Performance evaluation of lot dispatching and scheduling algorithms through discrete event simulation

The effect of wafer factory production rules on factory capacity, WIP (work in process), and cycle time is investigated. Algorithms involving lot start rules, equipment loading rules, and lot priority assignment rules are evaluated. Specific rules are found optimum for the factory analyzed here. The spread between worst-case and best-case operating rules is quantified. More importantly, during the course of the investigation it became apparent that reliable methods of rule enforcement and verification are vital, because the tendency is for the undisciplined factory to settle toward worst-case, operating rules