High resolution analysis of intermetallic compounds in microelectronic interconnects using Electron Backscatter Diffraction and Transmission Electron Microscopy

In this paper, methods for high resolution analysis of the intermetallics formed in the interfaces of microelectronic packaging interconnects are discussed. The application of Transmission Electron Microscopy (TEM) in combination with energy dispersive x-ray analysis and electron diffraction for a definite identification of intermetallic compounds is compared to new approaches based on Electron Backscatter Diffraction (EBSD). The application and the potential of EBSD to detect the Cu/Sn, Ni/Sn and Au/Al intermetallics being practically relevant for soldering and wire bonding is demonstrated. Since EBSD can be performed during standard Scanning Electron Microscopy (SEM), it is easier to perform and less expensive than TEM. Thus, the method may serve as a new tool supporting microstructure diagnostics and reliability investigations for new innovative technologies in microelectronic integration. However, TEM studies are still required for detailed investigations of thin intermetallic films and the related failure mechanisms due to their superior spatial resolution and defect detection capabilities.