Semiconductor device with conductive cap layer over conductive plug and method for forming the same

Abstract

The present disclosure relates to a semiconductor device including a semiconductor substrate, word lines, mask layers, spacers, a conductive plug, a conductive cap layer, and a dielectric layer. The word lines are disposed over the semiconductor substrate. The mask layers are disposed over the plurality of word line, respectively. The spacers are disposed over opposite sidewalls of the word lines and opposite sidewalls of the mask layers, respectively. The conductive plug is disposed between the word lines. The conductive cap layer is disposed over the conductive plug. The dielectric layer is disposed over the word lines and the spacers. Each of the spacers includes an inner spacer, an outer spacer, and an air gap. The inner spacer is in contact with the respective word line and the respective mask layer. The air gap is disposed between the inner spacer and the outer spacer.