Automatic control in microelectronics manufacturing: Practices, challenges, and possibilities

Abstract

Advances in modeling and control will be required to meet future technical challenges in microelectronics manufacturing. The implementation of closed-loop control on key unit operations has been limited due to a dearth of suitable in situ measurements, variations in process equipment and wafer properties, limited process understanding, non-automated operational practices, and lack of trained personnel. This paper reviews the state-of-the-art for process control in semiconductor processing, and covers the key unit operations of lithography, plasma etching, thin film deposition, rapid thermal processing, and chemical–mechanical planarization. The relationship of process (equipment) models to control strategies is elaborated because recently there has been a considerable level of activity in model development in industry and academia. A proposed control framework for integrating factory control and equipment scheduling, supervisory control, feedback control, statistical process control, and fault detection/diagnosis in microelectronics manufacturing is presented and discussed.