Song Xiaohui, Wu Shunli, Zhang Rui
School of Mechanical Engineering, Zhengzhou University, Zhengzhou 450001, China.
Institute of Applied Physics, Henan Academy of Sciences, Zhengzhou 450008, China.
Nanomaterials (Basel). 2021 May 21;11(6):1369. doi: 10.3390/nano11061369.
Surface bonding is an essential step in device manufacturing and assembly, providing mechanical support, heat transfer, and electrical integration. Molecular dynamics simulations of surface bonding and debonding failure of copper nanocones are conducted to investigate the underlying adhesive mechanism of nanocones and the effects of separation distance, contact length, temperature, and size of the cones. It is found that van der Waals interactions and surface atom diffusion simultaneously contribute to bonding strength, and different adhesive mechanisms play a main role in different regimes. The results reveal that increasing contact length and decreasing separation distance can simultaneously contribute to increasing bonding strength. Furthermore, our simulations indicate that a higher temperature promotes diffusion across the interface so that subsequent cooling results in better adhesion when compared with cold bonding at the same lower temperature. It also reveals that maximum bonding strength was obtained when the cone angle was around 53°. These findings are useful in designing advanced metallic bonding processes at low temperatures and pressure with tenable performance.
表面键合是器件制造和组装中的关键步骤，可提供机械支撑、热传递和电气集成。通过对铜纳米锥表面键合和脱粘失效进行分子动力学模拟，研究纳米锥的潜在粘附机制以及分离距离、接触长度、温度和锥尺寸的影响。研究发现，范德华相互作用和表面原子扩散共同影响键合强度，且不同的粘附机制在不同状态下起主要作用。结果表明，增加接触长度和减小分离距离可同时提高键合强度。此外，我们的模拟表明，较高温度会促进界面间的扩散，因此与相同低温下的冷键合相比，随后的冷却会产生更好的粘附效果。研究还表明，当锥角约为53°时可获得最大键合强度。这些发现有助于设计在低温低压下具有可靠性能的先进金属键合工艺。
