A wafer-level chip-scale package includes a semiconductor die having planar top and bottom surfaces and a plurality of metal pads formed at the top surface in an area array. A first protective layer is formed on the top surface of the semiconductor die, the first protective layer having a plurality of first apertures for allowing the metal pads to be opened upward. A second protective layer is formed on a surface of the first protective layer, the second protective layer having a plurality of second apertures which are larger than and overly corresponding first apertures of the first protective layer so that regions of the metal pads and the first protective layer are exposed to the outside of the semiconductor die. Solder balls are fused to each metal pad, which are opened to the outside through the first apertures of the first protective layer and the second apertures of the second protective layer.