Preparation of Nanotwinned Copper and Its Application in Advanced Packaging

Due to its excellent electrical conductivity and mechanical strength, nanotwinned copper has significant potential applications in the field of semiconductor packaging. Nanotwinned copper with (111) preferred orientation was prepared by direct current electrodeposition and applied it in the electroplating of copper pillars and redistribution layers (RDL). These studies show that the nanotwinned copper pillars prepared by a novel additive system have excellent microscopic uniformity with total indicated runout (TIR) value less than 8%. Copper pillars with nanotwinned structures are thermally stable below 450 °C. For the application of RDL, 4 μm line with nanotwinned copper structures could be obtained with a uniformity of <5%. The above results indicate that the innovative additive system has an excellent application prospect in advanced packaging nanotwinned copper plating.