X-ray inspection technology, by penetrating materials and capturing images of the internal structure, can discover hidden defects that cannot be identified by traditional optical inspection and plays an irreplaceable role in PCB manufacturing. Its core application scenarios are as follows:
Internal soldering inspection of packaged components such as BGA/CSP/QFN
Application scenarios:
The solder joints of packaged components such as BGA (Ball Grid Array), CSP (Chip Level Package), and QFN (Square Flat Leadless) are hidden beneath the chip, and traditional detection methods cannot directly observe them. X-ray can penetrate the packaging materials to detect whether there are defects such as voids, false soldering and bridging inside the solder joints.
Key value:
Test the porosity of the solder joints (such as whether the proportion of the porosity area exceeds 25%).
Identify problems such as ball offset, cold welding and short circuit.
Ensure the reliability of high-density packaging and avoid functional failure caused by soldering defects.
2. Detection of interlayer defects within PCBS
Application scenarios:
There may be short circuits, open circuits, interlayer offsets or defects in the copper coating within the holes in multi-layer PCBS. X-ray can detect the interlayer connection quality and internal structure through oblique scanning or tomography (CT) technology.
Key value:
Test the integrity of the copper coating in blind holes and buried holes.
Identify the locations of interlayer short circuits or open circuits.
Verify whether the PCB lamination process meets the design requirements.
3. Defect detection of tiny components and high-density circuits
Application scenarios:
In small components such as 0201 and 01005 or high-density interconnect (HDI) PCBS, the pin spacing of the components is extremely small (such as less than 0.3mm), and it is difficult to distinguish them by traditional detection methods. X-ray can detect whether the pins of components are aligned and whether the solder joints are full through high-resolution imaging.
Key value:
Ensure the welding quality of the tiny components.
Avoid circuit faults caused by false soldering or bridging of pins.
Adapt to the trend of miniaturization and high-density electronic products.
4. Detection of hidden defects such as false welding and cold welding
Application scenarios:
False welding or cold welding may show no obvious abnormalities on the surface, but there may be cracks or incompletely fused weld points inside. X-ray can detect whether the internal structure of solder joints is uniform through high-contrast imaging.
Key value:
Detect potential failure risks in advance to prevent product malfunctions during use.
Improve the long-term reliability of the product and reduce after-sales maintenance costs.
5. Assembly verification of complex-structured PCBS
Application scenarios:
In PCBS with complex structures such as heat sinks and shielding covers, components may be obscured. X-ray can penetrate obstructions and detect the welding quality of the covered area.
Key value:
Ensure the assembly integrity of complex-structured PCBS.
Avoid the problem of missed detection caused by occlusion.
6. Failure analysis and quality traceability
Application scenarios:
When a product malfunctions, X-ray can be used for failure analysis to locate the defect position and cause. Meanwhile, quality traceability can be achieved by saving the detection images.
Key value:
Quickly locate the root cause of faults and shorten the maintenance cycle.
Provide data support for the improvement of production processes.
Limitations
High cost: X-ray equipment is expensive and the maintenance cost is also high.
The detection speed is relatively slow: Compared with optical inspections such as AOI, X-ray detection is slower, which may affect the production rhythm.
Radiation safety: Protective measures should be taken to prevent operators from being harmed by radiation.
Application suggestions
Combined with other detection technologies: X-ray can be combined with technologies such as AOI and ICT (Online Testing) to form complementary detection solutions.
Optimize the inspection strategy: Focus on inspecting high-risk areas (such as BGA solder joints) to balance inspection costs and quality requirements.
Select the appropriate equipment: Choose 2D X-ray or 3D CT equipment according to the product requirements. 3D CT can provide more accurate internal structure analysis.
Summary
X-ray inspection is mainly used in PCB manufacturing to detect hidden defects and ensure the reliability of high-density packaging, and it is a key technology for improving product quality. Despite its high cost, it has irreplaceable value in the manufacturing of high-end electronic products. Through the reasonable application of X-ray inspection, the risk of product failure can be significantly reduced and customer satisfaction can be improved.
