ETCHING METHOD AND PLASMA PROCESSING DEVICE

To protect a mask and control the etching shape.SOLUTION: There is provided an etching method executed by a plasma processing device including: an RF source power supply which is coupled to a chamber and supplies an RF source signal; a bias power supply which is coupled to an electrode and supplies an RF bias signal and/or DC bias signal; and a gas supply unit which supplies gas into the chamber. The method comprises the steps of: (a) preparing a substrate having a mask having a recess and an object film; (b) supplying the RF source signal, supplying the RF bias signal and/or DC bias signal at a first power level and halogen-containing first gas, forming a protection film on the recess with plasma and etching the object film; and (c) supplying the RF source signal, supplying the RF bias signal and/or DC bias signal at a second power level lower than the first power level and a second gas, removing the protection film with plasma and etching the bottom of the recess in the width direction. The method sequentially executes the steps (b) and (c).SELECTED DRAWING: Figure 4 【課題】マスクを保護し、エッチング形状を制御する。【解決手段】チャンバに結合され、ＲＦソース信号を供給するＲＦソース電源と、電極に結合され、ＲＦバイアス信号及び／又はＤＣバイアス信号を供給するバイアス電源と、チャンバ内にガスを供給するガス供給部とを備えるプラズマ処理装置で実行するエッチング方法であり、（ａ）凹部を持つマスクと対象膜を有する基板を準備し、（ｂ）ＲＦソース信号を供給し、第１電力レベルのＲＦバイアス信号及び／又はＤＣバイアス信号とハロゲン含有第１ガスを供給し、プラズマにより凹部に保護膜を形成し、対象膜をエッチングし、（ｃ）ＲＦソース信号を供給し、第１電力レベルよりも低い第２電力レベルのＲＦバイアス信号及び／又はＤＣバイアス信号と第２ガスを供給し、プラズマにより保護膜を除去し、凹部の底部を幅方向にエッチングし、（ｂ）と（ｃ）を順に実行する。【選択図】図４