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.  2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.