Characterization of Crystallographic Orientation and Void Distribution at Bonding Interfaces of Cu Hybrid Joints by Cut-and-View FIB and EBSD.

In this study, various characterization techniques such as three-dimensional (3D) X-ray laminography, plan-view transmission electron microscopy (TEM), and cut-and-view electron backscattered diffraction were employed to examine the microstructures at the Cu/SiO2 hybrid bonding interfaces, including defects such as interfacial voids, as well as crystallographic orientation. A comparative analysis of their advantages and disadvantages is also presented. The results indicated that the nondestructive 3D X-ray laminography is able to check the bonding misalignment in a large area, but it lacked the resolution needed to detect small defects. High-resolution TEM (HR-TEM) analysis revealed a minimal crystal misorientation (∼0.1°), suggesting an excellent-ordered lattice at the bonding interface. Plan-view HR-TEM provides an effective and accurate approach for characterizing interfacial voids, because the distribution of the void ranges from 10 to 150 nm. In addition, the cut-and-view technique offers an excellent way to observe void distribution near the bonding interface and to elucidate the crystallographic direction for the whole Cu joint.