The semiconductor device includes a substrate, a bottom electrode, a capacitor dielectric layer, a top electrode, an etching stop layer, a first anti-reflective coating layer and a capping layer. The bottom electrode is on the substrate. The capacitor dielectric layer is on the bottom electrode. The capacitor dielectric layer has a first region and a second region adjacent to the first region. The top electrode is on the first region of the capacitor dielectric layer. The etching stop layer is on the top electrode. The first anti-reflective coating layer is on the etching stop layer, in which the first anti-reflective coating layer, the etching stop layer and the top electrode together have a sidewall. The capping layer overlies the sidewall, the etching stop layer, the second region of the capacitor dielectric layer, in which the capping layer is formed from oxide or nitride.