Optimization of slurry and process parameter on chemical mechanical polishing of CR-doped Sb2Te3 thin film

In this paper, we studied the composition of slurry including pH and the oxidizing agent Hydrogen Peroxide (H2O2) for Cr-doped Sb2Te3 (CST) thin film chemical mechanical polishing (CMP). Also the effects of the process parameters including down force and platen rotation rate were studied in detail. The results demonstrate that Material Removal Rate (MRR) has a relatively large dependence on pH values as well as the concentration of the oxidizing agent. Moreover, the MRR still exists when there is no down force and rotation, indicating that it is a mechanical abrasion assisted by chemical corrosion. Eventually, the root mean square (RMS) roughness was reduced from 4.02nm to 0.425nm and the MRR can be achieved at 100.45nm/min.