The present invention relates to an apparatus and method for polishing semiconductor substrates with improved throughput and reduced foot print. One embodiment of the present invention provides an apparatus for polishing a substrate. The apparatus comprises a base, four polishing stations disposed on the base, two load cups disposed on the base and a carousel supported by the base. The carousel comprises six substrate heads and is rotatable about a carousel axis. Each of the six substrate heads is configured to align with any one of the four polishing stations and the two load cups.