According to an aspect of the present inventive concept there is provided a method for forming an interconnection structure for a semiconductor device, the method comprising:
forming a conductive layer on an insulating layer,
forming above the conductive layer a first set of mandrel lines of a first material,
forming a set of spacer lines of a second material different from the first material, wherein the spacer lines are formed on sidewalls of the first set of mandrel lines,
forming a second set of mandrel lines of a third material different from the first and second materials, wherein the second mandrel lines fill gaps between the spacer lines,
cutting at least a first mandrel line of the second set of mandrel lines into two line segments separated by a gap by etching said first mandrel line of the second set of mandrel lines selectively to the set of spacer lines and the first set of mandrel lines,
cutting at least a first mandrel line of the first set of mandrel lines into two line segments separated by a gap by etching said first mandrel line of the first set of mandrel lines selectively to the set of spacer lines and the second set of mandrel lines,
removing the set of spacer lines, selectively to the first and second sets of mandrel lines, thereby forming an alternating pattern of mandrel lines of the first set and mandrel lines of the second set, and
patterning the conductive layer to form a set of conductive lines, wherein the patterning comprises etching while using the alternating pattern of mandrel lines as an etch mask.