Kinetics of adsorption of N-methylpolyvinylpyridine methyl sulfate on the copper surface from aqueous copper plating solutions based on sulfuric and methanesulfonic acids

• N.P. Andreeva¹, I.A. Kuznetsov¹, M.O. Agafonkina¹, O.A. Kozaderov², D.Yu. Vandyshev² and Kh.S. Shikhaliev²

¹ Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia
² Voronezh State University, Universitetskaya pl. 1, Voronezh, 394018, Russia

Abstract: This work presents a comprehensive ellipsometric study of competitive adsorption kinetics involving organic additives in acid solutions for copper electroplating. The research focuses on comparing the adsorption behavior of polymer substance N-methylpolyvinylpyridine-methyl sulfate (NMPV-MS) in sulfuric acid (H₂SO₄) and methanesulfonic acid (CH₃SO₃H) electrolytes containing chloride ions. NMPV-MS with different viscosity average molecular weights: M_v=800 g/mol and M_v=300,000 g/mol is investigated as a potential leveler for copper deposition. NMPV-MS adsorption depends on the molecular weight and the medium. Adsorption of NMPV-MS with M_v=800 in sulfate solution is observed only at concentrations higher than 0.128 g/L. In the methanesulfonic acid-based solution, adsorption begins already at an additive concentration of 0.0025 g/L. The NMPV-MS additive with M_v=300,000 adsorbs on the copper electrode surface from both solutions with nearly identical ellipsometric angle δ∆~–0.35°, that depends on the thickness of the adsorbed film. At a more negative potential of E=–0.4 V, no adsorption occurs even at concentration of the NMPV-MS C_soln=0.025 g/L. Specific features of the adsorption of organic additive compositions on the copper electrode surface at potential E=–0.2 V in sulfuric acid-based solutions used in through-silicon via (TSV) technologies were identified. The composition included leveling additives 2-aminobenzo[d]thiazole and NMPV-MS also containing a suppressor (polyethylene glycol) and an accelerator (4,4′-dithiodibenzenesulfonic acid) in the solution. It was found that, overall, the adsorption of the mixture of N-methylpolyvinylpyridine-methyl sulfate, polyethylene glycol, and 4,4′-dithiodibenzenesulfonic acid is more pronounced.

Keywords: copper, acid electrolytes, ellipsometry, N-methylpolyvinylpyridine-methyl sulfate, adsorption

Int. J. Corros. Scale Inhib., 2026, 15, no. 2, 321-330
doi: 10.17675/2305-6894-2026-15-2-18

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