Abstract: 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—Al bonding strength improvement layer, an Al layer, and a second ultra-thin copper foil, wherein the release layer may comprise a first metal (A3) having peeling properties, and a second metal (B3) and third metal (C3) facilitating the plating of the first metal (A3).

Abstract: The present invention relates to an electrolytic copper foil for a secondary battery, having excellent physical properties at a low temperature, and a method for producing the electrolytic copper foil. The electrolytic copper foil for a secondary battery shows little change in the physical properties, such as tensile strength and elongation, of a copper foil even at a low temperature and thereby exhibits excellent cycle properties at the low temperature. The electrolytic copper foil for a secondary battery is produced from a plating solution, containing total organic carbon (TOC), cobalt, iron and zinc, by using a drum and coated with a cathode active material, wherein the ratio between the TOC, cobalt, iron and zinc contained in the electrolytic copper foil follows the following formula 1: TOC/(cobalt+iron+zinc)=1.0-1.2.