Cu dry-fill on CVD Ru liner for advanced gap-fill and lower resistance

We describe Cu dry-fill on CVD Ru liner for advanced gap-fill and lower resistance for 22nm-node and beyond. Combination of Ru liner and iPVD Cu filling enables us to fill structures with enlarging Cu grains. Excellent step coverage and Cu wettability on Ru film allow Cu diffusion into trenches. 60% increase of grain size and 10% reduction of wiring resistivity were observed at 50nm-width trenches. We successfully fabricated low resistivity Cu interconnects with additional iPVD Cu planarization followed by CMP.