Abstract
This paper deals with influence of foil thickness on mechanical property of copper foil. Tensile tests were carried out for annealed Cu foils. The influence of foil thickness on the deformation, tensile strength and fracture morphology were investigated. In order to examine the mechanical property of Cu foils, the thickness of Cu foils ranges from 5 to 2000 microns and the average grain size of each specimen is 20 microns. The tensile strength of the foil thickness of 5 and 10 microns were lower than that of thicker foil. While the chisel-point fracture occurs if the grain size is larger than foil thickness, the intergranular fracture is observed if the grain size is smaller than foil thickness. The results are explained on the basis of texture differences; the deformation is constrained by the other nearby grains and the number of grain in the thickness direction decreases with increasing foil thickness. In the case of thickness 5 and 10 microns, only one grain exists through thickness direction. Therefore, the mechanical properties of the thinner foils are affected by foil thickness.
