Mechanical effect of process condition and abrasive concentration on material removal rate profile in copper chemical mechanical planarization

Recently, many researchers have studied the material removal mechanism of copper chemical mechanical planarization (CMP). On the basis of their previous works, we studied the mechanical effect of copper (Cu) CMP on the material removal rate profile. Copper CMP was performed using citric acid (C6H8O7), hydrogen peroxide (H2O2), colloidal silica, and benzotriazole (BTA, C6H4N3H) as a complexing agent, an oxidizer, an abrasive, and a corrosion inhibitor, respectively. In this paper, the abrasives and process condition are main mechanical factors of CMP. The colloidal silica, used as an abrasive in copper CMP slurry containing 0.01 M citric acid and 3 vol% hydrogen peroxide, controlled the wafer edge profile by abrading the wafer edge. The polishing pressure did not contribute to the material removal rate (MRR) profile, but did to the MRR. As the rotational velocity of the polishing head and table increased, the deviation of MRR profile became smaller. The results of this paper showed that the abrasive concentration was the key factor which controlled the wafer edge profile, and also the rotational velocity was the key factor which controlled wafer center profile of MRR.