A semiconductor device comprises a metal gate electrode, a passive device and a hard mask layer. The passive device has a poly-silicon element layer. The hard mask layer is disposed on the metal gate electrode and the passive electrode and has a first opening and a second opening substantially coplanar with each other, wherein the metal gate electrode and the poly-silicon element layer are respectively exposed via the first opening and the second opening; and there is a distance between the first opening and the metal gate electrode substantially less than the distance between the second opening and the poly-silicon element layer.