Abstract: A vacuum deposition system is shown in the form of a sputtering system for rigid disk substrates which uses a single vacuum envelope and a single transport to avoid multiple pump downs or valved isolation structures during the multiple coating processes or the transfer of workpieces between conveyer devices. Work stations carried by a modular processing unit provide a slotted opening through which work pieces supported on the transport enter and leave the work station and which affords sufficient restriction to enable a processing gas atmosphere to be maintained within the work station that is above the pressure of the vacuum envelope while being isolated from the adjoining work stations. The work stations are supported on and readily releasable from the modular processing units to allow service and target replacement to occur offline.