Methods of self-aligned multiple patterning. First and second mandrels are formed over a hardmask, and a conformal spacer layer is deposited over the first mandrel, the second mandrel, and the hardmask between the first mandrel and the second mandrel. A planarizing layer is patterned to form first and second trenches that expose first and second lengthwise portions of the conformal spacer layer respectively between the first and second mandrels. After patterning the planarizing layer, the first and second lengthwise portions of the conformal spacer layer are removed with an etching process to expose respective portions of the hardmask along a non-mandrel line. A third lengthwise portion of the conformal spacer layer is masked during the etching process by a portion of the planarizing layer and defines a non-mandrel etch mask.