Across-wafer sub-1 nm critical dimension uniformity control by etch tool correction

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.