Structural investigation of nanovoids around the interface of micro-vias by spherical aberration corrected scanning transmission electron microscopy

In this study, we investigated the microstructural characteristics of nanovoids that form during the electroless Cu plating process for micro-vias using a spherical aberration-corrected scanning transmission electron microscope. The nanovoids, which form during the early stages of the plating process, have a spherical shape with an outermost layer covered with Pd. They are not only empty spaces but partly filled with complexing agent elements, reaction production gas, and other materials.