Abstract: A slide transfer system is provided for transferring semiconductor wafers from a first carrier cassette to a second process cassette. The system includes a base, a transfer mechanism, and a locking mechanism. The base has a first surface for supporting the first cassette, and a second surface for supporting the second cassette adjacent to the first cassette. The transfer mechanism has a wafer engaging member supported by a slidable support member for reciprocating movement of the wafer engaging member across the first surface of the base. The locking mechanism has an actuator element positioned for engagement by the second cassette placed on the second surface, and a locking element. The locking element has a first position in which sliding movement of the transfer mechanism is prevented, and a second position in which sliding movement of the transfer mechanism is permitted. The actuator element is operable to move the locking element between the first and second positions.