A semiconductor device includes interlayer dielectrics stacked and spaced apart from each other, a channel layer passing through the interlayer dielectrics, line pattern regions each surrounding a sidewall of the channel layer to be disposed between the interlayer dielectrics, a barrier pattern formed along a surface of each of the line pattern regions and the sidewall of the channel layer, a reaction preventing pattern formed on the barrier pattern along a surface of a first region of each of the line pattern regions, the first region being adjacent to the channel layer, a protection pattern filled in the first region on the reaction preventing pattern, and a first metal layer filled in a second region of each of the line pattern regions.