High aspect ratio etch

A method for etching a layer in a processing chamber is provided. A plurality of cycles is provided, where each cycle comprises a deposition phase, a clearing phase, and an etching phase. The deposition phase comprises flowing a deposition gas comprising a fluorocarbon or hydrofluorocarbon gas into the processing chamber, maintaining a deposition phase pressure of at least 50 mTorr, transforming the deposition gas into a plasma, and stopping the deposition phase. The clearing phase comprises flowing a clearing gas comprising a halogen containing gas into the processing chamber, maintaining a clearing phase pressure of less than 40 mTorr, transforming the clearing gas into a plasma, and stopping the clearing phase. The etching phase comprises flowing an etching gas comprising a halogen containing gas into the processing chamber, maintaining an etching phase pressure of at least 30 mTorr, transforming the etching gas into a plasma, and stopping the etching phase.