Method providing multiple-processing of substrates

Abstract

Plural plasma etching vessels and a wafer queuing station are arrayed about a closed pentagonal locus with a wafer transfer arm therewithin all in a controlled vacuum environment. Wafers are movable within the controlled environment between the several plasma vessels and the wafer queuing station without atmospheric or other exposure so that possible contamination of the moved wafers is prevented. The system is selectively operative in either single-step or multiple-step processing modes, and in either of the modes, the several plasma etching vessels are operable to provide a desirably high system throughput. Wafer processing in each vessel is regulated by a state controller for processing a plurality of wafers from a single cassette, contained within the vacuum environment of the plural plasma etching vessels and wafer queuing station, to provide an orderly and efficient throughput of wafers for diverse or similar processing in the plural vessels. The wafer transfer arm is movable in R and .theta.. The plasma vessels each include first and second water-cooled electrodes that are movable relatively to each other so as to provide a selectable gap dimension therebetween. The wafer transfer arm is operative to pick-up the wafers by back-side contact only whereby front-side contact-induced contamination of the wafer surfaces is prevented. A sensor on the transfer arm is operative to provide a signal indication of proper wafer seating.