Effects of anisotropy on the reliability of TSV microstructure

Through silicon via (TSV) is a very important interconnect structure in 3D integrated packaging, and its reliability directly affects the reliable service life of 3D integrated packaging devices. TSVs contain multiple material interfaces, and there is a large thermal mismatch between the materials, which poses a serious challenge to its reliability under thermal cycling loads. In the available literatures, silicon (substrate) and copper (filler) materials have often been considered as isotropic materials for research and analysis. However, for micron-scale TSV structures, the orientation of silicon crystals and the orientation of copper grains can have a non-negligible effect on the stress and strain distribution and interface crack propagation of the structure, which in turn significantly affects the overall reliability of the TSV structure. This article explored in detail the influence of the anisotropy of silicon and copper on the reliability of TSVs, and particularly focused on the coupled effect of anisotropic of silicon and copper. In addition, the influence of copper plasticity was also analyzed.