At present, MEMS and micro/nano electronic packaging technology have an exhaustive range of applications in the field of mass-produced commercial products, such as cell phones, computer, automobiles, and pedometers, which cause a strong demand for the reliability of heat transfer in nano or micro scales. Wire bonding process has been widely used in the MEMS or devices packaging approach to create high aspect interconnection structures [1], hence, the thermal analysis, thermal design, and thermal management become more and more important for microelectronic system or microelectronic devices. The interfacial structures of dissimilar materials are suffering the high stress gradients due to the thermal and stiffness mismatches of the different materials [2, 3]. The interface structures of dissimilar materials are very prone to crack initiations under the heat flow effect. The heat transfer across the interface is a critical consideration for the thermal design in the IC or devices manufacturing.

Here we reveal the relationship between the atomic migration and thermal conductivity of Al/Cu interface in nanoscale heat transfer by using non-equilibrium molecular dynamics method.

To create the Al/Cu interface, the modified Embedded-atom method (EAM) for alloy is used to describe the interatomic interactions between Cu/Cu, and Al/Cu interface.

The results show that the interfacial diffusion is enhanced with the increase of the temperature from 400K-600K. The thermal conductivity of the Al/Cu interface, first increases, and then decreases.  When the temperature is over 600K, it reaches the recrystallization temperature of Al. which makes to Al atoms recrystallization. The recrystallization of Al atoms may reduce the heat transfer efficiency of the Al/Cu diffusion region. That is to say, it reduces the thermal conductivity of Al/Cu interface when the temperature is over 600K. This means that we can enhance the interfacial heat transfer efficiency of Al/Cu interface and the cooling efficiency of IC by heat treatment in advance on interface structures. This investigation is helpful for understanding the interfacial heat transfer mechanism of the interface structures in the IC, which is helpful for the design of the interface in micro/nano manufacturing and benefit for the estimate the reliability of the IC manufacturing.