A projection exposure system for printing the pattern formed on a reticle onto a wafer includes a reticle stage (5) and a wafer stage. A first reference plate (9) having a first reference pattern (MM1) formed thereon is mounted on the reticle stage (5), and a second reference plate (25) having a second...http://www.google.de/patents/US6236448?utm_source=gb-gplus-sharePatent US6236448 - Projection exposure system
