A semiconductor device of the present invention includes a semiconductor chip; an internal pad for electrical connection formed on a surface of the semiconductor chip; a stress relaxation layer formed on the semiconductor chip and having an opening for exposing the internal pad; an under-bump layer formed so as to cover a face exposed in the opening on the internal pad, an inner face of the opening and a circumference of the opening on the stress relaxation layer; a solder terminal for electrical connection with outside formed on the under-bump layer; and a protective layer formed on the stress relaxation layer, encompassing a periphery of the under-bump layer and covering a side face of the under-bump layer.