Applications of queuing theory and simulation to staffing in the semiconductor clean room environment

A major concern of management in the ultra expensive environment of semiconductor fabs and test floors is optimal utilization of equipment. Proper staffing of clean room operators and maintenance technicians in the manufacturing cells and clusters plays a major role in maximizing equipment utilization and overall throughput. This paper is about a more scientific and pro-active approach to the staffing issue than the classic methods used in the industry. It is TOC (Theory of Constraints) oriented, and designed to improve fab throughput. The models described in this paper were developed by engineers from Tefen USA. To date, they have been adopted by management teams in over 30 different fabs and test sites over the past two years, both in the US and in Europe