A tool portfolio planning methodology for semiconductor wafer fabs

Tool portfolio planning is an ongoing task in wafer fabs, as process, tool and product technologies evolve constantly and production in most times undergoes ramping-up. Precision and soundness of portfolio planning are therefore a crucial capability of wafer fab operation. This paper describes a tool portfolio planning methodology developed in a joint university-industry project. An improved static capacity model is first presented, in which an empirical formula is used to estimate the efficiency of batch tools. A portfolio planning procedure based on static capacity estimation and queueing analysis is next described. This procedure enables the portfolio solution space to be explored easily and has demonstrated superior performance in preliminary benchmarking in an industry case study