The formation of whiskers was examined at various time interval which set up as in 24 hour and 240 hours by using scanning electron microscope

The formation of whiskers was examined at various time interval which set up as in 24 hour and 240 hours by using scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX). The measurement of pure tin whiskers is according to the JESD201 standard which measure the axial length of whisker where the distance in between the pure tin plating surface towards the tip of the pure tin whiskers.
Based on the figure 4.5 above, there are several micropores exist among the microstructure of pure tin. Even though, the smaller grain size of pure tin enhanced the high rate of grain boundary diffusion, the presence of multiple micropores on the pure tin solder plating will become one of the factor which degenerate the formation of pure tin solder whiskers 57-58.The figure 4.6 shown the average value indentation of the Vickers microhardness on the pure tin bulk. The hardness of pure tin gradually decreasing through the indentation for each sample. The presence of the micropores will reduce the toughness and the hardness of the pure tin which also enhance the stress relaxation mechanism among the grains structures