Method of forming semiconductor device

A method of forming a semiconductor device, comprising:

• forming a material layer on a substrate;
• forming a first photoresist layer on the material layer through a first photomask, the first photoresist layer comprising a plurality of first openings paralleled extended along a first direction;
• forming a second photoresist layer on the material layer through a second photomask, the second photoresist layer comprising a plurality of second openings paralleled extended along a second direction, the second openings of the second photoresist layer across the first openings of the first photoresist layer to form a plurality of overlapped regions;
• forming a third photoresist layer on the material layer through a third photomask, the third photoresist layer comprising a plurality of first patterns arranged in an array arrangement, each of the first patterns overlapped each of the overlapped regions;
• and
• transferring the first openings of the first photoresist layer, the second openings of the second photoresist layer and the first patterns of the third photoresist layer to the material layer, to from a plurality of material patterns in an array arrangement.