Comparative investigation of TaN and SiCN barrier layer for Cu/ultra low k integration

Abstract This paper reports comparative studies of TaN and SiCN as barrier for Cu-porous dielectric ( k k (ULK) integration. Upon thermal annealing at 400 °C for different periods of time, TEM images revealed strong intermixing at the two interfaces of Cu/TaN/ULK structures but no sign of diffusion in Cu/SiCN/ULK structure even after being annealed at 400 °C for 150 min. The strong intermixing in the Cu/TaN/ULK structure results from grain boundaries in the TaN film and porosity of the dielectric, while the excellent reliability of the Cu/SiCN/ULK dielectric is ascribed to the amorphous structure and high thermal stability of the SiCN film.