The causes of BGA malfunctions include bump voids, cracks, warpages, and deformations. BGA bumps are located on the underside of the chip, and we cannot visually inspect them. The bump defects are also very small, around 10μm or less. X-ray enlarged observation is needed for the BGA inspections.
With a microfocus X-ray tube having a small focus spot size and low blur and an X-ray inspection device equipped with a high-resolution FPD, it is easier to observe enlarged BGA in the inspection. Also, in order to penetrate the overlap of backside components caused by the complexity of BGA packages, high-layer boards, and double-sided mounting, a higher tube voltage than before is necessary.
The μRay8600 top view type X-ray inspection system has high transmission power and a tube voltage of 130 kV, as well as its own high-performance micro-focus X-ray tube and 3 million pixels FPD, enabling magnification observation up to 180 times. In addition, it has a tiltable X-ray camera, so it can observe BGA bonding problems that could not be seen from directly above in a three-dimensional manner.
| Focal spot | Microfocus |
|---|---|
| X-ray tube voltage | 90 to 130 kV |
| Magnification | 100x or more |
