A semiconductor device is provided and contains a substrate, a first wiring layer, a first oxide film, a dielectric film, a first nitrogen layer, a second wiring layer, a via hole, and a second nitrogen layer. The first wiring layer is formed on the substrate, and the first oxide film formed on the first wiring layer. The dielectric film has a low dielectric constant and is disposed between the first and second wiring layers. The first nitrogen layer contains nitrogen and is formed in the first oxide film. The via hole is formed through the dielectric film and is disposed between the first wiring layer and the second wiring layer for electrically connecting the first wiring layer and the second wiring layer. The second nitrogen layer contains nitrogen and is formed on a side wall of the via hole. Since the first and second nitrogen layers prevent moisture from spreading to various portions of the semiconductor device, leak current between adjacent wirings of the wiring layers is prevented. Also, the chances that an opening will not form in the via hole when the via hole is created is reduced.