Semiconductor device and method for manufacturing the same

A method for manufacturing a semiconductor device including a plurality of wires each having a metal film and a hard mask made up of a first layer and a second layer, and a plurality of air gaps between each of the adjacent wires,

• the method comprising:
• forming a first insulating film on a semiconductor substrate;
• sequentially forming the metal film, a material film of the first layer and a material film of the second layer on the first insulating film;
• etching the metal film, the material film of the first layer and the material film of the second layer, to make a second internal angle smaller than a first internal angle, the second internal angle being formed by the under surface and the side surface of the second layer on a cross section of the second layer along a width of the wire, the first internal angle being formed by the under surface and the side surface of the first layer on a cross section of the first layer along the width of the wire;
• and
• forming a second insulating film on the second layer to make the air gap between each of the adjacent wires.