A semiconductor device includes a stacked gate structure, a plurality of stacks and a first conductive layer. The stacks are disposed aside the stacked gate structure and arranged along both a first direction and a second direction perpendicular to the first direction, wherein the stacks are extended continuously along the first direction and segmented in the second direction. The first conductive layer is disposed between segmented portions of the stacks along the second direction, wherein top surfaces of the segmented portions of the stacks are higher than a top surface of the first conductive layer.