Testing a BGA assembly board involves searching for a soldering fault. And it’s difficult to achieve this without using specific equipment. Also, the process helps to ensure that your PCB performs well.
Some of the tools you can use include endoscopes, industrial CT scanning machines, X-ray machines, JTAG, etc.
How do these tools help?
They have 2D and 3D vision, which helps you to easily detect problems. You can spot things like solder thieving, solder balls, missing solder balls, excess solder, paste bridging, etc.
Testing also helps you to confirm the correct placement of the solder balls. Plus, it ensures there’s no issue with each contact pad.
With that said, using X-ray images has its snags. For instance, it may be difficult to spot parts in the same location. Or you may even notice interference with the X-ray with background metals like POP parts.
Hence, you need caution when you align the BGA with the board. Furthermore, the testing tools help to supplement precise placement and offer a measure of quality assurance.