Correlation Between EUT Failure Levels and ESD Generator Parameters

Some system-level electrostatic discharge (ESD) tests repeat badly if different ESD generators are used. For improving repeatability, ESD generator specifications have been changed, and modified generators have been compared in a worldwide round robin test. The test showed up to 1 : 3 variations of failure levels. Multiple parameters that characterize ESD generators have been measured. This paper correlates the parameters to test result variations trying to distinguish between important and nonrelevant parameters. The transient fields show large variations among different ESD generators. A correlation has been observed in many equipment under tests (EUTs) between failure levels and the spectral content of the voltage induced in a semicircular loop. EUT resonance enhances the field coupling, and is the dominate failure mechanism. The regulation on the transient field is expected to improve the test repeatability.