A study of electrostatic discharge effects of the SAW pattern by the FDTD method [IDT SAW filters]

The purpose of this paper is to estimate the influences of the electrostatic discharge (ESD) of SAW patterns by the full-wave approach, based on the finite-difference time-domain (FDTD) method. According to the ESD standard of MIL-STD-883C method 3015.7, models of resistors and capacitors are adopted to simulate the excitation of human-body ESD situations. Our approach has been applied to two cases in which the distributions of electric fields and current on the SAW substrate in the time-domain are shown. The simulation results help designers judge whether the strength of electric fields on the SAW pattern is strong enough to discharge the extra charge or the currents is so huge that it destroys the pads. Finally, the efficiencies of sacrificial electrodes and guard rings are discussed.