Nanotwinned copper micro-cone array fabricated by pulse electrodeposition for low-temperature bonding

Abstract This paper reports Cu micro-cone arrays with densely packed vertical nanotwins by pulse electrodeposition without any template. The morphology of nanotwinned Cu (nt-Cu) micro-cones can be modulated by the chloride concentration in the electrolyte. Based on the analysis of scanning electron microscopy and transmission electron microscope, the twinning step driven growth may lead to the formation of the nt-Cu micro-cones. The shear strength of low-temperature solid-state bonding with nt-Cu micro-cones exhibits approximately 50% enhancement compared with twin-free Cu micro-cones. The fabrication of nt-Cu expands the scope of nanotwinned materials, leading to promising applications in 3D electronic packaging fields.