Microstructure and texture analysis of advanced copper using electron backscattered diffraction and scanning transmission electron microscopy

Abstract

In this article, we focus on the characterization of copper interconnect by Electron Backscattered Diffraction (EBSD) in the final aim of reliability issue investigation. In a first time we demonstrate that we achieve to characterize copper lines of 70 nm width after some improvements in sample preparation. Then, after showing that EBSD is well adapted to characterize our structure even for very small dimensions (line width smaller than 100 nm), we propose to associate Transmission Electron Microscope in scanning mode (STEM) to complete information given by EBSD and localize defects due to electromigration. We begin by highlighting the very good correspondence between EBSD map and STEM images on line with small microstructure and finally we apply both techniques on a tested copper line after electromigration. In this case we show the relevance of using STEM to localize the defect due to electromigration which can not be seen on EBSD map.