DRY ETCHING METHOD

摘要

An etching method such that the selectivity of etching with respect to the mask and the substrate is not impaired when the bias voltage applied to a sample is boosted to improve the etching rate. A voltage having a positive pulse waveform is applied to the sample as the bias voltage and the interval of the pulse waveform is controlled to a prescribed value. In addition, a plasma is produced by applying a voltage having a positive waveform as the bias voltage and adding a gas containing such light elements as H, He, etc., to a process gas. Since the energy distribution of ions made incident on the sample can be made narrow, the selectivity of etching of the substrate material and the mask material can be improved while the high etching rate and anisotropy of the etching are maintained.