Novel Failure Analysis Techniques for 1.8 µm Pitch Wafer-to-Wafer Bonding

In this paper, different methods and novel tools for non-invasive failure localization and high-resolution material analysis in cutting edge wafer-to-wafer bonded devices will be discussed. The presented techniques combine non-invasive imaging of the internal device build up and accurate target preparation to gain access to the region of interest. The presented concepts include 3D X-ray microscopy as well as 3D FIB-SEM tomography in combination with various imaging techniques and novel laser-based sample preparation. The first part of the paper will focus on the potential and advantages of each FA method. To demonstrate a full workflow based on daily FA work conditions, a test sample is analyzed in the second part.