Methods and structures for forming the anodic oxidation layer to protect the metal surface, and improvement in appearance is described. In some embodiments, the methods involve forming a positive electrode oxide layer on the bottom of the metal is a metal surface on the bottom to be observed. In some embodiments, the methods involve the formation of the first anode oxide layer and adjacent the second anode oxide layer on the angled surface, the interface between these two anodizing layers is uniform in a regularly. The photo masking techniques for providing a sharp corner defined on the anodic oxidation, and the texture screen pattern on the metal surface and the tool are described. In addition, they are described techniques and tools for providing the anodic oxidation resistance component in the manufacture of electronic devices.