APPARATUS AND METHOD FOR MEASURING BENDING LEVEL OF RETICLE STAGE DRIVING MIRROR

摘要

PURPOSE: An apparatus and method for measuring bending of reticle stage driving mirror is provided to periodically measure bending level of a driving mirror using an array mark of a reticle and a plate without stop of operation. CONSTITUTION: The apparatus includes a reticle(13) having array mark(13a) engraved on its surface and which measuring rays(12) from an exposing light reach; a reticle stage on which the reticle is operably mounted; a projection optical instrument(14) disposed under the reticle stage so that the measuring rays can pass through; an array sensor module(15) mounted the plate stage(16) which is disposed under the reticle stage; a reticle stage driving mirror(17) disposed at an side of the reticle stage; a laser interferometer disposed and fixed at a side of the reticle stage driving mirror.