Simple tool of analysis for cycle time reduction

This paper describes a simple and easy to understand technique of achieving cycle time reduction in a semiconductor fab. The technique uses a spreadsheet that calculates theoretical queue time (based on operations research queuing theory) with consideration to the negative effect of very high priority lots ("super hot lots"). The theoretical queue time is compared with actual queue times to identify factory bottlenecks and the best opportunities for cycle time improvement. When this queue time control was introduced, jab cycle time improved 24%.