Furnace tool allocation and sequencing problem Furnace tool group is very often a bottleneck in semiconductor fabrication [1]. Furnace tools are characterized by long processing times with batching requirements, stringent limitations on times to wait for furnace processing and heterogeneous configurations of individual tools. Effective furnace tool scheduling is very important to improve productivity and reduce production cycle time [2, 7], but is quite challenging to fab operation management because of its complexity.