a method in a plasma processing system for etching a feature through a dielectric layer of a dual damascene stack on a semiconductor substrate is disclosed . the method includes placing the substrate in a plasma processing chamber of the plasma processing system . the method further includes flowing an etchant gas mixture into the plasma processing chamber , the etchant gas mixture being configured to etch the dielectric layer . the method additionally includes striking a plasma from the etchant source gas . the method also includes etching the feature through the dielectric layer while applying a bias rf signal to the substrate , the bias rf signal having a bias rf frequency of between about 27 mhz and about 90 mhz . the bias rf signal further has a bias rf power component that is configured to cause the feature to be etched in accordance to predefined etch rate parameters and etch profile parameters at the bias rf frequency .