First dopant regions and second dopant regions are provided at both sides of the gate structures. Conductive lines cross over the gate structures and are connected to the first dopant regions. Each of the conductive lines includes a conductive pattern and a capping pattern disposed on the conductive pattern. Contact structures are provided between the conductive lines and are connected to the second dopant regions. Each of the contact structures includes a lower contact pattern disposed on the second dopant region and an upper contact pattern disposed on the lower contact pattern. A bottom surface of the upper contact pattern is lower than a top surface of the conductive pattern.