Pt has been investigated as a metal passivation material to achieve low-temperature Cu–Cu direct bonding process. With 10-nm Pt passivation layer capping on Cu surface, a good bonding surface with no oxides and small grain size can be obtained. During the low-temperature bonding process, Cu atoms diffuse through the passivation layer and form a new layer without any pretreatment. This bonding scheme with Pt passivation layer provides a solution for Cu low-temperature bonding, with excellent bonding strength, good electrical performance, and ability to endure temperature variation. In addition, both chip- and wafer-level bonding process have been successfully demonstrated, showing a high potential to be applied on 3-D integrated circuit (IC) and heterogeneous integration.

中文翻译：

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3-D集成中具有Pt钝化层的低温Cu-Cu直接键合的研究

铂已经作为一种金属钝化材料进行了研究，可以实现低温Cu–Cu直接键合工艺。通过在Cu表面覆盖10 nm Pt钝化层，可以获得没有氧化物且晶粒尺寸小的良好粘合表面。在低温键合过程中，Cu原子扩散穿过钝化层并形成新层，而无需任何预处理。这种具有Pt钝化层的键合方案为Cu低温键合提供了解决方案，具有出色的键合强度，良好的电性能以及耐温度变化的能力。此外，芯片级和晶圆级键合工艺均已成功进行了演示，显示出可应用于3-D集成电路（IC）和异构集成的巨大潜力。