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Published online by Cambridge University Press: 15 March 2011
We present the influence of the electrochemical plating recipe and the bath chemistry on Cu grain size evolution and its link to corrosion of Cu interconnects. Our results demonstrate the fact that Cu corrosion depends on the combination of (i) solution type and (ii) Cu quality. The latter is influenced by geometrical factors such as line width and pattern density as well as the electroplating parameters such as plating recipe and bath chemistry. Organic and inorganic acid based model-CMP solutions are used to make a comparison in terms of the interactions with the Cu surface. It is shown that an organic acid based solution etches Cu independent of the Cu quality. However, etching by an inorganic acid based solution reveals line width (0.2 μm <w<1.0 μm) and pattern density dependence (16%< pd< 72 %) with the narrow lines being etched more rapidly both for isolated and semi-dense structures. This kind of geometry dependent etch behavior by the inorganic acid based solution is also shown to be a function of the electroplating process parameters in contrast to an organic acid based one.