The use of organic additives is a common thing to improve the properties of copper layer elaborated from a sulfate plating bath. Especially, levelling effects and brightness intensity can be strongly enhanced. But this practice is not without its disadvantages, with high costs, risks of defects in the supply chain, and health and environmental issues [1]. An interesting alternative consists in the current modulation currently named pulsed currents [2] to replace the use of organic molecules to control the roughness of copper deposits. If several works still exist in this field, their application to plating on rough surfaces (Sa around 2 μm) has not been explored yet and the pulse sequence design requires an exhaustive knowledge of each compound effects. In a previous study [3], the mode of operation of industrial organic additives was defined. The modulated current is mainly used to influence the electrocrystallization mechanism, thereby controlling the mechanical and physical properties of the deposited metal [4]. Since the nucleation rate is proportional to the current density, the use of pulsed and reverse currents can reduce porosity and create deposits with finer grain sizes. This allows them to achieve significantly higher densities than their static counterparts [5]. When the current is interrupted at Toff, the active metal ions diffuse into the electrode, where their concentration decreases due to the deposition process. This process promotes the formation of new and smaller grains [6]. Copper layers microstructure and roughness, can, therefore, be greatly modified under the influence of the deposition overpotential. Moreover, the other pulse current parameters, like pulse frequency, have an effect on the surface roughness.[1]: https://www.anses.fr/en/content/carcinogenic-mutagenic-and-reprotoxic-substances-cmrs[2]: P. Leisner, M. Fredenberg and I. Belov, Pulse and pulse reverse plating of copper from acid sulphate solutions, Transactions of the Institute of Metal Finishing, Vol 88 N° 5, 2010.[3]: J. Dematos, M-P. Gigandet and J-Y. Hihn, Organic Additive Free Copper Plating, Oral Communication, ISE, 74th Annual Meeting, Lyon, France, sept. 2023.[4]: Green, T. A., Su, X. & Roy, S. Pulse electrodeposition of copper in the presence of a corrosion reaction. J. Electrochem. Soc. 168, 062515 (2021).[5]: Kim, M. J. et al. Pulse electrodeposition for improving electrical properties of Cu thin film. J. Electrochem. Soc. 157, D564 (2010).[6]: J.C. Puippe and F. Leaman, Theory and Practice of Pulse Plating, American Electroplaters and Surface Finishers Society, 1986. Figure 1
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