Data-Driven Life Modeling of Electrochemical Migration on Printed Circuit Boards Under Soluble Salt Contamination

Abstract

Under the air pollution environment, the dust enters the electronic products and deposits on the printed circuit boards (PCB) during the service life. Soluble salts in the airborne dust can reduce the critical humidity and increase the ion concentrations on condensed water film on PCB, which has been proven to aggravate the insulation failure of the high-density PCB caused by electrochemical migration (ECM). It is practical application significance for how to establish a life model to evaluate the ECM of PCB under the interaction of soluble salt with temperature, relative humidity, and electric field strength. In this paper, through the temperature humidity bias acceleration experiment, the ECM failure of PCB under the contamination of the different concentrations of NaCl solution is simulated, and the ECM characteristics and failure mechanism are studied through the change of surface insulation resistance (SIR) and the morphology and element compositions of migration products. The time to the insulation failure of PCB under different conditions are obtained by the analysis of SIR curves. Based on the data-driven method, the life modeling of ECM failure of PCB under soluble salt contamination is studied by multivariate non-linear regression and machine learning methods, such as support vector regression, gradient boost regression tree, and random forest regression. It is proved that it is valid to use machine learning to establish the ECM failure life model of PCB in complex environments with limited life data.

Review—Electrochemical Migration in Electronic Materials: Factors Affecting the Mechanism and Recent Strategies for Inhibition

“…Although a higher temperature may lower the chances of formation of moisture layer, its impact on ECM can be drastic if the RH is maintained high. Zhou et al 43 reported that the surface insulation resistance (SIR) of the PCB samples decreased by several orders of magnitude once they were inserted into a high temperature and humidity chamber (65°C-85°C/ 75%-90%RH), indicating the immediate condensation of water and formation of water film on the PCB surface in a harsh condition with high humidity and temperature.…”

“…The study on the effects of contaminants on the ECM of electronic materials is expanded as the exposure of electronics to diverse environment is inevitable. Dust is one of the most commonly found pollutants from the service and industrial environments, 14,43,55 while in harsh environments, more contaminants such as H 2 S, 56 SO 2 , 57 volcanic ash 25,58 and mold 59 are found. The pollutants or the contaminants contain soluble ionic salts and acids which can have severe impacts on the ECM of electronic materials.…”