Oliver Scholz

In situ real-time x-ray quality assessment of BGA and uBGA connections during soldering

While solder joints of integrated circuits in BGA and uBGA packages can be tested with 3D-computed tomography, this process is time consuming and too expensive for anything but samples or small production volumes. This paper explores approaches to facilitate a 2D-imaging testing system for BGA and uBGA solder joints. Non-standard pad geometries can be used to cause a deformation of the solder balls during soldering; this deformation is detectable in a 2D-image. By integrating a compact X-Ray-source/detector unit into a reflow soldering station, controlling the quality of the solder joints in real-time during soldering will become possible. This information can then be fed back into the soldering station in order to optimize the soldering process.