A semiconductor device and a fabrication method thereof are proposed. A first dielectric layer is formed on a semiconductor substrate having at least one bond pad, wherein the first dielectric layer has a first opening for exposing the bond pad and a second opening at a predetermined position for redistribution. A first metallic layer is applied on the first dielectric layer and in the first and second openings. A second metallic layer and a third metallic layer are formed on the first metallic layer at positions corresponding to the first and second openings, respectively. A second dielectric layer and a solder bump are formed on the second and third metallic layers, respectively. The second metallic layer can assure electrical quality of the first metallic layer corresponding to the first opening without having an electrical break of the first metallic layer for redistribution.