Ferroelectric thin films such as Pb(Zr,Ti)O-3, SrBi2Ta2O9, and Bi3.25La0.75Ti3O12 (BLT) thin films have been widely investigated for non-volatile ferroelectric memories. BLT thin films show advantages such as highly fatigue resistance, low processing temperature, and large remanent polarization. The patterning of these ferroelectric thin films with a vertical sidewall and without plasma damage is strongly required. Chemical mechanical polishing (CMP) process was investigated for the vertical sidewall patterning of BLT thin films. Removal rate and within-wafer non-uniformity (WIWNU%) were examined by change of process parameters. Potential of hydrogen (pH) in slurry was varied for an improvement of the removal rate and WIWN-U%. Surface roughness of BLT thin films after CMP process for the improvement of densification was inquired into by atomic force microscopy. The excellent performance such as 188.4 nm/min of removal rate, 2.61% of WIWN-U%, 0.95 nm of root mean square roughness, and 6.94 nm of peak-to-valley roughness was obtained. This result will lead the CMP process to pattern the BLT thin films for the vertical sidewall without plasma damage. (C) 2006 Elsevier B.V. All rights reserved.