The invention discloses a
semiconductor device and a forming method thereof. The forming method of the
semiconductor device comprises the following steps: providing a substrate, wherein a first conductive layer is arranged on the surface of the substrate, a sacrificial layer is arranged on the surface of the first conductive layer, a
mask layer is arranged on the surface of the sacrificial layer, and the
mask layer is exposed on part of the surface of the sacrificial layer; taking the
mask layer as a mask,
etching the sacrificial layer until the first conductive layer is exposed, and forming a first opening and a second opening in the sacrificial layer; forming conductive films on the surface of the
mask layer and on the side walls and bottom surfaces of the first opening and the second opening; forming
dielectric layers full of the first opening and the second opening on the surfaces of the conductive films; removing part of conductive films on the surface of the
mask layer so as to pattern the conductive films after the
dielectric layers are formed, forming a first
plug in the first opening, forming a second
plug in the second opening, and forming a second conductive layer on the surface of the
mask layer, wherein the second plug and the second conductive layer are in electrical open circuit; and electrically connecting the second conductive layer with the first plug. Therefore, the performance of the formed
semiconductor device is stable and good.