Mitigating electrostatic discharge (ESD) in solid CO2 pellet cleaning of printed wiring boards and assemblies

This report discusses the results of investigaling charge generation and techniques to mitigate electrostatic discharge (ESD) in solid CO₂ pellet cleaning of printed wiring boards (PWBs) and assemblies. To determine the effectiveness of the ESD mitigation technique, an ESD event detection system was used to monitor ESD events in real-time. This ESD event detection system could sense and display ESD events as small as 50 volts. With the ESD event detection system and the water mist ESD mitigation, we have successfully used solid CO₂ pellets to clean a PWB test vehicle populated with very sensitive integrated circuits and fully functional circuit packs with no ESD damage.