Preparation and performance of semiconductor device bonding joints based on Cu@Sn@Ag preform

Herein, a 110 A commercial, Si continuous current diode with high heat dissipation power is attached to Cu@Sn@Ag preform, formed by electroplating and physical vapor deposition, and pressed into a preformed sheet under a pressure of 5-10 MPa. The prepared dense three-dimensional network of Cu/Cu₃Sn/Ag₃Sn joint, based on Cu@Sn@Ag preform obtained using transient liquid-phase diffusion soldering technology, can withstand high temperatures up to 600 °C in power device applications. The mechanical and thermal performance and power cycle reliability of the Cu@Sn@Ag joint are investigated and comparatively analyzed with PbSn5Ag2.5 joints. The results show that the average shear strength of the Cu@Sn@Ag joint is ∼35 MPa, which exceeds that of PbSn5Ag2.5 solder joint, and is similar to that of sintered nano-silver solder joint; the minimum thermal resistance of the corresponding device is ∼0.18 K W^-1, near to that of PbSn5Ag2.5 joint. The growth rate of the forward voltage drops below 2% following 150 000 active power cycles, with a junction temperature difference below 60 °C, meeting the requirements of reliability test standards for vehicle specifications. It is concluded that the performance and power cycle reliability of the Cu@Sn@Ag joint are better than those of the PbSn5Ag2.5 joint.