A novel conditioning technique using High Pressure Micro-Jet (HPMJ) with ultra pure water pressurized to 3-20 MPa was applied to unwoven fabric polyester pads to be used for silicon wafer CMP. In this study, HPMJ conditioning was compared between "no conditioning" and "brush conditioning", evaluating their performances by the removal rates, pad surface observations and SEM images. Rremoval rates of "no conditioning" and "brush conditioning" decreased due to clogging of the pad surfaces as number of polishing increased. The removal rates of HPMJ conditioning were 30 % higher than the brush conditioning when 20 wafers were polished. As a result, it has been confirmed that HPMJ is the most effective conditioning for unwoven fabric polyester pads in silicon polishing process.