A semiconductor device includes a substrate, a plurality of conductive pads formed in consecutive conductive layers, and a bump structure. The plurality of conductive pads is aligned and arranged one above another over the substrate. The plurality of conductive pads comprises a first conductive pad and a second conductive pad. The first conductive pad is above the second conductive pad. A redistribution layer extends the second conductive pad. The first conductive pad is not extended by a redistribution layer. The bump structure is formed directly on the first conductive pad and electrically coupled to the plurality of conductive pads.