutions were carried out on highly polished (001) copper surfaces at a wide range of current densities under galvanostatic conditions. The study was performed by means of x‐ray diffraction. The deposition morphology was observed with a scanning electron microscope. Correlation among internal structure, surface morphology, solution composition, and plating conditions were examined. The results were compared with previous studies from sulfate solutions. Epitaxial growth was observed in the early stage of deposition. The effect of the anion on the change from single crystalline to polycrystalline growth at further stage was analyzed. A specific adsorption of the different anions in relation to their ionic size was considered as a critical feature. As a comparative study the action of an addition agent was also considered.