Discussion of humidity's influence on electrostatic discharge

Many factors have been considered to be responsible for the poor repeatability of electrostatic discharge(ESD) test. Among which, humidity is an environmental factor in real word and very critical to ESD phenomena. In this paper we propose a physical mechanism to explain the relationship between humidity and gravity of ESD. According to this physical mechanism, temperature plays an important role in ESD event. Based on the physical mechanism, the gravity of ESD may be predicted if humidity, temperature and surface characteristics of EUT are available. And how to improve the accuracy of prediction is also discussed in this paper.