A method for manufacturing a semiconductor device (10) includes, in the following order: forming a first insulating film (14) on a semiconductor substrate (12); forming, on the first insulating film (14), wiring in which at least the uppermost layer is made of Au (16); implanting ions, which do not impair insulating properties even when implanted into the insulating film (14), into the upper surface of the wiring (16) and a region not covered with the wiring (16) on the upper surface of the first insulating film (14); and forming a second insulating film (18) that covers the wiring (16).