Preparation of printable copper submicron particle paste

Abstract Thanks to the rise of flexible printed electronics, printable conductive pastes have received more and more attention, especially copper paste that can be prepared on a large scale at low cost. We first prepared submicron copper particles by reducing copper sulfate solution with glucose and hydrazine as the reducing agents and then modified the surface of copper submicron particles with formate and ethylene glycol for antioxidant treatment. The surface-modified copper particles exhibit better corrosion and oxidation resistance. Next, the copper submicron particles were dispersed in propylene glycol to make copper slurry. The copper conductive pattern with a low resistivity of 6.09×10 −4 Ω·cm can be fabricated by printing copper paste with a dispensing machine, followed by a sintering process in an argon atmosphere at 200°C for 10 min. As prepared copper conductive patterns have excellent mechanical flexibility on polyimide (PI) substrate, which will be conducive to the large-scale application of copper paste on flexible substrates.