Effective modeling of factory throughput times

Abstract

Describes an effective approach to TPT modeling. Though this approach can be used in any factory, our focus here is limited to predicting TPT in a semiconductor wafer fabrication facility. We describe an abstract simulation that runs very quickly on standard PCs and is based on a model that focuses on the factors that have a major influence on TPT. The simple model includes machine assignments and variability of machine availability, operator assignments and variability of operator availability and transportation times and variability of transportation availability. The model can also handle a range of WIP management policies and include test wafer loading. Given the contents of the model, the simulation tool can be used to perform a variety of "what-if" analyses. The simulation approach as well as validation results based on implementation at actual fabrication sites are described.