PURPOSE: A semiconductor device is provided to improve the efficiency of an alloy process by including a dummy plug which provides the movement path of hydrogen. CONSTITUTION: A semiconductor layer (101) includes one or more unit devices. A first wire (120) is electrically connected to the unit devices. A diffusion preventing layer (106) is formed on the first wire. A wire insulation layer (105) is located on the diffusion preventing layer and includes a first region and a second region. A plug (108) is located on the first region of the wire insulation layer. A first dummy plug (109) is located on the second region of the wire insulation layer.
