Synergy effect of mixed sintering accelerator on the deoxidation and sintering property improvement of Cu nanoparticles at low temperature

In this paper, a mixed sintering accelerator of colophony and cetyltrimethyl ammonium bromide (CTAB) was developed to improve the sintering properties of Cu nanoparticles (NPs) paste. With the synergy effect of the mixed sintering accelerator, Cu NPs paste could be well sintered at 260 °C for 30 min under a pressure of 2 MPa, and the shear strength was greatly improved from 15 to 33 MPa. The fracture morphology of the Cu NPs joint transformed from brittle interface failure features to ductile dimple features, and the porosity in the sintered layer was significantly reduced. XRD analysis further confirmed that the synergy of colophony and CTAB could effectively remove the oxides in the Cu NPs paste during sintering, and thereby improve the sintering properties. This work can provide an applicable approach to improve the sintering properties of metal NPs and help to understand the synergy effect of sintering accelerators on the bonding behaviors of metal nanoparticles at low temperatures.