Abstract

Cu core solder ball (CCSB) is formed by a Cu core surrounded by solder alloy and is used as an interconnection material for 3D packaging. Herein, the electromigration behavior of CCSBs with an organic solderability preservative surface finish is compared with that of Sn–3.0Ag–0.5Cu (SAC) solder joint. The current density and temperature for electromigration test are 0.9 × 10⁴ A/cm² and 100 °C, which are in compliance with JEP154. The current density of the solder joint is analyzed using finite element method analysis and maximum current density of the SAC solder joint is 1.1 times higher than the CCSB solder joint. The CCSB solder joint is less affected by the current crowding effect because electrons move through the Cu core located at the center of the solder. A void form in the Cu electrode of the cathode that coincides with the simulated maximum current area of the solder joint. The electromigration reliability of the CCSB solder joint is superior to that of the SAC solder joint.

Graphic Abstract

中文翻译：

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高电流密度下铜芯焊点的电迁移行为

摘要

铜芯焊球（CCSB）由被焊料合金包围的铜芯形成，并用作3D封装的互连材料。在此，将具有有机可焊性防腐表面光洁度的CCSBs的电迁移行为与Sn-3.0Ag-0.5Cu（SAC）焊点的电迁移行为进行了比较。电迁移测试的电流密度和温度为0.9×10 ⁴  A / cm ²和100°C，符合JEP154。使用有限元分析法分析了焊点的电流密度，SAC焊点的最大电流密度是CCSB焊点的1.1倍。CCSB焊点受电流拥挤效应的影响较小，因为电子移动通过位于焊点中心的Cu核。阴极的Cu电极中的空隙形式与模拟的焊点最大电流区域重合。CCSB焊点的电迁移可靠性优于SAC焊点的电迁移可靠性。

图形摘要