Method for selectively etching with reduced aspect ratio dependence

US10541141B2 · kind B2 · utility

Assignee

• Lam Research Corporation · US

Inventors

• Adarsh Basavalingappa · Albany, US
• Peng Wang · San Diego, US
• Bhaskar Nagabhirava · Tigard, US
• Michael Goss · Hearst, CA
• Prabhakara Gopaladasu · Fremont, US
• Randolph F. Knarr · Goldens Bridge, US
• Stefan Schmitz · Stuttgart, DE
• Phil Friddle · Clifton Park, US

Key dates

• Filing date: Jul 25, 2018
• Grant date: Jan 21, 2020
• Expiry date: Jul 25, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/038
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method for selectively etching an etch layer with respect to a mask is provided. An etch process is provided comprising a plurality of etch cycles, wherein each etch cycle comprises providing a deposition phase and an etch phase. The deposition phase comprises providing a flow of a deposition phase gas, comprising a fluorocarbon or hydrofluorocarbon containing gas and an oxygen containing gas with a fluorocarbon or hydrofluorocarbon to oxygen ratio, providing a RF power, which forms the deposition phase gas into a plasma, and stopping the deposition phase. The etch phase, comprises providing a flow of an etch phase gas, comprising a fluorocarbon or hydrofluorocarbon containing gas and an oxygen containing gas with a fluorocarbon or hydrofluorocarbon to oxygen ratio that is lower than the fluorocarbon or hydrofluorocarbon to oxygen ratio of the deposition phase gas, providing a RF power, and stopping the etch phase.