Methods for manufacturing a data storage device are provided. A method may include forming an interlayer dielectric layer on a substrate, patterning the interlayer dielectric layer in a peripheral region of the substrate to form first trenches, forming first bit lines in the first trenches, patterning the interlayer dielectric layer between the first bit lines in the peripheral region to form second trenches extending along the first trenches after the formation of the first bit lines, and forming second bit lines in the second trenches.