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

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. [Display omitted] •Solder pastes with different sizes of Sn and Cu particles were prepared.•The sole intermetallic of Cu3Sn joints were obtained under ultrasonic for 10 s.•The joint exhibited promising shear strength of 46.54 MPa at 350 °C.•The joints exhibit great potential in high temperature packaging.