Enhancing the solid/liquid interfacial metallurgical reaction of Sn+Cu composite solder by ultrasonic-assisted chip attachment

Abstract

In this study, composite solder pastes with different sizes of Sn and Cu particles were prepared. A large fraction of solid/liquid interfacial contacts adjusted by the Cu particle sizes contributed to an ultra-rapid metallurgical reaction at a high in-situ temperature of 437.1 °C under ultrasonic waves. Thus, the sole IMC of high-melting-point Cu3Sn joints with a tiny proportion of residual Cu were obtained in air at 250 °C for 10 s under the ultrasonic-assisted transient liquid phase (TLP). The intermetallic joints exhibited the average shear strength of 49.96 MPa at ambient temperature. In particular, a promising shear strength of 46.54 MPa was obtained at the high temperature of 350 °C, which exhibits significant potential for the high temperature electronic devices.