Abstract: A method is provided for etching a dielectric structure. The dielectric structure comprises: (a) a layer of undoped silicon oxide or F-doped silicon oxide; and (b) a layer of C,H-doped silicon oxide. The dielectric structure is etched in a plasma-etching step, which plasma-etching step is conducted using a plasma source gas that comprises nitrogen atoms and fluorine atoms. As one example, the plasma source gas can comprise a gaseous species that comprises one or more nitrogen atoms and one or more fluorine atoms (e.g., NF3). As another example, the plasma source gas can comprise (a) a gaseous species that comprises one or more nitrogen atoms (e.g., N2) and (b) a gaseous species that comprises one or more fluorine atoms (e.g., a fluorocarbon gas such as CF4). In this etching step, the layer of C,H-doped silicon oxide is preferentially etched relative to the layer of undoped silicon oxide or F-doped silicon oxide. The method of the present invention is applicable, for example, to dual damascene structures.

Abstract: A method and apparatus for controlling characteristics of a plasma in a semiconductor substrate processing chamber using a dual frequency RF source is provided. The method comprises supplying a first RF signal to a first electrode disposed in a processing chamber, and supplying a second RF signal to the first electrode, wherein an interaction between the first and second RF signals is used to control at least one characteristic of a plasma formed in the processing chamber.

Abstract: A method and apparatus for generating and controlling a plasma in a semiconductor substrate processing chamber using a dual frequency RF source is provided. The method includes the steps of supplying a first RF signal from the source to an electrode within the processing chamber at a first frequency and supplying a second RF signal from the source to the electrode within the processing chamber at a second frequency. The second frequency is different from the first frequency by an amount equal to a desired frequency. Characteristics of a plasma formed in the chamber establish a sheath modulation at the desired frequency.

Abstract: A method is provided for etching a dielectric structure. The dielectric structure comprises: (a) a layer of undoped silicon oxide or F-doped silicon oxide; and (b) a layer of C,H-doped silicon oxide. The dielectric structure is etched in a plasma-etching step, which plasma-etching step is conducted using a plasma source gas that comprises nitrogen atoms and fluorine atoms. As one example, the plasma source gas can comprise a gaseous species that comprises one or more nitrogen atoms and one or more fluorine atoms (e.g., NF3). As another example, the plasma source gas can comprise (a) a gaseous species that comprises one or more nitrogen atoms (e.g., N2) and (b) a gaseous species that comprises one or more fluorine atoms (e.g., a fluorocarbon gas such as CF4). In this etching step, the layer of C,H-doped silicon oxide is preferentially etched relative to the layer of undoped silicon oxide or F-doped silicon oxide. The method of the present invention is applicable, for example, to dual damascene structures.