Wafer structure and method for fabricating the same

A wafer structure and a method for fabricating the same are provided. First, a wafer having a pad and a first protection layer with a first opening is provided. Next, a second protection layer with a second opening is formed on the first protection layer. Part of the pad and the first protection layer are exposed from the openings. The edges of the openings construct a step structure. Following that, an adhesion layer is formed on the pad, the step structure and the second protection layer. Afterwards, a photo-resist layer with a third opening is formed on the adhesion layer. Then, a barrier layer is electroplated onto part of the adhesion layer. Further, a wetting layer is formed on the barrier layer, and then the photo-resist layer and part of the adhesion layer exposed outside the barrier layer are removed. Finally, a solder layer is printed onto the wetting layer.