Effect of annealing process on the properties of through-silicon-via electroplating copper

This paper focuses on the influence of annealing process on the properties and microstructural evolution of through-silicon-via electroplating copper. Particular attention is paid to the interposer-related through-silicon-via applications, which is fabricated by via-last process with the diameter of 20 microns and above. A interposer was designed and fabricated with its diameter of 100 microns and its depth of 300 microns. A group of samples was not subjected to an annealing treatment, and the remaining three groups were annealed at 100 °C, 200 °C and 300 °C, respectively, and each annealing time was 3 hours under a nitrogen atmosphere. Through the grinding and polishing technology to observe the cross section of through-silicon-via, which is observed and characterized by scanning electron microscope. After the grinding and polishing process, it is very essential to use vibration polishing and SiO2 polishing solution to remove scratches and damage layers. And the grain size distribution and orientation are observed by electron back scattering diffraction technique.