METHODS OF MANUFACTURING SEMICONDUCTOR DEVICE

In a method of manufacturing a semiconductor device a substrate having a cell region and a peripheral region is prepared. A first cell-periphery structure including a conductive layer is formed over a surface of the substrate. In the cell region, a cell bit line trench is formed by patterning the first cell-periphery structure. A second cell-periphery structure including a second conductive layer is formed over the surface of the substrate. The second cell-periphery structure forms a cell bit line structure filling the cell bit line trench in the cell region, and is disposed over the first cell-periphery structure in the peripheral region. A periphery gate structure is formed by patterning the first and second cell-periphery structures in the peripheral region.