VACUUM CHUCK CONTROLLER FOR MEASURING OVERLAY OF WAFER

摘要

PURPOSE: A vacuum chuck controller for measuring the overlay of a wafer is provided to be capable of varying the positions of limit sensors without limit. CONSTITUTION: A vacuum chuck controller for measuring the overlay of a wafer is provided with a vacuum chuck(10) and a guide rail(20) installed at the lower portion of the vacuum chuck. At this time, a guide groove(21) is formed on the guide rail. The vacuum chuck controller further includes a plurality of limit sensors(31,32) connected with the guide groove of the guide rail for being moved along the guide groove and a sensor box(50) for transmitting a control signal to a driving source by detecting the proximity state of the limit sensors. Preferably, a cylinder is connected with the limit sensors for moving the limit sensors.