铜带缠绕型焊柱装联结构的板级热-机械可靠性研究

陶瓷基板与印制电路板之间的热膨胀系数差异较大导致的热失配,和大尺寸、高质量带来的抗振动性能下降,是这类器件板级装联失效的主要原因。针对铜带缠绕型焊柱CCGA板级装联结构在温度循环和随机振动载荷下焊点的失效模式和失效机理进行研究。结果表明,最大应力应变点出现在铜带与焊柱接触界面铜带边缘处,裂纹沿铜带缠绕方向的焊柱横截面向内扩展最终导致开裂。由于铜带和焊柱材料弹性模量性能差异较大,铜带与柱芯接触界面存在应力突变现象,器件长期使用过程中会出现焊柱与铜带剥离进而导致互连失效。铜带材质的选择、铜带与柱芯缠绕质量是影响铜带缠绕型焊柱高可靠应用的关键,铜带与焊柱间良好的冶金互连、铜带间隙充分的焊料填充是有效提高铜带缠绕型焊柱的抗热/机械性能的主要途径。

Research on the Board-Level Thermo-Mechanical Reliability of Copper Tape Wound Solder Column Planting Device

The thermal mismatch caused by the large difference in the thermal expansion coefficient between the ceramic substrate and the printed circuit board,and the decrease in anti-vibration performance caused by the large size and high quality are the main reasons for the failure of this type of device board cascade assembly.In this paper,the failure mode and failure mechanism of the solder joints of the copper tape-wound solder column CCGA board cascade structure under the temperature cycle and random vibration load are studied.The results show that the maximum stress and strain point appears at the edge of the copper strip at the contact interface between the copper strip and the solder column,and the crack propagates inward along the cross section of the solder column in the direction of the copper strip winding and eventually leads to cracking.Due to the large difference in the elastic modulus properties of the copper strip and the solder column material,there is a stress mutation phenomenon at the contact interface of the copper strip and the column core.During the long-term use of the device,the solder column and the copper tape will peel off and lead to interconnection failure.Therefore,the selection of copper strip material and the quality of copper strip and column core winding are the keys to the high-reliability application of copper strip wound welding columns.And the good metallurgical interconnection between the copper strip and the solder column and the sufficient solder filling of the copper strip gap are the main ways to effectively improve the thermal/mechanical properties of the copper tape wound solder column.