SEMICONDUCTOR DEVICE AND DATA STORAGE SYSTEM INCLUDING THE SAME

A semiconductor device includes a first substrate structure including a first substrate, circuit devices, first interconnection lines, bonding metal layers on upper surfaces of the first interconnection lines, and a first bonding insulating layer on the upper surfaces of the first interconnection lines and on lateral surfaces of the bonding metal layers, and a second substrate structure on the first substrate structure, and including a second substrate, gate electrodes, channel structures, second interconnection lines, bonding vias connected to the second interconnection lines and the bonding metal layers and having a lateral surface that is inclined such that widths of the bonding vias increase approaching the first substrate structure, and a second bonding insulating layer in contact with at least lower portions of the bonding vias. The bonding metal layers include dummy bonding metal layers not connected to the bonding vias and that contacts the second bonding insulating layer.