Cutting-Edge Inspection Challenges 

Koh Young’s Brent Fischthal explains how UHDI and advanced packaging are challenging inspection systems.

Advanced packaging seems to be accelerating the trend toward larger component packages. What are the new demands/challenges these packages put upon inspection?

The shift towards larger components and advanced packaging brings a host of challenges that impact the industry. These challenges include complexity, density, package diversity, and inspection methodologies, all of which necessitate a more innovative approach. 

First, the increased complexity associated with advanced packaging techniques introduces more intricate board designs with multiple chip types and miniaturized components. Furthermore, the drive towards higher density and smaller pitch, facilitated by advanced packaging solutions such as 2.5D and 3D packaging, places significant demands on inspection machines. For instance, inspection systems must reliably address challenges like 10um thin solder deposits, 50um component spacing, and highly-reflective components within densely populated areas, even where access might be limited. 

Moreover, the proliferation of diverse advanced packaging methods, including fan-out wafer-level packaging (FOWLP), system-in-package (SiP), and chiplets, requires inspection machines to accommodate a wider variety of package types and configurations. In addition, the variation in component heights, a common characteristic in advanced packaging due to designs like stacked die and heterogeneous packing, requires the inspection system to overcome the shadowing created by these height differences in order to make consistent and reliable measurements.


Besides larger component packages, OEMs and applications such as automotive are demanding much larger volumes of finished boards, with much higher yields and increased reliability. How does this change the role of inspection equipment? Surely just making the machinery faster isn’t the entire solution?

In the context of escalating production volumes, higher yields, and stringent reliability requirements, the inspection machine’s role is indeed more than just speed enhancement; it becomes a multifaceted, integral part of the manufacturing process. Larger and more complex packages, coupled with larger and more complex inspection data sets, makes efficient data handling, storage, and analysis imperative. This enables the identification of trends, root causes of defects, and process improvements. 

Within the context of Industry 4.0 and smart manufacturing initiatives, inspection machines must seamlessly share data with other systems to enable real-time feedback and process optimization. This requires an increasingly higher degree of connectivity, interoperability, and compatibility with factory automation systems. 

As production volumes surge, preserving product quality is of even more importance. Inspection machines assume the role of a gatekeeper, vetting components to ensure that only those meeting the quality criteria progress down the production line. Inspection is increasingly contributing to Statistical Process Control (SPC) techniques by capturing data for predictive analysis, SPC can preempt potential issues and enable proactive preventive measures. 

Finally, inspection machines contribute to data-driven decision-making, generating a wealth of data which offers valuable insights into both trends and defects, which, in turn, generates process improvement efforts. Koh Young Process Optimizer (KPO) is a current example of applying AI for real-time process adjustments. This integration into Industry 4.0 initiatives fosters seamless data flow, facilitating improved productivity and enhanced connectivity with other systems. 

In essence, the evolution of inspection means multifaceted roles: process control, quality assurance, data-driven decision-making, and defect prevention. These roles ensure that manufacturing processes remain efficient, reliable, and agile in meeting the demands of the modern industry landscape.

With that deep understanding of the materials: how much of that resides with the EMS engineers and operators, and how much of that is built into the Inspection equipment itself?

These new specialized materials need tailored approaches to inspection. Substrates often feature intricate microstructures and fine surface details. Optical inspection systems need to precisely capture these features and identify defects, which demands high-resolution imaging capabilities. While the manufacturer needs to have some resident expertise, forward-thinking inspection equipment providers–like Koh Young–help by delivering “material agnostic” solutions to help alleviate the challenges. 

For example, moiré phase-shift interferometry enhances the resolution of optical systems for defect detection, despite component reflectivity or substrate color, by providing detailed surface information, which then improves the sensitivity during inspection. Koh Young is making use moiré phase-shift interferometry to optimize lighting, imaging techniques, and contrast adjustments to deliver trustworthy measurement-based inspection solutions.

Furthermore, advanced data interpretation and analysis tools help make sense of the complex optical data generated during inspection. To achieve these accurate, reliable inspection results, some customization and calibration of optical inspection systems is essential.

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