Effect of mold on corrosion behavior of printed circuit board-copper and ENIG finished

With the development of miniaturization of electronic circuits and occurrence of growing number of project failure cases, the corrosion behavior of printed circuit board (PCB) becomes a non-ignorable scientific issue under the hygrothermal condition with mold. In this paper, the corrosion behavior of unfinished PCB (PCB-Cu) and PCB finished by electroless nickel immersion gold (PCB-ENIG) in mold environment was studied using scanning Kelvin probe (SKP). The mold growth behavior was observed by stereo microscope and SEM, and the corrosion products were analyzed by EDS. The results showed that the number of mold increased on the surface of PCB-Cu and PCB-ENIG specimens under hygrothermal condition. After a growth cycle of 28 d, the new generation of conidium formed with good activity. After 84 d mold test, corrosion occurred on both two kinds of specimens and it was more severe on PCB-ENIG. Meanwhile the activity of mold was an inhibitor in the corrosion process of PCB-Cu and a promoter in the pore corrosion process of PCB-ENIG.