US Patent 11469171 Semiconductor devices including contact plugs

A semiconductor device includes a lower circuit structure including a lower conductive pattern on a substrate, a middle wiring structure including horizontal wiring on the lower circuit structure, and a middle circuit structure on the middle wiring structure and including a stacked structure of alternating wiring and insulation layers. A channel structure extends through the stacked structure and contacts the horizontal wiring. A contact plug contacting the first lower conductive pattern and the horizontal wiring is in the middle wiring structure. A lowermost end of the channel structure is farther from a top of the substrate than a bottom of the horizontal wiring. An uppermost end of the contact plug is farther from the top of the substrate than the bottom of the horizontal wiring. The uppermost end of the contact plug is closer to the top of the substrate than a lowermost end of the wiring layers.