A method for providing features in an etch layer is provided. A sacrificial patterned layer with sacrificial features is provided over an etch layer. Conformal sidewalls are formed in the sacrificial features, comprising at least two cycles of a sidewall formation process, wherein each cycle comprises a sidewall deposition phase and a sidewall profile shaping phase. Parts of the sacrificial patterned layer between conformal sidewalls are removed leaving the conformal sidewalls with gaps between the conformal sidewalls where parts of the sacrificial patterned layer were selectively removed. Features are etched in the etch layer using the conformal sidewalls as an etch mask, wherein the features in the etch layer are etched through the gaps between the conformal sidewalls where parts of the sacrificial patterned layer were selectively removed.