The Effect of Additives and Substrate Conditions on the Copper Electrodeposition for Thin Film Applications

Abstract

The effect of surface states of substrate and additives on copper electrodeposition for thin film applications was investigated. Titanium substrate states were mechanically and chemically moderated and several additives such as Arabic gum, hydroxyl ethyl cellulose, and chlorine were used during electrodeposition process under a constant current condition with current density of 500 mA/cm2. Results obtained using SEM, X-ray, and AFM for early stage of copper nucleation and growth revealed that substrate conditions and additives appear to be effective in producing uniformly-distributed copper nuclei and their subsequent growth in a regulated manner of surface leveling. The shape of copper nuclei was clearly affected by the surface state of the substrate. It seems to be related with dislocations produced on the titanium cathode during surface moderating. Hardness, growth direction, and resistivity of copper deposits changed with the kind of additives.