A semiconductor device includes a first lower line and a second lower line on a substrate, the first and second lower lines extending in a first direction, being adjacent to each other, and being spaced apart along a second direction, orthogonal the first direction, an airgap between the first and second lower lines and spaced therefrom along the second direction, a first insulating spacer on a side wall of the first lower line facing the second lower line, wherein a distance from the first airgap to the first lower line along the second direction is equal to or greater than an overlay specification of a design rule of the semiconductor device, and a second insulating spacer between the airgap and the second lower line.