Method of forming a hard mask and method of forming a fine pattern of semiconductor device using the same

A method of forming a hard mask, comprising:

• forming a first hard mask layer on a substrate;
• forming a first sacrificial pattern by photolithography on the first mask layer, the first sacrificial pattern having substantially identical features spaced from one another in a first direction by a first pitch;
• subsequently forming side walls extending over sides of the features of the first sacrificial pattern, respectively, wherein the side walls delimit a respective recess between each pair of adjacent ones of the features of the first sacrificial pattern;
• removing all parts of the first sacrificial pattern while leaving the side walls extending upright on the first hard mask layer;
• and
• subsequently etching the side walls and the first hard mask layer to form a pattern of features located at positions corresponding to the locations of all of the sidewalls, respectively, wherein the features located at positions corresponding to the locations of all of the sidewalls are spaced from one another by a pitch that is a fraction of the first pitch.

A method of forming a hard mask, comprising:

• forming a first hard mask layer on a substrate;
• forming a first sacrificial pattern of substantially identical features on the first hard mask layer, wherein the features are spaced from one another in a first direction by a first pitch;
• removing a portion of the first hard mask layer exposed between features of the first sacrificial pattern to form recesses in the first hard mask layer;
• forming a conformal hard mask layer over the first sacrificial pattern and surfaces of the first hard mask layer defining the bottom of the recesses to a thickness equal to the thickness of the portion of the first hard mask layer removed from between the features of the first sacrificial pattern, and such that the conformal hard mask layer delimits recesses each of which extends between a respective pair of adjacent ones of the features of the first sacrificial pattern;
• forming a second sacrificial pattern within the recesses delimited by the conformal hard mask layer;
• removing upper portions of the second hard mask layer to expose the first sacrificial pattern;
• subsequently removing the first sacrificial pattern and the second sacrificial pattern;
• and
• subsequently etching the conformal hard mask layer and the first hard mask layer to form a hard mask having a pattern of features composed of residual portions of the first hard mask layer and residual portions of the conformal hard mask layer disposed on the residual portions of the first hard mask layer