An integrated circuit device includes a conductive line including a metal layer and an insulation capping structure covering the conductive line. The first insulation capping structure includes a first insulation capping pattern that is adjacent to the metal layer in the insulation capping structure and has a first density, and a second insulation capping pattern spaced apart from the metal layer with the first insulation capping pattern therebetween and having a second density that is greater than the first density. In order to manufacture the integrated circuit device, the conductive line having a metal layer is formed on a substrate, a first insulation capping layer having the first density is formed directly on the metal layer, and a second insulation capping layer having the second density that is greater than the first density is formed on the first insulation capping layer.