Tunable Step Coverage of In-Situ Pe-Ald in ETCH Chamber for Sidewall Protection During 3D Nand High Aspect-Ratio Etch

摘要

We presented in-situ PE-ALD in etch chamber with good reproducibility and step coverage tunability. Step coverage of 149% can be achieved at 75:1 high aspect-ratio. The post-etch results demonstrated the film is stoichiometrically consistent meaning that there is little trade-off between film quality and step coverage. With fast switching between different gas lines, this in-situ PE-ALD process can be inserted at any point in etch recipes, which helps a lot for sidewall protection during 3D NAND high aspect-ratio etch.