Indium tin oxide (ITO) CMP was performed by change of de-ionized water (DIW) temperature in pad conditioning process. DIW with high temperature was employed in pad conditioning immediately before ITO-CMP. The removal rate of ITO thin film polished by silica slurry immediately after pad conditioning process with the different DIW temperatures dramatically increased to 93.0 nm/min after pad conditioning at DIW of 75 oC, while that after the general conditioning process at 30 oC was about 66.1 nm/min. The grains of ITO thin film became indistinguishable by CMP after pad conditioning with the high-temperature DIW. The carrier density decreased with the increase of conditioning temperature. The hall mobility rapidly increased regardless of conditioning temperature. The uniformity of optical transmittance also improved.