Boron Trichloride Atomic Layer Etching for Plasma-Free Oxide Repair

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Solution Overview

Problem

Existing semiconductor fabrication processes face challenges in effectively addressing damage from etching and environmental exposures in sensitive structures, as conventional post-etching methods may not sufficiently repair damage and may further harm the structures.

Innovation Solution

A method involving providing a wafer with an oxygen-containing material to a processing chamber, exposing the material to a halogen-containing gas to form a modified oxygen-containing layer, and then exposing this layer to boron trichloride in a plasma-less environment to remove the modified layer, thereby addressing damage and exposure issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional post-etching methods are used to address damage from etching and environmental exposures, then some repair may be achieved, but the structures may be further damaged and the methods are insufficient to adequately address the damage

Engineering Contradiction:

Improvestructure integrityVSAvoiddamage from etching and environmental exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a controlled modification of the oxide layer immediately after etching, before the structures are exposed to further environmental damage. The halogen-containing gas modifies the oxide surface in advance, creating a protective or more resilient state that prevents subsequent damage while allowing controlled removal of the modified layer

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a halogen-containing gas as an intermediary substance that mediates between the damaging etching process and the final structure. The halogen modifies the oxide layer to create a volatile oxychloride that can be selectively removed with boron trichloride, thereby protecting the underlying structure from direct exposure to harsh conditions while still allowing precise material removal

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If plasma is used to remove modified layers, then removal efficiency may be improved, but additional damage and exposure to structures may occur

Engineering Contradiction:

Improvelayer removal efficiencyVSAvoiddamage from plasma exposure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the plasma-based removal mechanism with a purely chemical vapor phase reaction using boron trichloride. Instead of using energetic plasma ions to physically sputter or chemically etch the modified layer, the process uses thermal chemical reactions where boron trichloride gas reacts with the halogen-modified oxide to form volatile products that desorb from the surface, eliminating plasma-induced damage while maintaining efficient removal

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the removal process from plasma-state chemistry to thermal vapor-phase chemistry. By operating in the vapor phase at controlled temperatures without plasma activation, the process achieves selective removal of the modified layer through thermally activated chemical reactions, avoiding the harmful effects of plasma while maintaining productivity

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method effectively removes modified layers from the wafer surface without using plasma, thereby minimizing further damage and improving the integrity of the structures, while also being cost-effective and widely available.

Implementation Method 1

exposing the oxygen-containing material to a halogen-containing gas to form a modified oxygen-containing layer

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

exposing the modified oxygen-containing layer to boron trichloride to remove the modified layer from the surface of the wafer

Methodology Applied

Scientific EffectLigand exchange: Chemical Bonding

Implementation Method 3

exposing the modified oxygen-containing layer forms a volatile oxychloride

Methodology Applied

Scientific EffectVolatile compound formation: Evaporation

Implementation Method 4

exposing the oxygen-containing material to be etched to the halogen-containing gas includes igniting the halogen-containing gas to form a halogen-containing plasma

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS20250125155A1Atomic layer etching using boron trichloride

Publication Date: 2025.04.17 LAM RES CORP

AI summary

Methods and apparatuses for etching materials using a boron trichloride during atomic layer etching are provided. The method comprises providing a wafer to a processing chamber, the wafer having an oxygen-containing material, exposing the oxygen-containing material to a halogen-containing gas to form a modified oxygen-containing layer on a surface of the wafer, and exposing the modified oxygen-containing layer to the boron trichloride to remove the modified layer from the surface of the wafer.