A composite rule combining due date control and WIP balance in a wafer fab

Different single dispatching rules aim at different objectives, for instance, SPT (shortest processing time) rule is good at minimizing cycle time and ODD (operation due date) rule intends to minimize deviation between lateness and target due date to achieve better on-time delivery. While some advanced rules called composite rules combine the characteristics of those basic single rules into one composite dispatching rule such as MOD (modified operation due date) which is a combination of SPT and ODD rule. In this paper, a new composite rule which combines ODD, SPT and LWNQ rules (least work at next queue) is developed with the objective of due date control and workload balance. A design of experiment is used to determine the appropriate scaling parameter for this composite rule. The simulation results show significant improvement versus the use of MOD rule.