Method for Etching a Silicon-Containing Substrate

摘要

Techniques herein provide a chamber and substrate cleaning solution for etching and removing byproducts between separate etching steps. Such techniques include using a cleaning step based on fluorine chemistry, which is executed in between separate etch steps or divided etch steps. Such a technique can be executed in situ for improved efficiency. Other benefits include increasing etching depth/aspect ratios, and preventing post-etching defects including physical contact with neighboring gates, etc. Techniques herein are especially beneficial when applied to relatively small feature openings.

主权项

1. A method for processing a substrate, the method comprising:
positioning a substrate in a chamber of a plasma processing system, the substrate having a masking layer positioned over a silicon-containing layer, the masking layer defining openings less than 40 nanometers; executing a first etching process that anisotropically etches a first portion of the silicon-containing layer using the masking layer as an etch mask and using plasma formed from a first process gas that includes a bromine-containing gas or a chlorine-containing process gas; executing a chamber cleaning step that includes removing chamber wall residue using plasma formed from a second process gas that includes a fluorine-containing process gas, the chamber wall residue includes products from the first etching process, the chamber cleaning step being executed while the substrate is positioned in the chamber of the plasma processing system; and executing a second etching process that anisotropically etches a second portion of the silicon-containing layer using the masking layer as an etch mask and using plasma formed from a third process gas that includes the bromine-containing gas or the chlorine-containing gas, wherein the first etching process and the second etching process create a space in the substrate having an aspect ratio value greater than 7.0 as calculated from a top of the masking layer to a bottom of the second portion of the silicon-containing layer.