The Cu/barrier/low-k SiCOH/Si structures were fabricated and their thermal stability was investigated. SiCOH films were deposited by plasma-enhanced chemical vapor deposition using divinyldimethylsilane (DVDMS) and O-2. As barrier materials, tungsten and tungsten nitride films were deposited by chemical vapor deposition using W(CO)(6) and NH3 sources at 450 degrees C. Variations of scanning electron microscopy and x-ray diffraction results of Cu/barrier/low-k SiCOH/Si were examined depending on the annealing temperature. Both results showed that W and W2N film were stable up to 500 and above 600 degrees C, WO3 nanorods were grown from the sample surface. It is thought that the thermal stability of the Cu/barrier/SiCOH/Si structure is closely related with the thermal destruction of the W and WNx films. (c) 2006 American Vacuum Society.