A device includes a substrate, a first structure, a second structure, a third structure and a bumper. The first structure is over the substrate. The second structure is over the substrate, wherein the second structure has a first end coupled to the first structure. The third structure is over the substrate, wherein the third structure is coupled to a second end of the second structure. The bumper is between the substrate and the third structure, wherein the bumper is a multi-layered bumper including a first conductive feature, a dielectric feature and a second conductive feature. The dielectric feature is over the first conductive feature. The second conductive feature is over the dielectric feature and electrically connected to the first conductive feature.