Queuing Strategy Optimization In Semiconductor Manufacturing

Semiconductor (Chip or IC) manufacturing is recognized as the most complex of manufacturing process in technology-intensive industries, and it is also with the most expensive of manufacturing equipments in capital-intensive industries. Compared with other manufacturing processing, there is a unique character during semiconductor manufacturing, which is showed as Work-in-process Re-entry. WIP Re-entry means WIP return to the same equipment for processing in different sequence with many times. This characteristic makes the queuing theory of semiconductor manufacturing difficult to approximate optimization. Because of huge investment, furious competition, high depreciation cost…it pressurize investors pay more attention to mean service time of manufacturing equipments.This paper is divided into three chapters. The first chapter is summary of current queuing theory research of semiconductor manufacturing. The second chapter is mathematical modeling building for mean service time of semiconductor manufacturing equipments and mean waiting queue of WIP, which depend on the Probability distribution function of classic queuing theory, within reasonable assumptions and mathematical derivation, to achieve optimization of manufacturing equipments. The last chapter is in-depth analyze the unique character during semiconductor (Chip or IC) manufacturing -WIP re-entry, and verify the queuing theory through simplified mi ni-FAB, especially describe the optimization of WIP re-entry, with using the method of mathematical matrix, through which can show the difference between these two queuing strategies apparently.