A new Cu/Ni/Ag preform solder for die attachment of power electronics

This paper presents a novel Cu-based die attachment material for interconnection with bare Cu substrate, verifying the successful sintering process between power chip and Cu substrate. The attachment materials are based on Cu/Ni/Ag preform by pressing the mixture of Cu@Ni@Ag powders and Ag nanoparticles. By inserting a dense layer of Ni interface between Cu and Ag, this material can solve the problem that Cu or Cu@Ag powders are prone to oxidation during the process of sintering. Also, the shear strength can reach over 20 MPa of the joint after sintering at 300 °C under a pressure of 15 MPa. The Cu/Ni/Ag preform shows great potential for the application of power electronics packaging with high power density, high integration and high-temperature working environments.