Integrated metrology and advanced process control in semiconductor manufacturing

Traditional semiconductor manufacturing relies on a fixed process-recipe combined with a classical statistical process control that is used to monitor the production process. Leading-edge manufacturing processes require higher levels of precision and accuracy, which necessitate the use of a tighter process control: Advanced Process Control (APC) has become a critical component to improve the performance, yield, throughput, and flexibility of the manufacturing process through run-to-run, wafer-to-wafer and within wafer control. The complexity of device manufacturing process as well as the strong coupling effect of several input parameters on the final process outputs prohibit the use of a classical single variable feedback control method. Therefore, a multivariate, model-based APC system has been developed in conjunction with feed-forward and feedback mechanisms to automatically determine the optimal recipe for each wafer based on both incoming wafer and tool properties. The APC system uses wafer metrology, process models and sophisticated algorithms to provide dynamic fine-tuning of intermediate process targets that enhance final device targets. The design of the APC system enables scalability of the control solutions across single chamber, a tool, multi-tools, a module and multi-modules using similar building blocks, concepts and algorithms.