Mn_2O_3 Slurry Reuse by Circulation Achieving High Constant Removal Rate

摘要

Fumed silica is widely used in SiO_2 chemical mechanical polishing (CMP). In semiconductor processes, only fresh slurry is used, and used slurry is disposed. Sustainable development demands a reduction in waste. Since reuse of slurry is effective for reducing the amount of used slurry generated, we investigated the reuse of Mn_2O_3 slurry and conventional fumed silica slurry. In both cases, abrasive concentration decreases as reuse time increases. The removal rate for Mn_2O_3 slurry maintains a value 4 times that of the conventional fumed silica slurry during slurry reuse, because the removal rate for Mn_2O_3 slurry is almost constant for solid concentrations between 1.0 and 10wt%. Pad conditioning was not performed for Mn_2O_3 slurry. The removal rate for conventional slurry decreases as the number of times of reuse increases, even when pad conditioning is appropriately performed.