Validity and Applicability of Spark-resistance Formulae for Micro-gap Sparks in Parallel Disc Electrodes

抄録

Micro-gap electrostatic discharges (ESDs) cause serious malfunction in electronic devices. To elucidate the mechanism, it is indispensable to understand the spark behavior of micro-gap ESDs. For this reason, two types of spark-resistance formulae proposed by Rompe-Weizel and Toepler have often been used so far to explain the spark process, while the verification and applicability of these formulae still remain unknown even at present. We previously measured spark currents from a human volunteer with charge voltages of 200 V or 2000 V in order to show which spark-resistance formula can better explain the spark process. The result showed that the behavior of sparks from 200 V and 2000 V charged human can be better represented by the Toepler's and Rompe-Weizel's formulae, respectively. In this study, a new measurement setup for spark currents, which are difficult to be directly measured due to the charge neutralization through the spark channel, is developed by using parallel disc electrodes. The setup allows to simply estimating the spark current and the corresponding spark voltage from the measured discharge currents. From this setup and the Matlab analyses, we confirm that spark currents through the spark channel are almost identical to discharge currents from the disc electrodes with charge voltages of 500 V or 4000 V, which reveals that the Toepler's and Rompe-Weizel's formulae can be better applied to the prediction of the dynamic spark behavior with charge voltages of 500 V and 4000 V, respectively, despite the fact that the spark lengths derived from the most commonly used spark constants of the Rompe-Weizel formula agree fairly with the measured spark lengths, while the spark lengths by the Toepler's formula are considerably smaller compared to the measured results. The finding obtained above supports our previous study.