Steady-state throughput and scheduling analysis of multi-cluster tools for semiconductor manufacturing: An decomposition approach

Abstract—Cluster tools are widely used as semiconductor manu-facturing equipment. While throughput analysis and scheduling of single-cluster tools have been well-studied, research work on mul-ticluster tools is still at an early stage. In this paper, we analyze steady-state throughput and scheduling of multicluster tools. We consider the case where all wafers follow the same visit flow within a multicluster tool. We propose a decomposition method that re-duces a multicluster tool problem to multiple independent single-cluster tool problems. We then apply the existing and extended re-sults of throughput and scheduling analysis for each single-cluster tool. Computation of lower-bound cycle time (fundamental period) is presented. Optimality conditions and robot schedules that re-alize such lower-bound values are then provided using “pull ” and “swap ” strategies for single-blade and double-blade robots, respec-tively. For an-cluster tool, we present ( ) lower-bound cycl