Tombstoning PCB Soldering

Tombstoning PCB Soldering Problems

A type of open, known by a number of names (including crocodiling, surfboarding, Manhattan effect, drawbridging, Stonehenge effect, billboarding, etc.). This is a soldering defect in which a chip has been pulled into a vertical or near-vertical position with only one side soldered to the PCB. It is typically caused by force imbalances during the reflow soldering process.

Process and design-related causes of Tombstoning in PCB Soldering:

• Improper pad design
• Improper pad trace
• Improper solder mask application
• Via in pad draining solder from connection
• Trace with solder mask over it running under component causing a fulcrum effect on the component

Reflow-related causes of Tombstoning in PCB Soldering:

• Improper pad design may be aggravated by use of nitrogen. The nitrogen increases surface tension of the metals to the extent that a previously marginal problem becomes distinct.