A method of forming a semiconductor device includes following steps. First of all, plural first openings and plural second openings are sequentially formed on a material layer disposed on a substrate, with the second openings across the first openings to form plural overlapped regions. Then, plural patterns arranged in an array arrangement are formed, with each pattern overlapped each overlapped region, respectively. After that, transferring the first openings, the second openings and the patterns to the material layer, to from plural material patterns in an array arrangement. In another embodiment of the present invention, the first openings and the second openings may be replaced by plural first patterns and plural second patterns, while the patterns are replaced by plural openings.