Investigation of thermo-mechanical stresses and reliability of 3D die-stack structures by synchrotron x-ray micro-diffraction

In this work, thermo-mechanical stresses and reliability of 3D die-stack structures developed for the Hybrid Memory Cube (HMC) technology are investigated using experiments and modeling analysis. Synchrotron x-ray micro-diffraction measurements are used to directly measure the stress distribution around Cu vias in different die levels. High resolution stress mappings are obtained and verified by finite element analysis (FEA). The FEA is applied to estimate the stress effect on device mobility changes and the warpage of the integrated structure.