Disclosed herein is a method of manufacturing a semiconductor device, including the steps of: forming an interlayer insulating film on a semiconductor substrate; forming a metal mask on the interlayer insulating film; forming a pattern trench in the metal mask and the interlayer insulating film by etching away parts of the metal mask and the interlayer insulating film; forming a conductive layer on the interlayer insulating film so as to fill in the pattern trench; and polishing the excessive conductive layer and the metal mask on the interlayer insulating film so as to leave the conductive layer in the pattern trench. |