The integrity of the Cu/IMP Ta2.3N metallization under different annealing ambients has been investigated by Rutherford backscattering spectrometry (RBS), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy techniques. Results from XRD and TEM show that the as-deposited amorphous Ta2.3M barrier crystallizes upon annealing at 500 degrees C, forming a Ta2N crystalline phase. The sheet resistance of Cu/Ta2.3N metallization remains unchanged upon annealing in Ar or N-2 UP to 750 degrees C. No observable interdiffusion was detected by RES upon annealing at temperatures below 500 degrees C in Ar or N-2 However, above 500 degrees C, the integrity of Cu/Ta2.3N metallization begins to degrade due to out-diffusion of a small amount of Ta into Cu. On the other hand, in an N-2/20% O-2 ambient, the sheet resistance of the metallization is found to increase drastically upon annealing at a temperature above 200 degrees C, an observation that has been attributed to the formation of porous Cu oxide layer. Delamination of Cu oxide from oxide/barrier interface occurs at 400 degrees C. The result highlights the importance of isolating Cu/Ta2.3N metallization from oxygen exposure during back end processing.