System providing multiple processing of substrates

Abstract

The present invention includes plural plasma etching vessels and a wafer queuing station arrayed with a wafer transfer arm in a controlled environment. Wafers are movable within the controlled environment one at a time selectably between the plasma vessels and the wafer queuing station without atmospheric or other possible contamination. The system is selectively operative in either single-step or multiple-step processing modes. In the preferred embodiment, the plasma vessels and the queuing station are arrayed about a closed pentagonal locus with the wafer transfer arm disposed within the closed locus. The wafer transfer arm is movable between the plasma etching vessels and the wafer queuing station. Selectably actuable vacuum locks are provided between the plasma etching vessels and the wafer transfer arm to maintain an intended atmospheric condition and to allow wafer transport therethrough. The plasma vessels each include first and second water-cooled electrodes that are movable relatively to each other. The wafer transfer arm is operative to pick-up the wafers by back-side and peripheral wafer contact only. A sensor on the transfer arm provides an indication of proper wafer seating. Wafer processing in each vessel is regulated by a state controller for processing a plurality of wafers from a single cassette to provide an orderly and efficient throughput of wafers for diverse or similar processing in the plural vessels.