Plasma etching method
AssigneeTokyo Electron Limited
InventorTetsuya Nishizuka
Life of this patent
Estimating the term…
Abstract
This invention relates to a method for conducting an etching process which uses a plasma of a process gas. This etching process is conducted on a wafer W including a substrate 101, an underlying film 102, 103 formed on the substrate, and a film 104 to be etched that is formed on the underlying film. A main etching gas formed up of a chlorine-containing gas and an oxygen-containing gas, and a nitrogen-containing gas are used as the process gas. In this etching method, etching is conducted under a condition that an N2+/N2 intensity ratio of N2+ to N2, derived from emission spectra of the plasma, is at least 0.6.
Claims5
An etching method comprising the steps of:
- providing an object including a substrate, an underlying film made of a silicon-containing film formed on the substrate, and a film to be etched that is made of a tungsten-containing film formed on the underlying film;
- and
- using a plasma of a process gas to carry out an etching process for the object, wherein:
- a chlorine-containing gas, an oxygen-containing gas, and a nitrogen-containing gas are used as the process gas to etch the tungsten-containing film under a condition that an N2+/N2 intensity ratio of N2+ to N2, derived from emission spectra of the Plasma, is at least 0.6,
- the chlorine-containing gas is a Cl2 gas, the oxygen-containing gas is an O2 gas, and the nitrogen-containing gas is an N2 gas, and
- the silicon-containing film is a polysilicon film, and the tungsten-containing film is a tungsten film of a stacked structure of a tungsten nitride film and a tungsten film.
Dependencies are inferred from the claim text.