μ-CT investigation of tin whisker growth mechanisms

The current paper considers the applicability of micro-tomographic methods for the investigation of growth mechanisms of metallic tin whiskers. Tin whiskers are metallic fibers that grow spontaneously from lead-free tin-coated surfaces, causing short circuit related issues in electronic devices, therefore making this phenomenon an interesting topic for in-depth analysis. In order to investigate such minuscule structures by X-rays, a tomographic setup employing a direct-converting pixel large area detector based on the Timepix readout ASIC is used. Featuring an extraordinary contrast and high dynamic range, these detectors have proven to be powerful tools in the analysis of samples containing fine features of low radiographic absorption.Initial tomographic results reveal fully 3D morphological information on tin whiskers, albeit at lower spatial resolution than by scanning electron microscope (SEM), which is the commonly used method to investigate this phenomenon. However, the additional morphological information obtained by micro-tomography gives additional means of analysis, likely to help understand the underlying growth mechanisms.