Interface micro-structure via ultrafast laser ablating in diamond/Cu joint to achieve high strength bonding and high efficiency heat conduction

The high strength and efficient heat transfer of diamond/Cu cooling plate pose significant challenges for cutting-edge technologies, such as thermal management of electronics. In this paper, we reported a method to simultaneously enhance the mechanical properties and heat transfer performance of diamond/Cu joint by utilizing diamond interface micro-structures prepared by picosecond laser. The ablation behavior of picosecond laser on diamond surface and the effect of diamond graphitization on the properties of joints were analyzed. Meanwhile, by characterizing the shear strength and thermal diffusivity of diamond/Cu joints, the strengthening mechanism on the joint performance was explored. Compared to the flat interface in the original joint, laser-treated joints exhibited an increase in shear strength of up to 29 %, reaching 213 MPa, and an increase in thermal diffusivity of up to 11 %, reaching 212.1 mm²/s. These excellent properties were affiliated with designed interface micro-structure and distribution of interface layers. This study aims to provide novel insights into achieving efficient heat transfer and high strength at diamond/metal plates for heat management.