Electrical properties and thermal stability of Ta/TaN/SiCN tri-layer barrier

We report the effect of a Ta/TaN/SiCN tri-layer barrier on the electrical properties and thermal stability of single damascene (SD) lines for Cu-ultra low k (2.3) integration. It was found that by incorporating a thin SiCN layer between the Ta/TaN barrier and ultra low k material, the leakage current can be significantly reduced and the breakdown voltage can be enhanced. A thermal treatment at 200°C for 40 hours can further improve the leakage current but with slight decrease in breakdown voltage.