Micro- and nano-DIC deformation analysis for electronic packaging applications

This paper presents an automated digital image correlation (DIC) system for in-plane micro-deformation analysis. The system features microscale resolution, realtime thermal ramp and cycling loading, image auto-positioning and autofocus for image acquisition, and novel element-based DIC algorithm. The DIC tool is demonstrated to a micro-deformation measurement application of a solder joint in a plastic ball grid array (BGA) package. The solder joint deformation has been investigated under two loading cases, temperature ramp and temperature cycling. Finite element analysis was conducted and the U and V displacements, and calculated strain distribution in the solder joint is compared with the DIC measured result. The measured and predicted displacement fields under temperature ramp give good agreement. Research on nano-scale DIC measurements must employ an atomic force microscope (AFM) for in-situ digital imaging of in-plane deformation. It was discovered through calibration that AFM scanner drift is a intrinsic error and thus a correction methodology is required for DIC application. The application the AFM/DIC technique is used for deformation characterization of solder interconnection in a micro-thermoelectric cooler system subject to a small temperature gradient of +25C to -25C