Tomb stone effect
The tombstone effect is observed during the reflow soldering process on components with 2 contact surfaces. It describes a situation where a SMD component after reflow stands upright, the upper contact surface being now without electrical contact. The component stands on the assembly like a “tombstone”. The cause for the one-sided raise of the component lies in the surface tension of the solder, and on the fact that the solder on one side of the component melts earlier than the other. This can be avoided through an even temperature distribution, through smaller temperature gradients and though the use of special “anti-tombstoning” solder pastes.