A simulation study on line management policies with special focus on bottleneck machines

A 300mm wafer fab is one of the most complex systems in the world. How to optimize this system in terms of planning and scheduling is critical for profitability of the semiconductor companies considering billions of dollars of initial investment involved. Line management or fab wide scheduling is more important than area level scheduling although the latter has higher resolution and is considered as a harder problem. Traditional line management policies focus on pre-determined bottlenecks and has proven to be successful. However, for a dynamic fab with changing bottlenecks, some potential issues have been discovered. This paper used simulation as a tool to study the issues involved and propose an improved line management policy.