Study of diffusion mechanism in low-temperature bonding method based on surface Cu microcones

Study of diffusion mechanism in low-temperature bonding method based on Cu microcones is reported. A Sn layer was electrodeposited on the Cu microcones and the electrodeposited Cu substrate then annealing at bonding temperature 463 K. IMC grains of Sn/Cu-microcones diffusion samples grew slow with smaller size. The special morphology of Cu microcones was beneficial for the growth of intermetallic layer in short annealing time and the advantage disappeared with longer annealing time, which ensured the good performance of this bonding method.