Figure 7: SEM images of soldering area: (a) multiple pits of parabolic/pyramidal shape, (b) and (c) two views of soldering area with a consecutive zigzag shape.

Figure 7: SEM images of soldering area: (a) multiple pits of parabolic/pyramidal shape, (b) and (c) two views of soldering area with a consecutive zigzag shape.

Figure 7: SEM images of soldering area: (a) multiple pits of parabolic/pyramidal shape, (b) and
(c) two views of soldering area with a consecutive zigzag shape.

Figure 7: SEM images of soldering area: (a) multiple pits of parabolic/pyramidal shape, (b) and
(c) two views of soldering area with a consecutive zigzag shape.