The kinetic [formula omitted] isotope effect in electroless copper plating. A DEMS study

Abstract

DEMS studies in electroless copper plating solution were carried out using a thin-layer flow-through cell within the electrode potential range − 1.0 V to 0.7 V ( SHE). The effect of H D substitution in both formaldahyde and water on the rate of anodic oxidation of formaldehyde to formate was investigated by on-line mass spectrometry in electroless copper plating solutions and in Cu(H)-free solutions under controlled electrode potential as well as under open-circuit conditions. A negligible H D isotope effect was found in electroless copper plating solution for H 2O replacement by D 2O within the potential range − 0.7 to −0.4 V and under open-circuit conditions. The dependence of the k H k D value for H D substitution in formaldehyde on the electrode potential was enhanced in electroless plating solution at low ( ca. −0.6 V) anodic potentials. The rupture of the CH bond of formaldehyde is concluded to be the rate-limiting step in anodic oxidation of formaldehyde on copper and in electroless copper plating.