A Greedy Dynamic Priority Dispatching Policy for Intrabay in Semiconductor Wafer Fabrication System

The automation of intrabay system in 300mm semiconductor wafer fabrication system is complex due to complicated product mixes, mass and dynamic transportation demands, transportation deadlock, and vehicle blockage. To obtain better overhead hoist transport (OHT) dispatching solution in intrabay system, a fuzzy logic based greedy dynamic priority dispatching policy is proposed. With experimental data from a 300mm semiconductor wafer fabrication system, it is demonstrated that the proposed approach has the better comprehensive performance than FEFS dispatching rule in aspect of cycle time, delivery time, transport time, movement, throughput, due date satisfaction, and WIP in intrabay system.