Methods of fabricating a semiconductor device are provided. The methods may include forming a hard mask film on a lower film and forming first spacers on the hard mask film. The first spacers may define an exposure region of the hard mask film, and the exposure region may include a patterning portion and a non-patterning portion. The methods may also include forming a mold film on the first spacers and forming a blocking pattern in the mold film. The blocking pattern may vertically overlap the non-patterning portion. The methods may further include exposing the first spacers by removing the mold film after forming the blocking pattern.