A semiconductor device includes a substrate having a magnetic random access memory (MRAM) region and a logic region, a first metal interconnection on the MRAM region, a second metal interconnection on the logic region, a stop layer extending from the first metal interconnection to the second metal interconnection, and a magnetic tunneling junction (MTJ) on the first metal interconnection. Preferably, the stop layer on the first metal interconnection and the stop layer on the second metal interconnection have different thicknesses.