Automated X-ray inspection method for fillet-less mounted chip components

Chip components mounted on the printed circuit board are rapidly being miniaturized. Furthermore, the filletless chip soldering technique, which does not use a solder fillet, is widely used in portable products such as mobile phones. However, there is no method to inspect the soldering of fillet-less chip mounting. In this paper, we propose an automated X-ray inspection technique for fillet-less chip mounting. It extracts three inspection parameters from the X-ray image. In the experiments, we evaluate the repeatability and inspecting ability of the technique and confirm that sufficient information for failure detection is obtained. An automated X-ray inspection system using this technique is now in operation at some factories, so in conclusion our automated method would be useful in practice.