Advanced semiconductor devices are disrupting traditional failure analysis workflows and creating demand for instrumentation that enables flexible capabilities to address these technology inflections. Such trends can be observed across multiple development areas, including faster processing, increased memory bandwidth, and power delivery. In every case, shrinking structures, complex packaging architecture, and advanced materials drive the need for efficient, precise targeting for regions of interest (ROI) over a wide range of length scales. An important example is the implementation of wide-bandgap (WBG) semiconductors, such as SiC and GaN, in advanced power devices. Various complexities are introduced, not only in device architecture, but also in defectivity analysis by conventional methods. As a result, high quality and high throughput failure analysis is achieved with specialized use of several plasma focused ion beam (PFIB) species best suited to these materials. Here we demonstrate such sample preparation for workflows involving electrical failure analysis (EFA) and localization, cross-sectional and volume analysis using scanning electron microscopy (SEM), as well as lamella preparation for transmission electron microscopy for physical failure analysis (PFA).

Continued advancements in the architecture of 3D packaging have increased the challenges in fault isolation and failure analysis (FA), often requiring complex correlative workflows and multiple inference-based methods before targeted root cause analysis (RCA) can be performed. Furthermore, 3D package components such as through-silicon-vias (TSVs) and micro-bumps require sub-surface structural characterization and metrology to aid in process monitoring and development throughout fabrication and integration. Package road-mapping has also called for increased die stacking with decreased pitch, TSV size, and die thickness, and thus requires increased accuracy and precision of various stateof- the-art analytical techniques in the near future. Physical failure analysis (PFA), process monitoring, and process development will therefore depend on reliable, high-resolution data directly measured at the region of interest (ROI) to meet the complexity and scaling challenges. This paper explores the successful application of plasma-FIB (PFIB)/SEM techniques in 2D and 3D regimes and introduces diagonal serial sectioning at package scales as a novel approach for PFA and metrology. Both 2D and 3D analysis will be demonstrated in a high bandwidth memory (HBM) package case-study which can be applied more broadly in 3D packaging.