Semiconductor devices and methods of forming the same are provided. The methods may include forming first and second line patterns. The first line pattern has a first side facing the second line pattern, and the second line pattern has a second side facing the first line pattern. The methods may also include forming a first spacer structure on the first side of the first line pattern and a second spacer structure on the second side of the second line pattern. The first and the second spacer structures may define an opening. The methods may further include forming a first conductor in a lower part of the opening, forming an expanded opening by etching upper portions of the first and second spacer structures, and forming a second conductor in the expanded opening. The expanded opening may have a width greater than a width of the lower part of the opening.