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 semi-conductor 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.