Sherlock Investigates: Microcircuit Failure Analysis
Microcircuit Failure Analysis is rarely ever done by users these days because it is such a costly endeavor. Today’s microcircuits (or Chips) are so small and dense that accessing the inner parts has to be left the most advanced laboratories.
One of the most singular analyses ever found in my records was the "Cecil the Seasick Sea Serpent" failure found in collaboration with the Martin Marietta Failure Analysis Lab. It shows the emitter metallization of a transistor on the die that was blown apart. The Scanning Electron Microscope photograph was taken at a magnification of 1000 times.
Failure analysis rarely shows such detail that leads directly to the cause as easily as this one. The metallization that lifted, (Which looks like Cecil from the "Beany and Cecil" TV show), It was caused by some external Electrical Over Stress from an external source. The damage was on Pin 14 of the device so the cause could traced back to the source. It was probably caused by some large Electrostatic Discharge or by some Test Equipment glitch.
|Sherlock Investigates: Microcircuit Failure Analysis|
|Did you take an optical image before removing the passivation for SEM analysis? Bullseye discoloration of the glass might have provided a clue regarding ESD vs. simple circuit overstress.|
Did my share of this type of analysis back in the 1980's at McDonnel-Douglas Astronautics. Pretty rusty today. :)