Patent ID: 8431331

Claim:
A method of forming fine patterns of a semiconductor device, the method comprising: forming a plurality of first mask patterns on a substrate so that the plurality of first mask patterns are equally separated from one another respectively by spaces, in a direction parallel to a main surface of the substrate; forming a capping film comprising an acid source on side walls and on an upper surface of each of the plurality of first mask patterns; forming a second mask layer on the capping film on the side walls and on the upper surface of each of the plurality of first mask patterns so as to fill each of the spaces; forming a plurality of acid diffused regions extending from the capping film on the side walls and on the upper surface of each of the plurality of first mask patterns into the second mask layer by diffusing acid obtained from the acid source from the capping film; and forming a plurality of second mask patterns corresponding to a portion of the second mask layer which remain in each of the spaces after removing the acid diffused regions of the second mask layer.