Electromigration in the Flip Chip Solder Joint of Sn-8Zn-3Bi on Copper Pads
Electromigration in the Flip Chip Solder Joint of Sn-8Zn-3Bi on Copper Pads
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DOI：
10.1007/s11664-007-0139-z
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发表时间：
2007-06
影响因子：
2.1
通讯作者：
W. Lin;A. Wu;S. Lin;T. Chuang;K. Tu
中科院分区：
文献类型：
--
作者：
W. Lin;A. Wu;S. Lin;T. Chuang;K. Tu
研究了温度为120°C，电流密度分别为4 × 103 A/cm ~ 2和4.5 × 104 A/cm ~ 2时，Cu焊盘上Sn-8 Zn-3Bi倒装焊凸点的电迁移现象。由于极性效应，在阳极形成的Cu-Zn金属间化合物（γ相）的厚度远大于阴极。焊点在4.5 × 104 A/cm 2的应力下经过117 h后失效，抛光后可以清楚地看到阴极处的空洞形成。然而，正是凸块边缘的熔化导致焊点失效。电流密度分布的模拟表明，电流密度分布不均匀，电流拥挤发生在凸点。结果表明，电流密度的增加与焦耳加热影响熔化和增强损伤的焊点在电迁移。
Electromigration in Sn-8Zn-3Bi flip chip solder bumps on Cu pads has been studied at 120°C with an average current density of 4 × 103A/cm2and 4.5 × 104A/cm2. Due to the polarity effect, the thickness of the intermetallic compound Cu-Zn (γ-phase) formed at the anode is much greater than that at the cathode. The solder joint fails after 117 h of stressing at 4.5 × 104A/cm2, and void formation at the cathode can clearly be seen after polishing. However, it is the melting at the edge of the bump that causes the solder joint to fail. A simulation of the current density distribution indicates that the current density is not distributed uniformly, and current crowding occurs inside the bump. The results indicate that the increase of current density associated with Joule heating has affected melting and enhanced damage in the solder joint during electromigration.