Optimization on Chemical Mechanical Planarization of Chromium Doped Antimony Telluride (Cr-SbTe) for PCM Devices

This study explores the effect of pH and oxidizer concentration on the chemical mechanical planarization (CMP) of Cr-DOPED Sb
₂
Te
₃
(CST) thin film using the colloidal silica-based slurry. In this work, CMP of CST was investigated in the presence of Acidic Permanganate as an oxidizer. The influence of slurry parameters including pH values, concentration of oxidizer was investigated. And the effects of the process parameters including down force was studied in detail. The results observed a monotonic increase in Material Removal Rate (MRR) with increasing oxidizer concentration indicating its importance in defining the MRR. Finally, it is verified that slurry with Acidic Permanganate has no influence on the electrical property of the post-CMP CST film through the resistivity test. And the best effect of the root mean squre(RMS) roughness was reduced from 4.28nm to 0.52nm and the MRR can be achieved at 287.56nm/min.