[IEEE 2018 IEEE 14th International Conference on Automation Science and Engineering (CASE) - Munich, Germany (2018.8.20-2018.8.24)] 2018 IEEE 14th International Conference on Automation Science and Engineering (CASE) - Simulation-based Performance Assessment of Tool Requalification Strategies in Wafer Fabs

摘要： In this paper, we discuss requalification strategies for stepper tools in semiconductor wafer fabrication facilities (wafer fabs). Before processing lots on steppers, the steppers have to be qualified. A mathematical programming formulation is used periodically to determine appropriate qualification plans. These plans will be implemented at the shop-floor. Dur-ing consecutive planning epochs, certain already established qualifications of steppers can be canceled, for instance, due to stepper breakdowns. We study the performance of several re-qualification strategies in this situation. Therefore, we use a discrete-event simulation framework that allows for applying the mathematical programming formulation in a rolling hori-zon manner and for performing the requalification strategies while the production is executed in the simulation. We demon-strate by designed simulation experiments that some of the pro-posed strategies perform well with respect to throughput and cycle time while requiring only a low additional qualification effort.