Modeling Of Electrochemical Migration Caused By Interaction Of Dust Particles And Temperature & Humidity Environment

With the miniaturization of the electronic devices, the spacing of the multi-wire connector contacts becomes smaller, so that the failure of electrochemical migration (ECM) gets to be much easier. In the actual work environment, dust particles can enter the electronic equipment and attach to the surface of the circuit board, which affects the performance of the circuit board and even leads to failure. Therefore, it is necessary to study the influencing factors of particle contamination on ECM of printed circuit board.This paper studied the effect of dust particles on ECM, mainly focusing on two problems, one was the ion concentration changed by soluble salt, the other was insoluble particle distribution density. Firstly, based on the Faraday's law,the physical model was established, and the influence of soluble salt in the dust on ECM of the circuit board was investigated by water drop experiment. And then select the influence of dust coverage density, as a significant factor of dust,the ECM was analyzed by experiments. The empirical life model of the influence of particle coverage density on the failure of circuit board was proposed by fitted experimental data. Finally, temperature humidity bias experiment was carried out by scattering the actual dust on the circuit board,which could study the effect of actual dust on insulation failure of circuit board.The dust particles are composed of soluble and insoluble substances. Firstly,NaCl has been selected to be the soluble constitution in dust particles for simulation. According to study results, there is power function between time to failure (TTF) of printed circuit board (PCB) and concentration of saline solution.When intervals between neighbor wires and voltage are constants, TTF gradually decreases with concentration of saline solution increasing. Secondly,quartz has been chosen to be the insoluble constitution for simulation. With detailed discussion, the critical dust cover density has been found, which forms power function with TTF of PCB and exponent of the function is positive first and negative then . Finally, related models describing natural dust particles with their soluble constitution have been developed. Besides, impact on electrochemical migration, caused by soluble and insoluble constitution in dust particles, has been studied with the help of temperature and humidity bias (THB)experiment of dust-covered PCB.