US Patent 10043966 Semiconductor device including via plugs

A semiconductor device includes a lower insulating layer on a substrate, a lower wiring layer extending on the lower insulating layer, a lower surface of at least a part of the lower wiring layer being covered by the lower insulating layer, a plurality of via plugs extending in a first direction on the lower wiring layer, the plurality of via plugs including a real via plug and a first dummy via plug connected to the part of the lower wiring layer covered by the lower insulating layer, and an upper wiring layer overlapping the lower wiring layer and extending in a second direction different from the first direction on the real via plug, the upper wiring layer not overlapping the dummy via plug.