BGA Inspection: Significance and Techniques

With the ever-increasing speed at which technology develops, electronic devices have become increasingly compact and portable. The use of BGAs and other comparable devices has rapidly gained acceptance in contemporary PCB design. However, it is quite challenging to inspect these devices after assembly. Consequently, a BGA reballing method was developed to meet the needs of the market.

BGA Inspection: Overview

BGA inspection is a method for checking the integrity of the connectivity between a chip and a printed circuit board. The standoff height of the package, the reliability of the connections, and other factors are all examined during BGA inspections.  Since the inspection area for BGAs is so small, extra methods are usually necessary in order to get a thorough glimpse at the connectivity.

Why Is BGA Inspection Important?

When inspecting a BGA, it’s important to remember that the solder joints are hidden beneath the package. Despite the challenges, BGA inspection is crucial for several reasons, such as:

  • Challenges in Soldering

Soldering BGA components is challenging due to the need to apply sufficient heat to the array so that all balls in the grid melt adequately to form solder junctions. High failure rates can be attributed to the combination of a large number of connections and challenging soldering conditions. Experts can catch these issues through thorough inspections, preventing the shipment of defective components.

  • The unreliability of electrical testing

The PCB design by the FS PCBA is tested for its electrical integrity by passing a current through it during an electrical test. In contrast, the BGA components must be linked for this form of test to determine whether the current is active or not. 

These tests are unreliable since they can only detect a small subset of problem types, and even then, they can’t specify exactly where the defects are. When used in conjunction with other inspection methods, this one can provide a more thorough picture of where and how often errors occur.

  • Material reuse

Rework stations allow for the removal of BGAs with solder defects so that they can be reconditioned or replaced. Defects are caught early in the inspection process, allowing for the material to be salvaged.

  • Quality control

Because the reliability of the BGA SMT assembly is dependent on the quality of the physical connections, a thorough examination of the connections is an integral part of BGA quality control. 

Common flaws and recurring issues can also be uncovered through inspections. Instances of recurring faults may point to problems with the PCB product design or the manufacturing and assembly process, making these measurements crucial.

  • Cost reduction

Fewer flaws will make it to subsequent stages of production if inspection processes are thorough. It could be more expensive to fix defects that make it past inspection but are discovered later in the manufacturing process. 

The longer the flaw goes undetected, the more money your business will lose. This emphasizes the importance of taking precautions and finding solutions quickly.

BGA Inspection Methods

  • Electrical Testing

As part of an electrical test, a BGA is subjected to a current in order to gauge the board’s reliability from a power standpoint. After the BGA component has been attached, the test will detect whether or not the current is flowing. It is helpful to perform this kind of test in order to detect electrical faults like open circuits and short circuits.

Electrical testing is an essential part of the inspection process, but test sites under BGA components can be tricky to locate. Electrical tests alone can be a challenge when trying to fulfill evaluation standards. Ball grid array inspections often utilize a combination of electrical tests and other testing methods to root out problems.

  • Visual Examination or Optical Analysis

When a BGA and its connections are inspected with optics technology, the process is known as optical inspection or visual inspection. In the past, this method only yielded limited results because it required the use of the naked eye or microscopes. However, the advent of the endoscope has been very helpful for this sort of investigation.

Despite the endoscope’s medical roots, its ability to visually check microscopic items in tight spaces makes it a natural fit for BGAs. The system relies on a camera fitted with a powerful zoom lens and an associated monitor to provide detailed, up-close views of the object under scrutiny. For more complex image collection and measurement, this tech is frequently used in tandem with visualization software.

  • X-Ray Diagnostic

X-ray inspection is the most modern approach for checking the quality of BGAs. Because of the top-down nature of the X-ray image, the ball grid and soldering patterns may be thoroughly examined. 

The tilt capability of modern X-ray inspection equipment allows for the analysis of solder connection geometry from a variety of perspectives. Solder faults such as solder bridges, popcorning, and excess solder can be easily detected using this technology thanks to the high resolution of the images produced.

X-ray inspection technology, like endoscopes, has several uses outside BGA testing. Inspection of vias and through-holes, surface-mount defect analysis, and inspection of lead-free solder are a few examples.

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