Evaluations on scheduling in semiconductor manufacturing by backward simulation

Manufacturing is today often characterized by a growing number of customer-specific products that have to be manufactured and delivered in given lead times, according to concrete delivery dates. Thus, highly relevant questions like “When to start a production order at latest, in order to stay within my lead time?” are answered by more or less primitive, backward-oriented planning approaches and without taking into consideration uncertainty or alternatives. It gets more complex, if different products are to be produced and the more complex the underlying manufacturing system is (e.g. semiconductor with re-entry cycles). These questions could be answered more specifically, more detailed and more robust, if discrete, event-based simulation (DES) would be applied in a backward-oriented manner. This paper describes evaluation results from the semiconductor domain and names restrictions and limits. They also show, that the backward-oriented simulation approach can be applied successfully for the scheduling of customer-specific orders.