As process technology progresses beyond the 7 nm node, the critical dimension uniformity (CDU) requirement is now in the sub-1 nm regime due to patterning complexity or smaller patterning size. In this report, across-wafer CDU improvement by etch tool correction using the Hydra uniformity system in an advance Lam Research etch tool for a 7 nm FEOL logic application is discussed. The results show that CDU is improved by 60% compared to baseline performance of 3σ < 1 nm, and the post etch CDU is comparable to the ultimate target CDU of post EUV litho development. In conclusion, superior post-etch across-wafer CDU is achieved using the Hydra uniformity system by correcting local non-uniformity after the radial contribution is reduced by traditional multizone ESC tuning.

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Changwoo Lee, "Across-wafer sub-1 nm critical dimension uniformity control by etch tool correction," Proc. SPIE 10963, Advanced Etch Technology for Nanopatterning VIII, 109630G (Presented at SPIE Advanced Lithography: February 27, 2019; Published: 20 March 2019); https://doi.org/10.1117/12.2519383.