Study of the intrinsic time dependent dielectric breakdown (TDDB) of dielectric copper diffusion barriers was realized using a unique planar capacitor (Pcap) test structure. The test vehicle has several advantages over the metal dot method. The most important one is the elimination of field enhancement effect which could be more than 50% in the case of metal dots. In order to test the effectiveness of this test vehicle, two different dielectric barriers, one conventional SiCN film and the other a BN film still under development, were selected for TDDB evaluations. Significant differences were observed between the two films in TDDB lifetime, the shape parameter beta of the Weibull failure time distributions, and the characteristics of the current versus time curves. The BN film had a degradation of more than four orders of magnitude in TDDB lifetime than SiCN. The Weibull shape parameter beta of SiCN was 8.4, among the highest values that have been reported for any dielectric barrier films, versus 1.4 for the boron nitride film. Furthermore, the SiCN film showed a decrease in current versus time curves during the initial stage of the stressing, a trend which is typically related to charge trapping in defect-free films. This was not the case for the BN film where the leakage currents were much higher. The results demonstrate that the Pcap test structure is an effective vehicle to evaluate the intrinsic reliability of dielectric barrier films. (C) 2011 Elsevier B.V. All rights reserved.