Multi-Platen Multi-Head Polishing Architecture

A method of operating a polishing apparatus, comprising:

• transporting a first substrate from a transfer station past a first polishing station to a second polishing station without polishing the first substrate at the first polishing station;
• transporting a second substrate from the transfer station to the first polishing station;
• polishing the first substrate at the second polishing station and simultaneously polishing the second substrate at the first polishing station;
• transporting the first substrate from the second polishing station past a third polishing station to a fourth polishing station without polishing the first substrate at the third polishing station;
• transporting the second substrate from the first polishing station past the second polishing station to the third polishing station without polishing the second at the second polishing station;
• and
• polishing the first substrate at the fourth polishing station and simultaneously polishing the second substrate at the third polishing station.

A polishing apparatus comprising:

• N polishing stations where N is an even number equal to or greater than 4, each polishing station including a rotatable platen to support a polishing pad;
• a substrate transport apparatus comprising a plurality of substrate transfer stations, a robot configured to transfer a substrate into a selectable one of the plurality of substrate transfer stations, and M carrier heads where M is an even number equal to or greater than N, each carrier head configured to receive a substrate from a substrate transfer station and to move from the substrate transfer station to a polishing station;
• and
• a controller configured to cause the substrate transport apparatus to load a first substrate at a first transfer station into a first carrier head and load a second substrate at a second transfer station into a second carrier head, move the first substrate from the first transfer station to a first polishing station without polishing the first substrate at another station, move the second substrate to a second polishing station without polishing the second substrate at another station, simultaneously polish the first substrate at the first polishing station and the second substrate at the second polishing station in a first polishing step, move the first substrate from the first polishing station to a third polishing station without polishing the first substrate at another station and move the second substrate from the second polishing station to a fourth polishing station without polishing the second substrate at another station, simultaneously polish the first substrate at the third polishing station and the second substrate at the fourth polishing station in a second polishing step, and unload the first substrate and the second substrate from two of the plurality of carrier heads at the plurality of substrate transfer stations.