Fabrication of AlN/Cu composite structure via laser surface metallization assisted direct bonding technology

In this work, an innovative and cost-effective method was proposed to fabricate AlN/Cu composite structures. The AlN ceramic was metallized by nanosecond laser irradiation without consuming extra materials. The metallurgical combination between AlN ceramic and Cu was successfully achieved based on the AlCu eutectic reaction at a relatively low temperature of 620 °C. Under the laser irradiation, the AlN ceramic was thermally decomposed to form an Al layer and microgroove. As the laser power increased, more Al was produced on the ceramic surface and the microgroove became deeper. The microstructure, mechanical, and heat transfer properties of the AlN/Cu joints were investigated. The maximum shear strength of the joint was 11.25 MPa when the laser power was 56 W, and the maximum thermal conductivity was 162 W/(m·K) when the laser power was 42 W. The approach of laser-induced direct metallization of ceramics in this work provides a novel strategy for the integration of ceramics/metals composite structures.