Integer programming-based real-time scheduler in semiconductor manufacturing

This paper demonstrates how an integer programming-based real-time scheduling heuristic approach can be applied for semiconductor manufacturing. Two integer programming formulations of a simplified version of this problem are proposed to model (1) a full-enumeration scheduling problem which minimizes the makespan (Cmax), and (2) a real-time scheduling problem which simply maximizes job assignments at the current state. The real-time scheduler´s overall effectiveness in terms of solution quality and run time is evaluated through computer experiments. The real time scheduler is based on an iterative procedure to calculate the makespan, where a simulator is developed to read the integer programming output and to update the job and machine information at each state. The experimental study shows how a well-defined integer programming-based real-time scheduling heuristic can generate a near-optimal solution.