A MILP-based batch scheduling for two-stage hybrid flowshop with sequence-dependent setups in semiconductor assembly and test manufacturing

In semiconductor assembly and test manufacturing, it is critical to optimize the scheduling of constraint stations to improve the system performance. This paper presents a continuous-time mixed-integer linear programming (MILP) model for the short-term batch scheduling with sequence-dependent setups in semiconductor assembly and test manufacturing to minimize the total completion time of the products. We formulate the problem of scheduling the two constraint stations and develop the MILP-based heuristic scheduling framework. The heuristic algorithm pre-determines the batch size according to the practical business rules and allocates the least flexible machines to the qualified high volume products. The system implementation at a semiconductor ATM factory demonstrates a significant reduction in total completion time compared to the traditional scheduling approach.