A semiconductor memory device in semiconductor devices may store digital data. As the electronic and semiconductor industries become highly sophisticated, the requirement for high-integration of semiconductor memory devices is gradually increasing. For example, as portable electronic devices such as laptop computers, mobile phones, digital cameras and MP3 players advance, requirements for semiconductor memory devices capable of storing more data are increasing. To satisfy these consumer requirements, highly integrated semiconductor memory devices are required.
Generally, the minimum line width of fine patterns constituting a semiconductor memory device may be decreased for higher integration of a semiconductor memory device. By two-dimensionally decreasing the minimum line width of the fine pattern, more memory cells may be integrated in a limited area.
However, due to various factors such as photolithography process parameters, the amount by which the minimum line width is decreased may be limited. Moreover, as the line widths of the fine patterns decrease, the characteristics of the fine patterns may be deteriorated, thereby reducing semiconductor memory device reliability. Accordingly, much research is actively being conducted in pursuit of new methods for implementing semiconductor memory devices that are highly integrated and have superior characteristics.