This paper presents a methodology to optimize semiconductor FAB operations by integrating simulation and scheduling. Due to the complexity and dynamic nature of modern FABs, tradi- tional simulations fail to capture realistic interactions between AMHS simulation and schedul- ing. To address this, we propose a coupled simulation approach that allows real-time schedule updates and system status synchronization, enhancing responsiveness to fluctuations. Experimen- tal results, based on the SMT2020 model, demonstrate improved production efficiency when jointly utilizing the real-time scheduler (RTS) and real-time dispatcher (RTD), compared to their isolated use. Key performance indicators, including total output, on-time delivery rate, and equipment utilization, suggest optimal FAB efficiency at specific dispatching loss thresholds, highlighting the importance of tailored RTS and RTD strategies. This approach provides a foun- dation for FAB digital twin research, with potential applications in real-world semiconductor manufacturing.
