Production control in semiconductor manufacturing with time constraints

In this paper, production of lots under time constraints in a semiconductor wafer fabrication is investigated. A time constraint covers a sequence of process steps and has a maximum time that lots must spend in these steps. Lots which violate a recommended time constraint have to be scrapped or reprocessed. Accordingly, controlling the entrance of lots in a time constraint is critical in semiconductor fabrication. An approach is developed to estimate whether a given lot may satisfy time constraints or not. Some numerical experiments are presented with industrial data.