(Digital Presentation) An Advanced Process Control Scheme for Fin Etching Process in Front-End-of-Line FinFET High Volume Production

As FinFET scales down to advanced technology nodes, Fin profile and Critical Dimension (CD) control are becoming a huge challenge due to the increased number of processes. For a stable wafer-to-wafer CD performance, Advanced Process Control (APC) system is widely deployed in high volume manufacturing production. In this work, we present a novel implementation of an APC-based fuzzy control system in the Fin etching process within the widely-used Self-aligned Quadruple Patterning (SaQP) scheme. Feed-forward APC is applied to the two processes: 1) Atomic Layer Deposition (ALD) process for fin hard-mask etching and 2) fin etching process with fuzzy control. With the deployment of the APC system, the inline metrology variation performance of Fin CD improved from ±3.5% to ±1.8%. The Cp and Cpk are increased by 29% and 32%, for various key inline parameters. The APC-based fuzzy control scheme shows great potential for the advanced nodes.