Electrical properties of damascene silver wires with widths between Ϸ60 and 840 nm and heights between Ϸ100 nm and 300 nm are presented. The superconformal electrodeposition process by which the seam-free and void-free metallizations were fabricated is summarized. The chemical-mechanical polishing plus oblique ion sputtering process by which metal overburden was removed from the field adjacent to the wires is detailed. The size-dependent resistivity of the wires is obtained and interpreted in terms of intrinsic resistivity, grain boundary reflection, and surface scattering. Quantitative analysis of the last is accomplished using a different implementation of the Fuchs-Sondheimer formalism for wires of rectangular geometry and nonzero surface specularity that is derived herein.

Cu electrochemical mechanical planarization ͑ECMP͒ is currently being investigated to replace or supplement Cu chemical mechanical planarization ͑CMP͒ due to the introduction of porous low-k dielectric materials, which may not withstand the mechanical force applied during conventional CMP. Electrolytes for Cu ECMP at pH 3 containing 5-phenyl-1-H-tetrazole ͑PTA͒, hydroxyethylidenediphosphoric acid, and oxalic acid are investigated using electrochemical methods and polishing of Cu-coated blanket and patterned wafers. The Cu removal rate and the planarization efficiency during Cu ECMP can be approximated using electrochemical measurements of the Cu removal rate, with and without surface abrasion. These results predict a 500 mV potential window within which the Cu removal rate is greater than 600 nm/min and the planarization efficiency is greater than 0.90. However, high planarization efficiencies are only obtained when silica abrasives are included within the ECMP electrolyte. In situ electrochemical impedance spectroscopy results indicate that the interfacial impedance is increased by the presence of silica, suggesting that silica is incorporated into the PTA-based passive film and is thus needed for effective planarization. Electrochemical quartz crystal microbalance experiments indicate that PTA may provide better Cu surface passivation at a high anodic potential than benzotriazole, which is widely used during Cu CMP.

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