Novel Cu@Ag Micro/Nanoparticle Hybrid Paste and Its Rapid Sintering Technique via Electromagnetic Induction for High-Power Electronics

Due to the harsh working environments up to 600 & DEG;C,the explorationof high-temperature interconnection materials is significantly importantfor high-power devices. In this study, a hybrid paste including Cu@Agcore-shell microparticles (MPs) and Ag nanoparticles (NPs)was designed to achieve Cu-Cu bonding. The Cu@Ag MPs exhibitedexcellent oxidation stability in an air atmosphere with the Ag layercoating on the Cu core. Ag NPs fill the pores among the Cu@Ag MPsand reduce the sintering temperature of the hybrid paste. The Cu-hybridpaste-Cu joints were formed via electromagnetic induction heatingwithin approximately 15 s. When sintered at 26 kW, the shear strengthof the joint reached 48 MPa, the porosity decreased to 0.73%, andthe resistivity was down to 13.25 & mu;& omega;& BULL;cm. Furthermore,a possible interconnection mechanism at the contact interface betweenthe Cu substrate and the sintered hybrid paste was proposed, whichis related to the melting point of metal particles and the effectof magnetic eddy currents. This fast bonding technology inspires anew approach to interconnection for high-power devices under highoperation temperatures.