Influence of slurry components on copper CMP performance in alkaline slurry

Abstract In this work, we have designed copper chemical mechanical planarization (CMP) experiments to investigate the effect of slurry components on the planarization performance of copper wafer in the presence of two different surfactants including ammonium dodecyl sulfate (ADS) and fatty alcohol polyoxyethylene ether (AEO). Copper CMP was performed at pH 10.5 using hydrogen peroxide (H 2 O 2 ), silica, benzotriazole (BTA), and FA/O II (a unique alkaline macromolecular organic chelating agent with high activation energy) as an oxidizer, an abrasive, a corrosion inhibitor and a complexing agent, respectively. As hydrogen peroxide is added in the copper slurry, the material removal rate (MRR) increases rapidly and then decreases slowly as a function of the concentration of H 2 O 2 . The within-wafer non-uniformity (WIWNU) declines and the surface roughness decreases first and then ascends with the increase of the H 2 O 2 concentration. The addition of BTA has a large effect on the MRR, WIWNU and copper surface roughness. The MRR decreases to approach a minimum as a function of the BTA concentration. While the copper surface WIWNU fluctuates and the surface roughness increases with increasing the amount of BTA. As FA/O II is chosen to be a complexing agent, the MRR increases prominently and the WIWNU decreases with the increase of the FA/O II concentration. The surface roughness also decreases indicating that the addition of FA/O II can effectively improve the surface planarization performance in the present copper CMP experiments. The mechanism of the corresponding experimental results is also elucidated and discussed. All the results show that the copper surface planarization performance could be strictly controlled by proper configuration of the slurry components and an optimal choice of the concentrations of the constituents can obtain a high removal rate, low WIWNU and small surface roughness of the copper wafer in alkaline slurries.