A semiconductor device having conductive bumps and a fabrication method thereof is proposed. The fabrication method includes the steps of forming a first metallic layer on a substrate having solder pads and a passivation layer formed thereon, and electrically connecting it to the solder pads; applying a second covering layer over exposed parts of the first metallic layer; subsequently, forming a second metallic layer on the second covering layer, and electrically connecting it to the exposed parts of the first metallic layer; applying a third covering layer, and forming openings for exposing parts of the second metallic layer to form thereon a conductive bump having a metallic standoff and a solder material. The covering layers and the metallic layers can provide a buffering effect for effectively absorbing the thermal stress imposed on the conductive bumps to prevent delamination caused by the UBM layers.