A semiconductor device and a fabrication method thereof are provided. A semiconductor substrate having a plurality of bonding pads is prepared, and a first passivation layer, a second passivation layer and a metallic layer are successively formed on the semiconductor substrate. A third passivation layer is further applied on the semiconductor substrate and has a plurality of openings for exposing a portion of the metallic layer, wherein each of the openings is shifted in position from a corresponding one of the bonding pads by a distance not exceeding a radius of the bonding pad. A plurality of solder bumps are bonded to the exposed portion of the metallic layer and have a larger contact area with the third passivation layer. This provides better buffer to reduce stress exerted on the solder bumps, thereby preventing problems of cracking and delamination as in the prior art.