Adaptive RF Matching Network for Plasma Power Load Modulation

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Solution Overview

Problem

Existing plasma generation systems face inefficiencies due to impedance mismatch between RF generator modules and plasma chambers, which are not optimized for varying power levels and loads, leading to reduced efficiency and the need for additional components like switching amplifiers and voltage adjustments.

Innovation Solution

A system and method that dynamically control the matching network based on RF power output to adapt amplifier and generator output impedances, allowing for real-time load modulation and optimized efficiency without requiring supply voltage adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a fixed impedance matching network is used to match the plasma chamber impedance, then the power transfer efficiency is optimized at a specific operating point, but the efficiency drops significantly when operating away from that point

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidadaptability to varying power levels
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the impedance matching network adaptive rather than fixed. The matching network dynamically adjusts its parameters based on the operating conditions (power level, plasma impedance) to maintain optimal power transfer efficiency across varying operating points. This is achieved through real-time measurement of plasma impedance and adjustment of matching network components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of the impedance matching network based on operating conditions. By measuring the plasma impedance and calculating optimal matching parameters, the system adjusts the matching network components (such as variable capacitors or inductors) to maintain maximum power transfer efficiency across different power levels and plasma states.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the RF generator module is operated below maximum power to improve efficiency, then energy loss is reduced, but the overall power output and productivity are compromised

Engineering Contradiction:
Improveenergy lossVSAvoidpower output
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent implements feedback by continuously monitoring the actual power delivered to the plasma and the impedance conditions. Based on this feedback, the system adjusts the RF generator output and matching network parameters in real-time to maximize power transfer efficiency at the desired power level, rather than operating at a fixed suboptimal point.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts operating parameters based on real-time measurements of plasma conditions and power delivery efficiency. This allows the RF generator to operate at maximum power when needed while maintaining high efficiency through adaptive matching, rather than being constrained to a fixed low-power operating point.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If switching amplifiers and PWM control are used to improve efficiency at partial power levels, then energy loss is reduced, but the device complexity increases

Engineering Contradiction:
Improveenergy lossVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent makes the impedance matching network multi-functional by designing it to simultaneously perform impedance matching and power level optimization. This single adaptive matching network replaces the need for separate switching amplifiers and PWM control circuits, achieving efficiency improvement without increasing device complexity.

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

4Loss of energy

If the supply voltage is lowered to increase RF generator efficiency, then energy loss is reduced, but the maximum available power and adaptability to different power levels are reduced

Engineering Contradiction:
Improveenergy lossVSAvoidadaptability to different power levels
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent uses dynamic impedance matching to achieve high efficiency across the full power range without requiring voltage reduction. The adaptive matching network compensates for efficiency losses that would otherwise require lower operating voltages, allowing the RF generator to maintain full power capability while operating efficiently at all power levels.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4697374A1System and method for plasma generation
Publication Date: 2026.02.18 ROHDE & SCHWARZ GMBH & CO KG
  • EP4697374A1 patent drawingFigure 1
  • EP4697374A1 patent drawingFigure 2
  • EP4697374A1 patent drawingFigure 3

AI summary

The invention relates to a system (10) for plasma generation. The system (10) comprises a radio frequency, RF, generator module (12), a matching network (14) and at least one plasma chamber (16). The matching network (14) is connected to an output interface (20) of the RF generator module (12) such that the matching network (14) is arranged between the RF generator module (12) and the plasma chamber (16). The RF generator module (12) is configured to output via the output interface (20) an RF signal. The RF generator module (12) has at least one amplifier (18) with an amplifier output impedance (ZA). The RF generator module (12) has a generator output impedance (ZG). The system (10) comprises a control module (28) that is configured to control the matching network (14) in dependence of an RF power to be outputted via the output interface (20), thereby adapting the amplifier output impedance (ZA) of the at least one amplifier (18) and the generator output impedance (ZG) of the RF generator module (12) in order to perform a load modulation of the at least one amplifier (18) and the RF generator module (12). Further, a method for plasma generation is described.