Detection of defects of BGA by tomography imaging

To improve a cost performance and the reliability of PC boards, an inspection of BGA is required in the surface mount process. Types of defects at BGA solder joints are solder bridge, missing connection, solder voids, open connection and miss-registration of parts. As we can find mostly solder bridge in these defects, we pick up this to detect solder bridge in a production line. The problems of image analysis for the detection of defects at BGA solder joints are the detection accuracy and image processing time according to a line speed of production. To get design data for the development of the inspection system, which can be used easily in the surface mount process, it is important to develop image analysis techniques based on the X ray image data. We attempt to detect the characteristics of the defects of BGA based on an image analysis. Using the X-ray penetration equipment, we have captured images of an IC package to search an abnormal BGA. Besides, in order to get information in detail of an abnormal BGA, we tried to capture the tomographic images utilizing the latest imaging techniques.