Sampling-based release control of multiple lots in time constraint tunnels

Abstract

Semiconductor wafer fabrication probably includes the most complex and constrained manufacturing processes due to its intricate and time-varying environment. This paper focuses on Time Constraint Tunnels (TCTs), which can have a very high impact on the yield and reliability of final products. More precisely, the original problem faced by managers of controlling the release of multiple lots in a TCT is addressed in the context of a wafer facility operating in a High-Mix Medium-Volume manufacturing environment. To support the management of TCTs in an industrially acceptable context, a chedulingbased sampling method is proposed to estimate the probability that multiple lots released at the entrance of a given TCT leave this TCT on time. In order to investigate the industrial viability and identify the limitations of the probability-estimation approach, numerical experiments are conducted on real-life data and analyzed through the prism of several relevant performance criteria. Insights gathered from this numerical analysis are then used to discuss the specific management requirements that stem from the criticality of TCTs in semiconductor manufacturing facilities