多层陶瓷电容器端电极可靠性的显微研究

Research on Microstructure Reliability of the Termination Electrode of MLCC

多层陶瓷电容器(MLCC)端电极在实际使用过程中,其电性能会随着时间发生不同程度的偏离,可焊性、耐焊接热等可靠性降低。针对多层陶瓷电容器端电极锡镀层在焊接过程中发生焊接失效问题,利用扫描电子显微镜(SEM)分析了正常样品和可焊性变差样品锡镀层的微观结构,并运用X线能谱(EDS)仪对问题样品进行成分分析。其结果表明,可焊性变差样品端电极表面锡镀层出现了因氧化产生的异常区域,并通过后期的可焊性实验验证了分析结果,找出了端电极焊接失效的原因,并提出应对端电极氧化问题的改进措施。

In practical application,the electronic parameter of multilayer ceramic capacitor（MLCC） will change and the reliability will degrade until MLCC is judged to be failure.Aimed at the problem of tin-coating in MLCC devices,the microstructure and components of tin-coating are studied with SEM and EDS,and the welding failure modes occurred in the outer-electrode are documented.The results show that there have been some abnormal areas on the tin-coating of samples with weldable problem produced by oxidation.Later strict solderability tests prove the results of the analysis and find the reasons for welding failure.Improved measures are also suggested according to the analysis.