A simulation-based cost modeling methodology for evaluation of interbay material handling in a semiconductor wafer fab

In the next generation of semiconductor wafer fabrication facilities, decisions concerning material handling systems will be a major factor in initial facility cost, operational cost, production cycle times and possibly product yield percentages. The wafers will increase in diameter to 300 mm and a new front opening unified pod (FOUP) has been designed to carry them, both increasing the weight of a production lot. This increase requires substantial automation for ergonomic and quality reasons. As a result, semiconductor manufacturers are asking, “what level of automation is financially justifiable?” Automation suppliers have stated that automation saves money, but have as yet not produced a sufficiently detailed financial analysis proving their premise. In this paper, both a fully automated and a manual material handling system are simulated and compared in a thorough cost analysis. Sensitivity analysis is performed on inflation rate, interest rate, die price, wafer start rate, and yield percentage to validate the results of the analyses