Three-Dimensional Solder Joint Inspection (3D-SJI) is a basic concept for solder joint inspection, which Omron Corporation advocates. It is aimed at ensuring both functionality and reliability of products by inspecting not only electric contact, but also the joint strength of solder joints by accurately capturing and inspecting the shape of the solder joint section. In order to capture 3D shape of solder, Omron uses its original technologies for both visible (optical) and non-visible (X-ray) inspections.
For visible (optical) inspection, the company has achieved hybrid 3D measurement technology, which combines Color-Highlight and phase shift (Fig. 1). By combining the captured solder shape with high secularity through Color-Highlight and accurate height measurement through phase shift, 3D-SJI accommodates variations of the gloss and shape of the solder surface.
For non-visible (X-ray) inspection, the high-accuracy 3D computed tomography (3D-CT) technology is adopted. One challenge was the achievement of high-speed inspection practical for inline inspection. To overcome this challenge, Omron has developed an inspection principle called parallel CT imaging. In this principle, the X-ray camera is moved horizontally without rotation in the XY stage imaging system to secure a large visual field size that can be used for inspection, making it possible to reduce the number of FOV’s (field of views), which becomes a factor to increase inspection time. In software processing, high-speed, high-accuracy 3D-CT has been achieved through parallel processing of the imaging of projection image, and the reconstruction of 3D image [graphics processing unit (GPU)]. This has enabled automatic detection of head-in-pillow (HIP) as shown in Photo 1 and Photo 2, which is a typical defect mode of ball grid arrays (BGAs), in a practical tact in mass production inline inspection.
At SMT Hybrid Packaging 2018, Omron showcases two new models that exemplify 3D-SJI: VT-S530 printed circuit board (PCB) inspection system (Photo 3) and VT-X750 high-speed automated X-ray CT inspection system (Photo 4), in Booth 300, Hall 4A.
VT-X750 Achieves Inline Full Inspection
The new model VT-X750 is equipped with an ultra-high-speed imaging technology, which employs a newly designed imaging method, while maintaining high detection capability using the 3D-CT method. Combined with Omron’s original automated inspection know-how, which the company has nurtured over the years, VT-X750 has achieved the fastest automated inspection speed in the industry on the basis of the company’s survey in Oct. 2017. It employs Omron’s newest NJ Series machine controller. Employing the most advanced vibration control, it has achieved more than twice the inspection speed as compared with the company’s existing model. In addition, it has expanded component types that it can inspect to include bottom electrode components, multilayer components, such as package-on-packages (PoPs), and insertion components, such as press-fit connectors. It also supports rich inspection applications, including back-fillet inspection of IC leads and void inspection. Through the improvement of inspection speed and the expansion of the coverage of automated inspection logic, VT-X750 has enabled inline X-ray inspection and a total inspection of all surfaces.
In terms of inspection capabilities, VT-X750 has achieved the reproduction of solder shape that is necessary for ensuring joint strength with high repeatability through Omron’s original 3D-CT reconstruction algorithm. By quantifying mounting conditions, including solder shape, it enables inspection of non-defective products criteria based on standards, and strongly supports the minimization of the risk of overlooking unknown defects, and vertical and stable start of inspections. In addition, it accommodates stringent design requirements for products, including the adoption of high-density packaging and multilayer components, accompanying the downsizing of PCBs. 3D-CT visualizes solder shape and reduces design restrictions caused by the inspection process.
In terms of safety, VT-X750 has reduced radiation exposure to the products. The above-described high-speed imaging technology has enabled imaging with short-time X-ray irradiation without sacrificing the quality of inspection images. Furthermore, by locating the X-ray source under the board, it has physically reduced direct exposure on the surface of PCBs on which important components are mounted. In addition, it is equipped standard with a low-energy cut filter, which suppresses the effects of exposure, thereby minimizing the
IoT Solution on SMT: Q-up Auto
Using quality data of the SMT line, which can be obtained from 3D-SJI, Q-up Auto monitors variations in measurement values even during the production of good-quality products and detects signs of defects. In addition, by linking the quality data and production data that can be obtained from manufacturing equipment,
including chip mounter, and by monitoring and analysing them, Q-up Auto analyses the trend of defects at the point of origin of the production process and visualizes the process quality (Fig. 2). Targeting the European market, Omron has been advancing compliance with Hermes Standard, a machine-to-machine (M2M) standard initiated by ASM Assembly Systems Ltd., in an effort to contribute to the achievement of zero-defect SMT lines.
Omron will exhibit their inspection portfolio at SMT Hybrid Packaging 2018 at booth 300 in hall 4A. In addition, Omron systems will be displayed also at the show area “Future Packaging” of the Fraunhofer Institute, in cooperation with der ATEcare Service GmbH & Co. KG, at booth 434, hall 5.