The effect of surface morphology and crystal structure on the thickness of copper foil

This study aimed to investigate the effects of thickness and heating temperature on the surface characteristics and electric characteristic of copper foil. The copper foils with 5, 10, 20, and 25 μm thick were formed by electrodeposition in the electrolyte composing of Cu 100 g/L and H₂SO₄ 100 g/L at 200 mA/cm². In addition, the RTA(rapid thermal annealing) was executed by using 10 μm thick copper foil. SEM, XRD, AFM and four-point probe were performed to characterize the morphology and electric characteristics of copper foil. The crystal size and surface roughness increased with the increasing thickness of copper foil. The minimum specific resistance was observed in the electrodeposited copper foil with 15 μm thick. After RTA treatment of 10 μm thick copper foil, the lowest value of specific resistance (2.03 μΩ-cm) and surface roughness (176.3 nm) was measured in the group treated 300°C, respectively. Especially, it is expected that the RTA treatment at 300°C is good for increasing resistance of electromigration.