Method of manufacturing semiconductor device

A method of manufacturing a semiconductor device comprising:

• forming active patterns extending in a first direction and spaced apart from one another along a second direction perpendicular to the first direction on a substrate;
• forming a polygonal mask pattern having a first width and a second width along the second direction on the active patterns;
• forming an active region having the first width and the second width by executing a first etching process using the mask pattern;
• forming a first cutting mask for removing a first corner rounding at which the width of the active region is changed from the first width to the second width;
• and
• removing the first corner rounding by executing a second etching process using the first cutting mask.

A method of manufacturing a semiconductor device comprising:

• forming first trenches that define active pattern extending in a first direction and spaced apart from one another along a second direction perpendicular to the first direction on a substrate;
• forming first insulating layers filling the first trenches;
• forming a polygonal mask pattern having a first width and a second width in the second direction;
• forming a second trench for defining a portion having the first width of the polygonal active region by executing a first etching process using the mask pattern;
• forming second insulating layers filling the second trenches;
• forming a first cutting mask for removing a first corner rounding at which a width of the active region is changed from the first width to the second width;
• and
• removing the first corner rounding by executing a first etching process using the first cutting mask.