Provided is a semiconductor device comprising a device region on a substrate, an interlayer dielectric layer on the device region, a first interface layer on a side of the interlayer dielectric layer, a low-k dielectric layer spaced apart from the interlayer dielectric layer across the first interface layer and having a dielectric constant less than that of the interlayer dielectric layer, and a conductive line in the low-k dielectric layer. The first interface layer comprises a first sub-interface layer in contact with the low-k dielectric layer, and a second sub-interface layer in contact with the interlayer dielectric layer. The second sub-interface layer has hydrogen permeability less than that of the first sub-interface layer.