Abstract: A method for etching features into a porous low-k dielectric etch layer is provided. A plurality of cycles is performed in a plasma processing chamber. Each cycle comprises a deposition phase and an activation phase. The deposition phase comprises flowing a deposition gas comprising a fluorocarbon and/or hydrofluorocarbon gas, creating a plasma in the plasma processing chamber using the deposition gas, depositing a fluorocarbon or hydrofluorocarbon containing layer, and stopping the flow of the deposition gas. The activation phase comprises flowing an activation gas comprising a noble gas and a carbon etching additive, creating a plasma in the plasma processing chamber using the activation gas, providing an activation bias in the plasma processing chamber, wherein the activation bias causes the etching of the low-k dielectric layer, with consumption of the fluorocarbon or hydrofluorocarbon containing layer, and stopping the flow of the activation gas.

Abstract: A method for etching features into a porous low-k dielectric etch layer is provided. A plurality of cycles is performed in a plasma processing chamber. Each cycle comprises a deposition phase and an activation phase. The deposition phase comprises flowing a deposition gas comprising a fluorocarbon and/or hydrofluorocarbon gas, creating a plasma in the plasma processing chamber using the deposition gas, depositing a fluorocarbon or hydrofluorocarbon containing layer, and stopping the flow of the deposition gas. The activation phase comprises flowing an activation gas comprising a noble gas and a carbon etching additive, creating a plasma in the plasma processing chamber using the activation gas, providing an activation bias in the plasma processing chamber, wherein the activation bias causes the etching of the low-k dielectric layer, with consumption of the fluorocarbon or hydrofluorocarbon containing layer, and stopping the flow of the activation gas.