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Semiconductor Fab Solutions

ZEISS NLX

In-line 3D X-ray inspection for advanced packaging

Advanced packaging drives semiconductor design into the third dimension, combining complex stacking and dense interconnects in ever smaller form factors. These architectures extend functional capability, but at the same time the resulting 3D structures become increasingly difficult to inspect and control using established techniques. ZEISS NLX introduces in-line 3D X-ray laminography at 300 mm wafer level, providing volumetric, non-destructive insight into internal structures within stacked dies, such as micro bumps and through silicon vias (TSVs). As an automation-ready system for semiconductor fabs, NLX® supports the introduction of robust 3D inspection into existing process flows, from early process development to high-volume production.

  • Non-destructive 3D X-ray inspection of advanced packaging structures
  • Consistent 3D imaging and analysis up to the edge of the wafer
  • Designed for in-line integration and high-throughput inspection
  • X‑Guard dose control for sensitive areas
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Close-up of a semiconductor wafer with a dense grid of microchips, showing repeating rectangular patterns and fine circuitry details across the surface.

Inspection challenges in advanced packaging

Complex 3D structures require more than 2D inspection

As feature sizes shrink and device concepts move into the third dimension, advanced packaging introduces multi-layer architectures, fine‑pitch interconnects and densely stacked components. Conventional two‑dimensional X‑ray inspection remains useful for certain tasks, but it only provides projected information and offers limited access to the true three‑dimensional arrangement of structures. With rising layer count and complexity, interpreting features and defect modes from 2D projections alone becomes increasingly ambiguous. Scanning Acoustic Microscopy (SAM) can address selected use cases, but requires coupling media and is not generally suited for full‑wafer inspection or all material stacks.

At the same time, fabs must meet demanding requirements for throughput, cleanliness, automation and device protection. This combination of complex 3D structures and tight process windows creates a need for inspection systems that deliver volumetric information at wafer level and can be reliably integrated into semiconductor production.  

3D visualization of a layered grid structure composed of numerous small, rounded elements arranged in dense, repeating patterns, shown from a slightly elevated perspective.

Imaging principle of ZEISS NLX

3D X-ray laminography for wafer-level inspection

ZEISS NLX is a 3D X-ray laminography system designed for inspection and metrology of advanced packaging structures on 300 mm wafers. It reconstructs three-dimensional volume data from multiple projections and provides access to internal features without mechanically opening or destructively preparing the sample. Quantitative results can be derived directly from the reconstructed volume, supporting both dimensional measurements and defect detection.

The advantage of laminography compared to conventional CT is its suitability for flat, laterally extended samples such as semiconductor wafers. The NLX® imaging concept is optimized to achieve very high resolution on such flat objects while capturing complex near-surface and stacked structures at wafer level. This combines high spatial resolution with a measurement geometry and acquisition strategy that support high-throughput operation for advanced packaging applications.

The system architecture is aligned with semiconductor fab requirements. A ZEISS proprietary X‑ray source and a dedicated beamline are combined with a mechanical and optical design optimized for sensitivity, stability and dose control. X‑Guard complements this concept with dedicated shielding that minimizes X‑ray exposure in sensitive areas on the wafer to avoid any damage. NLX® can be integrated as an in‑line or near‑line system in existing process flows and supports automation‑ready inspection directly at wafer level.  

Application areas

Metrology and defect detection for advanced packaging structures ZEISS NLX addresses inspection and metrology tasks that arise when complex 3D interconnects and stacked devices must be controlled at wafer level. The system is suited for front-end related advanced packaging developments as well as for high-volume production of established designs.
Stylized diagram showing a structured grid of connected vertical elements with highlighted directional arrows, alongside a magnified view of a micro-scale array on a layered base.

3D metrology for advanced packaging structures

ZEISS NLX supports three-dimensional metrology on advanced packaging wafers. Solder bump height and shape can be analyzed in 3D to help secure mechanical stability and consistent thermal behavior of packages and stacks. Measurements of shift, overlay and tilt contribute to the precise alignment of layers within high-bandwidth memory and other stacked devices.

