Influence of Grain Orientation on the Microstructural Characterization in Cu During (self)-Anneal using a Surface Acoustic wave Technique

Abstract

AbstractThis paper describes the influence of microstructure, or more specifically grain orientation and grain size, on the in-line monitoring of copper interconnect properties during (self)-anneal using surface acoustic wave spectroscopy (SAWS). In electroplated Cu after (self)-anneal the SAWS frequency is lower for samples annealed at higher temperature because of the lower porosity induced elasticity. In sputtered Cu, the SAWS frequency shows a clear correlation with grain size, which is induced by a strong re-orientation of the copper film from the as-deposited (111) texture (E=190 GPa) to a strongly (100) textured super grain structure (E=78GPa).