This paper describes superconformal feature filling during zinc electrodeposition in a sulfate electrolyte. Localized bottom-up filling of Through Silicon Vias (TSVs) with no deposition on the sidewalls or the field around them is demonstrated in electrolytes containing a deposition rate suppressing additive. This behavior is seen when feature filling proceeds at potentials in proximity to where suppression breakdown and localized zinc deposition are noted in electroanalytical measurements with planar rotating disk electrodes. The favorable comparison with previous results for bottom-up feature filling of Cu, Au and Ni further demonstrates the central role of additive-derived negative differential resistance (NDR) in extreme bottom-up feature filling. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected]. All rights reserved.