Issue link: https://iconnect007.uberflip.com/i/831357
70 SMT Magazine • June 2017 by Paul D. Scott, Ph.D., IBEX INNOVATIONS, and Evstatin Krastev, Ph.D., P.E., NORDSON DAGE Abstract X-ray inspection systems are key tools for quality control, yield enhancement, and failure analysis of PCBs and semiconductor devices. In many cases, these capable tools provide the only non-destructive techniques for inspection of electronic components. There have been sig- nificant improvements in the X-ray inspection capabilities (both 2D and 3D) in the last sever- al years. In this paper we report a new develop- ment that permits material and thickness infor- mation to be obtained via 2D X-ray inspection. While absorption contrast X-ray imaging is a very powerful inspection technique, it does not exploit all of the information present with- in the X-ray beam transmitted through a sam- ple. A new technology has been recently devel- oped that, instead of simply measuring the to- tal absorption of the X-ray beam, also enables changes in the beam energy to be resolved. This allows the effects of thickness and density to be decoupled, enabling both to be determined. This quantitative composition and thickness information can then be used to provide new levels of insight in PCB and semiconductor in- spection, potentially leading the way to a new generation of X-ray inspection technology. It is quite straightforward to accommodate this technology in an existing 2D X-ray (2DX) inspection system. Advanced software algo- rithms need to be incorporated and an intuitive user interface is provided. We present an overview of this new tech- nology and give examples of other industries where this technology is being adopted, as well as example applications for the PCB and semi- conductor industries. Introduction The need to inspect electronic components and assemblies non-destructively is the main driver behind the development and advance- ment of the X-ray inspection technology for the electronics industry. In many cases, X-Ray inspection (2D and 3D) provides the only non- destructive techniques to inspect optically hid- den components and solder joints such as BGA, POP, QFN, flip chips, through holes, TSVs, mi- crobumps, copper pillars, etc. 2D X-RAY INSPECTION with Materials and Thickness Identification FEATURE