Preparation of Ultra-thin Copper Foil with Low Profile and High Tensile Strength on Surface of 18-µm Carrier Copper Foil

Ultra-thin copper foil (UTCF) is the basic material for the electronic industry. However, most of them suffer common problem of low strength and wrinkles. Here, 5-µm UTCF with smooth surface (Rz = 1.68 µm) and high tensile strength ( 340 MPa) was prepared on the surface of conventional 18-µm copper foil. The 18-µm copper foil acted as a supporting carrier and we call it carrier copper foil. We selected gelatin as the additive in the plating solution and deeply investigated its impact on the surface roughness and tensile strength of UTCF. The results suggest that gelatin refines the shape of the grain and is more favorable to the copper foil the orientation (111) texture which benefits the low profile and high tensile strength. The optimal concentration of gelatin is about 0.2 g/L. Its microstructures as well as the mechanical properties were further analyzed by scanning electron microscopy, electron backscattered diffraction and X-ray diffraction.