Fused Silica Tube Plasma Cleaning for Restored Microwave Coupling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The frequent coating of dielectric tubes in microwave plasma processing chambers reduces the effective lifetime of the tubes, leading to increased costs and downtime due to decreased electronic coupling between the antenna and plasma, necessitating frequent replacements.

Innovation Solution

Exposing the dielectric tubes to a cleaning gas containing a fluorine-containing compound and generating a microwave plasma to clean the tubes, thereby removing the coating and maintaining transparency and electronic coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If plasma deposition processes are used to deposit films on substrates, then film deposition is achieved, but coating accumulates on the dielectric tube causing decreased electronic coupling and reduced tube lifetime

Engineering Contradiction:

Improvefilm deposition efficiencyVSAvoiddielectric tube lifetime

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent implements a cleaning process that removes accumulated coating from the dielectric tube surface, effectively recovering the tube's original performance characteristics. By periodically discarding the harmful coating accumulation through fluorine-based plasma cleaning, the tube's electronic coupling efficiency is restored, extending its operational lifetime without requiring replacement.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent converts the harmful effect of coating accumulation into a beneficial cleaning process. By introducing fluorine-containing gases that react with the carbon-based deposition coating to form volatile fluorocarbon compounds, the previously harmful coating becomes a removable substance that can be efficiently eliminated through plasma processing, thereby restoring tube performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Duration of action of stationary object

If the dielectric tube is cleaned frequently to maintain electronic coupling, then tube lifetime is extended, but processing chamber downtime increases

Engineering Contradiction:

Improvedielectric tube lifetimeVSAvoidprocessing chamber downtime

Core Design Contradiction:

Duration of action of stationary objectVSLoss of time

Solution Approach 1:

The patent merges the cleaning operation with the existing plasma processing chamber, eliminating the need for separate cleaning equipment or external tube removal procedures. By integrating the fluorine-based plasma cleaning capability into the same chamber used for film deposition, the system can perform maintenance cleaning without requiring additional equipment or extensive setup time.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a self-service cleaning mechanism where the processing chamber itself performs the cleaning function using fluorine-containing gases introduced during or between deposition cycles. The chamber's plasma generation capability is utilized to clean the dielectric tube in-situ, eliminating the need for external cleaning services or equipment and minimizing downtime.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If microwave plasma is generated using a waveguide within the dielectric tube, then plasma processing is enabled, but coating accumulates on the tube surface reducing coupling efficiency

Engineering Contradiction:

Improveplasma generation capabilityVSAvoidelectronic coupling efficiency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements periodic cleaning cycles using fluorine-based plasma to remove coating accumulation from the dielectric tube surface. By alternating between deposition operations and cleaning operations, the system maintains reliable electronic coupling efficiency over extended periods. The periodic intervention prevents the gradual degradation that would otherwise occur from continuous coating accumulation during plasma processing.

Inventive Principle:

Principle #19Periodic action

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 significantly extends the lifetime of the dielectric tubes by removing the coating, allowing for continued efficient operation and reducing the need for frequent replacements, with cleaned tubes showing at least double the lifetime of uncleaned ones.

Implementation Method 1

generating a microwave plasma from the cleaning gas to clean the dielectric tube

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

microwave energy is applied to a waveguide (also called an antenna or electrode), which couples to a gas in the processing chamber, causing the ignition of the gas into a plasma

Methodology Applied

Scientific EffectMicrowave plasma:

Data Source

PatentUS20240363317A1Method of plasma cleaning of fused silica tubes

Publication Date: 2024.10.31 APPLIED MATERIALS INC

AI summary

Methods and apparatus for cleaning a dielectric tube are described. The dielectric tube is exposed to a cleaning gas comprising a fluorine-containing compound and a microwave plasma is generated. The dielectric tube is cleaned to restore transparency and increase electronic coupling between the microwave waveguide and the plasma through the dielectric tube.