SEM-DIC Based Nanoscale Thermal Deformation Studies of Heterogeneous Material

Abstract

Full-field thermal deformation experiments on electronic packaging materials for areas from 50 × 50 to 10 × 10 μm² and temperatures from RT to ≈200 ^°C have been successfully performed in a Zeiss Ultraplus Thermal Field Emission SEM using 2D-DIC. First, polishing methods for heterogeneous electronic packages containing silicon, Cu bump, dielectric layer, substrate and FLI (First level interconnect) have been studied to achieve sub-micron surface flatness. Using novel self-assembly techniques, a dense, randomly isotropic high contrast pattern has been successfully applied over the surface of test samples. A high precision Physik Instrumente (PI) Piezo nanopositioning stage has been used to help implement essential drift and spatial distortion correction procedures, which were recently shown to be effective in removing distortions from SEM images. Using thin ceramic films to reduce thermal effects on the FEG SEM source, results indicate that the method is capable of measuring local thermal expansion in selected regions, improving our understanding of these heterogeneous material systems under controlled thermal environmental conditions.