Semiconductor device and method of manufacturing the same

A method of manufacturing a semiconductor device comprising:

• forming, on a first insulating film, a second insulating film and etching parts of the first and second insulating films, said parts belonging to the same region, thereby forming a trench;
• burying a wiring layer in the trench;
• causing an upper part of the wiring layer to retreat below an upper surface of the second insulating film;
• forming a third insulating film made from a material different from a material of the second insulating material on the wiring layer and the second insulating film;
• etching the third insulating film with a higher selection ratio of the third insulating film to the second insulating film so that a via hole is formed;
• and
• burying a via plug in the via hole.