Material transport system

Abstract

A system for loading and unloading semiconductor wafers includes a frame having a charging opening, a platform mounted on the frame and movable between a deployed position and a retracted position, and a movable closure for the charging opening for opening and closing a horizontal path through the charging opening. In the deployed position, the platform has a generally level orientation adjacent the charging opening and projects away from the frame for receiving thereon a cassette adapted to support therein a plurality of the semiconductor wafers to be passed though the charging opening. In one embodiment, the platform is elevationally movable on the frame between a retracted lowered position distant from the charging opening and a deployed raised position adjacent the charging opening. In another embodiment, the platform is rotationally movable on the frame between the deployed position having a generally level orientation located generally adjacent the charging opening and the retracted position folded against the frame. The loading and unloading system includes a transport system for advancing a cassette from a remote location and delivering the cassette onto the platform in the deployed position. The transport system includes a nest member for supporting a cassette at spaced apart locations enabling reception therebetween of the platform in the deployed position so that the cassette can selectively be transferred, in one instance, from the nest member to the platform and, in another instance, from the platform to the nest member.