Bi-objective schedule control of batch processes in semiconductor manufacturing

This paper presents the concept of schedule control using two contradicting objectives in dynamic scheduling of backend batch processes in a semiconductor industry. A convex combination approach is presented to achieve the desired level of control in dynamic scheduling considering the two contradicting objectives, viz., the mean cycle time and the maximum tardiness. At each decision instance during simulation, an appropriate job referred as pareto-job is selected using the convex combination approach and loaded on the machine for processing. We demonstrate using simulation experiments the concept of schedule control, and show how a batch processing machine can be controlled at specified operating conditions (scheduling objectives) dictated by the market requirements.