Apparatus and methods for spacer deposition and selective removal in an advanced patterning process

Embodiments herein provide apparatus and methods for performing a deposition and a patterning process on a spacer layer with good profile control in multiple patterning processes. In one embodiment, a method for depositing and patterning a spacer layer during a multiple patterning process includes conformally forming a spacer layer on an outer surface of a patterned structure disposed on a substrate, wherein the patterned structure has a first group of openings defined therebetween, selectively treating a first portion of the spacer layer formed on the substrate without treating a second portion of the spacer layer, and selectively removing the treated first portion of the spacer layer.