Superconformal Film Growth: Mechanism and Quantification

The mechanism and modeling of superconformal film growth used in the electrochemical fabrication of 3-D Cu interconnects is briefly reviewed. The central role of electrolyte additives in controlling feature filling is fully described by the curvature enhanced adsorbate coverage (CEAC) mechanism developed at NIST. The key feature of the CEAC mechanism is redistribution of adsorbed additives through changes of local surface area as dictated by mass conservation and the relative strengths of adsorption. By examining the competition between rate suppressing, accelerating and deactivating adsorbates on planar surfaces the CEAC enables detailed prediction of shape evolution during electrodeposition on 3-D patterned surfaces that are found to be in excellent agreement with feature filling experiments.