AUTO LEVELLING DEVICE OF STEPPER

摘要

PURPOSE: An auto leveling device of a stepper is provided to achieve the high precision of the leveling by adjusting the size of the leveling beam. CONSTITUTION: A leveling device of a stepper comprises a beam source(21) for generating a leveling beam. A parallel lens(22) is installed at a front portion of the beam source(21) so as to allow the leveling beam incident into a wafer(27) to be parallel. An iris(23) for adjusting the size of the leveling beam is installed at a front side of the parallel lens(22). A reflected leveling beam is focused by a focusing lens(24). The focusing lens(24) is installed in an optical axis of the leveling beam which is reflected from the wafer(27). A position detecting device(25) is installed at a rear side of the focusing lens(24) so as to detect the position of a beam spot. A leveling stage(26) is installed on a wafer stage and is driven according to the beam spot signal.