In addition, spacing between dies and layers, for example chip gap and related distances, can be evaluated to support the optimization of thermal management and mechanical robustness. These metrology capabilities provide quantitative input for process development, monitoring and optimization.  

Stylized diagram showing a structured grid of connected vertical elements with highlighted directional arrows, alongside a magnified view of a micro-scale array on a layered base.

3D defect inspection of interconnects and interfaces

Beyond dimensional measurements, ZEISS NLX provides non-destructive 3D insight for defect inspection in advanced packaging interconnects. The system supports the detection of voids in micro bumps and C4 bumps and reveals missing or bridged bumps that would affect electrical or mechanical integrity.

Through-silicon vias (TSV) can be examined for voids and cracks. Cold joint defects and other critical failure modes within solder joints and bonding interfaces can likewise be visualized in the reconstructed volume. This allows users to localize issues in depth and to distinguish defective parts early in the process flow.  

NLX®-100 and NLX®-100M

ZEISS NLX is available in configurations that share the same core imaging and analysis capabilities but differ in their level of automation and handling concept.

  • NLX®-100

    Fully automated in-line configuration for high-volume production
    NLX 100

    ZEISS NLX-100 is the fully automated in-line configuration of the platform. It includes automated wafer loading via an Equipment Front End Module (EFEM), alignment functions and integration into fab automation systems. NLX®-100 is designed for continuous use in high-volume manufacturing environments where repeatability, cleanliness and stable inspection processes are essential. It is suited for fabs that want to integrate 3D X-ray inspection as a standardized step in their advanced packaging lines.

  • NLX®-100M

    Flexible configuration for near-line inspection and in-line process development
    NLX 100M

    ZEISS NLX-100M provides the same core imaging concept and software environment, but with a reduced level of automation. It is particularly suitable for near-line inspection, pilot lines and engineering tasks, where flexibility and access to detailed 3D information are more important than maximal throughput. NLX®-100M gives process and development teams the ability to investigate wafers in depth, using the same reconstruction and evaluation workflows as the fully automated system.

Data evaluation, automation and AI

Data evaluation on ZEISS NLX is powered by ZEISS INSPECT X-Ray, enabling 3D metrology, defect inspection and automated inspection flows in a single environment. The software links volume data, analysis routines and inspection recipes to turn 3D X-ray information into reliable input for process and quality decisions.

3D visualization of a red structure with green cross-sectional planes for statistical process analysis.

Statistical evaluation and process monitoring

ZEISS INSPECT X-Ray consolidates measurement and defect information across wafers and lots and presents it in statistical views. Distributions can be analyzed, trends tracked and drifts in critical parameters identified over time. In this way, random variation can be separated from systematic shifts, meaningful control limits can be defined and process adjustments can be justified with quantitative data. In day-to-day production, this supports more stable processes and reduces the risk of unnoticed degradation in advanced packaging steps.

Multiple grayscale microscopy images featuring highlighted regions and a 3D visualization for automated AI-powered defect detection.

Automation and AI-supported inspection

ZEISS NLX inspection flows can be defined as recipes in the analysis environment: regions of interest, acquisition settings, metrology tasks and defect criteria are specified once and then executed consistently across wafers and lots. This helps standardize complex 3D inspections and ensures that defined inspection strategies are applied uniformly.

AI-based routines within the platform automatically highlight and segment relevant structures and defects in the volume data. This provides a more consistent basis for defect decisions, reduces the effort required for manual review and allows inspection concepts to be transferred to new devices and process variants with limited adaptation. 

Anything is imaginable – a lot is possible

ZEISS enables semiconductor manufacturers worldwide to establish stable processes along the entire wafer lifecycle. As advanced packaging becomes more complex and three-dimensional, reliable access to internal structures at wafer level is essential for process control, yield and time to ramp.

ZEISS NLX is a 3D X‑ray laminography system for inspection and metrology of advanced packaging structures on 300 mm wafers. It provides non-destructive insight into internal features such as micro bumps, TSVs and stacked dies and is designed for in-line integration and high-throughput wafer-level inspection.

For further information please contact our experts.  

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