尘土覆盖密度对电路板电化学迁移失效的作用  

The Effect of Dust Covering Density on Electrochemical Migration Failure of Circuit Board

作　　者：周怡琳[1] 鲁文睿 Zhou Yilin;Lu Wenrui(School of Automation Beijing University of Posts and Telecommunications,Beijing 100876 China)

机构地区：[1]北京邮电大学自动化学院,北京100876

出　　处：《电工技术学报》2020年第12期2526-2533,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(61674017)。

摘　　要：高密度电封装在一定温湿环境和电位差作用下,相邻线路、焊点之间易发生电化学迁移导致绝缘失效。在尘土污染严重的情况下,电子设备内部的尘土颗粒沉积改变了电路板表面临界湿度,从而改变电化学迁移的失效机理和时间。该文采用温湿偏置实验研究13~18μm粒径的尘土颗粒覆盖密度与环境温度、湿度、电场强度交互作用下对电路板电化学迁移失效时间的影响,发现颗粒覆盖密度造成的电化学迁移失效时间呈非单调变化。颗粒覆盖密度低于350μg/cm2时,失效时间与颗粒覆盖密度呈负指数函数;高于350μg/cm2时,呈正指数函数。从颗粒吸附水分与改变晶枝生长路径两方面分析了颗粒分布在高、低密度区对电化学迁移失效的作用机理,为建立尘土污染环境下高密度电路板的可靠性检测方法奠定了基础。Under certain temperature,relative humidity and potential difference,the electrochemical migration(ECM)between adjacent wires and solder joints is prone to cause insulation failure in the high-density electrical packaging.In the case of serious dust pollution,the deposition of dust particles inside the electronic equipment changes the critical humidity of the circuit board surface,thereby changing the failure mechanism of ECM and time to failure(TTF).This paper studied the effects of the dust particle coverage density of 13-18μm diameter on the TTF of ECM of circuit board under the interaction of environmental temperature,relative humidity and electric field intensity by temperature and humidity bias(THB)experiments.It was found that the TTF of ECM caused by particle covering density was nonmonotonic.When the particle coverage density was lower than 350μg/cm2,the TTF and particle coverage density presented a negative exponential function;when the particle coverage density was higher than 350μg/cm2,it had a positive exponential function.The failure mechanism of ECM in high-and low-density zones was analyzed from the aspects of moisture adsorption and dendritic growth path change.It lays a foundation for establishing the reliability detection method of high-density circuit board in dusty environment.

关 键 词：电化学迁移 温湿偏置实验 尘土覆盖密度 电路板 

分 类 号：TM207[一般工业技术—材料科学与工程]