Apparatus and method of forming self-aligned cuts in a non-mandrel line of an array of metal lines

A method includes providing a structure having a first hardmask layer, second hardmask layer and mandrel layer disposed respectively over a dielectric stack. An array of mandrels is patterned into the mandrel layer. A gamma trench is patterned into the second hardmask layer and between the mandrels. Self-aligned inner spacers are formed on sidewalls of the gamma trench, the inner spacers forming a portion of a pattern. The pattern is etched into the dielectric stack to form an array of alternating mandrel and non-mandrel metal lines extending in a Y direction and being self-aligned in a perpendicular X direction. The portion of the pattern formed by the inner spacers is utilized to form a pair of non-mandrel line cuts in a non-mandrel line. The non-mandrel line cuts are self-aligned in the Y direction.