A method of fabricating a semiconductor device is described. A plurality of first films and a plurality of second films are alternately formed on a substrate. A hole is formed in the first and second films. A first metal layer is formed on a surface of the hole. The first metal layer is removed from a bottom surface of the hole. A second metal layer may be formed on a surface of the first metal layer after removing the first metal layer from the bottom surface of the hole. The bottom of the hole exposed from the first and second metal layers may be processed to increase a depth of the hole.