Translating fab cycle time and output targets into production control requirements for tool groups

Throughput rate and cycle time are two of the major production targets of a fab. As a fab is often operated under distributed production flow control, the overall delivery specifications can be achieved only when individual tool groups are operated to meet appropriate local performance requirements. In this paper, a control parameter extraction methodology is proposed to establish an explicit relationship between production targets of a fab and local flow control parameters in terms of mean rates and upper bounds on variations of input processes for each tool group. These parameters can further be utilized to derive managerially tangible requirements for cycle times and wafer-in-processes and to create guidelines for distributed production control leading to the desired delivery specifications. Validations over two benchmark fab models demonstrate that our approach is mostly within 95% of accuracy and requires less than one millisecond of CPU time.