Patent ID: 8420545

Claim:
A plasma etching method for preparing high-aspect-ratio structures, comprising the steps of: forming a mask on a substrate, wherein the mask has a pattern; placing the substrate with the mask into a plasma etching apparatus, wherein the plasma etching apparatus comprises a processing chamber, an upper electrode plate and a lower electrode plate, the upper electrode plate and the lower electrode plate are disposed in the processing chamber, and the lower electrode plate includes a chuck for holding the substrate; introducing a processing gas into the processing chamber; continuously supplying an upper source RF power and a DC power to the upper electrode plate during the plasma etching process; supplying a bias RF power to the lower electrode plate so as to generate a plasma in the processing chamber to etch the substrate according to the pattern of the mask, wherein the bias RF power is supplied discontinuously during the plasma etching process, wherein the bias RF power is a pulse power and is alternately switched on and off, and wherein the bias RF power is supplied during the on state and the bias RF power is cut off during the off state; and the processing gas is removed from the processing chamber and an additional gas is introduced into the processing chamber when the bias RF power is switched to the off state.