Abstract: In an embodiment, a wafer stage module comprises: a stage divided into an exposure zone and a measurement zone; a plurality of chucks configured to be respectively moved between the exposure zone and the measurement zone; guides parallel to each other at both edge sides of the wafer stage; a plurality of first sliders slideably disposed along the plurality of guides; a plurality of beams vertically connecting the plurality of first sliders; and a pair of second sliders formed on each of the plurality of beams, for holding and moving each of the plurality of chucks and for swapping the plurality of chucks without moving on each of the plurality of beams, thus avoiding a travel time of the chucks.