Provided is a semiconductor device. The semiconductor device includes a conductive pattern disposed on a semiconductor substrate. First and second conductive lines disposed on the conductive pattern and located at the same level as each other, are provided. An isolation pattern is disposed between the first and second conductive lines. A first vertical structure passing through the first conductive line and conductive pattern is provided. A second vertical structure passing through the second conductive line and conductive patterns is provided. An auxiliary pattern passing through the conductive pattern and in contact with the isolation pattern is provided.