Rapid formation of intermetallic joint using Cu-Sn nanocomposite interlayer based on patterned copper nanowire array

This paper presents a novel strategy for transient liquid phase bonding (TLPB) in three-dimensional integrated circuit (3D IC) integration that utilizes a preformed Cu-Sn nanocomposite interlayer based on patterned copper nanowire array. This unique interlayer significantly accelerates the bonding process by ∼10 times compared with traditional TLPB using monolithic Sn layer, thanks to the Cu nanowire array grown through template-assisted electrodeposition. It only takes ∼ 2 min to achieve intermetallic joints with refined microstructures through TLPB at 250 °C with the preformed Cu-Sn nanocomposite interlayers.