Heuristic tabu search scheduling algorithm for wet-etching systems in semiconductor wafer fabrications

To improve overall equipment efficiency (OEE) of a semiconductor wafer wet-etching system, a heuristic tabu search scheduling algorithm is proposed for the wet-etching process in the paper, with material handling robot capacity and wafer processing time constraints of the process modules considered. Firstly, scheduling problem domains of the wet-etching system (WES) are assumed and defined, and a non-linear programming model is built to maximize the throughput with no defective wafers. On the basis of the model, a scheduling algorithm based on tabu search is presented in this paper. An improved Nawaz, Enscore, and Ham (NEH) heuristic algorithm is used as the initial feasible solution of the proposed heuristic algorithm. Finally, performances of the proposed algorithm are analyzed and evaluated by simulation experiments. The results indicate that the proposed algorithm is valid and practical to generate satisfied scheduling solutions. Copyright © 2013 by High Technology Letters Press.