A new weakly alkaline slurry for copper planarization at a reduced down pressure

This study reports a new weakly alkaline slurry for copper chemical mechanical planarization (CMP), it can achieve a high planarization efficiency at a reduced down pressure of 1.0 psi. The slurry is studied through the polish rate, planarization, copper surface roughness and stability. The copper polishing experiment result shows that the polish rate can reach 10032 Å/min. From the multi-layers copper CMP test, a good result is obtained, that is a big step height (10870 Å) that can be eliminated in just 35 s, and the copper root mean square surface roughness (sq) is very low (< 1 nm). Apart from this, compared with the alkaline slurry researched before, it has a good progress on stability of copper polishing rate, stable for 12 h at least. All the results presented here are relevant for further developments in the area of copper CMP.