A composite copper foil contains a carrier layer, a release layer and an ultra-thin copper layer in this order. In the composite copper foil, the release layer includes a binary alloy or a ternary alloy comprising nickel, and is formed into an amorphous layer, and the ultra-thin copper layer is peelable from the carrier layer. A method of fabricating the composite copper foil includes preparing a carrier layer, forming a release layer which is amorphous on the carrier layer by electroplating using an electrolyte that comprises nickel, and forming an ultra-thin copper layer on the release layer by electroplating.