Corrosion Simulation Of Electronic Materials In Atmospheric Environment

As an indispensable part of the whole material industry,electronic materials are widely used in electronic equipment.Due to the development of miniaturization and high integration,corrosion in atmospheric environment has a serious impact on the performance of internal electronic circuits and components,resulting in the failure of electronic equipment.Copper-clad printed circuit board（PCB-Cu）and Electroless nickel/immersion gold printed circuit board（PCB-ENIG）treatment technology has been applied in PCB process due to its excellent electrical conductivity,so the corrosion of PCB-Cu and PCB-ENIG in atmospheric environment has become a research hotspot.In this paper,based on the corrosion mechanism and cellular automata theory,the basic reaction of PCB-Cu and PCB-ENIG in the electrochemical migration corrosion process was analyzed.Different substances involved in the reaction were abstracted as cells in cellular automata,local evolution rules were set up,and corrosion models were established to simulate the electrochemical migration corrosion process of PCB-Cu and PCB-ENIG.The main research contents and results are as follows:1、The electrochemical corrosion mechanism of PCB-Cu was analyzed and cellular automata model was established.According to the dissolution,crystallization and dendrite phenomena in the corrosion process,four parameters,namely electrolyte concentration c,corrosion probability P_dis,crystallization probability P_cry and reduction probability P_red,were introduced to simulate the corrosion morphology change of PCB-Cu in the voltage coupling humid and hot environment,and the influence of different parameters on the corrosion evolution process of PCB-Cu was analyzed.The simulation results show that Cu dissolves at the anode,a large amount of crystallization products are formed at the edge of the anode plate,and a small amount of dendrites are formed at the edge of the cathode plate.The corrosion morphology is basically consistent with the experimental distribution.With the increase of c,P_dis and P_cry,the number of crystal products in the anode plate increased,while the number of dendrites in the cathode plate decreased,while with the increase of P_red,the number of crystal products decreased and the number of dendrites increased.2、Based on the PCB-Cu electrochemical migration corrosion model,combined with the PCB-ENIG corrosion mechanism,the electrolyte concentration c,the corrosion probability of Ni layer P_dis1,the corrosion probability of substrate Cu P_dis2,the crystallization probability of Ni SO₄·6H₂O P_cry and reduction probability P_red were introduced according to the dissolution phenomenon of transition layer Ni and base Cu.The corrosion morphology of PCB-ENIG was simulated and the influence of different parameters on the corrosion evolution was analyzed.The simulation results show that there are defects or microholes in the gold plating layer of PCB-ENIG anode plate,the Transition layer Ni dissolves first,and the crystallization products appear at the edge of anode plate.After a period of time,The Cu substrate is gradually exposed to participate in the corrosion process,and dendrite products are generated near the cathode plate.The corrosion morphology is basically consistent with the experimental distribution.With the increase of c,P_dis1,P_dis2 and P_cry,the number of crystal products in the anode plate increased,and the number of dendrites increased with the increase of P_dis1,P_dis2 and P_red,respectively.