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SEIRAS Study of Chloride Mediated Polyether Adsorption on Cu



Thomas P. Moffat, Daniel Josell, Lee J. Richter


Surface enhanced infrared absorption spectroscopy (SEIRAS) was used to examine the co- adsorption of a selection of polyethers with Cl- under conditions relevant to superconformal Cu electrodeposition in CuSO4-H2SO4 electrolytes. In 0.1 mol/L H2SO4 a potential dependent mixed SO42--H3O+/H2O layer forms on weakly textured (111) Cu thin film surfaces. With the addition of 1 mmol/L NaCl the SO42--H3O+/H2O adlayer is displaced and rapidly replaced by an ordered halide layer that disrupts the adjacent solvent network leading to an increase in non-hydrogen bonded water that makes the interface more hydrophobic. The altered wetting behavior facilitates co- adsorption of polyethers, such as poly(ethylene glycols), polyoxamers, or polyoxamines. Interfacial water is displaced by co-adsorption of the hydrophobic polymer segments on the Cl- terminated surface while the hydrophilic ether oxygens are available for hydrogen bond formation with the solvent. The combined polyether-Cl- layer serves as an effective suppressor of the Cu electrodeposition reaction by limiting access of Cu2+aq to the underlying metal surface. This insight differs from previous efforts that suggest polymer binding is mediated by Cu+ species.
Journal of Physical Chemistry C


copper, superconformal, superfilling, polyethylene glycol, SEIRAS, FT-IR, suppressor, inhibitor


Moffat, T. , Josell, D. and Richter, L. (2018), SEIRAS Study of Chloride Mediated Polyether Adsorption on Cu, Journal of Physical Chemistry C, [online], (Accessed April 21, 2024)
Created August 31, 2018, Updated February 26, 2020