2 April 2014 High speed optical metrology solution for after etch process monitoring and control
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Monitoring and control of the various processes in the semiconductor require precise metrology of relevant features. Optical Critical Dimension metrology (OCD) is a non-destructive solution, offering the capability to measure profiles of 2D and 3D features. OCD has an intrinsic averaging over a larger area, resulting in good precision and suppression of local variation. We have studied the feasibility of process monitoring and control in AEI (after etch inspection) applications, using the same angular resolved scatterometer as used for CD, overlay and focus metrology in ADI (after develop inspection) applications1. The sensor covers the full azimuthal-angle range and a large angle-of-incidence range in a single acquisition. The wavelength can be selected between 425nm and 700nm, to optimize for sensitivity for the parameters of interest and robustness against other process variation. In this paper we demonstrate the validity of the OCD data through the measurement and comparison with the reference metrology of multiple wafers at different steps of the imec N14 fabrication process in order to show that this high precision OCD tool can be used for process monitoring and control.
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Anne-Laure Charley, Anne-Laure Charley, Philippe Leray, Philippe Leray, Wouter Pypen, Wouter Pypen, Shaunee Cheng, Shaunee Cheng, Alok Verma, Alok Verma, Christine Mattheus, Christine Mattheus, Baukje Wisse, Baukje Wisse, Hugo Cramer, Hugo Cramer, Henk Niesing, Henk Niesing, Stefan Kruijswijk, Stefan Kruijswijk, "High speed optical metrology solution for after etch process monitoring and control", Proc. SPIE 9050, Metrology, Inspection, and Process Control for Microlithography XXVIII, 90501H (2 April 2014); doi: 10.1117/12.2047280; https://doi.org/10.1117/12.2047280

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