The present disclosure provides a method of forming fine interconnection for semiconductor devices. The method includes the following steps: A substrate is provided. A first core layer is formed over the substrate. The first core layer includes a base portion, a plurality of extending line portions extending from the base portion along a first direction, and a plurality of isolated line portions isolated from the base portion. Subsequently, a spacer is formed on the sidewalls of the first core layer. A second core layer is then formed to over the substrate. The second core layer includes a plurality of surrounding line portions surrounding the plurality of isolated line portions, and includes a plurality of enclosed line portions enclosed by the plurality of extending line portions. The spacer is removed to form a plurality of openings between the first core layer and the second core layer. The first core layer and the second core layer are alternately arranged along a second direction perpendicular to the first direction after removing the spacer.