Method of plasma-enhanced atomic layer etching

Abstract

A method for etching a layer on a substrate includes at least one etching cycle, wherein an etching cycle includes: continuously providing an inert gas into the reaction space; providing a pulse of an etching gas into the continuous inert gas flow upstream of the reaction space to chemisorb the etching gas in an unexcited state on a surface of the substrate; and providing a pulse of RF power discharge between electrodes to generate a reactive species of the inert gas in the reaction space so that the layer on the substrate is etched.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to a method of atomic layer etching (ALE), particularly to a method of plasma-enhanced ALE (PEALE).[0003]2. Description of the Related Art[0004]In order to cope with various processing accompanying microminiaturization and complex structures of semiconductor devices, precision of processing has been remarkably improved by new technology such as double-patterning. However, conventional etching technology such as continuous etching using excited reaction species may be difficult to form fine, narrow convex-concave patterns and may cause defects of shape. Thus, development of etching technology which is capable of performing atomic layer-level etching and is suitable for e.g., double-patterning processes, becomes important. However, low etching rate, poor controllability over directionality of etching, or the like need to be improved.[0005]Any discussion of problems and solutions in ...

AI Technical Summary

Benefits of technology

This patent describes a method for atomic layer-level etching that has several features. First, an etching gas is supplied to a reaction space using a mass flow controller, and an inert gas is added continuously to improve purging efficiency. Next, a plasma is used for etching by adding an oxidizing or reducing gas to control the etching rate. The process temperature is controlled between 0°C and 250°C. Finally, the directionality of etching can be controlled to perform either anisotropic or isotropic etching by selecting the type of reactant gas and etching conditions. Overall, this method provides efficient and controlled etching at the atomic layer level.

Problems solved by technology

However, conventional etching technology such as continuous etching using excited reaction species may be difficult to form fine, narrow convex-concave patterns and may cause defects of shape.

However, low etching rate, poor controllability over directionality of etching, or the like need to be improved.

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