SIMPLE PERFORMANCE MODELS FOR INTEGRATED PROCESSING TOOLS

Integrated processing tools are becoming increasingly prevalent in mod ern fabs. Integrated tools consist of several process modules connecte d around a central handler such that the modules can process several w afers from the same lot simultaneously. Lithography cells and vacuum c luster tools are examples of integrated processors. Simple, intuitive models of the cycle time, throughput, and wafer cost of integrated too ls are introduced. The models use two measurable parameters that aggre gate tool operations: the incremental cycle time is the average increa se in cycle time resulting from a lot size increment of one wafer and the fixed cycle time is the portion of cycle time that is independent of lot size. One example shows how an empirical analysis of a commerci al CVD cluster tool was used with the models to identify opportunities to increase tool throughput. In a second example, analytical models o f the incremental and fixed cycle times are used to provide insight in to the effects of tool configuration on performance, Finally, simulati ons of single integrated tools are used to show some limitations of th e model.