Substrate and pretreatment dependence of Cu nucleation by metal–organic chemical vapor deposition

The nucleation of copper (Cu) with (hfac)Cu(VTMS) organometallic precursor is investigated for Si, SiO2, TiN, and W2N substrates. As the deposition temperature is increased, the dominant growth mechanism is observed to change from the nucleation of Cu particles to the clustering of Cu nuclei around 180 °C independent of the employed substrates. It is also observed that the cleaning of substrate surfaces with the diluted HF solution improves the selectivity of Cu nucleation between TiN and SiO2 substrates. Dimethyldichlorosilane treatment is found to passivate the surface of TiN substrate, contrary to the generally accepted belief, when the TiN substrate is cleaned by H2O2 solution before the treatment.