A semiconductor device is provided. The semiconductor device includes a first porous interlayer insulating film having a low dielectric constant and including a first region and a second region, a second interlayer insulating film formed on the first interlayer insulating film in the first region, a plurality of first conductive patterns formed in the second interlayer insulating film such that the plurality of first conductive patterns are spaced apart from each other, at least one second conductive pattern formed in the first interlayer insulating film in the second region and air gaps disposed at lateral sides of the plurality of first conductive patterns.