Dedication load based dispatching rule for photolithograph machines with dedication constraint

摘要

This paper addresses a semiconductor wafer fabrication (FAB) scheduling problem with dedication constraint. Under dedication constraint, a fabrication lot must be processed using the same photo machine at all photolithography (photo) steps. To solve the utilization decrease of photo machines by dedication, we propose a dedication load as the sum of the workload of lots dedicated to each photo machine. When a photo machine becomes available to process a new lot, if its dedication load is less than the average of similar machines, then the photo machine will be assigned to process the first step of a new lot in the event that one is available. To prove the performance of this proposed dispatching rule, we developed a simulation model based on MIMAC6, and conducted a simulation by using MOZART®. The proposed dispatching rule was implemented and outperformed conventional dispatching rules.