An apparatus for etching a dielectric layer contained by a substrate is provided. An etch reactor comprises a top electrode and a bottom electrode. An etch gas source supplies an etch gas into the etch reactor. A first Radio Frequency (RF) source generates a first RF power with a first frequency and supplies the first RF power into the etch reactor, whereas the first frequency is between 100 kilo Hertz (kHz) and 600 kHz. A second RF source generates a second RF power with a second frequency and supplies the second RF power into the etch reactor, whereas the second frequency is at least 10 mega Hertz (MHz).