A semiconductor device includes bit lines and a common source line connected to a memory cell array, wherein the bit lines and the common source line are spaced apart from each other in a first level; a pad pattern spaced apart from the bit lines and the common source line in the first level; a first insulating layer covering the bit lines, the common source line, and the pad pattern; a shielding pattern overlapping with the bit lines and disposed on the first insulating layer; a first upper line and a second upper line spaced apart from each other above the shielding pattern; a plurality of contact plugs extending from the first and second upper lines toward the bit lines, common source line, and pad pattern, wherein one or more of the plurality of contact plugs connect the shielding pattern to the second upper line.