Enhancement of Iodine Adsorption Using I2 Plasma for Seedless Catalyst-Enhanced CVD of Copper

Abstract

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 (C2H5I) vapor. Alternatively an I-2 plasma treatment improved iodine adsorption on TiN films and even on an oxide film of SiO2. In addition, the iodine adatoms on TiN and SiO2 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. (C) 2003 The Electrochemical Society.