Copper electrodeposition onto the dendrimer-modified native oxide of silicon substrates

Adherent copper films were electrochemically grown onto the native oxide surfaces of Si wafers modified by the adsorption of polyamidoamine (PAMAM) dendrimers. Metallic nuclei of copper grow at isolated nucleation sites, associated with adsorbed dendrimers, and film coalescence can be observed above a metal thickness of about 10,000 monolayers (∼2.5 μm). Film microstructure depends on the deposition mode; higher coverage and better adhesion were obtained by galvanostatic control of the deposition process. It is hypothesized that reduction of Cu2+ ions complexed with functional groups of the chemisorbed dendrimer leads to the formation of metallic copper nuclei, and that metal films grow from these nuclei. Further improvement of this process may open the way to the direct integration of metal electrodeposition with silicon microfabrication processes and selective deposition by dendrimer patterning.