US Patent 7871879 Method of manufacturing semiconductor memory device

A method of manufacturing a semiconductor memory device includes forming a device separation film on a semiconductor substrate using a mask pattern for defining an entire source line region as an active region to separate a device separation region from an active region; forming a stack gate structure on the semiconductor substrate; forming a common source line by implanting impurity ions into the semiconductor substrate in the source line region; and performing an impurity ion implantation process on the semiconductor substrate to form a drain region.