Under a certain temperature and humidity environment and potential difference, electrochemical migration is easy to occur between adjacent lines and solder joints, resulting in insulation failure. In the case of serious dust pollution, the deposition of dust particles in electronic equipment changes the critical humidity on the surface of circuit board, thus changing the failure mechanism and time of electrochemical migration.
Zhou Yilin and Lu Wenrui, researchers from the school of automation of Beijing University of Posts and telecommunications, wrote an article in the 12th issue of Journal of Electrotechnics in 2020, using temperature humidity bias experiment to study 13 ~ 18? The influence of dust particle coverage density with m particle size on the electrochemical migration failure time of circuit board under the interaction of ambient temperature, humidity and electric field intensity. It is found that the electrochemical migration failure time caused by particle coverage density changes non monotonically.
The particle coverage density is less than 350? At g / cm2, the failure time and particle coverage density have a negative exponential function; Above 350? G / cm2, positive exponential function. The mechanism of particle distribution in high and low density areas on electrochemical migration failure is analyzed from the two aspects of particle adsorption of water and changing the growth path of crystal branches, which lays a foundation for establishing the reliability detection method of high-density circuit board in dust polluted environment.