A load lock includes a chamber including an upper portion, a lower portion, and a partition between the upper portion and the lower portion, the partition including an opening therethrough. The load lock further includes a first port in communication with the upper portion of the chamber and a second port in communication with the lower portion of the chamber. The load lock includes a rack disposed within the chamber and a workpiece holder mounted on a first surface of the rack, wherein the rack and the workpiece holder are movable by an indexer that is capable of selectively moving wafer slots of the rack into communication with the second port. The indexer can also move the rack into an uppermost position, at which the first surface of the boat and the partition sealingly separate the upper portion and the lower portion to define an upper chamber and a lower chamber. Auxiliary processing, such as wafer pre-cleaning, or metrology can be conducted in the upper portion.