Abstract: Wafers from cassettes placed in a cassette holder at a loading station are transferred by a loader to a conveyor and through a wafer processing stage. From the conveyer, the wafers are delivered to an unloader at an unloading station. The unloader transfers the wafers to cassettes held in a cassette holder at the unloading station. The cassettes may be loaded into the rear of the loading station and removed from the rear of the unloading station. The cassette holders support plural stacks of at least two cassettes which are independently indexed upwardly and downwardly. The stacks of cassettes are also carried by a cassette positioner which is transversely shiftable to position a first stack in a wafer transfer zone while a second stack is in a cassette transfer zone spaced from the wafer transfer zone and vice versa. The loader may include an arm which is linearly translated and is rotated about its longitudinal axis to invert the wafer for delivery to a destination location.

Abstract: A water slide for semiconductor wafer processing minimizes water usage by confining water to flow within spaced-apart grooves in the absence of a wafer. When a wafer passes down the water slide, a meniscus of water formed above the grooves is spread out to occupy the space underneath the wafer and prevent it from contacting the water slide as the wafer travels down the water slide.