A semiconductor device and a method of manufacturing a semiconductor device may be provided. The semiconductor device may include first channel layers arranged in a first direction. The semiconductor device may include second channel layers adjacent to the first channel layers in a second direction crossing the first direction and arranged in the first direction. The semiconductor device may include insulating layers stacked while surrounding side walls of the first and second channel layers. The semiconductor device may include conductive layers interposed between the insulating layers, and including first metal patterns extended in the first direction and second metal patterns extended in the first direction while surrounding the side walls of the first channel layers.