Finite-capacity production planning algorithms for a semiconductor wafer fabrication facility

We consider the problem of production planning for a semiconductor wafer fabrication facility producing application-specific integrated circuits to customer order. Using a simple planning algorithm based on forward scheduling for work-in-progress and backward scheduling for new orders, the effects of the level of detail at which the production process is modelled was examined. A simulation study showed that considering all near-constraint workcentres explicitly as having finite-capacity gives the best results. Also examined were the effects of undercapacity planning, and it was shown that when coupled with a shop-floor scheduling procedure driven by the planned completion date rather than customer due dates, significant improvements in both delivery performance and system predictability were obtained.