Indian Journal of Science and Technology

Abstract

A semiconductor production system has sophisticated manufacturing operations and needs high capital investment for its expensive equipment, which warrants efficient real-time flow control for wafers. To dispatch carriers of wafers in the semiconductor lines, this paper presents an unload request logic, which determines the destination of a carrier of wafers when a carrier finishes its operation, and a load request logic, which determines the next carrier to fill the newly available buffer space when a carrier leaves a buffer. The dispatching procedure first determines the transportation time of each carrier to its destination by each unit of transportation equipment and determines the destination machine by the unload request logic or target carrier by the load request logic. When there is no available buffer space at the machine tool, the procedure allows carriers to stay at the current buffer and determines the delay time, which is used to determine the destination in the unload request logic. Performance of the material flow control procedure is verified by an example.
Keywords: Control, Material Flow, Semiconductor, Transporter, Wafer.