This PTH-via corroded open likely because the top part of the via was not plugged by the solder mask and activated solder flux was entrapped in the via.

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Check out SEM Lab, Inc.  to learn more.

Check out SEM Lab, Inc.  to learn more.

Check out SEM Lab, Inc.  to learn more.

BSE SEM image of excess solder condition on gull-wing solder joint. This condition defeats the inherent mechanical compliance of the gull-wing component lead.

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BSE SEM image of a chemically decapsulated diode.

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Warpage induced die crack on BGA.

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Electrical overstress damage of GaAlP LED.

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BGA warpage causes solder joint fracture, collapsed central solder balls, and head-in-pillow defects.

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Check out SEM Lab, Inc.  to learn more.