Circuit/Electromagnetic hybrid simulation of electrostatic discharge in contact discharge mode

In this paper, we describe a hybrid simulation technique for electrostatic discharge (ESD) events in contact discharge mode. The proposed technique is based on circuit, electrostatic field, and full-wave simulations. The circuit simulation is performed to obtain the currents which is used as the input excitation in the subsequent full-wave simulation. A circuit to be analyzed is the equivalent circuit model of an ESD generator attached with a ground strap and a target object. Meanwhile, we perform the electrostatic field simulation in order to calculate electric field distribution around the generator charged before the discharging phase. Finally, a computational domain excluding the ESD generator and the ground strap is analyzed by means of the full-wave simulation based on the finite-difference time-domain (FDTD) method. In other words, we do the full-wave simulation for only a part of the whole computational domain by using the input currents as external effects to the target object. Because the hybrid simulation can take a low computational cost relative to existing full-wave techniques, it can reduce the total CPU time and the amount of memory consumption. We compare the accuracy and the CPU time of our approach with those of the conventional FDTD solver to show the adequacy of the hybrid simulation method.