21st Century Inspection: Lectronics Gains X-ray Vision

Christi Beck-Levicki Press

Originally published in US Tech Magazine. 

Analyzing solder joints for leadless components has always been tricky business. Traditionally, the electronics manufacturing industry has relied on manual visual inspection or 2D X-ray systems or not a connection is acceptable.

One of the latest solutions for circuit board assemblies packed with BGAs and QFNs is 3D X-ray inspection. In order to guarantee a product’s performance throughout its entire lifecycle, the tiny, hidden solder balls underneath bottom-terminated components need to be seen and analyzed.

Both 2D X-ray and visual inspection are highly unreliable and subjective. Without an accurate picture of what’s going on underneath the component packages, technicians won’t always agree on what constitutes an appropriate solder joint.

Nikon XT V 160 X-ray inspection system. (Credit: Desiree Molnar)

To remove the subjectivity of measuring accurate connections in leadless components, Saline Lectronics recently invested in a Nikon XT V 160 Varian 1313Dx system with X.Tract technology. Upgrading from a 2D X-ray system, this new, high-quality PCB inspection system allows the company’s technicians to get inside, underneath, and take a highly-magnified look at component connections for complex PCB assemblies.

“Our old machine was simply an X-ray,” comments Scott Sober, VP of operations and manufacturing at Lectronics. “The Nikon XT is a proper inspection tool. With it, I will definitively know that my manufacturing process is providing excellent results for all bottom-terminated components.”



X-Ray Vision

The Nikon XT V 160 will expose any hidden features allowing further examination of BGAs and other array-style packages as well as inspect heels of solder joints, fine pitch packages, and the internal characteristics of solder joints. With a proprietary NanoTech 160 kV X-ray spot and electromagnetic lens, the system is equipped with the latest digital imaging technology available and produces clear, sharp images at the micron level.

The Nikon X-ray system will also serve as an excellent process development tool for Lectronics. Getting clear pictures of specific areas on a PCB assembly that were not previously seen on the company’s older X-ray, will help to reveal any hidden, unknown defects. With defects being brought to light sooner in the assembly process, the company’s manufacturing team can engage in root-cause analysis, and update production procedures in order to prevent the defects from recurring. In fact, the Nikon system will validate manufacturing processes by providing visual proof that a solder joint is good — proving that the oven profile is accurate for that specific circuit board assembly.

“The Nikon Metrology team envisioned that Saline Lectronics would implement the Nikon XT V X-ray inspection system as a quality control tool to complement their existing testing and inspection process,” says Frank Wiencek, Midwest business development manager at Nikon Metrology.” The Nikon XT V system allows Lectronics to see the quality of solder joints and other features of multi-layer boards that can’t be seen with optical inspection.”

With the automated inspection mode feature on the Nikon XT V 160, the company is able to program a variety of routines into the system that function as batch automated X- ray inspection (AXI). These routines automatically inspect a certain PCB assembly, or area of components on the board, and perform a full 2D and 3D analysis of the region of interest. This will enable the company’s technicians to quickly and intuitively run routines of repeated inspections for production circuit board assemblies.

Running routines will help the company’s team save time on first-time builds as well as during the troubleshooting process of any production fallout. The intelligent program control feature on the X-ray allows for customizable system control, which makes setting up the camera for each assembly seamless and quick.

Powerful Laminography

“We chose the Nikon system because of the X.Tract software,” says Jason Sciberras, Lectronics manufacturing manager. “The laminography technology gives us an unprecedented, magnified view of any ball underneath a BGA. Even if the BGA has 2,000 balls, I can examine each one individually from any angle. This technology will completely revolutionize how we measure appropriate connections.”

Close-up 3D rendering of BGA balls on a specific plane and angle. (Credit: Nikon Metrology)

X.Tract works by taking 2D images at the sub-micron level 360° around the PCBA or component of interest. Those sliced, 2D images are then reconstructed into a detailed 3D model that can be analyzed on any plane with the X.Tract analysis tool. The highly-magnified 3D image will give the company’s technicians insight into defects that are typically obscured in standard 2D X-ray systems, such as head-on-pillow (HoP), open solder joints and cracks. X.Tract also isolates views of the different layers of complex component packages such as package-on- package (PoP) or multi-chip modules.

As Lectronics’ customers continue to design highly-complex, extremely dense circuit board assemblies, it’s crucial that both the company’s manufacturing technicians and its engineers can properly inspect and guarantee the manufacturing quality of those products. “This is a new tool for looking at things we haven’t been able to see before,” comments Alex Johnson, associate engineer at Lectronics.

Quality Improvements

The enhanced visual inspection of the Nikon X-ray system will afford in-depth analysis during troubleshooting that will be enormously beneficial to Lectronics’ test engineers. In previous cases of unknown test failures, if the board had a micro-BGA or QFN, the PCB assembly may be sent out for cross- sectioning and destructive testing to determine the root cause. By examining these components in-house, without destroying the PCB, the company will not only guarantee a faster resolution to test fallout, but also save clients precious time and money.

The 3D X-ray technology will be beneficial to the company’s mechanical assembly technicians as they assemble and complete different types of box build products. Of all the different products that Lectronics assembles, electro-mechanical builds make up about 40 percent of the total business. With this new 3D X-ray analysis, technicians will be able to see inside closed box build units to guarantee that everything is sitting correctly inside of the unit. The X-ray system will prove that components are not put under any additional stress after mechanical assembly is finalized.

Jason Sciberras, manufacturing manager, and Denise Kuenzer, senior process engineer, operating the Nikon XT V (Credit: Desiree Molnar).

The Inspect-X feature provides a full, real-time, automated reporting system that details the X-ray system’s inspection results. Reports are fully customizable and will detail the analyzed results of the specific components that were inspected with both 2D and 3D images of the solder connections underneath components. The Inspect-X reports also clearly define passed and failed components with quantifiable data.

These Inspect-X reports are valuable to the company’s customers. With a variety of customers in the medical and aerospace industries with Class 3 assembly requirements, the company is now able to supply these clients with real-time data and 3D visual images that guarantee the solder joints on their assemblies, and thus guarantee the functionality and reliability of the entire PCBA.

“As a future-thinking organization, we are always investing in the appropriate tools and resources to provide our customers with unparalleled quality,” says Mario Sciberras, Lectronics president and CEO. “The Nikon X-ray system will better ensure quality for highly-complex circuit board assemblies with leadless components.”