霉菌对裸铜和镀金处理的印制电路板腐蚀行为的影响

采用扫描Kelvin探针测试技术研究了裸铜印制电路板(PCB-Cu)和无电镀镍金处理印制电路板(PCB-ENIG)在霉菌作用下的腐蚀行为,通过体视学显微镜、扫描电镜和能谱分析对PCB的腐蚀和霉菌生长情况进行了观察和分析.结果表明,在湿热环境下霉菌在2种材料表面均能良好生长并且数量逐渐增加,28 d完成一个生长代谢周期且分生孢子活性良好;84 d后试样表面都出现了腐蚀产物,PCB-ENIG腐蚀更为严重.霉菌的生长代谢作用在一定程度上能抑制PCB-Cu表面霉菌生长区域的腐蚀,但是对PCB-ENIG的微孔腐蚀起促进作用.

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 PCBENIG 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.