In Situ Reduction-Sintering to Produce Copper Interconnects for High Temperature Electronics

This study presents a special in situ reduction-sintering of CuO and Cu nanoparticles. The microstructure and strength of sintered Cu joints by CuO and Cu nanoparticle were compared. The reduced Cu particles of CuO have a larger size of 1 μm and lower sinterability which results in an insufficient sintering of Cu. In contrast, the sintered Cu nanoparticle structure shows a strong bonding of Cu and plastic deformation after fracture. Owing to the removal of the original oxide and limitation of its re-appearing during sintering by the proposed method, high sintered Cu joint strength over 30 MPa was achieved without the need for pressurized sintering or protective gas atmospheres.