Semiconductor wafer fabrication involves one of the most complex manufacturing processes ever used. To control such complex systems, it is a challenge to determine appropriate dispatching strategies under various system conditions. Dispatching strategies are crucial for the system performance, especially for the real time control of the system. In this paper, an interval variant rescheduling mechanism is proposed. In order to deploy different dispatching rules to different intrabays, k-means is used for clustering the intrabays of the fab. Then genetic algorithm (GA) is used for searching dispatching rule sets which promote better performance. In terms of the system conditions corresponding to dispatching rules, the support vector machine (SVM) classifier is constructed as the scheduler. In addition, the adaptive neuro-fuzzy inference system (ANFIS) prediction model is built for the sake of on-line deciding the scheduling intervals. The results indicate that applying the proposed mechanism to obtaining dispatching strategies is an effective method considering the complexity and variation of semiconductor wafer fabrication systems