Low-Temperature Oxidation-Sintering Behaviors of Cu Fine Particles

Cu fine-particle paste is a promising material to form low-cost interconnect for flexible electronics devices. It has been reported that particles can be sintered at low temperature (well below the half of melting point) through two-step heat treatment processes oxidation and reduction. However, mechanism sintering not clear yet. In this study, we investigated process fine by thermal gravimetric analysis (TGA) in range 200°C∼300°C, X-ray diffraction (XRD), microstructural observation. was found from TGA initially rate-controlled surface reaction then diffusion grain boundaries Cu2O. Transmission electron microscopy observation revealed formation core (Cu)-shell (Cu2O) structure during process. The adjacent Cu2O shells were bonded each other resulting cross-linked structure. subsequent reduction led porous oxygen removal, but maintained, which would make low-temperature body as robust solidified solder Ag paste.