Patent ID: 7993814

Claim:
A method for forming patterns using a single mask comprising: disposing a photo mask over a semiconductor substrate where first line shape patterns are formed on the photo mask and a first space pattern is disposed between the first line shape patterns, arranging a focal length to a focusing position; performing a first exposure process at the focusing position to form the first line shape patterns and the first space pattern on the semiconductor substrate; arranging the focal length of the photo mask to a defocusing position, which deviates from the focusing position, to transcribe a second line shape pattern and a second space pattern having a reversed image of the first line shape patterns and the first space pattern with respect to the photo mask to the semiconductor substrate; and performing a second exposure process at the defocusing position to turn the first space pattern into the second line shape pattern and to turn the first line shape patterns into the second space pattern on the same location where the first exposure process is performed on the semiconductor substrate.