A Case Study of Problems in JEDEC HBM ESD Test Standard

There is a current need for modification of EIA/JEDEC Human-Body model (HBM) electrostatic discharge (ESD) test standard, which does not define start and step test voltages. In the current standard, some measurements start at several kilovolts, which ignore the fact that ESD protection devices may fail under low voltage stresses. In this paper, a grounded-gate structure with an n-well ballast resistor connecting its drain and PAD is investigated for HBM ESD sustaining levels. When tested with a Zapmaster starting from 1 kV, the withstand voltage exceeds 8 kV, whereas the structure failed at 350 V when the test starts from 50 V. The test results from a transmission-line-pulsing system validate the phenomenon. The reason for the failure is also studied and confirmed with optical-beam-induced resistor change system failure analysis results. To address this general issue, a suggestion for improving the present HBM ESD testing standards for industry applications is made.