A process for manufacturing a thin and stable copper (Cu, 30) film on a porous aluminum oxide (PAO, 20) film on an aluminum alloy substrate (Al, 10), the process comprising: - anodization of the aluminum alloy substrate resulting in a regularly ordered PAO film; the PAO film and the remaining aluminum alloy thereby forming a PAO/aluminum substrate, - optionally etching said PAO/aluminum substrate for further opening of the top of the pores in the surface of said PAO film after said anodization, and - electrodepositing copper on said PAO/aluminum substrate, the electrodepositing comprises the use of direct current, preferably in the interval of 5-20 V, more preferably 10-15 V, so as to deposit metallic copper (30', 30") both: 1) in the open pores of the regularly ordered PAO film, and simultaneously or subsequently, 2) on the top of the regularly ordered PAO film, so as to form a copper film on top of the PAO film, wherein said anodization is performed so as to improve the adhesion and electrochemical corrosion stability of the later electrodeposited copper on said PAO/aluminum substrate, characterised in that the substrate - between and/or during any of the steps for electrodepositing copper 1) in the open pores of the substrate, and 2) on the top of the substrate so as to form a copper film on top of the substrate - is mechanically treated to remove, at least partly, any copper (30") electrodeposited on top of the substrate before the pores are filled with copper. - anodization of the aluminum alloy substrate resulting in a regularly ordered PAO film; the PAO film and the remaining aluminum alloy thereby forming a PAO/aluminum substrate, - optionally etching said PAO/aluminum substrate for further opening of the top of the pores in the surface of said PAO film after said anodization, and - electrodepositing copper on said PAO/aluminum substrate, the electrodepositing comprises the use of direct current, preferably in the interval of 5-20 V, more preferably 10-15 V, so as to deposit metallic copper (30', 30") both: 1) in the open pores of the regularly ordered PAO film, and simultaneously or subsequently, 2) on the top of the regularly ordered PAO film, so as to form a copper film on top of the PAO film, - electrodepositing copper on said PAO/aluminum substrate, the electrodepositing comprises the use of direct current, preferably in the interval of 5-20 V, more preferably 10-15 V, so as to deposit metallic copper (30', 30") both: 1) in the open pores of the regularly ordered PAO film, and simultaneously or subsequently, 2) on the top of the regularly ordered PAO film, so as to form a copper film on top of the PAO film, 1) in the open pores of the regularly ordered PAO film, and simultaneously or subsequently, 2) on the top of the regularly ordered PAO film, so as to form a copper film on top of the PAO film, wherein said anodization is performed so as to improve the adhesion and electrochemical corrosion stability of the later electrodeposited copper on said PAO/aluminum substrate, characterised in that the substrate - between and/or during any of the steps for electrodepositing copper 1) in the open pores of the substrate, and 2) on the top of the substrate so as to form a copper film on top of the substrate - is mechanically treated to remove, at least partly, any copper (30") electrodeposited on top of the substrate before the pores are filled with copper.