Enhancement of Iodine Adsorption Using I[sub 2] Plasma for Seedless Catalyst-Enhanced CVD of Copper

The promotion of iodine adsorption on copper diffusion barrier metal of TiN using I 2 plasma for the seedless catalyst-enhanced chemical vapor deposition (CECVD) of copper is presented. Iodine atoms, catalytic surfactant, were not sufficiently absorbed on TiN with a simple exposure to ethyl iodide ( C 2 H 5 I ) vapor. Alternatively an I 2 plasma treatment improved iodine adsorption on TiN films and even on an oxide film of SiO 2 . In addition, the iodine adatoms on TiN and SiO 2 also showed the catalytic surfactant effect on the following metallorganic CVD of copper. The improvement in iodine adsorption on the TiN substrate was confirmed with secondary-ion mass spectroscopy analysis. By utilizing the I 2 plasma treatment directly on the copper diffusion barrier metal, the bottom-up filling of copper on submicrometer features was also realized in the CECVD of copper without preparing copper seed layers.