Simulation-Assisted ION Angle Tuning in High Aspect-Ratio (HAR) ETCH for Wafer Edge Bottom Etch Enhancement

This paper provides insights for ion tilt's impacts on HAR etch. We used Coventor virtual fabrication model to compare etch profile with respect to different ion tilt angles, and conduct simulation-based movie study on how etch front evolved with tilted ions. With the help of virtual metrology, we established the correlation between ion tilt angle and feature tilt angle which can be used to guide wafer edge plasma sheath tuning. The ion angle characterization results have been verified on production wafer, and wafer edge etch stop suffer rate can be reduced from 8.17% to 0.44%.