Tombstone Analysis

Ribbon Tombstone Analysis The tombstone effect describes a phenomenon where small smt components (like resistors or capacitors) are partially or completely lifted from one of its copper pads (looking like a tombestone in a cemetery) during reflow soldering.PCB-Investigator helps to find those critical components and to avoid defects.

Tombstone Analysis

The 'Tombstone Analysis' takes a detailed view on every small 2-pin component, as they are the most endangered for defects caused by the so called tombstone effect. The analysis checks the difference in the pin connection of the two pins for each component. The higher the pin connection differences (e.g. 100µm on Pin1 and 400µm on Pin2), the more uneven is the heat expansion and therefore the cooling-down after the reflow process. When a pin is cooling down much faster than another one, there is an unintended mechanical tension, which might lift up the component on one pin - the so called tombstone effect.


Tombstone Analysis Setting


  1. You have different filter options to identify the components that should be analyzed:
    • Large Side: The large side (e.g. width) should be less than the entered value
    • Small Side: The small side (e.g. length) should be less than the entered value.
    • Property: A given property must contain a certain value string
  2. In the settings section, you can define the minimum connection difference in % that should be reported, and if a connection via a drill should be considered with its circumference or not (Via in Pad).
  3. The result list contains all violations with the corresponding component reference and other important information. Critical errors can also be marked for later use (e.g. in the 'Extended Design Report'). If the 'precision' flag is set to '~', the calculation was too complex (due to e.g. overlapping of tracks) and a graphical estimation of the connection was used instead. The result therefore is less precise and should be reviewed in every case.
  4. The last result can be saved and reloaded here. This stored result is also used in the 'Extended Design Report'.


Pin 1 of a R62 is connected with 508µm, Pin 2 with only 178µm. This is a difference of 186%
Tombstone Analysis Example