Low temperature Cu sinter joining on different metallization substrates and its reliability evaluation with a high current density

Cu sinter joining technology have got a lot attention for next-generation wide band gap (WBG) power modules which will subject a high temperature above 250 °C and a high current density. In this study, bonding performances of Cu sinter joining on different metallization substrates were investigated at a low temperature low pressure in N2 atmosphere. Die shear strength and fracture behavior of the joint structure on bare Cu substrate and different metallized Cu substrates including Cu/Ni-P, Cu/Ni-P/Au, Cu/Ni-P/Co-W-P, Cu/Ni-P/Pd-P/Au were evaluated. The results show that Cu sinter joining on bare Cu substrate possessed the highest shear strength above 60 MPa, further better than that other Cu substrate with metallization layers. In addition, reliability evaluation of Cu die attached structure on bare Cu substrate and Ni-P metallized substrate during a power cycling in a high current density of 814.8 A/cm
²
were also investigated. The results show almost not on-resistance change after 3000 cycles for the both cases.