Semiconductor wafers in plastic cassettes are loaded into (and later unloaded from) an input/output station serving a CVD furnace and thereafter the cassettes are non-manually transported by a programmable elevator to and from a flat-finder, a wafer transfer machine (where the wafers are transferred to a boat) and in-process storage. The boats are non-manually transported by a second programmable elevator to and from the wafer transfer machine, in-process boat storage and a boat loader (or process chamber directly). The cassettes can be loaded or unloaded while one or both of the elevators are operating. Up to eight human assisted steps are reduced to only two such steps.Furnaces having more than one processing chamber have a loading station, in-process cassettes and boat storage and boats dedicated to each processing chamber so that there is no cross contamination between processing chambers caused by the boats and the cassettes in which wafers are delivered to the process are the same cassettes in which process wafers are returned to the input/output station so that there is no cross contamination of the wafers caused by the cassettes.