Preparation of Ag-Cu nanoparticle film using a dual-beam pulsed laser deposition for power electronic packaging

Ag-Cu nanoparticles, integrating the advantages of Ag and Cu, are promising materials for power electronic packaging. In this work, a novel dual-beam pulsed laser deposition method was proposed to prepare an Ag-Cu nanoparticle film with various component ratios and used for die attach at low temperatures. The as-deposited Ag-Cu nanoparticle film was mainly composed of Ag-Cu solid solution, Ag element, and Cu element, and most of the nanoparticles were in the alloying state. The Ag-Cu sintered joint presented a dense microstructure with 10.8% porosity, and the shear strength of Ag-Cu sintered joints could reach 60 MPa at 250 °C. The sintered joint porosity increased as more Cu were added in the Ag-Cu nanoparticle film, resulting in a decrease in the interfacial connection ratio. The fracture mode of sintered joints gradually changed from the sintered layer to the mixed sintered layer and interface fracture. The dual-beam pulsed laser deposition method could guide in designing the component ratios of bimetallic nanoparticles.