Supporting Advanced Packaging with Integrated Semiconductor Failure Analysis Workflows

Key takeaways

• Semiconductor failure analysis of advanced packaging technologies requires the connection of electrical and physical evidence across multiple length scales to identify root cause.
• Non-destructive methods such as X-ray computed tomography, scanning acoustic microscopy, and lock-in thermography can be used to localize defects for subsequent targeted investigation.
• Focused ion beam scanning electron microscopy (FIB-SEM) can be leveraged for targeted, site-specific examination and extraction of buried regions of interest.
• Following FIB-SEM milling, high-resolution transmission electron microscopy (TEM) can perform atomic-scale structural and elemental characterization to fully interrogate a failure mechanism.
• Correlating this multimodal evidence, along with 3D reconstruction of serial 2D data, helps failure analysis teams converge on a defensible root cause.
• Thermo Fisher Scientific brings together a range of solutions, helping you combine failure localization, targeted sample preparation, and high-resolution imaging and elemental analysis.

The importance of multimodal semiconductor failure analysis

Advanced packaging technologies, such as 2.5D, 3D, and heterogeneous integrated circuits, support the growing demand for high-performance, power-efficient, and miniaturized semiconductor devices. As these packaging structures become more complex, they necessitate increasingly sophisticated failure analysis methodologies that identify defects and improve yield while also helping to ensure product reliability.

Failure analysis can no longer be treated as a sequence of isolated measurements; identifying the root cause of buried defects requires the connection of electrical and physical evidence across multiple length scales, from package-level localization to atomic-scale characterization. This blog explores an integrated semiconductor failure analysis workflow that combines a range of Thermo Scientific technologies, supporting efficient and robust characterization.

The limitations of non-destructive defect localization

Non-destructive localization of defects is traditionally the first step in a failure analysis workflow. This typically involves techniques such as X-ray computed tomography, scanning acoustic microscopy, or lock-in thermography, all of which are capable of defect localization within certain material types. (The Thermo Scientific ELITE System, for instance, is a thermal fault localization tool that is particularly well-suited for the identification of microcracks, short circuits, and resistive defects.)

Among these techniques, however, no single one can fully capture the root cause of a failure, particularly in advanced packaging structures, where layers may be composed of multiple materials, and defects can be buried within complex, heterogeneous, and 3D structures.

Buried interconnect failures require site-specific access

The structure of HBM stacks, microbumps, TSVs, interposers, and other advanced packages can result in suspected failure sites that sit beneath several layers. Once such a defect has been localized, non-destructive techniques are no longer sufficient for full root cause identification. Focused ion beam scanning electron microscopy (FIB-SEM) is capable of targeted, site-specific sample preparation that can expose and extract buried regions of interest for further analysis. Through sequential FIB milling and SEM imaging, 3D reconstructions can also be generated, helping analysts understand the spatial distribution of defects throughout complex packaging structures. The Thermo Scientific Helios Hydra PFIB-SEM supports such work with gallium-free plasma FIB; this ion source is capable of preparing a wider range of samples, as it avoids the risks associated with traditional Ga FIB, i.e., gallium implantation. With the Helios Hydra PFIB-SEM, failure analysis teams can perform site-specific cross-sectioning and 3D imaging for a detailed examination of internal structures and interfaces.

Semiconductor failure analysis at the nanoscale

Despite its benefits, FIB-SEM is limited in its imaging resolution, and visualization with this instrument may be insufficient to fully reveal a failure mechanism, as advanced packaging failures can originate from extremely small structural and material changes. Defects such as contamination, oxidation, delamination, and crack initiation may require substantially higher-resolution characterization to distinguish symptoms from root causes. Transmission electron microscopy (TEM) enables this atomic-scale imaging, supporting the examination of solder joints and intermetallic compounds, as well as voids, cracks, and interfaces. Combined with elemental analysis and chemical mapping, TEM can also help identify contamination or oxidation associated with a failure.

Transmission electron microscopy can also reveal how cracks initiate and propagate through interfaces, as well as defects extending across multiple layers. Combining TEM instruments, such as the Thermo Scientific Talos TEM, with FIB-SEM sample preparation allows for precise access to regions of interest followed by the atomic-scale structural and elemental characterization needed to fully interrogate a failure mechanism.

Advanced packaging requires 3D failure analysis

Conventional 2D cross-sections can reveal a wide variety of information about a failure, but the inherent three dimensional nature of advanced packages means that defects can extend through layers and structures. 3D TEM and FIB-SEM tomography address this challenge by enabling the multiscale, 3D reconstruction of whole areas of interest. With Thermo Scientific Avizo Software, failure analysis teams can efficiently integrate this data from multiple sources, supporting comprehensive 3D visualization of complex structures and defects. This collection of Thermo Scientific instrumentation and software is designed for interconnectivity, streamlining an otherwise intricate data collection and analysis workflow.

The importance of correlative, multi-modal failure analysis workflows

When identifying failure mechanisms in advanced packaging, the objective is not simply to collect a wide variety of images and measurements; it is to correlate multimodal evidence so that it converges on a defensible root cause. The more integrated the various steps in an analytical workflow, the clearer the connections between the failure and the underlying defect. Thermo Fisher Scientific brings together a range of solutions, helping you combine failure localization, targeted sample preparation, and high-resolution imaging and elemental analysis.

As advanced packaging continues to increase device density and structural complexity, the question is no longer simply “Which failure-analysis tool should I use?” but rather, “How do I obtain the most holistic view of the failure, and follow that evidence to root cause?” By combining failure analysis across scales and modalities, you can improve the accuracy and efficiency of your defect identification and characterization, ultimately supporting greater packaging reliability and performance.

Learn more about end-to-end semiconductor failure analysis

Read our full whitepaper to find out more about the multimodal failure analysis workflow from Thermo Fisher Scientific, designed specifically to meet the challenges of advanced semiconductor packaging.

See the full whitepaper on advanced packaging failure analysis >

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