AN AUTOMATED LOADING AND UNLOADING SYSTEM FOR A MAGLEV WAFER TRANSPORT PATH

This article discusses an automated loading and unloading system for p lacing silicon wafers on a carrier. While the system has broad applica tion, we are particularly interested in the automated loading of wafer s onto a carrier which is moved along a transport path using a magneti c levitation (maglev) drive mechanism. The automated loading and unloa ding system consists of two parts: a wafer carrier which can move alon g the path and which is purely passive, and a loading and unloading de vice which uses vacuum and electrical power. The wafer carrier uses a magnetic clamping mechanism to prevent the wafer from sliding when the carrier moves along the path. The electromagnetic loading and unloadi ng device is designed to firmly hold the wafer using vacuum suction an d may be carried by a robot. Only the bottom surface and edge of the w afer are touched by the carrier and the loader-unloader. The loader-un loader described here, when combined with a maglev transport path, is potentially very useful as a means of connecting the processing tools in a cluster or connecting the workstations along a semiconductor fabr ication line.