Plate-like article conveying system

Abstract

A conveying system particularly suitably usable to convey a plate-like article such as a reticle or mask which is usable in transferring a microcircuit forming pattern onto a semiconductor wafer, is disclosed. The conveying system includes a first hand mechanism, a second hand mechanism and a reticle changing mechanism. The first hand mechanism is operable in the neighborhood of a reticle library to load and unload a reticle to and from a reticle cassette and also operable to convey a reticle between the library position and a first midway position. The second hand mechanism is operable to convey a reticle between a reticle setting position within an exposure apparatus and a second midway position. The reticle changing mechanism is operable to hold, at a time, a reticle supported at the first midway position by the first hand mechanism and a reticle supported at the second midway position by the second hand mechanism. Also, the reticle changing mechanism is operable to convey these reticles, at a time, so that their positions are interchanged. This arrangement allows conveyance of plural reticles between the library position and the reticle setting position in the exposure apparatus, while effecting sequential changing of the reticles. Further, the reticle library is made movable relatively to the first hand mechanism and in a direction along which the reticle cassettes are disposed in a layered fashion. This assures efficient utilization of the first hand mechanism, for plural reticle cassettes. Thus, the conveying system permits high-speed reticle changing.