2 April 2014 Compensating process non-uniformity to improve wafer overlay by RegC
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The introduction of double and triple patterning tightened the Overlay current nodes’ specifications across the industry to levels of 5nm and 3nm respectively. Overlay error is a combination of Intra-field and field-to-field errors. The Intra-field error includes several systematic signatures, such as overlay magnitude differences between X and Y axes, field center vs edge and more. The recent developments in scanner technology improved the intra-field Overlay to high orders. In this work we have quantified the state-of-the-art residual overlay errors and applied the RegC® (registration/overlay control) process, a new solution of deep sub-nanometer pattern shift, to further improve the overlay process control, in addition to the current lithography’s state-of-the-art capabilities. As a result we managed to reduce the baseline overlay error by more than one nanometer and reduced systematic intrafield non-uniformities, by removing the 3 sigma difference between X and Y to zero. The combination of intra-field control by RegC® with high order correction per exposure (CPE) by the scanner provides a new era of overlay control required for the 2x and 1x multiple patterning processes.
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Philippe Leray, Philippe Leray, Shaunee Cheng, Shaunee Cheng, Avi Cohen, Avi Cohen, Erez Graitzer, Erez Graitzer, Vladimir Dmitriev, Vladimir Dmitriev, Shiran Rehtan, Shiran Rehtan, Nadav Wertsman, Nadav Wertsman, } "Compensating process non-uniformity to improve wafer overlay by RegC", Proc. SPIE 9050, Metrology, Inspection, and Process Control for Microlithography XXVIII, 905015 (2 April 2014); doi: 10.1117/12.2048081; https://doi.org/10.1117/12.2048081

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