ABSTRACT

This chapter describes the most common performance metrics of interest to factory modelers. In contrast to dynamic modeling, static modeling does consider detailed dynamics of how lots flow through a fab, so static modeling cannot determine inventory levels or cycle time. The chapter discusses the minimum number required can reduce work-in-process (WIP) inventory and cycle time for a given throughput. Thus, dynamic modeling can be used to determine WIP inventory levels and cycle times, as well as throughput and capacity. Queueing models attempt to predict performance metrics such as throughput and cycle time by deriving sets of sophisticated mathematical expressions that describe the flow, and queueing of lots in the fab. Factory modeling is used to predict the effect of decisions on factory performance, before incurring the risk or cost of actually implementing the decisions. A common objective of factory modeling is the design of a fab that meets specified performance requirements.