Abstract: Embodiments of the present disclosure generally relate to a method for etching a film stack with high selectivity and low etch recipe transition periods. In one embodiment, a method for etching a film stack having stacked pairs of oxide and nitride layers is described. The method includes transferring a substrate having a film stack formed thereon into a processing chamber, providing a first bias voltage to the substrate, etching an oxide layer of the film stack while providing the first bias voltage to the substrate, providing a second bias voltage to the substrate, the second bias voltage greater than the first bias voltage, and etching a nitride layer of the film stack while providing the second bias voltage to the substrate.