The present invention provides a method of manufacturing a semiconductor device including using a first photomask to form a sacrificial block on a hard mask layer in a first region, a first dummy pattern on the sacrificial block, a first spacer on sidewalls of the sacrificial block and a second spacer in a second region; using a second photomask to form a feature mask on the first dummy pattern and a fin cutting mask on the second spacer; and performing a fin cutting process to remove a portion of the first dummy pattern, a portion of the sacrificial block underlying the portion of the first dummy pattern and the first spacer to form a feature spacer and to remove a portion of the second spacer without being covered with the fin cutting mask to form a fin spacer.