A series of polishing experiments have been carried out using Mn2O3 as abrasive grains to examine the polishing characteristics of CMP for oxygen-free copper. It has been found that the polishing rate increases as the polishing speed and/or polishing pressure increases, also the role of polishing speed on the polishing rate is more significant than that of the polishing pressure. The effects of the polishing conditions are however small, when polishing a finished surface roughness of about Ra 5 nm. A long polishing time, with an approximately constant polishing rate, can be achieved, without dressing, with a polishing pressure P = 9.4 kPa. It was found that higher polishing pressures could achieve a higher polishing rate, however the polishing pressure would decrease as the polishing time increased.