Journal of Materials Science. Materials in Electronics vol:23 issue:4 pages:945-951
The "direct-on-barrier" electroplating of copper on ruthenium from a 1 mol dm(-3) solution of CuCl in the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide, [C(2)mim][N(CN)(2)], is reported. Continuous layers of copper with a preferential Cu(111) orientation were obtained from this electrolyte. The copper coatings were investigated by top view scanning electron microscopy (SEM), X-ray diffraction (XRD), and focused ion beam transmission electron microscopy (FIB-TEM). The nucleation density was both theoretically and experimentally evaluated by the Scharifker-Hills model and transmission electron microscopy, respectively. The direct plating of copper on resistive substrates for advanced interconnects and package is a promising new application of ionic liquids.