The carrier-foil-attached ultra-thin copper foil according to one embodiment of the present invention comprises a carrier foil, a release layer, a first ultra-thin copper foil, a Cu-diffusion prevention layer, an Al layer, and a second ultra-thin copper foil, wherein the release layer may comprise a first metal (A2) having peeling properties, and a second metal (B2) and third metal (C2) facilitating the plating of the first metal (A2).