Fabrication of joint based on Cu@Sn@Ag core–shell preform under ambient atmosphere for high-temperature applications

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

“…The porosity of the solder layers of devices A4 and A5 assembled using the optimized Cu@Sn@Ag preforms is ∼6–8%, and their maximum thermal resistance is 0.19 K W −1 , which is similar to that of the commercial PbSn5Ag2.5 solder assembly devices. This is attributed to the uniformly distributed Cu particles inside the Cu@Sn@Ag solder layer, thus greatly improving the overall thermal conductivity of the solder (144 W m −1 K −1 ), 22 which is nearly five times that of the commercial PbSn5Ag2.5 solder (26 W m −1 K −1 ). 23 Owing to the uneven thickness, the Cu@Sn@Ag layer exhibits thermal resistance that exceeds that of the commercial PbSn5Ag2.5 solder layer.…”