Enhanced Anti-Oxidation Copper-Based Conductive Inks for Low Porosity Copper Films in Power Electronics

Copper-based conductive inks have been extensively researched due to their low sintering temperature and high anti-oxidation properties for various electrical devices. However, the unstable oxidation properties of copper (Cu) limit its practical application. The existing anti-oxidation methods adopted in copper sintering often reduce copper strength and reliability. Therefore, the study presents a novel copper composite ink comprising copper precursors, copper microparticles, organic protective agents, and antioxidants. The sintering process is simple, requiring only 20 min at$300~^{\circ }$C in nitrogen without any additional pressure. As a result, sintered copper with an oxidation rate of only 3.21 wt% was successfully obtained using the mixed ink of copper particles and precursors. The porosity of the sintered copper is 10.69%, which is a 71.77% reduction compared to the copper sintered by using pure copper precursor ink, due to the synergistic effect. Furthermore, the study discusses and analyzes the lattice growth mechanism and synergy mechanism of copper particles and their precursors during copper sintering.