Patent ID: 9396960
Filing Date: 2016-07-19
CPC Classification: H01J,H01L

Claim Text:
1. A plasma processing method of performing a plasma etching process on a multilayer film formed on a target substrate arranged in a processing chamber with a patterned mask layer as a mask by generating plasma of a processing gas, wherein the multilayer film includes a laminated film in which a first film and a second film having different relative permitivities are alternately formed on a base silicon film, a main etching process of forming a recess portion in the laminated film to a predetermined depth and an over etching process of further forming the recess portion until the base silicon film is exposed are performed by introducing the processing gas including a fluorocarbon-based gas and an oxygen gas into the processing chamber to generate the plasma and by performing the plasma etching process, in the over etching process, a first over etching process in which a ratio of a flow rate of the oxygen gas to a flow rate of the fluorocarbon-based gas is set to be increased as compared to the main etching process and a second over etching process in which the ratio of the flow rate of the oxygen gas to the flow rate of the fluorocarbon-based gas is set to be reduced as compared to the first over etching process are repeatedly performed two or more times, and in the over etching process, a high frequency power for bias is pulse-modulated and applied in a pulse form to a mounting table configured to mount thereon the target substrate.