High Resolution X-Ray CT for Advanced Electronics Packaging

Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge (see [1]). So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations. The main NDE methods for electronics packaging are scanning acoustic microscopy and X-ray macrostructure analysis like X-ray radiography and X-ray computed tomography (CT) (see [2] & [3]). Our presentation will focus on X-ray nano focus computed tomography as a method for component development, process development and reliability research. We will discuss the potentials and the limits of X-ray NDE techniques, illustrated by crack observation in solder joints, evaluation of micro vias in PCBs and interposers and the investigation of a complex SiP like a USB memory device. We will show tomography results with voxel sizes less than 800nm. To reach these results we developed special techniques to prepare the samples for high resolution CTs. Figure 1 shows the tool, a prepared specimen and a high resolution CT result picture