A Multiagent-Based Decision-Making System for Semiconductor Wafer Fabrication with Hard Temporal Constraints

This paper presents a decision-making system for semiconductor wafer fabrication facilities, or wafer fabs, with hard interoperation temporal constraints. The decision-making system is developed based on a multiagent architecture that is composed of scheduling agents, workcell agents, machine agents, and product agents. The decision-making problem is to allocate lots into each workcell to satisfy both logical and temporal constraints. A dynamic planning-based approach is adopted for the decision-making mechanism so that the dynamic behaviors of the wafer fab such as aperiodic lot arrivals and reconfiguration can be taken into consideration. The scheduling agents compute quasi-optimal schedules through a bidding mechanism with the workcell agents. The proposed decision-making mechanism uses a concept of temporal constraint sets to obtain a feasible schedule in polynomial steps. The computational complexity of the decision-making mechanism is proven to be $O(\Lambda\mathhat{}3\cdot L)$, where $\Lambda$ is the number of operations of a lot and $L$ is the cardinality of the temporal constraint set.