A real-time scheduling algorithm of wet-etching system with residency constraints in semiconductor wafer fabrications

A wet-etching process is a key flow in wafer fabrications. The wet-etching process involves a complex interplay operation of zero wait and no-intermediate storage, and shared robots. To improve the utilities of a semiconductor wafer wet-etching system efficiently, according to characteristics of the wet-etching system, a problem domain of the real-time scheduling was supposed and defined, and strategies of resolving the scheduling problem were proposed. A real-time scheduling algorithm with residence constraints was presented as well. On the basis of the mentioned above, a heuristic real-time algorithm were built for minimizing makespan with no defective wafer. Finally, the performances of the proposed algorithm were analyzed with simulation experiments. The results indicate that the proposed algorithm is valid and practical for generating satisfactory schedule solutions.