A heuristic to determine equipment setup changes based on estimated lot arrivals in a semiconductor fab

Certain classes of tools used in the semiconductor industry require the tools to be setup differently in order to process different types of products. In cases of large setup times, it is important to minimize the number of setup changes in order to improve the overall equipment utilization. Minimizing the number of setup changes needs to be balanced with the restriction on the product queue times. Further, it is important that the cycle time of low volume products is not penalized in order to improve equipment utilization. This article presents a heuristic algorithm to determine the setup for each tool in a workstation based on the estimated arrival times of different products at the workstation. The approach described here takes into account the number of tools, their capability, and the expected workload for each setup over a predetermined horizon. The heuristic is independent of the product mix released into the line.