Resonant Circuit Plasma Ignition Without Separate Igniter

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Solution Overview

Problem

Standard inductively coupled RF plasma systems face difficulties in reliably igniting and sustaining plasma due to the absence of strong electric fields and capacitive coupling, requiring separate ignition circuitry that needs to be deactivated after ignition.

Innovation Solution

An apparatus with a resonant circuit comprising symmetrical capacitance and inductance, excited by an excitation circuit, and coupled via a transformer to the plasma chamber, allowing for plasma ignition without additional circuitry and sustaining the plasma with a resonant inductance that shifts frequency post-ignition, eliminating the need for separate ignition circuitry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard inductively coupled RF plasma systems are used, then plasma can be generated, but reliable plasma ignition is difficult due to absence of strong electric fields and capacitive coupling

Engineering Contradiction:
Improveplasma ignition reliabilityVSAvoidignition circuitry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the ignition function and plasma sustaining function into a single resonant circuit system. The resonant circuit generates both the strong electric fields needed for ignition and the continuous RF power for plasma maintenance, eliminating the need for separate ignition circuitry while ensuring reliable plasma ignition.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resonant circuit operates at a specific resonant frequency that maximizes voltage amplification and electric field strength. By tuning the circuit to resonate, the system achieves the high electric fields necessary for reliable plasma ignition without requiring additional ignition devices, thus improving ignition reliability while maintaining simple device architecture.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If separate ignition circuitry is used to ignite plasma, then plasma ignition can be achieved, but the ignition circuitry must be switched off after ignition adding operational complexity

Engineering Contradiction:
Improveoperational simplicityVSAvoidcircuitry structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The resonant circuit is designed to perform multiple functions: it generates strong electric fields for plasma ignition and simultaneously provides continuous RF power for plasma sustaining. This multi-functional design eliminates the need for separate ignition circuitry that would require switching operations, thereby simplifying both device structure and operational procedures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the ignition function from a separate ignition circuit and integrates it into the main resonant circuit system. By removing the need for distinct ignition circuitry, the system eliminates the complexity of switching operations and circuit deactivation, achieving both structural and operational simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Use of energy by moving object

If inductively coupled RF power is used for plasma generation, then plasma can be sustained, but the coupling efficiency is insufficient without strong capacitive coupling

Engineering Contradiction:
Improveenergy coupling efficiencyVSAvoidcircuit configuration
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The resonant circuit is designed to operate at its resonant frequency, where the impedance matching and energy transfer efficiency are maximized. This resonant operation enhances the coupling efficiency between the RF power source and the plasma, allowing effective energy transfer through inductive coupling alone, without requiring additional capacitive coupling structures.

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

Enables reliable and cost-effective plasma generation and maintenance by using a floating resonant circuit that ignites and sustains plasma without additional ignition circuitry, ensuring efficient energy transfer and reduced cooling fluid contamination.

Implementation Method 1

The resonant circuit can be excited at resonance frequency prior to igniting the plasma. This leads to a high voltage over the resonant capacitance.

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Implementation Method 2

a resonant circuit comprising a resonant capacitance and a resonant inductance, an excitation circuit for exciting the resonant circuit, a coupling element for coupling RF power from the inductance into a plasma chamber

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

Electromagnetic fields about the induction coils sustain a gas plasma discharge within a plasma chamber

Methodology Applied
Scientific EffectInductive coupling: Electromagnetic Induction

Data Source

PatentEP2878005B1Apparatus for generating and maintaining plasma for plasma processing
Publication Date: 2019.05.15 TRUMPF HUETTINGER SP ZOO
  • EP2878005B1 patent drawingFigure 1
  • EP2878005B1 patent drawingFigure 2
  • EP2878005B1 patent drawingFigure 3

AI summary

An apparatus for generating and maintaining plasma for plasma processing using inductively coupled RF power. The apparatus includes a resonant circuit having a resonant capacitance and a resonant inductance, an excitation circuit for exciting the resonant circuit, and a coupling element for coupling RF power from the inductance into a plasma chamber.