Abstract: Methods and apparatuses for patterning carbon-containing material over a layer to be etched are provided herein. Methods involve trimming carbon-containing material by atomic layer etching including exposing the carbon-containing material to an oxygen-containing gas without a plasma to modify a surface of the carbon-containing material and exposing the carbon-containing material to an inert gas and igniting a plasma to remove the modified surface of the carbon-containing material. Methods may be used for multiple patterning techniques such as double and quad patterning. Methods also include depositing a conformal film over a carbon-containing material patterned using atomic layer etching without breaking vacuum. The oxygen-containing gas may be one containing any one or more of oxygen, ozone, water vapor, nitrous oxide, carbon monoxide, formic acid vapor and/or carbon dioxide.