A semiconductor device includes a stacked structure with first conductive layers and insulating layers that are stacked alternately with each other, second conductive layers located on the stacked structure, first openings passing through the second conductive layers and the stacked structure and having a first width, second conductive patterns formed in the first openings and located on the stacked structure to be electrically coupled to the second conductive layers, data storage patterns formed in the first openings and located under the second conductive patterns, and channel layers formed in the data storage patterns and the second conductive patterns.