Job releasing and throughput planning for wafer fabrication under demand fluctuating make-to-stock environment

Abstract

In the semiconductor industry, dynamic changes in demand force companies changing the product mix makes the production planning challenging. This paper aims at an environment where product mix changes periodically and presents a production scheduling system to plan the wafer lot release and throughput. The proposed system is designed on the make-to-stock basis with the objective of meeting demand forecast while maintaining production smoothness. Two modules are included in the system. Preliminary analysis module analyzes throughput and cycle time distributions for different product mixes so as to determine relative parameters to be used as the inputs to the job releasing plan. In the production scheduling module, with the considerations of the attainment of demand forecast, production smoothness, and commitment of the due dates of the released job orders, the job release schedule and completion time table are prepared. A simulation model of a semiconductor fab is used as the base case to demonstrate the effectiveness and efficiency of the proposed system.