A semiconductor device includes an insulating interlayer disposed on a substrate, a first protection pattern, a first barrier pattern, a first adhesion pattern, and a first conductive pattern. The insulating interlayer includes a via hole and a first trench. The via hole extends through a lower portion of the insulating interlayer. The first trench is connected to the via hole and extends through an upper portion of the insulating interlayer. The first protection pattern covers a lower surface and sidewalls of the via hole and a portion of a lower surface and a lower sidewall of the first trench, and includes a conductive material. The first barrier pattern covers the protection pattern and an upper sidewall of the first trench. The first adhesion pattern covers the first barrier pattern. The first conductive pattern is disposed on the first adhesion pattern, and fills the via hale and the first trench.