Comparative study on ALD/CVD-Co(W) films as a single barrier/liner layer for 22−1x nm generation interconnects

ALD-Co(W) was found to have a potential to replace the conventional PVD-Ta/TaN bi-layer in further shrinking interconnects as a single-layered barrier/liner material. We could confirm good barrier property of CVD/ALD-Co(W) film by BTS-TVS method after 350°C annealing. ALD-Co(W) showed lower resistivity of 60 μΩ-cm and good adhesion to Cu. Complete trench filling with Co(W) followed by Cu seed deposition was demonstrated. These properties were confirmed to be derived from W stuffing into grain boundaries of oxygen-free ALD-Co(W) films. We would like to suggest ALD-Co(W) as a next-generation barrier/liner layer for future development.