A semiconductor device includes: a substrate having a magnetic tunneling junction (MTJ) region and a logic region; an inter-metal dielectric (IMD) layer on the substrate; a first metal interconnection in the IMD layer on the logic region; and protrusions adjacent to two sides of the first metal interconnection. Preferably, the first metal interconnection further includes a via conductor and a trench conductor and the protrusions includes a first protrusion on one side of the via conductor and a second protrusion on another side of the via conductor.