Loading...
Technical Insight

Magazine Feature
This article was originally featured in the edition:
2024 Issue 8

Next Gen 3D X-Ray Inspection for Advanced Packaging: To see better. Faster. More.

News

As 3D IC packaging becomes ever more intricate and demanding, traditional inspection techniques are struggling to keep up. 3D X-ray inspection, powered by AI, is transforming how manufacturers view their products, offering a higher resolution without sacrificing speed or damaging valuable samples.

By Joscha Malin, Director Product Marketing Software Solutions, Comet Yxlon

As the demand for miniaturization grows, semiconductor packaging design is rapidly evolving. Manufacturers are now incorporating 2.5D and 3D ICs into their production, pushing the boundaries of functionality within increasingly compact volumes. This shift brings new challenges, not only in designing robust initial prototypes but also in managing the higher manufacturing and material costs associated with more complex structures. To maintain a competitive edge, manufacturers must adopt comprehensive inspection strategies that help increase yield and accelerate time-to-market without compromising on reliability.

Crucial to the success of these inspection strategies is the ability to detect defects early within the design and manufacturing process. The sooner manufacturers can identify and resolve issues, the faster they can scale up production, ultimately leading to improved yield and a faster path to market success. This is where advanced inspection technologies, particularly 3D X-ray inspection, come into play.

Bridging the Gap with 3D X-Ray Inspection
Historically, inspection methods for 3D ICs have relied on three primary technologies: optical inspection, 2D X-ray, and focused ion beam scanning electron microscopy (FIB-SEM). Each technology brings its own strengths and weaknesses. Optical inspection offers speed and repeatability but lacks the level of detail necessary for comprehensive 3D analysis. FIB-SEM provides unmatched resolution, but it’s a slow, destructive process. Meanwhile, 2D X-ray falls in between—offering non-destructive insight but often lacking the speed or resolution required for today’s complex 3D IC structures. 3D X-ray inspection fills the gap between these technologies, delivering detailed, non-destructive insights in a fraction of the time required for a FIB-SEM analysis. What’s driving its rise now, especially for advanced semiconductor packaging, isn’t just the improvement in X-ray hardware, but the breakthroughs in software and AI that support it.

As 3D IC packaging becomes ever more intricate and demanding, traditional inspection techniques are struggling to keep up. 3D X-ray inspection, powered by AI, is transforming how manufacturers view their products, offering a higher resolution without sacrificing speed or damaging valuable samples. By harnessing AI-driven image analysis, 3D X-ray technology can detect even the smallest defects, like voids or misalignments, with incredible precision. These systems use advanced reconstruction algorithms and data segmentation techniques to reveal fine details inside complex structures. AI further accelerates this process, providing insights at a scale and speed that were previously unattainable, ultimately boosting yield and quality.

The Three Pillars of Effective Inspection: Clarity, Efficiency, and Insight
For any inspection technology to be successful, it must excel in three key areas, all heavily dependent on software:
Clarity: This refers to the quality of the captured image, particularly how well the technology can visualize small details within complex structures. In the case of 3D X-ray, the combination of high-quality hardware and advanced reconstruction algorithms ensures exceptional image clarity, making even minute defects visible.
Efficiency: Automation plays a vital role here. The ability to quickly gather and process images into usable data can significantly reduce inspection times and improve throughput. AI enhances this by automating much of the defect recognition process, allowing operators to focus on critical decision-making rather than manual inspection.
Insight: Beyond what is visible to the eye, the real value lies in the data derived from the images. Advanced software can interpret this data to provide actionable insights, allowing manufacturers to make informed decisions. For instance, defects such as voids in solder bumps or “head-in-pillow” issues can be precisely measured and categorized, offering clear guidance on whether they fall within acceptable parameters.

The beloW scan of a commercially available CPU (figure. 1), captured with Comet Yxlon’s CA20 inspection solution, highlights what is already possible with today’s technology, revealing detailed information about C4 bumps, including defects such as voids of only 10 microns in diameter. These scans take just minutes, highlighting the speed and precision of modern 3D X-ray technology



Figure 1: A close up rendering of C4 bumps (diameter: 65µm) within a commercially available CPU. All image property rights remain with Comet Yxlon and images are not to be copied or distributed.

In another example, a “virtual slice” is taken from a reconstructed 3D volume of a GPU, allowing users to view 2D cross-sections of different layers within the chip, including C4 bumps, interposer bumps, and high-bandwidth memory (HBM) bumps (figure 2). This type of detail would be highly challenging to obtain with optical inspection or 2D X-ray due to the stacked nature of the layers obscuring underlying features.

While capturing high-resolution images is critical, the true power of 3D X-ray lies in the AI-powered software behind it. Assisted defect-recognition software such as Comet Yxlon’s CoS Insights package can rapidly detect and analyze the size and severity of defects, such as solder bump misalignments, and head-in-pillow issues. By measuring key parameters, like bump shift, die tilt, and the likelihood of defects forming, this technology provides a comprehensive understanding of the part’s condition, allowing manufacturers to spot these defects early and prevent costly issues down the line.