Generating Cycle Time-Throughput Curves using Effective Process Time based Aggregate Modeling

In semiconductor manufacturing, cycle time-throughput (CT-TH) curves are often used to make a trade-off between throughput and mean cycle time of bottleneck workstations. To generate CT-TH curves, detailed simulation models, and analytical queueing approximations are typically used. However, detailed models require much development time and are computationally expensive. Analytical models based on for instance a closed-form G/G/m queueing expression may not generate accurate curves for semiconductor equipment, in particular for equipment that have wafers of multiple lots in process at the same time. In this paper we show that a recently developed aggregate modeling approach based on the effective process time is able to generate more accurate CT-TH curves for equipment with multiple process steps.