A proposal on optimized scheduling methodology and its application to an actual-scale semiconductor manufacturing problem

Semiconductor manufacturing process flows typically include several hundred process steps, using hundreds of machines repeatedly. The production schedule for such a re-entrant flexible flow shop is extremely difficult to be optimized. Furthermore, in recent years, it has become increasingly difficult to use machines effectively because of the product mix increase and also the production lot size decrease. In this paper we apply the well-known cooperative scheduling method, Lagrangian Decomposition and Coordination method, into an actual large scale model in semiconductor manufacturing. Then we show that the proposed method successfully creates a well-performed production schedule as we expected.