A full-factory simulator as a daily decision-support tool for 300MM wafer fabrication productivity

We describe a discrete event simulator developed for daily prediction of WIP position in an operational 300 mm wafer fabrication factory to support tactical decision-making. The simulator is distinctive in that its intended prediction horizon is relatively short, on the order of a few days, while its modeling scope is relatively large. The simulation includes over 90% of the wafers being processed in the fab and all process, measurement and testing tools. The model parameters are automatically updated using statistical analyses performed on the historical event logs generated by the factory. This paper describes the simulation model and the parameter estimation methods. A key requirement to support daily and weekly decision-making is good validation results of the simulation against actual fab performance. Therefore, we also present validation results that compare simulated production metrics against those obtained from the actual fab, for fab-wide, process, tool and product specific metrics.