A method for manufacturing a semiconductor integrated device includes steps of forming an integrated circuit element on a semiconductor substrate, forming internal wiring, forming a groove along a scribe line on a back surface of the semiconductor substrate to expose a portion of the internal wiring, forming a metal film covering at least the groove, patterning the metal film to form external wiring and removing the metal film at a bottom portion of the groove, forming a protection film covering the external wiring and the bottom portion of the groove, and separating the semiconductor substrate along the scribe line.