PCB X-ray inspection for reliable electronic manufacturing

PCB inspection is becoming more demanding as board designs grow denser and more intricate. Hidden solder joints, layered assemblies, and internal structures make it increasingly difficult to assess quality using surface-level methods alone.

X-ray inspection provides non-destructive visibility inside assembled PCBs, enabling manufacturers to evaluate internal features and identify defects that cannot be seen externally. This is particularly important in applications such as automotive electronics, AI server infrastructure, and consumer devices, where performance and reliability requirements are high.

Why PCB inspection matters

As PCB designs evolve, so do the associated risks. Greater component density and more complex layouts increase the likelihood of defects occurring within the structure of the board.

Common risks include:

Hidden solder joints in package types such as Ball Grid Array (BGA), Land Grid Array (LGA), Through Hole Technology (THT)
Increasing component density
Defects that are not visible from the surface

At the same time, manufacturers must balance quality with operational demands, including:

Sustaining production flow
Minimizing scrap and rework
Meeting reliability expectations in demanding applications

X-ray inspection helps address these requirements by providing insight into internal structures without interrupting or damaging the product.

Common inspection challenges

Producing reliable electronic components requires inspection methods that can keep pace with increasingly precise manufacturing requirements. Manual inspection and surface-level checks are limited when critical features are hidden inside the board or beneath components. For this reason, automated inspection technologies such as AOI and AXI play an important role in helping manufacturers maintain consistent quality control.

Together, AOI and AXI address different inspection needs:

AOI supports fast visual checks of accessible surfaces
AXI provides non-destructive visibility into internal features where many critical reliability risks occur

How X-ray inspection helps

X-ray inspection provides non-destructive visibility into internal PCB features, enabling a more complete understanding of assembled boards including:

Non-destructive internal inspection: internal solder joints, voids, and structural features can be evaluated without altering the PCB.
Improved visibility with CT techniques: planar CT separates overlapping features, making complex assemblies easier to interpret.
Flexible deployment: depending on configuration, X-ray inspection can offer detailed offline analysis as well as integration into production workflows.

X-ray imaging examples

Examples of imaging of component parts

Insulated Gate Bipolar Transistor (IGBT)

Smartwatch

UVTRON operating principle step 1

Check for voids (air bubbles).

Driver assistance system (circuit section)

UVTRON operating principle step 2

Numerous voids (air bubbles) were observed.

Engine Control Unit (ECU)

UVTRON operating principle step 3

Cracks and voids were identified.

Ball Grid Array (BGA)

Smartphone

UVTRON operating principle step 1

Numerous voids (air bubbles) were observed.

Driver Assistance System (circuit section)

UVTRON operating principle step 2

Numerous voids (air bubbles) were observed within the BGA.

Engine Control Unit (ECU)

UVTRON operating principle step 3

Numerous voids (air bubbles) were observed.

Ceramic capacitor

Smartphone

UVTRON operating principle step 1

I checked the internal structure of a multilayer ceramic capacitor (0402 size).

Wire bonding

Engine Control Unit (ECU)

UVTRON operating principle step 1

We checked for defects in the PCB wire bonding by passing through metal components such as heat sinks.

Reliable inspection in real-world production conditions

Responsive Padding

Inspection systems must operate consistently in demanding production environments, often within continuous inline workflows. Hamamatsu supports these requirements with X-ray detection technologies designed to:

Provide 24/7 stable operation over extended periods
Maintain consistent image performance
Integrate into inspection systems used in production environments

This enables reliable inspection performance in industrial workflows without adding unnecessary disruption to production.

Technologies for PCB X-ray inspection

Microfocus X-ray (MFX)

MFX supports high-resolution imaging by reducing focal spot size, enabling clearer visualisation of fine features in PCB assemblies.

High-resolution detectors

Detector selection plays an important role in overall inspection performance. Options include:

TDI cameras for high-resolution, high-speed imaging
Flat panel sensors (FPS) for flexible system integration and CT

These technologies can be applied across a range of inspection scenarios, from detailed analysis to production-oriented use cases.

A complete X-ray inspection approach

Effective PCB inspection depends on how technologies work together within a system: resolution, sensitivity and throughput are defined by a combination of X-ray source, detector and system geometry.

Hamamatsu supports this approach by providing key source and detector technologies that can be combined into inspection platforms aligned with application requirements.

Built for the realities of PCB inspection

These technologies support the needs of:

System integrators developing inspection equipment
PCB manufacturers and EMS providers
Process and quality engineers responsible for yield and performance

Preliminary NDT evaluation

Hamamatsu Photonics proposes optimal solutions for non-destructive testing through trial testing.

At Hamamatsu Photonics, we conduct preliminary evaluations for non-destructive testing by performing trial scans using various X-ray sources, sensors, and cameras. Rather than manufacturing non‑destructive testing equipment ourselves, we focus on guiding customers toward the most suitable devices, drawing on our expertise in light sources, detectors, and related components, without bias toward any particular manufacturer.

In addition to recommending optimal devices, we also provide optimal guidance based on years of experience, including tips and know-how for image acquisition.

Please contact our X-ray NDT team to arrange a preview screening.

Responsive Padding

Mobile Padding

PLD in SMD package