Abstract: A chemical mechanical polishing apparatus includes a polishing pad, a wafer carrier, a first ring, a second ring, a pad conditioning unit and at least one cleaning solution supply pipe. The first ring surrounds the semiconductor wafer and the edge of the wafer carrier. The second ring surrounds the first ring. The cleaning solution supply pipes are connected to the second ring and/or to the pad conditioning unit to supply the cleaning solution into the gaps between the rings, the wafer carrier and portions of the pad conditioning unit to remove solidified slurry from the gaps.