Method and apparatus for rapid pump-down of a high-vacuum loadlock

A gas expansion module for use with semiconductor wafer loadlocks and other regulated-pressure components of semiconductor processing tools is provided. The gas expansion module may be barometrically isolated from the loadlock or other component and pumped down to a vacuum condition while the loadlock is performing operations at a higher pressure, such as ambient atmospheric conditions. After an initial pump-down of the loadlock is performed, the gas expansion module may be fluidly joined to the loadlock volume and the gases within each allowed to reach equilibrium. A further pump-down of the combined volume may be used to bring the loadlock pressure to a desired vacuum condition.