Method for fast loading substrates in a flat panel tool

The present disclosure generally relates to a method and apparatus for loading, processing, and unloading substrates. A processing system comprises a load/unload system coupled to a photolithography system. The load/unload system comprises a first set of tracks having a first height and a first width, and a second set of tracks having a second height and a second width different than the first height and first width. An unprocessed substrate is transferred from a lift pin loader to a chuck along the first set of tracks on a first tray while a processed substrate is transferred from the chuck to the lift pin loader along the second set of tracks on a second tray. While a first tray remains with a substrate on the chuck during processing, the load/unload system is configured to unload a processed substrate and load an unprocessed substrate on a second tray.