Plasma Exhaust Recirculation Using Byproduct Concentration Feedback

Solution Overview

Problem

Existing plasma processes waste valuable gases like fluorine and nitrogen trifluoride, leading to high abatement costs and environmental emissions, as byproducts are not effectively recycled or reused.

Innovation Solution

A system that measures the concentration of byproducts like silicon tetrafluoride in the exhaust of a process chamber, recirculating unused fluorine radicals and gases back to a remote plasma source for reuse, while filtering out harmful residues, thereby optimizing gas utilization and reducing waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If byproduct gases are abated and wasted, then environmental emissions are controlled, but abatement costs and energy consumption increase

Engineering Contradiction:

Improveenvironmental emissionsVSAvoidabatement energy

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The system recovers valuable fluorine-containing gases from the exhaust stream by measuring byproduct concentration and selectively recirculating the exhaust back to the plasma source when byproduct levels are low, while discarding exhaust when byproduct levels are high. This recovers valuable process gases that would otherwise be wasted to abatement, reducing both abatement costs and energy consumption.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The system uses a sensor to continuously measure the concentration of fluorine-containing byproducts in the exhaust and feeds this information back to a controller that adjusts the exhaust recirculation accordingly. This closed-loop feedback control enables dynamic optimization of gas recovery while maintaining environmental compliance.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If byproduct gases are abated and wasted, then environmental compliance is maintained, but abatement costs increase

Engineering Contradiction:

Improveenvironmental complianceVSAvoidabatement costs

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The system recovers valuable fluorine-containing gases from the exhaust stream by measuring byproduct concentration and selectively recirculating the exhaust back to the plasma source when byproduct levels are low, while discarding exhaust when byproduct levels are high. This recovers valuable process gases that would otherwise be wasted to abatement, reducing both abatement costs and energy consumption.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The system uses a sensor to continuously measure the concentration of fluorine-containing byproducts in the exhaust and feeds this information back to a controller that adjusts the exhaust recirculation accordingly. This closed-loop feedback control enables dynamic optimization of gas recovery while maintaining environmental compliance.

Inventive Principle:

Principle #23Feedback

3Productivity

If exhaust is recirculated to process chamber, then gas utilization efficiency is improved, but byproduct concentration may increase

Engineering Contradiction:

Improvegas utilization efficiencyVSAvoidbyproduct concentration

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The system uses a sensor to continuously measure the concentration of fluorine-containing byproducts in the exhaust and feeds this information back to a controller that adjusts the exhaust recirculation accordingly. This closed-loop feedback control enables dynamic optimization of gas recovery while maintaining environmental compliance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the exhaust recirculation based on real-time byproduct concentration measurements. The controller modulates the recirculation flow rate or on/off timing based on the measured byproduct levels, enabling adaptive control that maximizes gas recovery while preventing excessive byproduct accumulation.

Inventive Principle:

Principle #15Dynamics

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 approach enhances the efficiency of plasma processes by minimizing gas waste, reducing costs, and decreasing environmental emissions, while extending the life of processing equipment.

Implementation Method 1

the sensor may be configured to measure a concentration of a byproduct of a process (e.g., silicon tetrafluoride) in an exhaust of the process chamber

Methodology Applied

Scientific EffectInfrared absorption: Absorption (EM radiation)

Implementation Method 2

generating a plasma using a remote plasma source. The plasma further includes fluorine radicals, where the fluorine radicals react with a silicon-containing film

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS20250349525A1Recirculation control for a plasma process using a byproduct concentration

Publication Date: 2025.11.13 APPLIED MATERIALS INC

AI summary

A system includes a remote plasma source, a process chamber, an exhaust line connected to the process chamber, a recirculation line connected to the process chamber, and a sensor to measure a concentration of a byproduct, such as silicon tetrafluoride, in an exhaust of the processing chamber. The system also includes a controller to release the exhaust of the processing chamber through the exhaust line or the recirculation line based on the measured concentration of the byproduct in exhaust of the process chamber.