We generalize the Wilemski-Fixman-Weiss decoupling approximation to calculate the transient rate of absorption of point particles into multiple sinks of different sizes, shapes, and reactivities. As an application we consider the case involving two spherical sinks. We obtain a Laplace-transform expression for the transient rate that is in excellent agreement with computer simulations. The long-time steady-state rate has a relatively simple expression, which clearly shows the dependence on the diffusion constant of the particles and on the sizes and reactivities of sinks, and its numerical result is in good agreement with the known exact result that is given in terms of recursion relations.

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The polymer additives are key factor materials in the Cu electroplating process, essential for controlled acceleration and inhibition of Cu deposition. In this study, the degradation behavior of a polymer additivepoly(ethylene glycol) (PEG)-during the Cu electroplating was investigated by MALDI-TOF MS technique. The PEG was completely degraded after 4 h at a constant electric current density of 13 mA/cm 2 , whereas it showed no degradation without an electric field even at a very low pH (pH < 1). The pathways and energetics of PEG degradation by electrolysis in aqueous chloride medium was investigated using density functional theory calculations at the same time. It demonstrated how facile the decomposition of PEG internal radical is, which is generated via the hydrogen abstraction from PEG by hydroxyl radical formed at the anode in aqueous chloride medium under an electric field.

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