Wafer-Level Cu/Sn to Cu/Sn SLID-Bonded Interconnects With Increased Strength
Wafer-Level Cu/Sn to Cu/Sn SLID-Bonded Interconnects With Increased Strength
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DOI：
10.1109/tcpmt.2011.2156793
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
He Liu;G. Salomonsen;Kaiying Wang;K. Aasmundtveit;N. Hoivik
中科院分区：
文献类型：
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作者：
He Liu;G. Salomonsen;Kaiying Wang;K. Aasmundtveit;N. Hoivik
通过将两层 Cu/Sn 结构相互键合，实现了互连的晶圆级 Cu-Sn 固液互扩散 (SLID) 键合。通过机械、电学和微观技术对键合互连进行了研究。 Cu-Sn SLID 互连是通过 260°C 的晶圆级键合创建的。键合互连的剪切强度为 45 MPa，电阻为 100 mΩ 量级。 Cu/Sn 到 Cu/Sn 键合方案的一个主要优点是避免熔融 Sn 到 Cu 的动态润湿，并且只需用液到液集成来代替。此外，通过在铜焊盘处设计 15 μm 的裕度以容忍任何 Sn 扩散，成功解决了 Cu/Sn SLID 系统中的 Sn 溢出问题。讨论了电镀铜锡层的均匀性要求，这对于成功实现晶圆级键合至关重要。这种晶圆级 Cu-Sn SLID 键合工艺是一种很有前景的 3D 组装和封装技术。
Wafer level Cu-Sn solid liquid interdiffusion (SLID) bonding of interconnects was achieved by bonding two-layered Cu/Sn structures to each other. The bonded interconnects were investigated by mechanical, electrical and microscopic techniques. The Cu-Sn SLID interconnects were created by wafer-level bonding at 260°C. The bonded interconnects show shear strength of 45 MPa and a resistance of the order 100 mΩ . A major advantage of the Cu/Sn to Cu/Sn bonding scenario is to avoid the dynamic wetting of molten Sn to Cu, and simply replace with a liquid to liquid integration. Furthermore, the Sn overflow problem in a Cu/Sn SLID system was successfully addressed by designing a margin of 15 μm at the Cu pads to tolerate any Sn spreading. The uniformity requirement for electroplated Cu-Sn layers, which is crucial for achieving successful wafer-level bonding, is discussed. This wafer-level Cu-Sn SLID bonding process is a promising technique for 3-D assembly and packaging.