A semiconductor device is provided. The semiconductor device includes a substrate, a plurality of fins comprising a first fin, a second fin, a third fin, a fourth fin and a fifth fin, each of the plurality of protruding from the substrate in a first direction, and spaced apart from one another in a second direction that intersects the first direction and a plurality of trenches comprising a first trench, a second trench, a third trench and a fourth trench, each of the plurality of trenches being formed between adjacent fins of the plurality of fins, wherein variation of a first width of the first trench and a third width of the third trench is smaller than a first variation, wherein variation of a second width of the second trench and a fourth width of the fourth trench is smaller than a second variation, and wherein the second variation is greater than the first variation.