In integrated circuits manufacturing industry, metal organic chemical vapor deposition (MOCVD) TiN thin films are widely used as barrier layers. To remove impurities such as carbon and oxygen in as-deposited films, a N-2/H-2 in situ plasma treatment (IPT) is usually applied. In this paper, transmission electronic microscopy analysis and electrical tests were carried to study the properties of MOCVD TiN thin films in real structures, especially under different conditions of IPT and film thickness. IPT efficiency was proved to be significantly higher at horizontal planes than vertical planes due to the plasma motion perpendicular to wafer surface. This leads to an obvious difference of film thickness and structure at different locations in real structures. It was also found that IPT efficiency is sensitive with via size and aspect ratio in our electrical properties study. (c) 2006 Elsevier B.V. All rights reserved.