The tombstone effect, also known as the tombstoning effect, occurs when an SMT (Surface Mount Technology) component rises on one side during the soldering process, resembling a tombstone in a cemetery. This effect is observed in smaller resistors and capacitors in form factors ranging from 0201, 0402, 0603 to 0805. The cause of this effect lies in imbalances in the surface tensions of SMD pads.

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These imbalances can arise from:

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• Layout: Varied dimensions of SMD pads, unfavorable trace or via connections.

• Incorrect amount of solder paste: When too much or too little solder paste is applied to the solder pads, or when the quantities are uneven.

• Offset during stencil printing.

• Offset during component placement.

• Temperature profile: The temperature profile during the soldering process can also have an impact, especially a rapid temperature rise, which strongly influences the tombstone effect.

• Uneven heating: Uneven heat distribution during the soldering process and temperature shadows caused by nearby components with high mass can provoke the tombstone effect.

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The tombstone effect leads to interruptions in the circuit, as the components are no longer soldered to both pads with their terminals.