Influence of Aging Atmosphere on the Thermal Stability of Low-Temperature Rapidly Sintered Cu Nanoparticle Paste Joint

摘要

Isothermal aging tests of low-temperature rapidly sintered Cu-Cu joints were conducted at 180 degrees C for 72 h under air and vacuum atmospheres, respectively. Shear strength, micromorphology and elemental analysis of the joints before and after aging were characterized. The experimental results indicated that organics in nano-paste were not capable of sustainably inhibiting the oxidation of Cu nanoparticles under high-temperature and high-oxygen conditions. The shear strength degraded as low as 5.12 MPa after air aging, and a nanoporous and filamentous structure was formed due to the continuous growth of Cu oxides on the surface of the sintered nanoparticles. Nevertheless, the porosity of the as-sintered structure reduced with the formation of a large area interconnection microstructure under low-oxygen aging conditions, thereby the shear strength of the sintered joints notably improved up to 20.03 MPa after vacuum aging.