Patent ID: 9543158
Date: 2017-01-10
CPC Classifications: H01J,H01L

Claim:
1. A method of forming an etched feature in dielectric material on a semiconductor substrate, the method comprising: (a) generating an etching plasma comprising an etching reactant, exposing the substrate to the etching plasma, and partially etching the feature in the dielectric material, wherein the substrate comprises a mask layer; (b) after (a), depositing a protective film on sidewalls of the feature, wherein the protective film is deposited along substantially the entire depth of the feature, wherein the mask layer is substantially preserved during (b), and wherein depositing the protective film comprises: (c) repeating (a)-(b) until the feature is etched to a final depth, wherein the protective film deposited in (b) substantially prevents lateral etch of the feature during (a), and wherein the feature has an aspect ratio of about 5 or greater at its final depth.