A method for cycle time estimation of semiconductor manufacturing toolsets with correlations

Abstract

This paper proposes a cycle time estimation method for typical toolsets in Semiconductor Fabrication Facilities (Fabs). Due to sophisticated process flows and requirements of the process, queueing models for toolsets can become very complicated and their performance has been unsatisfactory due to the low accuracy of their results. In this paper, we first study the performance of classical queuing models using a high volume manufacturing toolset as our case study and discuss the potential causes for failure of classical models in predicting its cycle time. Then we propose a new approach for estimating the cycle time of toolsets that have inherent correlation between their arrival and service processes. Finally we apply this method to our case study toolset and show that the accuracy of cycle time estimation is improved significantly compared to use of classical queueing models.