Generalized Overall Equipment Effectiveness for integrated scheduling and process control

The coupling of process control and production scheduling will grow tight in future fab and products. Such a trend requires integration to reduce fab cost and to improve fab effectiveness in terms of product yield and throughput performance. By focusing on the individual tool productivity, this research proposes Generalized Overall Equipment Effectiveness (GOEE). The generalization first develops a novel equipment output-based calculation of OEE instead of the equipment state-based one by exploiting readily available measurements from fab operations: the number of output lots and the number of unqualified lots such as reworks and scraps from current measurements. The second generalization is the calculation of Predictive OEE (POEE) by predicting the number of output lots based on production schedule and expected machine availability and the number of reworks and scraps based on estimation from virtual metrology and/or other advanced process control models. GOEE quantifies the trade-off on tool effectiveness between production schedule and process control. An exemplary application of GOEE to allocating a Chemical Vapor Deposition (CVD) tool demonstrates its potential value in decision integrating process control and production scheduling.