On the importance of optimizing in scheduling: The photolithography workstation

Abstract

This paper analyzes the impact of scheduling decisions on the capacity of a semiconductor manufacturing workstation. The study was conducted on real industrial data of a well-known bottleneck workstation, namely photolithography, which includes various complex constraints. The results of our numerical experiments show the importance of an effective optimization algorithm and how it impacts capacity, i.e. the cycle times of lots and thus the ability to schedule more lots. Additional computational results illustrate that, when the problem complexity is reduced by ignoring setup times, the impact of determining optimized schedules is also reduced.