X-Ray Computed Tomography and Laminography Measurements of a 3D-Stacked IC

Advanced semiconductor packages manufactured using heterogeneous integration techniques challenge many conventional non-destructive testing processes. A three-dimensional (3D) structure of stacked integrated circuits (ICs), for example, complicates many existing non-destructive testing techniques. X-ray-based imaging methods, on the other hand, can fully penetrate the part and are ideal for visualizing the complex 3D heterogeneity. In this research, two related X-ray-based 3D imaging techniques, X-ray computed tomography (XCT) and X-ray computed laminography (XCL), are used to measure over-molded modules on a laminate substrate that includes stacked flip-chip Gallium Nitride on Silicon Carbide (GaN-on-SiC) dies. Differences between XCT instruments, XCT instruments versus an XCL instrument, and acquisition parameter settings on 3D reconstructions of the sample are explored. Reference measurement results are compared for image quality, acquisition time, and imaging artifacts. We discuss the current capabilities, limitations, and a potential outlook/roadmap for improving throughput for these types of instruments.